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PubMed2006

CT appearance of radiation injury of the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) for lung cancers: are patients with pulmonary emphysema also candidates for SBRT for lung cancers?

PURPOSE: The purpose of this study was to analyze the computed tomographic (CT) appearance of radiation injury to the lung and clinical symptoms after stereotactic body radiation therapy (SBRT) and evaluate the difference by the presence of pulmonary emphysema (PE) for small lung cancers. METHODS AND MATERIALS: In this analysis, 45 patients with 52 primary or metastatic lung cancers were enrolled. We evaluated the CT appearance of acute radiation pneumonitis (within 6 months) and radiation fibrosis (after 6 months) after SBRT. Clinical symptoms were evaluated by Common Terminology Criteria for Adverse Events, version 3.0. We also evaluated the relationship between CT appearance, clinical symptoms, and PE. RESULTS: CT appearance of acute radiation pneumonitis was classified as follows: (1) diffuse consolidation, 38.5%; (2) patchy consolidation and ground-glass opacities (GGO), 15.4%; (3) diffuse GGO, 11.5%; (4) patchy GGO, 2.0%; (5) no evidence of increasing density, 32.6%. CT appearance of radiation fibrosis was classified as follows: (1) modified conventional pattern, 61.5%; (2) mass-like pattern, 17.3%; (3) scar-like pattern, 21.2%. Patients who were diagnosed with more than Grade 2 pneumonitis showed significantly less no evidence of increased density pattern and scar-like pattern than any other pattern (p=0.0314, 0.0297, respectively). Significantly, most of these patients with no evidence of increased density pattern and scar-like pattern had PE (p=0.00038, 0.00044, respectively). CONCLUSION: Computed tomographic appearance after SBRT was classified into five patterns of acute radiation pneumonitis and three patterns of radiation fibrosis. Our results suggest that SBRT can be also safely performed even in patients with PE.

Aged↗
PubMed2006

Pelvic bone complications following radiation therapy of gynecologic malignancies: clinical evaluation of radiation-induced pelvic insufficiency fractures.

OBJECTIVE: To investigate the incidence, clinical and imaging finding of insufficiency fractures (IF) of the female pelvis following radiation therapy. METHODS: We reviewed the radiation oncology records of 158 patients with gynecologic malignancies who underwent external beam radiation therapy of the whole pelvis between April 1993 and March 2004. All patients underwent computed tomography (CT) scan every 6 months in follow-up after radiation therapy and magnetic resonance imaging (MRI) and radionuclide bone scan were added when the patients complained of a pelvic pain. RESULTS: Eighteen of 158 patients (11.4%) developed IF in the irradiated field with a median interval of 6 months (range 3-51) from the completion of external beam radiation therapy. The cumulative incidence of symptomatic IF at 5 years calculated with Kaplan-Meyer methods was 13%. Median age of the patients who developed IF was 70 years (range 48-88), and all of them were postmenopausal. IF occurred in the sacloiliac joints, upper limb of pubic bone, acetabulum, sacral body and 5th lumbar vertebra. Twelve of 18 patients had multiple lesions and 8 had symmetric longitudinal fracture lines parallel to the sacroiliac joints. Avoidance of weight bearing by bed rest and analgesics provided good pain relief in all patients, although symptoms lasted from 3 to 20 months. CONCLUSIONS: Radiation-induced pelvic IF following radiation therapy for gynecologic malignancies were frequently observed in the postmenopausal patients within 1 year after external beam radiation therapy. Symmetric fractures of the both sacroiliac joints were the characteristic pattern of pelvic IF. Knowledge of characteristic imaging pattern of IF is essential in order to rule out the bone metastasis. Therapy recommendations are conservative with analgesics.

Aged↗
PubMed1996

The effect of ionizing radiation on signal transduction: antibodies to EGF receptor sensitize A431 cells to radiation.

What determines the degree of cell-resistance or sensitivity to ionizing radiation is not yet known. As a corollary to the ability of ceramide to induce apoptosis, some questions arise as to whether malignant cells escape apoptosis because of their inability to mount a ceramide response to inducers of apoptosis. To shed more light on the molecular mechanisms of tumor cell response to radiation, we tested whether exposure to ionizing radiation (of 200-1000 cGy) is associated with changes in ceramide levels in A431 tumor epithelial cells and whether the ability of ceramide to induce apoptosis is inhibited by protein kinase C (PKC) activation. Our studies demonstrate an immediate decrease in cellular levels of ceramide in response to radiation, while sphingosine levels increase. Under the same conditions the cellular 1,2-diacylglycerol (DAG) levels decrease as well, being accompanied by the translocation of PKC alpha from the membrane to the cytoplasm. Elevation of membrane PKC levels by 12-O-tetradecanoylphorbol 13-acetate (TPA) treatment had no effect on cell survival after irradiation, while treatment with EGF during and after irradiation augmented cell survival. Moreover, monoclonal antibodies to the EGF receptor (EGFR) sensitize cells to radiation by facilitating radiation-induced apoptosis. It is thus plausible that in human Squamous carcinoma cells, radiation activates predominantly the EGFR to induce resistance, while both sphingomyelin and PKC signal transduction pathways are deactivated and demonstrate no significant role in the modulation of the sensitivity or the resistance of A431 cells to ionizing radiation.

Antibodies↗
PubMed1997

Risk factors for development of radiation pneumonitis following radiation therapy with or without chemotherapy for lung cancer.

PURPOSE: To determine the risk factors contributing to development of radiation pneumonitis (RP) in patients with lung cancer who undergo radiation therapy to the thorax. METHODS AND MATERIALS: Development and severity of RP were retrospectively analyzed for 89 patients with lung cancer who underwent radiation therapy with or without chemotherapy at the National Shikoku Cancer Center Hospital between 1991 and 1995. The severity of RP was determined using a modified grading scale based on that of the Radiation Therapy Oncology Group and the European Organization for the Research and Treatment of Cancer. RESULTS: Fifty-two (58%) patients developed RP: 34 patients with Grade 1, 5 with Grade 2, 8 with Grade 3, and 5 with Grade 5 RP. Severe RP tended to develop earlier than less severe RP, but not to a significant extent (p = 0.151). On logistic regression analysis including both patient condition and treatment factors, development of Grade 1 or more severe RP was most frequently observed for Stage I-II disease (p = 0.011). The use of chemotherapy, large daily radiation dose, and once-daily fractionation (vs. twice-daily fractionation) were possibly related to the development of RP (p = 0.057, p = 0.069, and p = 0.092, respectively). For the group of 48 patients who underwent chemoradiation therapy, the use of large daily radiation dose was a significant risk factor for RP (p = 0.014). In addition, the use of once-daily fractionation was a marginally significant risk factor (p = 0.052). Among chemotherapy drugs administered, cisplatin was a favorable factor (p = 0.011), while adriamycin was a risk factor (p = 0.061). CONCLUSIONS: In radiation therapy for lung cancer, administration of a large daily dose should be avoided in order to prevent RP, particularly when radiation therapy is combined with chemotherapy.

Adult↗
PubMed2001

Bi-modality (chemo-radiation) versus tri-modality (chemo-radiation followed by surgery) treatment for carcinoma of the esophagus.

The purpose of the study was to investigate the difference in overall survival in patients with localized carcinoma of esophagus treated using chemo-radiation (bi-modality, BM) or chemo-radiation followed by surgery (tri-modality, TM). From 1981 to 1999, 65 patients were identified who had localized carcinoma of the esophagus treated with either concurrent chemo-radiation (BM, n=22) or concurrent chemo-radiation followed by surgery (TM, n=43) at the University of Texas Medical Branch at Galveston. All 65 patients received concurrent chemotherapy and external beam radiation. Radiation was delivered by linear accelerators (greater-than-or-equal 6 MV), except in one patient who had part of his treatment given by a Co-60 machine. Chemotherapy consisted of 5-fluorouracil and cisplatin plus minus vinblastine under different regimens. Median follow-up time was 10 months (range=1-195 months) for all patients. Of the 14 patients still alive, the median follow-up time was 32 months (range=2-192 months). No difference in overall survival was detected between the two treatment groups, BM vs. TM (P=0.394) despite a selection bias favoring the TM group. Five-year survival rates of the BM and TM groups were 17% and 18%, respectively; 10-year survival rates were 17% and 12%, respectively. The presence of significant past medical history (P=0.017) and a complete pathologic response in the TM group (P < 0.001) were significant independent predictors of survival. We did not find any difference in survival between chemo-radiation or chemo-radiation followed by surgery in patients with localized carcinoma of the esophagus. Use of biologic markers and functional imaging should be explored in order to segregate patients with different tumor biology for treatment using different treatment strategies.

Aged↗
PubMed2004

Radiation-induced cardiomyopathy as a function of radiation beam gating to the cardiac cycle.

Portions of the heart are often unavoidably included in the primary treatment volume during thoracic radiotherapy, and radiation-induced heart disease has been observed as a treatment-related complication. Such complications have been observed in humans following radiation therapy for Hodgkin's disease and treatment of the left breast for carcinoma. Recent attempts have been made to prevent re-stenosis following angioplasty procedures using external beam irradiation. These attempts were not successful, however, due to the large volume of heart included in the treatment field and subsequent cardiac morbidity. We suggest a mechanism for sparing the heart from radiation damage by synchronizing the radiation beam with the cardiac cycle and delivering radiation only when the heart is in a relatively hypoxic state. We present data from a rat model testing this hypothesis and show that radiation damage to the heart can be altered by synchronizing the radiation beam with the cardiac cycle. This technique may be useful in reducing radiation damage to the heart secondary to treatment for diseases such as Hodgkin's disease and breast cancer.

Angioplasty↗
PubMed1993

Radiation-induced breast cancer: long-term follow-up of radiation therapy for benign breast disease.

BACKGROUND: From the 1920s through the 1950s, radiation therapy was used in Sweden as a treatment for benign breast diseases. It is now known that exposure of the breast to ionizing radiation increases the relative risk of subsequent breast cancer, especially for younger women. However, the degree to which the patient's age contributes to the elevation of risk for subsequent development of breast cancer is not yet completely understood. PURPOSE: The purpose was to study the risk of breast cancer after irradiation of the female breast and, in particular, to analyze the duration of the effect and the risk for women older than 40 years at first exposure. METHODS: In this cohort study, data were obtained through population-based registers. The exposed group consisted of 1216 women (median age, 40 years) who, during the period spanning 1925 through 1954, received radiation therapy for benign breast disease. The reference group consisted of 1874 women (median age, 36 years) who had the same diagnosis during that time period but did not receive radiation therapy. The radiation doses were determined from the original medical records (mean dose, 5.8 Gy; range, 0.003-50.1 Gy). The follow-up lasted up to 60 years after first exposure. The incidence rate ratio was analyzed with Poisson regression models. RESULTS: The total number of breast cancers in the exposed cohort was 198 versus 101 in the unexposed cohort. Overall, the radiation-associated incidence rate ratio was 3.58 (95% confidence interval = 2.77-4.63). The dose-response gradient was statistically significant (P < .001) but leveled off at higher doses. The incidence rate ratios decreased starting about 25 years after first exposure but were at increased levels throughout the entire follow-up period. The incidence rate ratio decreased with age at first exposure but was significantly increased (P < .001) even when the age at time of first exposure was greater than 40 years. CONCLUSIONS: Total dose, age at first exposure, and time since first exposure were all determinants of the incidence rate ratio of breast cancer after exposure of the breast to ionizing radiation. A statistically significant increase in the incidence of breast cancer following radiation treatment of various benign breast diseases was observed even among women older than 40 years at the time of first treatment. IMPLICATIONS: These findings need to be considered when weighing the relative benefits versus risks of generalized screening of younger women for breast cancer by mammography.

Adult↗
PubMed1992

Effects of ultraviolet radiation on murine epidermal Langerhans cells: doses of ultraviolet radiation that modulate ICAM-1 (CD54) expression and inhibit Langerhans cell function cause delayed cytotoxicity in vitro.

Low doses (100 J/m2) of ultraviolet B (UVB) radiation from sunlamp fluorescent FS20 tubes inhibit the ability of freshly isolated murine epidermal Langerhans cells (LC) to support anti-CD3 MoAb-induced T-cell mitogenesis and selectively inhibit the upregulation of ICAM-1 expression by LC without causing appreciable cytotoxicity in short-term (less than or equal to 24 h) incubations (J Immunol 146:3347-3355, 1991). In the present study, epidermal cells (EC) were exposed to UVB radiation or were sham-irradiated and cultured for 24, 48, or 72 h when LC were recovered, enumerated, and assayed for simultaneous expression of I-A antigens and ICAM-1 by flow cytometry. UVB-irradiated LC that had been cultured for 24 h exhibited levels of I-A antigens comparable to those on unirradiated LC but expressed substantially less ICAM-1. After 48 and 72 h, cultured UVB-irradiated LC expressed somewhat lower levels of I-A antigens and markedly less ICAM-1 than unirradiated controls. Although similar numbers of LC were recovered from cultures initiated with UVB-irradiated and unirradiated epidermal cells after 24 h, far fewer identifiable LC were recovered from cultures seeded with irradiated cells at 48 and 72 h (approximately 50 and approximately 10% of control, respectively). The effect of UVB radiation on the survival of LC in vitro was not reversible with exogenous TNF alpha (125 U/ml) alone or granulocyte/macrophage colony-stimulating factor (5 ng/ml) and IL-1 (50 U/ml) in combination, although these cytokines had modest effects on the expression of I-A antigens and ICAM-1 by cultured UVB-irradiated LC. Results of survival studies performed with enriched LC preparations demonstrated that UVB radiation was clearly cytotoxic for LC and did not merely downregulate surface expression of I-A antigens or alter LC buoyant density. Exposure of LC to radiation from blacklight fluorescent (UVA) tubes (0.25 J/cm2) in the presence of 8-methoxypsoralen (1 micrograms/ml; PUVA) or monochromatic UVC radiation (20 J/m2) also inhibited LC accessory cell function. Results of survival studies performed with EC that had been exposed to PUVA or UVC radiation before culture were similar to those of studies performed with UVB-irradiated cells, although PUVA- and UVC-induced LC cytotoxicity was much more pronounced 48 h after culture initiation than UVB-induced cytotoxicity. UVA radiation alone augmented LC recovery at 24 and 48 h, but did not influence I-A antigen or ICAM-1 expression.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2002

Radiation chemistry and the Radiation Research Society: a history from the beginning.

Radiation chemistry studies began in the early 20th century with observations involving the decomposition of various materials by X rays and radium. Hugo Fricke recognized that the chemical effects of radiation should be studied to help understand the response of living systems to radiation, and in 1928 he established a laboratory to conduct such studies. Early radiation chemists were intimately involved in the founding of the Radiation Research Society and contributed substantially to its interdisciplinary culture. In this historical review, the highlights of research in radiation chemistry leading up to the founding of the Radiation Research Society in 1952 are discussed. The status of the field is established at that point, and a sampling of the major accomplishments from then until the present is presented, with emphasis on those scientists who have contributed substantially to the life and culture of the Radiation Research Society.

History, 20th Century↗
PubMed2004

[Usefulness of 3D conformal radiation therapy for reduction of radiation-induced white matter injury].

PURPOSE: The usefulness of three-dimensional conformal radiation therapy(3DCRT) in decreasing radiation-induced white matter changes(WMC) was assessed. MATERIAL AND METHODS: Thirty-seven patients(age 5-77 years, mean 42 years; male/female = 11/26) with primary intracranial tumors received 40 Gy or more, and were followed up with MRI for more than one year. Thirty-four patients underwent chemotherapy(with a platinum drug, 16; without a platinum drug, 18). Nineteen were treated with 3DCRT (radiation dose, range 60-64 Gy, mean 60.2 Gy; maximum width of radiation field, range 7-16 cm, mean 12.5 cm) and 18 were treated with non-3DCRT (radiation dose, range 40-62.4 Gy, mean 53.4 Gy; maximum width of radiation field, range 4-19 cm, mean 12.3 cm). RESULTS: WMC occurred in 37% of the 3DCRT group and 50% of the non-3DCRT group. Among the patients with WMC, Karnofsky performance scale(KPS) deteriorated in none of the 3DCRT group, whereas KPS deteriorated in 3 of 9 in the non-3DCRT group. All the patients with deterioration of KPS were at least 50 years of age. KPS did not strictly correlate with the severity of white matter changes on MRI. Chemotherapy with a platinum drug increased the incidence of WMC. Age(< 50 years vs. > or = 50 years), gender, radiation technique(3DCRT vs. non-3DCRT), radiation dose(< 60 Gy vs. > or = 60 Gy), maximum field-size(< 12 cm vs. > or = 12 cm), and maximum boost-field size(< 10 cm vs. > or = 10 cm) were not relevant to the incidence and severity of WMC. CONCLUSION: Though 3DCRT did not decrease the incidence and severity of white matter change on MRI, it may be useful to preserve the KPS, especially for older patients.

Adolescent↗
PubMed2004

Uptake of 18F-fluorocholine, 18F-fluoroethyl-L-tyrosine, and 18F-FDG in acute cerebral radiation injury in the rat: implications for separation of radiation necrosis from tumor recurrence.

UNLABELLED: Differentiation between posttherapy radiation necrosis and recurrent tumor in humans with brain tumor is still a difficult diagnostic task. The new PET tracers (18)F-fluoro-ethyl-l-tyrosine (FET) and (18)F-fluorocholine (N,N-dimethyl-N-(18)F-fluoromethyl-2-hydroxyethylammonium [FCH]) have shown promise for improving diagnostic accuracy. This study assessed uptake of these tracers in experimental radiation injury. METHODS: In a first model, circumscribed lesions were induced in the cortex of 35 rats using proton irradiation of 150 or 250 Gy. After radiation injury developed, uptake of (18)F-FET, (18)F-FCH, and (18)F-FDG was measured using autoradiography and correlated with histology and disruption of the blood-brain barrier as determined with Evans blue. In a second model, uptake of the tracers was assessed in acute cryolesions, which are characterized by the absence of inflammatory cells. RESULTS: Mean (18)F-FET, (18)F-FCH, and (18)F-FDG standardized uptake values in the most active part of the radiation lesion and the contralateral normal cortex (in parentheses) were 2.27 +/- 0.46 (1.42 +/- 0.23), 2.52 +/- 0.42 (0.61 +/- 0.12), and 6.21 +/- 1.19 (4.35 +/- 0.47). The degree of uptake of (18)F-FCH and (18)F-FDG correlated with the density of macrophages. In cryolesions, (18)F-FET uptake was similar to that in radiation lesions, and (18)F-FCH uptake was significantly reduced. CONCLUSION: Comparison of tracer accumulation in cryolesions and radiation injuries demonstrates that (18)F-FET uptake is most likely due to a disruption of the blood-brain barrier alone, whereas (18)F-FCH is additionally trapped by macrophages. Uptake of both tracers in the radiation injuries is generally lower than the published uptake in tumors, suggesting that (18)F-FET and (18)F-FCH are promising tracers for separating radiation necrosis from tumor recurrence. However, the comparability of our data with the literature is limited by factors such as different species and acquisition protocols and modalities. Thus, more studies are needed to settle this issue. Nevertheless, (18)F-FCH and (18)F-FET seem superior to (18)F-FDG for this purpose.

Acute Disease↗
PubMed1986

Midsummer solar UV-radiation in Finland compared with the UV-radiation from phototherapeutic devices measured by different techniques.

Midsummer solar UV-radiation in southern Finland was measured by a spectroradiometer, polysulphone film dosimeters, and a solid-state UV-meter. Solar UV-irradiance was compared with radiation from different phototherapy devices (UVB, SUP, and PUVA therapy equipment). Measured by the spectroradiometer, the solar UVB irradiance at noon was 55 microW/cm2; it varied from 60 to 79 microW/cm2 according to the doses received by the film dosimeters on clear, sunny days in June. A solid-state detector gave a markedly overestimated UVB irradiance of 235 microW/cm2. Solar UVB radiation would lead to 1.5 MEDs in 2 hours around midday, 2.9 MEDs in 4 h and 8 MEDs in 12 h in midsummer at latitudes in southern Finland. Solar UVB radiation corresponds to that emitted from PUVA treatment devices, but the UVA (315-400 nm) radiation of the latter is about 3-fold that of solar radiation. The UVA radiation from SUP and PUVA treatment devices resembled each other but the former emitted more radiation at the lower wavelengths of 315-340 nm. The UVB irradiance of the UVB therapeutic device was 25-55 times the irradiance of the sun.

Finland↗
PubMed2006

Fractionated X-radiation treatment can elicit an inducible-like radioprotective response that is not dependent on the intrinsic cellular X-radiation resistance/sensitivity.

Inducible responses are well documented to play a role in the radiation response of cells. However, it is not known whether clinically relevant fractionated X-radiation treatment could elicit an inducible-like radioprotective response and whether there is a direct correlation between the inducible radiation response phenomenon and the intrinsic radiation response of the cell. Therefore, the purpose of this study was to determine whether closely related human colorectal tumor (HCT116) clones treated with fractionated X rays could elicit an inducible-like radiation response to a subsequent acute (i.e. single) X-ray challenge, and whether the magnitude of the inducible-like response correlates with the intrinsic X-ray resistance of the responding clones. After fractionated X irradiation, only the radiosensitive clone showed enhanced clonogenic survival with a subsequent acute X-ray exposure. Cell cycle changes or the selection of subclones with increased intrinsic radiation resistance induced by the fractionated X rays were excluded as the basis of this enhanced tolerance, suggesting the presence of an inducible-like radioprotective response. Using the comet assay, we found similar amounts of intrinsic DNA damage among the clones after acute X irradiation. Our findings demonstrate that fractionated X-ray treatment can elicit an inducible-like radioprotective response and represent the first evidence that this response is independent of the intrinsic radiation resistance/sensitivity of the responding cells.

Cell Line, Tumor↗
PubMed2005

A novel radiation protection drape reduces radiation exposure during fluoroscopy guided electrophysiology procedures.

OBJECTIVE: The purpose of this study was to evaluate a novel disposable lead-free radiation protection drape for decreasing radiation scatter during electrophysiology procedures. BACKGROUND: In recent years, there has been an exponential increase in the number of electrophysiology (EP) procedures exposing patients, operators and laboratory staff to higher radiation doses. METHODS: The RADPAD was positioned slightly lateral to the incision site for pectoral device implants and superior to the femoral vein during electrophysiology studies. Each patient served as their own control and dosimetric measurements were obtained at the examiner's elbow and hand. Radiation badge readings for the operator were obtained three months prior to RADPAD use and three months after introduction. RESULTS: Radiation dosimetry was obtained in twenty patients: 7 electrophysiology studies, 6 pacemakers, 5 catheter ablations, and 2 implantable cardioverter-defibrillators. Eleven women and nine men with a mean age of 63 +/- 4 years had an average fluoroscopy time of 2.5 +/- 0.42 minutes per case. Mean dosimetric measurements at the hand were reduced from 141.38 +/- 24.67 to 48.63 +/- 9.02 milliroentgen (mR) per hour using the protective drape (63% reduction; p < 0.0001). Measurements at the elbow were reduced from 78.78 +/- 7.95 mR per hour to 34.50 +/- 4.18 mR per hour using the drape (55% reduction; p < 0.0001). Badge readings for three months prior to drape introduction averaged 2.45 mR per procedure versus 1.54 mR per procedure for 3 months post-initiation (37% reduction). CONCLUSION: The use of a novel radiation protection surgical drape can significantly reduce scatter radiation exposure to staff and operators during a variety of EP procedures.

Electrophysiologic Techniques, Cardiac↗
PubMedDate not supplied

[Solar cosmic radiation and the radiation hazard of space flight].

Present-day data on the spectrum of solar radiation in the source and near the Earth are discussed as applied to the radiation safety of crewmembers and electronics onboard manned and unmanned spacecraft. It is shown that the slope of the solar radiation spectrum changes (flattens) in the low energy range. Quantitative information about absolute solar radiation fluxes near the Earth is summarized in relation to the most significant flares of 1956--1978. The time-related evolution of the solar radiation spectrum in the interplanetary space is described in quantitative terms (as illustrated by the solar flare of 28 September 1961). It is indicated that the nonmonotonic energy dependence of the transport path of solar radiation in the interplanetary space should be taken into consideration. It is demonstrated that the diffusion model of propagation can be verified using solar radiation measurements in space flights.

Cosmic Radiation↗
PubMed2004

New technologies in radiation therapy for pediatric brain tumors: the rationale for proton radiation therapy.

BACKGROUND: Pediatric brain tumors are frequently treated with radiation therapy and often cured. The long-term side effects of treatment with high-energy X-rays (photons) can be substantial. Proton radiation therapy may limit these late effects. PROCEDURE: The physical difference between photon and proton irradiation is compared. The clinical benefits of the superior physical properties of proton beam radiation therapy are explained for children with brain tumors. RESULTS: At biologically equivalent doses, proton radiation therapy offers tumor control similar to photon radiation therapy. The superior physical properties of proton beams make this mode of radiation therapy less likely to cause late effects. CONCLUSIONS: For many children with brain tumors, proton beam radiation therapy may limit the late effects of radiation therapy and therefore offer an advantage over techniques using photons.

Brain Neoplasms↗
PubMed1984

Combined radiation and hyperthermia: comparison of two treatment schedules based on data from a registry established by the Radiation Therapy Oncology Group (RTOG).

A registry established by the Radiation Therapy Oncology Group provides data for assessing the impact of clinical heating in a set of non-randomized patients treated with hyperthermia in participating member institutions from 1/77 to 6/81. This analysis focuses on tumor response when localized hyperthermia is produced by microwave and applied pursuant to two distinctly different treatment schedules. Hyperthermia treatments were biweekly and combined with daily radiation treatments in one patient group, and combined with biweekly radiation treatment in another. Sample X consists of 65 patients who received a course of therapy using combined hyperthermia and radiation in consecutive treatment sessions each separated by at least 48 hours, but no more than 96 hours. Sample Y consists of 34 patients who received further radiation after the start of a course of combined therapy--either between or at the end of a series of combined treatment sessions. The average length of heat treatment was 72 minutes for Sample X and 32 minutes for Sample Y patients. None of the patients received concurrent chemotherapy; all received between 3 and 13 hyperthermia treatments; all had superficial, measurable tumors. On the average, Sample X patients received 704 total minutes of heat compared to Sample Y patients who received 233 total minutes of heat. Total tumor radiation doses ranged from 17.0 Gy to 44.0 Gy among Sample X patients with 92.3% receiving radiation at either 3 Gy or 4 Gy per fraction. In Sample Y the range for total tumor dose was 16.0 Gy to 70.2 Gy with 73.4% of the patients receiving radiation at 2.5 Gy or less per fraction. Generally, the two treatment schedules achieved similar levels of tumor response. Among treated tumors in Sample X and Sample Y, complete regression rates were 52.4 and 61.8%, respectively, and partial regression rates were 16.9 and 14.7%. Adenocarcinoma and squamous cell carcinoma in both samples responded well to these combined treatments. Only in Sample X was there a statistically significant trend of decreasing complete regression rate when the treated tumor sizes increased. Best responses to treatment generally occurred between 28 and 84 days after completion of the combined therapy course. There were no differences between the two samples with respect to median days to best response or response duration. Blister, ulcer or wet desquamation were reported in 47.7% of Sample X as the maximum skin reaction. In contrast, only 20.6% of Sample Y had these complications.(ABSTRACT TRUNCATED AT 400 WORDS)

Adenocarcinoma↗
PubMed1993

High-dose preoperative radiation for cancer of the rectum: impact of radiation dose on patterns of failure and survival.

PURPOSE: A variety of dose-time schedules are currently used for preoperative radiation therapy of rectal cancer. An analysis of patients treated with high-dose preoperative radiation therapy was undertaken to determine the influence of radiation dose on the patterns of failure, survival, and complications. METHODS AND MATERIALS: Two hundred seventy-five patients with localized rectal cancer were treated with high-dose preoperative radiation therapy. One hundred fifty-six patients received 45 Gy, +/- 10% (low-dose group). Since 1985, 119 patients with clinically unfavorable cancers (fixed, low-lying, or deeply ulcerated) were given a higher dose, 55 Gy, +/- 10%, using a shrinking field technique (high-dose group). All patients underwent curative resection. Median follow-up was 66 months in the low-dose group and 28 months in the high-dose group. Patterns of failure, survival, and complications were analyzed as a function of radiation dose. RESULTS: Fourteen percent (38/275) of the total group developed a local recurrence; 20% (31/156) in the low-dose group as compared with 6% (7/119) in the high-dose group. The actuarial local recurrence rate at 5 years was 20% for the low-dose group and 8% for the high-dose group, and approached statistical significance with p = .057. For tethered/fixed tumors the actuarial local recurrence rates at 5 years were 28% and 9%, respectively, with p = .05. Similarly, for low-lying tumors (less than 6 cm from the anorectal junction) the rates were 24% and 9%, respectively, with p = .04. The actuarial rate of distant metastasis was 28% in the low-dose group and 20% in the high-dose group and was not significantly different. Overall actuarial 5-year survival for the total group of patients was 66%. No significant difference in survival was observed between the two groups, despite the higher proportion of unfavorable cancers in the high-dose group. The incidence of complications was 2%, equally distributed between the two groups. CONCLUSION: High-dose preoperative radiation therapy for rectal cancer results in excellent local control rates. However, in clinically unfavorable cancers a higher dose (55 Gy) of preoperative radiation can be given safely with significantly improved local control. Careful clinical staging is helpful in selectively treating patients with unfavorable tumors to a higher preoperative radiation dose and thus optimizing their outcome.

Adenocarcinoma↗