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At least 1,135 records · Page 63Linked to original sources
PubMed1988

Health aspects of radio-frequency radiation accidents. Part I: Assessment of health after a radio-frequency radiation accident.

The health aspects of an accident involving nine men exposed to 4.1 GHz radio-frequency radiation (RFR) is described. Two were exposed to levels of 4.6 mW/cm2 for up to 90 minutes, which exceeds the current Australian standard of 1 mW/cm2, while the other seven were exposed to lower levels. For staff in the high-exposure group, the dose rate was calculated for the whole body, skin, eyes, and pituitary. Comprehensive medical examinations were performed on all staff, including follow-up ophthalmological examinations over a period of nine months. Various abnormalities were found in all staff but, with the possible exception of hair loss, there was no consistent gradient of effect in the occurrence of abnormality between the groups. Various problems in conducting the investigation are discussed. It was concluded that the exposure had not resulted in harmful effects.

Accidents, Occupational↗
PubMed1988

Health aspects of radio-frequency radiation accidents. Part II: A proposed protocol for assessment of health effects in radio-frequency radiation accidents.

A protocol is proposed for the assessment of health effects following a radio-frequency radiation accident. The protocol is intended to ensure uniform recording of exposure and medical data. This should meet the requirements of the individuals exposed as well as contributing to scientific knowledge. Difficult aspects about the collection of exposure and medical data are discussed and the need to consider the feelings of the exposed individual(s) is emphasized.

Accidents↗
PubMed1988

Physiological effects of 2.8 GHz radio-frequency radiation: a comparison of pulsed and continuous-wave radiation.

Ketamine-anesthetized female Sprague-Dawley rats were exposed individually to far-field 2.8 GHz continuous wave (CW) and pulsed (2 microseconds, 500 pps) radio-frequency radiation (RFR) at average power densities of 30, 45, and 60 mW/cm2 [specific absorption rates (SAR) of 8.4, 12.6, and 16.8 W/kg, respectively] and to pulsed RFR at 75 mW/cm2 (SAR = 21 W/kg). Intermittent exposures were conducted to repeatedly increase colonic temperature from 38.5 to 39.5 degrees C. Colonic, tympanic, and subcutaneous temperatures, electrocardiogram, respiratory rate, and arterial blood pressure were continuously monitored and recorded. The time required to effect a 1 degree C colonic temperature increase varied inversely with the average power density used during exposure; however, the rate of cooling was independent of the heating rate. During pulsed irradiation, heart rate increased significantly at average power densities above 30 mW/cm2; heart rate increase during CW exposure was not significant. Heart rate returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. Pulsed RFR exposure caused a significantly greater increase in subcutaneous and tympanic temperatures than did CW exposure; however, no significant difference was noted between the effects of CW or pulsed RFR upon the rats' colonic temperature responses (heating and cooling time), heart rate, blood pressure, and respiratory rate.

Animals↗
PubMed1994

Radiation response of mouse lymphoid and myeloid cell lines. Part I. Sensitivity to killing by ionizing radiation, rate of loss of viability, and cell type of origin.

The sensitivity of 10 mouse lymphoid or myeloid cell lines to gamma-ray- and DNA-associated 125I-decay-induced clonogenic cell killing have been compared with their rate of loss of viability (membrane integrity) and with their putative cell type of origin. The pseudodiploid haematopoietic cell lines showed D0 values for 125I-induced DNA double-strand breakage (dsb) that ranged from 7.7 +/- 0.7 to 40.8 +/- 2.8 decays. These lines generally appeared to be more sensitive to killing by radiation-induced DNA dsb than are fibroblast-like cell lines. The increased sensitivity of haematopoietic cell lines to killing by DNA dsb may be related to their mode of death (apoptosis versus necrosis). Mode of cell death may thus be an important factor in determining the 'inherent radiosensitivity' of normal cells/tissues. Haematopoietic cell lines that undergo rapid interphase apoptotic death showed extreme sensitivity to DNA dsb. The latter cell lines were found to have derived from immature lymphoid cells, and it is speculated that their high radiosensitivity might reflect the action of a mechanism that normally eliminates cells containing illegitimate V(D)J recombinase-induced DNA dsb.

Animals↗
PubMed1989

Randomized comparison of viral oncolysate plus radiation and radiation alone in uterine cervix carcinoma.

A randomized, controlled study was performed in patients with high-risk, untreated squamous cell carcinoma of the uterine cervix to evaluate the adjunctive use of viral oncolysate (VO) prepared from the SW756 cell line. Seventy-five patients were stratified by tumor volume and randomized to receive radiation therapy (RT) alone or RT plus intradermal immunization with VO. Fifty-one (68%) patients relapsed with a median survival (MS) of 29.1 months and a median progression-free interval (MPFI) of 18.0 months. No differences in MS or median PFI were observed by treatment arm or site of relapse, although a trend toward improved MS and median PFI in patients with small-volume primary lesions was suggested. Serum surface-binding antibody activity (greater than or equal to 1:8) to the SW756 cell line was detected in 14 of 41 unselected patients prior to therapy. Virus hemagglutination inhibitory activity (greater than or equal to 1:8) was detected in 37 of 41 patients before treatment. four-fold increases in titer were observed to the SW756 cell line in 83% and to influenza in 74% of patients tested after immunization. Preirradiation measurements of phytohemagglutinin-induced blastogenesis by the relative proliferation index (RPI) method in 39 patients revealed RPI values less than 0.58 in nine patients, eight of whom relapsed. At 3-6 months after the initiation of irradiation, 32 of 39 patients had values less than 0.58. Patients in the RT group with values less than 0.58 had significantly more relapses than those who received RT plus VO.

Adult↗
PubMedDate not supplied

Characteristics of an ethylene-polyethylene high-pressure ionization chamber and its potential for deriving radiation dose and quality information in neutron-gamma radiation fields.

A recently developed method for measuring dose and quality parameters in mixed neutron-gamma radiation fields is extended for neutron energy regions relevant to current neutron therapy. It is theoretically shown that if a polyethylene high-pressure ionization chamber filled with a gas mixture of 95% ethylene and 5% carbon dioxide is used at suitable gas pressures, it may overcome the limitations found for a similar tissue-equivalent chamber and measure both the gamma ray absorbed dose-fraction and the mean incident neutron energy for neutrons between 0.1 and at least 30 MeV, if certain conditions exist. The simultaneous use of the polyethylene high-pressure ionization chamber as a conventional neutron dosimeter also allows determination of both the neutron and gamma ray absorbed doses. Estimated accuracies are 15% for the mean incident neutron energy and 15%-30% for the doses determination. The present method may complement currently available techniques as it presents certain advantages in situations where the neutron spectrum is poorly known. If coupled with other dosimeters, the accuracy of the method can be improved.

Ethylenes↗
PubMed1993

Survival comparison of radiosurgery-eligible and -ineligible malignant glioma patients treated with hyperfractionated radiation therapy and carmustine: a report of Radiation Therapy Oncology Group 83-02.

PURPOSE: The purpose is twofold: (1) to identify the malignant glioma patients treated in a trial of hyperfractionated radiotherapy (RT) and carmustine (BCNU) who may have been eligible for a stereotactic radiosurgery (SRS) boost; and (2) to compare survival of such patients with that of those considered SRS-ineligible. PATIENTS AND METHODS: From January 1983 to July 1989, 778 malignant glioma patients were enrolled on Radiation Therapy Oncology Group (RTOG) 83-02, a randomized phase I/II hyperfractionated RT dose-escalation trial with BCNU chemotherapy. The SRS criteria used in a single-institution trial were applied to these patients; they are: Karnofsky performance status (KPS) of greater than 60; well-circumscribed tumor less than 4.0 cm; no subependymal spread; and a location not adjacent to brainstem or optic chiasm. RESULTS: Eighty-nine patients (11.9%) were identified as potentially SRS-eligible. The median survival times (MST) and 18-month survival rates of the 89 eligible and 643 ineligible patients were 14.4 versus 11.7 months and 40% versus 27%, respectively (P = .047). The MST and 18-month survival rate of the 544 SRS-ineligible patients with KPS greater than 60 were 12.1 months and 29%, respectively, and were not statistically inferior to the survival of the SRS-eligible group (P = .21). Multivariate analysis revealed age, KPS, and histopathology to be strongly predictive of survival, and SRS eligibility was also significantly predictive (P = .047). CONCLUSION: SRS-eligible patients enrolled on RTOG 83-02 had survival superior to that of the SRS-ineligible group, and this advantage is mainly due to the selection of a subgroup with a high minimum KPS.

Carmustine↗
PubMed1998

Phase III trial of neoadjuvant chemotherapy in patients with invasive bladder cancer treated with selective bladder preservation by combined radiation therapy and chemotherapy: initial results of Radiation Therapy Oncology Group 89-03.

PURPOSE: To assess the efficacy of neoadjuvant methotrexate, cisplatin, and vinblastine (MCV) chemotherapy in patients with muscle-invading bladder cancer treated with selective bladder preservation. PATIENTS AND METHODS: One hundred twenty-three eligible patients with tumor, node, metastasis system clinical stage T2 to T4aNXMO bladder cancer were randomized to receive (arm 1, n=61 ) two cycles of MCV before 39.6-Gy pelvic irradiation with concurrent cisplatin 100 mg/m2 for two courses 3 weeks apart. Patients assigned to arm 2 (n=62) did not receive MCV before concurrent cisplatin and radiation therapy. Tumor response was scored as a clinical complete response (CR) when the cystoscopic tumor-site biopsy and urine cytology results were negative. The CR patients were treated with an additional 25.2 Gy to a total of 64.8 Gy and one additional dose of cisplatin. Those with less than a CR underwent cystectomy. The median follow-up of all patients who survived is 60 months. RESULTS: Seventy-four percent of the patients completed the protocol with, at most, minor deviations; 67% on arm 1 and 81% on arm 2. The actuarial 5-year overall survival rate was 49%; 48% in arm 1 and 49% in arm 2. Thirty-five percent of the patients had evidence of distant metastases at 5 years; 33% in arm 1 and 39% in arm 2. The 5-year survival rate with a functioning bladder was 38%, 36% in arm 1 and 40% in arm 2. None of these differences are statistically significant. CONCLUSION: Two cycles of MCV neoadjuvant chemotherapy were not shown to increase the rate of CR over that achieved with our standard induction therapy or to increase freedom from metastatic disease. There was no impact on 5-year overall survival.

Aged↗
PubMed2000

Concurrent chemotherapy and pelvic radiation therapy compared with pelvic radiation therapy alone as adjuvant therapy after radical surgery in high-risk early-stage cancer of the cervix.

PURPOSE: To determine whether the addition of cisplatin-based chemotherapy (CT) to pelvic radiation therapy (RT) will improve the survival of early-stage, high-risk patients with cervical carcinoma. PATIENTS AND METHODS: Patients with clinical stage IA(2), IB, and IIA carcinoma of the cervix, initially treated with radical hysterectomy and pelvic lymphadenectomy, and who had positive pelvic lymph nodes and/or positive margins and/or microscopic involvement of the parametrium were eligible for this study. Patients were randomized to receive RT or RT + CT. Patients in each group received 49.3 GY RT in 29 fractions to a standard pelvic field. Chemotherapy consisted of bolus cisplatin 70 mg/m(2) and a 96-hour infusion of fluorouracil 1,000 mg/m(2)/d every 3 weeks for four cycles, with the first and second cycles given concurrent to RT. RESULTS: Between 1991 and 1996, 268 patients were entered onto the study. Two hundred forty-three patients were assessable (127 RT + CT patients and 116 RT patients). Progression-free and overall survival are significantly improved in the patients receiving CT. The hazard ratios for progression-free survival and overall survival in the RT only arm versus the RT + CT arm are 2.01 (P =.003) and 1.96 (P =. 007), respectively. The projected progression-free survivals at 4 years is 63% with RT and 80% with RT + CT. The projected overall survival rate at 4 years is 71% with RT and 81% with RT + CT. Grades 3 and 4 hematologic and gastrointestinal toxicity were more frequent in the RT + CT group. CONCLUSION: The addition of concurrent cisplatin-based CT to RT significantly improves progression-free and overall survival for high-risk, early-stage patients who undergo radical hysterectomy and pelvic lymphadenectomy for carcinoma of the cervix.

Adult↗
PubMed2004

Preliminary results from a phase II trial of conformal radiation therapy and evaluation of radiation-related CNS effects for pediatric patients with localized ependymoma.

PURPOSE: We conducted a phase II trial of conformal radiation therapy (CRT) for localized childhood ependymoma to determine whether the irradiated volume could be reduced to decrease CNS-related side effects without diminishing the rate of disease control. PATIENTS AND METHODS: Between July 1997 and January 2003, 88 pediatric patients (median age, 2.85 +/- 4.5 years) received CRT in which doses (59.4 Gy to 73 patients or 54.0 Gy after gross-total resection to 15 patients younger than 18 months) were administered to the gross tumor volume and a margin of 10 mm. Patients were categorized according to extent of resection (underwent gross total resection, n = 74; near-total resection, n = 6; subtotal resection, n = 8), prior chemotherapy (n = 16), tumor grade (anaplastic, n = 35), and tumor location (infratentorial, n = 68). An age-appropriate neurocognitive battery was administered before and serially after CRT. RESULTS: The median length of follow-up was 38.2 months (+/- 16.4 months); the 3-year progression-free survival estimate was 74.7% +/- 5.7%. Local failure occurred in eight patients, distant failure in eight patients, and both in four patients. The cumulative incidence of local failure as a component of failure at 3 years was 14.8% +/- 4.0%. Mean scores on all neurocognitive outcomes were stable and within normal limits, with more than half the cohort tested at or beyond 24 months. CONCLUSION: Limited-volume irradiation achieves high rates of disease control in pediatric patients with ependymoma and results in stable neurocognitive outcomes.

Brain↗
PubMed2005

Supradose intra-arterial cisplatin and concurrent radiation therapy for the treatment of stage IV head and neck squamous cell carcinoma is feasible and efficacious in a multi-institutional setting: results of Radiation Therapy Oncology Group Trial 9615.

PURPOSE: To determine the feasibility of high-dose intra-arterial (IA) cisplatin and concurrent radiation therapy (RT) for head and neck squamous cell carcinoma in the multi-institutional setting (Multi-RADPLAT). PATIENTS AND METHODS: Eligibility included T4 squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx. Patients received cisplatin (150 mg/m(2) IA with sodium thiosulfate 9 g/m(2) intravenous [IV], followed by 12 g/m(2) IV over 6 hours, weekly for 4 weeks) and concurrent RT (70 Gy, 2.0 Gy/fraction, daily for 5 days over 7 weeks). Between May 1997 and December 1999, 67 patients from three experienced and eight inexperienced centers were enrolled, of whom 61 were eligible for analysis. RESULTS: Multi-RADPLAT was feasible (ie, three or four infusions of IA cisplatin and full dose of RT) in 53 patients (87%). The complete response (CR) rate was 85% at the primary site and 88% at nodal regions, and the overall CR rate was 80%. At a median follow-up of 3.9 years for alive patients (range, 0.9 to 6.1 years), the estimated 1-year and 2-year locoregional tumor control rates are 66% and 57%, respectively. The estimated 1-year and 2-year survival rates are 72% and 63%, respectively. The estimated 1-year and 2-year disease-free survival rates are 62% and 46%, respectively. The rates of grade 4 and 5 toxicities at the experienced and the inexperienced institutions were 14% and 0% v 47% and 4%, respectively. CONCLUSION: This intensive treatment regimen for head and neck cancer is feasible and effective in a multi-institutional setting.

Adult↗
PubMed2006

Phase III trial of carmustine and cisplatin compared with carmustine alone and standard radiation therapy or accelerated radiation therapy in patients with glioblastoma multiforme: North Central Cancer Treatment Group 93-72-52 and Southwest Oncology Group 9503 Trials.

PURPOSE: In patients with newly diagnosed glioblastoma multiforme, to determine whether cisplatin plus carmustine (BCNU) administered before and concurrently with radiation therapy (RT) improves survival compared with BCNU and RT and whether survival using accelerated RT (ART) is equivalent to survival using standard RT (SRT). PATIENTS AND METHODS: After surgery, patients were stratified by age, performance score, extent of surgical resection, and histology (glioblastoma v gliosarcoma) and then randomly assigned to arm A (BCNU plus SRT), arm B (BCNU plus ART), arm C (cisplatin plus BCNU plus SRT), or arm D (cisplatin plus BCNU plus ART). RESULTS: Four hundred fifty-one patients were randomly assigned, and 401 were eligible. Frequent toxicities included myelosuppression, vomiting, sensory neuropathy, and ototoxicity and were worse with cisplatin. There was no difference in toxicity between SRT and ART. Median survival times and 2-year survival rates for patients who received BCNU plus RT (arms A and B) compared with cisplatin, BCNU, and RT (arms C and D) were 10.1 v 11.5 months, respectively, and 11.5% v 13.7%, respectively (P = .19). Median survival times and 2-year survival rates for patients who received SRT (arms A and C) compared with ART (arms B and D) were 11.2 v 10.5 months, respectively, and 13.8% v 11.4%, respectively (P = .33). CONCLUSION: Cisplatin administered concurrently with BCNU and RT resulted in more toxicity but provided no significant improvement in survival. SRT and ART produced similar toxicity and survival.

Adult↗
PubMed2006

Six-month androgen suppression plus radiation therapy compared with radiation therapy alone for men with prostate cancer and a rapidly increasing pretreatment prostate-specific antigen level.

PURPOSE: We evaluated whether treatment with 6 months of androgen-suppression therapy (AST) and radiation therapy (RT) compared with RT was associated with the time to prostate-specific antigen (PSA) recurrence, prostate cancer-specific mortality (PCSM), and all-cause mortality (ACM) in men with a pretreatment PSA velocity more than 2 ng/mL/yr. PATIENTS AND METHODS: The study cohort comprised 241 men with clinically localized or locally advanced prostate cancer treated with RT and AST or RT from 1989 to 2002. Cox regression and Gray's formulation were used to assess whether treatment was associated significantly with the time to PSA recurrence or ACM and PCSM, respectively, adjusting for known prognostic factors. RESULTS: Despite the significantly longer median follow-up, younger age at diagnosis, higher proportion of Gleason score 7 to 10, and advanced T-category cancers, significantly lower estimates of PSA recurrence (P < .001), PCSM (P = .007), and ACM (P < .001) were observed in men who were treated using RT and AST compared with RT. Treatment with RT and AST compared with RT was associated with a longer time to PSA recurrence (adjusted hazard ratio [HR], 0.22; 95% CI, 0.14 to 0.35; P < .001), PCSM (HR, 0.23, 95% CI, 0.09 to 0.64; P = .005), and ACM (HR, 0.30; 95% CI, 0.16 to 0.58; P < .001). CONCLUSION: Treatment using 6 months of AST and RT compared with RT in men with a pretreatment PSA velocity greater than 2 ng/mL/yr was associated with a longer time to PSA recurrence, PCSM, and ACM.

Aged↗
PubMed2003

Repair of radiation-induced DNA double-strand breaks is dependent upon radiation quality and the structural complexity of double-strand breaks.

Mammalian cells primarily repair DSBs by nonhomologous end joining (NHEJ). To assess the ability of human cells to mediate end joining of complex DSBs such as those produced by chemicals, oxidative events, or high- and low-LET radiation, we employed an in vitro double-strand break repair assay using plasmid DNA linearized by these various agents. We found that human HeLa cell extracts support end joining of complex DSBs and form multimeric plasmid products from substrates produced by the radiomimetic drug bleomycin, 60Co gamma rays, and the effects of 125I decay in DNA. End joining was found to be dependent on the type of DSB-damaging agent, and it decreased as the cytotoxicity of the DSB-inducing agent increased. In addition to the inhibitory effects of DSB end-group structures on repair, NHEJ was found to be strongly inhibited by lesions proximal to DSB ends. The initial repair rate for complex non-ligatable bleomycin-induced DSBs was sixfold less than that of similarly configured (blunt-ended) but less complex (ligatable) restriction enzyme-induced DSBs. Repair of DSBs produced by gamma rays was 15-fold less efficient than repair of restriction enzyme-induced DSBs. Repair of the DSBs produced by 125I was near the lower limit of detection in our assay and was at least twofold lower than that of gamma-ray-induced DSBs. In addition, DSB ends produced by 125I were shown to be blocked by 3'-nucleotide fragments: the removal of these by E. coli endonuclease IV permitted ligation.

Bleomycin↗
PubMed2003

Low doses of radiation increase the latency of spontaneous lymphomas and spinal osteosarcomas in cancer-prone, radiation-sensitive Trp53 heterozygous mice.

Mice heterozygous for Trp53 are radiation-sensitive and cancer-prone, spontaneously developing a variety of cancer types. Osteosarcomas in the spine lead to paralysis, while lymphomas lead rapidly to death, distinct events that provide objective measures of latency. The effects of a single low-dose (10 or 100 mGy), low-dose-rate (0.5 mGy/min) (60)Co gamma irradiation on lymphoma or spinal osteosarcoma frequency and latency, defined as time of death or of onset of paralysis, respectively, were examined. Compared to spontaneous lymphomas or to spinal osteosarcomas leading to paralysis in unexposed mice, an exposure of 7-8-week-old Trp53(+/-) mice to 10 or 100 mGy had no significant effect on tumor frequency, indicating no effect on tumor initiation. All tumors are therefore assumed to be of spontaneous origin. However, a 10-mGy exposure reduced the risk of both lymphomas and spinal osteosarcomas by significantly increasing tumor latency, indicating that the main in vivo effect of a low-dose exposure is a reduction in the rate at which spontaneously initiated cells progress to malignancy. The effect of this adaptive response persisted for the entire life span of all the animals that developed these tumors. Exposure to 100 mGy delayed lymphoma latency longer than the 10-mGy exposure. However, the 100-mGy dose increased spinal osteosarcoma risk by decreasing overall latency compared to unexposed control mice. That result suggested that this higher dose was in a transition zone between reduced and increased risk, but that the dose at which the transition occurs varies with the tumor type.

Animals↗
PubMedDate not supplied

[Delayed radiation-induced optic neuropathy in patients with tumors in the chiasmal-sellar area after radiation therapy].

Six clinical observations of a rare condition, delayed radiation-induced optic neuropathy (RON) are presented. RON developed in patients with brain tumors treated by radiotherapy and radiosurgery; in the majority of patients the condition developed during exposure to therapeutic doses; its incidence was 0.5% of the total number of patients treated by radiotherapy during this period. Asymmetrical chiasmal syndrome developed rapidly in all the patients. Clinical diagnosis of RON was confirmed by magnetic resonance tomography in all cases, and in one case by morphological analysis. Conservative therapy including hyperbaric oxygenation just stabilized the visual function. Remote period of observation was 42 months.

Adult↗
PubMed2002

[Current status of radiation therapy--evidence-based medicine (EBM) of radiation therapy. Radiotherapy for pharyngeal and laryngeal cancer].

Radiation therapy is the first choice of treatment for early pharyngeal and laryngeal cancers, especially those of the glottic larynx and nasopharynx. For advanced lesions without distant metastasis, more intensive treatments, i.e., chemoradiotherapy, multiple fractions per day, and conformal radiotherapy are introduced to improve local control and survival. However, the level of evidence-based medicine is different for each treatment modality. In this review, recent reports of radiotherapy for pharyngeal and laryngeal cancer are introduced from the point of view of the evidence level.

Combined Modality Therapy↗
PubMedDate not supplied

Protein expression of p53 and Bcl-2 has a strong correlation with radiation resistance of laryngeal squamous cell carcinoma but does not predict the radiation failure before treatment.

To examine what factors can precisely predict the radio-sensitivity or radio-resistance of early stage laryngeal squamous cell carcinomas (LSCC), protein expression of p53, Bcl-2 and Bax and loss of heterozygosity (LOH) at 3p and 9p loci were investigated. From June 1994 through June 1999, specimens of primary tumors were obtained by biopsy from 21 patients diagnosed as early stage LSCC at Miyagi Cancer Center Hospital under approved protocol. Labeling indexes of p53 and Bcl-2 were markedly increased in the recurrent tumors (n=8) and the differences were significant by statistical analysis (p=0.043 and p=0.015). However, when labeling indexes of the samples before treatment from non-recurrent cases were compared with those of the samples before treatment from recurrent tumors (n=13), no significant difference was observed. When LOH was examined, 16 out of these 21 cases were acceptable for evaluation, 4 of which (25%) had a relapse. Allelic loss at the 9p21 and 3p21 loci was found in 6 of 13 cases (46%) and 10 of 16 cases (63%), respectively. The frequency of LOH at the 3p21 locus in the recurrent cases was 100% (4 out of 4) and that in non-recurrent cases was 50% (6 out of 12). The frequency of LOH in recurrent tumors was apparently higher than that in non-recurrent tumors. Preservation rates of the larynx of the patients with 3p21 LOH negative tumors was very high (100%) and that of the patients with 3p21 LOH positive tumors was low. These results indicate that although expression of p53 and Bcl-2 had a strong correlation with recurrent LSCC treated by irradiation, immunohistochemical analysis of p53 and Bcl-2 in the sample before treatment was not able to predict the radiation failure. Moreover, our results also indicated that molecular research on genetic instability such as allelic loss may be more sensitive for the detection of radio-resistant tumor cells.

Aged↗