Biomedical subjects
Publications and source records attributed to Carlos A Perez.
Bone metastases in patients with prostate cancer are common. Prostate cancer patients also have a relatively long survival. Palliative radiation can provide effective symptom control in many clinical settings. This article focuses on the management of bone pain and its complications (pathological fractures and spinal cord compression) with radiation treatment.
PURPOSE: To review the outcome for 56 Stage I non-small-cell lung cancer treated definitively with three-dimensional conformal radiotherapy (3D-CRT) and to investigate the value of elective nodal irradiation in this patient population. METHODS AND MATERIALS: Between 1992 and 2001, 56 patients were treated with 3D-CRT for inoperable Stage I histologically confirmed non-small-cell lung cancer; 31 with T1N0 and 25 with T2N0 disease. All patients were treated with 3D-CRT to a median isocenter dose of 70 Gy (range 59.94-83.85) given in daily doses of 1.8 or 2 Gy. Prognostic factors were analyzed with respect to their impact on overall survival. Twenty-two patients received radiotherapy (RT) directed to elective regional lymphatics to doses of 45-50 Gy. The remaining 33 patients were treated to limited fields confined to the primary lung cancer with a margin. The patterns of failure were reviewed. RESULTS: The median follow-up was 20 months (range 6 months to 6 years). The actuarial local control rate was 88%, 69%, and 63%, at 1, 2, and 3 years, respectively. The actuarial cause-specific survival rate was 82%, 67%, and 51% at 1, 2, and 3 years, respectively. The actuarial overall survival rate was 73%, 51%, and 34% at 1, 2, and 3 years, respectively. The actuarial metastasis-free survival rate was 90%, 85%, and 81% at 1, 2, and 3 years, respectively. The RT dose was the only factor predictive of overall survival in our analysis. No statistically significant difference was noted in cause-specific or overall survival according to whether patients received elective nodal irradiation. Two of 33 patients treated with limited fields had regional nodal failure. CONCLUSION: Many patients with medically inoperable Stage I lung cancer die of intercurrent causes. The omission of the elective nodal regions from the RT portals did not compromise either the cause-specific or overall survival rate. Elective nodal failures were uncommon in the group treated with limited RT fields. A radiation dose 70 Gy was predictive of better survival in our population. We await the results of prospective trials evaluating high-dose RT in patients treated with RT alone for Stage I lung cancer.
PURPOSE: To evaluate the rates of low-grade late effects in patients treated for prostate cancer on Radiation Therapy Oncology Group (RTOG) 9406. MATERIALS AND METHODS: Between August 1994 and September 1999, 424 patients were entered on this dose escalation trial of three-dimensional conformal radiation therapy (3D-CRT) for localized adenocarcinoma of the prostate at doses of 68.4 Gy (level I) and 73.8 Gy (level II). We have previously reported Grade 3 or greater late toxicity of patients treated on the first two dose levels of this trial. This analysis examines the distribution of all late toxicities in these patients. All radiation prescriptions were a minimum dose to a planning target volume (PTV). Patients were stratified according to clinical stage and risk of seminal vesicle invasion (SVI) based upon Gleason score and presenting prostate-specific antigen. Group 1 includes patients with T1,2 disease with SVI risk < 15%, and Group 2 includes patients with T1,2 disease with SVI risk > 15%. Group 3 patients had T3 disease. Average months at risk after completion of therapy ranged from 21.4 to 40.1 months for patients treated at dose level I and 10.0 to 34.2 months for patients at dose level II. The frequency of all grades of late effects was compared with a similar group of patients treated in RTOG studies 7506 and 7706 with adjustments made for the interval from completion of therapy. The RTOG toxicity scoring scales for late effects were used for grading. RESULTS: The rate of Grade 3 or greater late toxicity continues to be low compared with RTOG historical controls. No Grade 4 or 5 late sequelae were reported in any of the 393 evaluable patients during the period of observation. The frequency of patients free of any complications was lower in RTOG 9406 than in historical controls. In the 73 Group 1 patients treated on dose level 1, there were 24 patients without sequelae compared with an expected rate of 39.7 (p = 0.013), and in 80 Group 3 patients at dose level II there were 24 patients without sequelae when 56.2 were expected (p < 0.0001). Other groups treated at these dose levels demonstrated a nonsignificant reduction in the rate of patients free of any side effects. These data suggest that the reduction in high-grade morbidity may be related to a shift of complications to lower grades. CONCLUSIONS: Morbidity of 3D-CRT in the treatment of prostate cancer is low. It is important to continue to closely examine late effects in patients treated in RTOG 9406. The primary objective of dose escalation without an increase rate of >/= Grade 3 sequelae has been achieved. However, the reduction in Grade 3 complications may have resulted in a higher incidence of Grade 1 or 2 late effects. Because Grade 2 late effects may have a significant impact on a patient's quality of life, it is important to reduce these complications as much as possible. Clinical trials should use quality-of-life measures to determine that trade-offs between severity and rates of toxicity are acceptable to patients.
PURPOSE: To evaluate in-field progression and survival of patients with unresectable non-small cell lung cancer (NSCLC) in relation to adequacy of coverage of thoracic regional nodal areas in the radiotherapy volume. MATERIALS AND METHODS: A total of 1705 patients from four large RTOG trials (78-11, 79-17, 83-11 and 84-07) were analyzed for this purpose. For each of these trials, the dose delivered to nodal regions was recorded and an assessment of adequacy of field borders was made. Each nodal site was assessed for progression, defined as in-field or out-of-field. In patients who had adequate borders on nodal regions, the results were analyzed according to the dose delivered. RESULTS: The majority (74%) of patients were between the age of 55-75. Forty-six percent of the patients had KPS of 60-80 and 52% had KPS of 90-100. Sixty percent of patients had a weight loss of less than 5% in the 6 months prior to diagnosis. Deviations from the protocol in field borders (borders not per protocol) were most frequent for the contralateral hilum (25.2%) and least frequent in the ipsilateral hilum (6.3%). The adequacy of ipsilateral hilar coverage was important for preventing the in-field progression (11.6 vs. 22% for adequately vs. inadequately covered ipsilateral hilum, respectively, P=0.01), however, did not influence the 2-year-survival (35 vs. 37%) or median survival (1.3 vs. 1.1 year). Neither the in-field progression nor the 2-year-survival were affected by adequacy of nodal coverage in the mediastinum, ipsilateral supraclavicular area and contralateral hilum, even when different doses were analyzed. CONCLUSION: These data suggest that elective irradiation of mediastinal, contralateral hilar and supraclavicular lymph nodes may not be necessary in the treatment of unresectable NSCLC.
The role of postoperative radiation therapy after radical prostatectomy is controversial. Radiation can be delivered as an adjuvant therapy in the immediate postoperative period for high-risk patients or as salvage therapy in the setting of a rising prostate-specific antigen. There are important issues that must be addressed when considering radiation therapy after prior prostatectomy. One issue is the determination of whether a patient has local disease amenable to salvage pelvic radiation or whether the patient has occult metastatic disease. In addition, the radiation oncologist must decide if an acceptable dose of radiation therapy can be administered safely to the prostate bed. There are no published randomized clinical trials on the topic of postprostatectomy radiation therapy, although several have completed accrual or are in progress. Based on the available literature, postoperative radiation is a safe option in the patient at high risk for local recurrence based on adverse pathology or clinical features (eg, extensive extracapsular disease, positive margins, high volume Gleason score >7, and so on). Administration of an adequate dose of prostate bed radiation (ie, >64 Gy) in men with these adverse prognostic features appears to effectively reduce prostate-specific antigen (PSA) recurrence rates. The protracted natural history of prostate cancer requires longer follow-up to determine if survival will be ultimately affected by adjuvant or salvage radiation therapy. Some urologists have advised a "wait and watch policy" for high-risk postprostatectomy patients. Administration of radiation therapy is done only if and when the PSA rises. However, data suggest this approach may have limited durability in high-risk prostate cancer and could reduce the likelihood of prolonged progression-free survival. This review summarizes published retrospective and prospective data to guide decision making in selecting appropriate candidates for postprostatectomy radiation therapy.
PURPOSE: A prospective Phase I dose escalation study was conducted to determine the maximally tolerated radiation dose in men treated with three-dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer. This is a preliminary report of toxicity at Level III (79.2 Gy) on 3D Oncology Group/Radiation Therapy Oncology Group (RTOG) 9406. METHODS AND MATERIALS: Between November 26, 1996 and October 1, 1998, 173 patients with clinically organ-confined prostate cancer (T1 and T2) were accrued to a Level III dose of 79.2 Gy. One hundred sixty-nine patients were available for analysis of toxicity. Patients were registered to two groups according to the risk of seminal vesicle invasion (SVI) on the basis of presenting PSA and Gleason score. Group 1 patients had a calculated risk of SVI <15%, and Group 2 patients had a risk of SVI > or = 15%. For Group 1 patients, the planning target volume (PTV) margins were 5-10 mm around the prostate only. For Group 2 patients, the same margins were applied to the prostate and seminal vesicles (PTV(1)) for the initial 55.8 Gy; then treatment volume was reduced to the prostate only (PTV(2)). To reduce the rectal dose on dose Level III, the minimum PTV dose was limited to 73.8 Gy, whereas the minimum gross target volume dose was 79.2 Gy, both in 44 fractions. The incidence of > or = 3 Grade late effects was compared to that in a similar group of patients treated on RTOG 7506 and 7706 studies. RESULTS: Acute tolerance to 79.2 Gy was excellent with no patients experiencing > or = Grade 3 acute toxicity. The acute toxicity rate was comparable to that reported for previous lower dose levels. With the median follow-up of 3.3 years (range: 0.4-4.4 years), a total of 4 patients (2.4%) experienced Grade 3 late toxicity, three cases of which were related to the bladder, and one related to the rectum. There were no Grade 4 or 5 late complications noted during the period of observation. These results are also comparable to those reported at dose Levels I and II. The expected incidence of > or = 3 Grade 3 late toxicity was calculated using historical data from two previous RTOG prostate cancer trials, 7506 and 7706. The calculated risk accounted for the difference in follow-up duration between patients in this study and the historical experience. The observed rate of > or = Grade 3 late effects for Group 1 (two cases) is significantly lower (p = 0.0002) than the 17.6 cases that would have been expected from the historical control. The observed rate for Group 2 (two cases) was also significantly lower (p = 0.0037) than the 12.1 cases expected. CONCLUSION: Based on excellent tolerance of 3D-CRT for stages T1 and T2 prostate cancer, further biological dose escalation has been pursued to Levels IV and V, 74 Gy and 78 Gy, respectively, at 2 Gy per day, in an attempt to reduce the total treatment duration. This trial has closed. A Phase III comparative RTOG trial is being developed to determine whether high-dose 3D-CRT improves efficacy.
PURPOSE: To investigate the impact of radiographic parameter and radiation technique on the volumetric dose of lung and heart for intact breast radiation. METHODS AND MATERIALS: Forty patients with both two-dimensional (2D) and computed tomographic (CT) simulations were enrolled in the study. Central lung distance (CLD), maximal heart distance (MHD), and maximal heart length (MHL) were measured under virtual simulation. Four plans were compared for each patient. Plan A used a traditional 2D tangential setup. Plan B used clinical target volume (CTV) based three-dimensional (3D) planning. Both plans C and D used a combination of a medial breast field with shallow tangents. Plan D is a further modification of plan C. RESULTS: Under the traditional tangential setup, the mean ipsilateral lung dose and volume at 20, 30, and 40 Gy correlated linearly with CLD (R = 0.85 approximately 0.91). The mean ipsilateral lung dose (Gy) approximated 4 times the CLD value (cm), whereas the percentage volume (%) of ipsilateral lung at 20, 30, and 40 Gy was about 10 times the CLD (cm). The mean heart dose and percentage volume at 20, 30, and 40 Gy correlated with MHD (R = 0.76 approximately 0.80) and MHL (R = 0.65 approximately 0.75). The mean heart dose (Gy) approximated 3 times the MHD value (cm), and the percentage volume (%) of the heart at 10, 20, 30, and 40 Gy was about 6 times MHD (cm). Radiation technique impacted lung and heart dose. The 3D tangential plan (plan B) failed to reduce the volumetric dose of lung and heart from that of the 2D plan (plan A). The medial breast techniques (plans C and D) significantly decreased the volume of lung and heart receiving high doses (30 and 40 Gy). Plan D further decreased the 20 Gy volumes. By use of the medial breast technique, the lung and heart dose were not impacted by original CLD and MHD/MHL. Therefore, the improvement from the tangential technique was more remarkable for patients with CLD >or= 3.0 cm (p < 0.001). CONCLUSIONS: The CLD and MHD impact the volumetric dose of lung and heart. The application of 3D planning for tangential breast irradiation does not decrease heart and lung dose. Adding a medial breast port significantly decreases percentage volume (PV) of lung and heart receiving high doses, especially when the CLD is excessive.
PURPOSE: To demonstrate a new interactive Internet-ready database for prospective clinical trials in high-dose-rate (HDR) brachytherapy for prostate cancer. METHODS AND MATERIALS: An Internet-ready database was created that allows common data acquisition and statistical analysis. Patient anonymity and confidentiality are preserved. These data forms include all common elements found from a survey of the databases. The forms allow the user to view patient data in a view-only or edit mode. Eight linked forms document patient data before and after receiving HDR therapy. The pretreatment forms are divided into four categories: staging, comorbid diseases, external beam radiotherapy data, and signs and symptoms. The posttreatment forms separate data by HDR implant information, HDR medications, posttreatment signs and symptoms, and follow-up data. The forms were tested for clinical usefulness. CONCLUSION: This Internet-based database enables the user to record and later analyze all relevant medical data and may become a reliable instrument for the follow-up of patients and evaluation of treatment results.
PURPOSE: Three-dimensional conformal radiation therapy (3D-CRT) has recently become widely available with applications for patients with non-small-cell lung cancer (NSCLC). These techniques represent a significant advance in the delivery of radiotherapy, including improved ability to delineate target contours, choose beam angles, and determine dose distributions more accurately than were previously available. The purpose of this study is to identify prognostic factors in a population of NSCLC patients treated with definitive 3D-CRT. METHODS AND MATERIALS: Between March 1991 and December 1998, 207 patients with inoperable NSCLC were treated with definitive 3D-CRT. Tumor targets were contoured in multiple sections from a treatment planning computed tomography (CT) scan. Three-dimensional treatment volumes and normal structures were reconstructed. Doses to the International Commission on Radiation Units and Measurements (ICRU) reference point ranged from 60 to 83.85 Gy with a median dose of 70 Gy. The median dose inhomogeneity was +/- 5% across planning target volume. Outcome was analyzed by prognostic factors for NSCLC including pretreatment patient and tumor-related factors (age, gender, race, histology, clinical stage, tumor [T] stage, and node [N] stage), parameters from our 3D-CRT system (gross tumor volume [GTV] in cm3), irradiation dose prescribed to isocenter, volume of normal lung exceeding 20 Gy (V20), and treatment with or without chemotherapy. The median follow-up time was 24 months (range, 7.5 months to 7.5 years). RESULTS: One and two-year overall survival rates for the entire group were 59% and 41%, respectively. Overall survival, cause-specific survival, and local tumor control were most highly correlated with the GTV in cm3. On multivariate analysis the independent variable most predictive of survival was the GTV. Traditional staging such as T, N, and overall clinical staging were not independent prognostic factors. Patients receiving ICRU reference doses > or =70 Gy had better local control and cause-specific survivals than those treated with lower doses (p = 0.05). Increased irradiation dose did not improve overall survival. CONCLUSIONS: GTV as determined by CT and 3D-CRT planning is highly prognostic for overall and cause-specific survival and local tumor control and may be important in stratification of patients in prospective therapy trials. T, N, and overall stage were not independent prognostic factors in this population of patients treated nonsurgically. The value of dose escalation beyond 70 Gy should be tested prospectively by clinical trial.
The aim of this study was to evaluate and compare the rates of grade 2 or worse late effects in patients treated for prostate cancer on Radiation Therapy Oncology Group (RTOG) 9406. The authors previously have reported the results of patients treated on the first 2 dose levels of this study with respect to grade 3 or greater late toxicity. This analysis examines the incidence of grade 2 toxicity in this study. From August 1994 to September 1999, 424 patients were entered on this dose escalation trial of 3-dimensional conformal radiation therapy (3D CRT) for localized adenocarcinoma of the prostate at doses of 68.4 Gy (level I) and 73.8 Gy (level II). All radiation prescriptions were a minimum dose to a planning target volume. Patients were stratified according to clinical stage and risk of seminal vesicle invasion based on Gleason score and presenting prostate-specific antigen. Average time at risk after completion of therapy ranged from 33.1 to 40.1 months for patients treated at dose level I and 15.6 to 34.2 months for patients at dose level II. The frequency of late effects > or = grade 2 was compared with a similar group of patients treated on RTOG studies 7506 and 7706 with adjustments made for the interval from completion of therapy. The RTOG toxicity scoring scales for late effects were used. The rate of grade 3 or greater late toxicity continues to be low compared with RTOG historical controls. No grade 4 or 5 late complications were reported in any of the 406 evaluable patients during the period of observation. Interestingly, the incidence of grade 2 late toxicity was increased relative to historical controls in all groups and dose levels. In group 1, level I and group 3, level II, the increase in grade 2 complications was statistically significant; 16 complications were observed in group 1, level I when 9.2 were expected (P =.026) and 22 were observed in group 3, level II when 7.6 were expected (P <.0001). When examining all late effects > or = grade 2, there were no significant differences in the rate of late effects in both groups and both dose levels with the exception of group 1, level II. This, in combination with the statistically significant decrease in late effects > or = grade 3, suggests that in most circumstances there has been a shift of grade 3 complications to grade 2. In group 1, dose level II there was a statistically significant reduction in > or = grade 2 late effects, suggesting there was no shift from grade 3 to grade 2 in these patients. In this circumstance there may have been a global reduction in all complications or a shift to late effects less severe than grade 2. In group 2, dose level II there is a trend (P =.085) toward this same result. It is important to continue to examine late effects closely in patients treated on RTOG 9406. The primary objective of dose escalation without an increase rate of > or = grade 3 complications has been achieved. However, the reduction in grade 3 complications may have resulted in a higher incidence of grade 2 late effects. Because grade 2 late effects may have a significant impact on a patient's quality of life, it is important to reduce these complications as much as possible. Improved conformal treatment delivery with intensity-modulated radiation therapy or the use of radioprotective agents could be considered. Clinical trials should use quality-of-life measures to determine that trade-offs between severity and rates of toxicity are acceptable to patients.
BACKGROUND: Because of the challenge in defining prognostic markers predictive of recurrence or progression, carcinoembryonic antigen (CEA) remains the most frequently used marker in colorectal cancer, despite its low sensitivity. We hypothesized that TA90-IC status and serum ganglioside levels might be useful markers and might be of prognostic significance in colorectal cancer. METHODS: Serum samples from 68 patients undergoing surgical treatment for histologically proven colorectal cancer were analyzed for the presence of CEA, serum gangliosides, and TA90-IC. Forty-one patients had node-negative disease, whereas 27 patients had limited metastatic disease. The intent was curative resection, even for patients with metastatic disease. Cryopreserved serum specimens were analyzed in a blinded fashion for total serum ganglioside levels (by an assay that detects lipid-associated sialic acids), for CEA, and for TA90-IC (by a murine monoclonal antibody-based enzyme-linked immunosorbent assay). A positive value for TA90-IC levels was defined as an optical density (OD) of more than 0.410 at 405 nm. RESULTS: Serum ganglioside levels were elevated more frequently than CEA concentrations (84% vs 44%). The combination of serum ganglioside and CEA values was more sensitive (88%) than CEA value alone (44%) in identifying patients with early-stage colorectal cancer. TA90-IC levels were elevated more frequently than CEA concentrations (56% vs 32%). The combination of TA90-IC and CEA values was more sensitive (72%) than CEA value alone (32%) in identifying patients with advanced-stage colorectal cancer. At an enzyme-linked immunosorbent assay cutoff level of 0.410, 15 (56%) patients had positive TA90-IC values. Fourteen patients alive with residual disease had a median OD TA90-IC level of 0.879, and only three patients had levels below the OD cutoff value of 0.410. Thirteen patients with no evidence of disease had a median level of 0.277, and only four patients had OD levels > or = 0.410. TA90-IC was significantly higher in the alive with residual disease patients than those rendered no evidence of disease (P = 0.02). CONCLUSIONS: We speculate that a multiple-marker analysis that combines CEA values with serum ganglioside and TA90-IC values may be more sensitive than CEA value alone for detecting colorectal cancer. The potential prognostic significance of TA90-IC status in advanced disease warrants further investigation.
PURPOSE: Gangliosides are tumor-associated antigens with many biologic functions, including complex interactions with cytokines and other modulators of the immune system. Serum total ganglioside level may be an ideal surrogate marker to predict tumor burden and response to treatment. Antibodies produced against tumor gangliosides may help predict survival. The purpose of this study is to determine whether the serum total ganglioside levels might predict the tumor burden in patients with soft tissue sarcoma, and whether the augmented anti-ganglioside immunoglobulin M (IgM) response might reflect the clinical outcome of these patients. METHODS: Serum TG levels were measured in the cryopreserved sera by estimating lipid-associated sialic acids from 97 patients before surgical resection of soft tissue sarcoma and from 39 age- and gender-matched healthy volunteers. All sera were analyzed for IgM titers (expressed natural log) by enzyme-linked immunosorbent assay against eight gangliosides (GM1, GM2, GM3, GD3, GD2, GD1a, GD1b, and GT1b). Cox regression was used for univariate and multivariate analyses of the variables affecting progression-free and overall survival. RESULTS: Serum TG levels were higher in soft tissue sarcoma patients than in healthy individuals (21.8 + 7.7 vs 16.1 + 2.7 mg/dL; P = 0.001). Larger tumors, high histologic grade, and more advanced stage of disease correlated with higher serum total ganglioside levels (P < 0.05). Anti-ganglioside titers to GM3, GD2, and GT1b were significantly higher in patients with soft tissue sarcoma, whereas anti-GD1a and GD1b titers were significantly higher in healthy subjects. The titers of antibodies against GM1, GM2, and GD3 in patients with soft tissue sarcoma were comparable to those of the healthy individuals. When compared with healthy controls, patients with low-grade tumors had higher titers of anti-GT1b, anti-GM3, and anti-GD2 antibodies, and patients with high-grade tumors had higher titers of anti-GT1b and anti-GD2 antibodies. These data suggest that the predominant gangliosides expressed by sarcomas may include GT1b and GD2. In addition, low-grade tumors may express an immunogenic species of GM3. On both univariate and multivariate analyses, augmented anti-GD1a IgM titers, age > 50 years, and retroperitoneal location were predictive of decreased overall survival, whereas augmented anti-GT1b titers were predictive of improved overall survival. CONCLUSIONS: Serum TG level may be a useful marker of tumor burden and response to treatment for soft tissue sarcoma. Anti-GD1a and anti-GT1b IgM titers predicted survival and may be of therapeutic and prognostic value in the management of soft tissue sarcoma.
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The remarkable technical developments obtained in radiation oncology have resulted in an increasing use of image-based treatment planning in radiation therapy for three-dimensional and intensity modulated radiation therapy, stereotactic irradiation and image-guided brachytherapy. There has been increased use of computer-based record and verify systems as well as electronic portal imaging to enhance treatment delivery. From the data presented it is evident that PET scanning and other functional imaging techniques play a major role in the definition of tumor extent and staging of patients with cancer. The recent introduction of a combined CT and PET scanner will substantially simplify image acquisition and treatment planning.