Radiation oncology investigations最新文献

An early noninvasive indicator of tumor response to therapy and the ability to predict clinical outcome may potentially enhance disease management. Currently, however, tumor response to therapy is often delayed, potentially compromising disease management. We examined the computed tomography (CT) number or Hounsfield unit distribution to follow lung tumor response to radiation treatment. To help interpret the results, we examined whether the CT number distribution follows a simple two-component model. The CT number distribution was derived from a CT-simulator for 11 patients with lung cancer before and after the initial radiation treatment (1-1.5 months, average 3,407 cGy). Clinical outcomes were followed in 8 patients who received 5,580-6,660 cGy. All patients were scanned serially, using identical radiation imaging parameters (voltage, current, scan time, and slice thickness) in a CT-simulator. The lung tumors were digitally contoured, and software windows were applied to avoid inclusion of lung tissue in the analysis. Histograms and statistical analysis of the CT numbers for the tumor were generated. Radiation-induced CT number or Hounsfield unit (HU) shifts exceeding a threshold (13 HU) in lung tumors were associated with (P=0.04) local control (> or = 10 months). Initial lung tumor size (below 100 cm3) was less well-associated with local control (P=0.26). The change in standard deviation of the CT numbers (derived from the more careful contouring and using software windows) induced by radiation treatment correlated with the change in average CT number (R2=0.71). The change in standard deviation did not correlate with a change in tumor volume (R2=0.02). Radiation treatments reduced the average CT number (P < 0.001). In summary, radiation reduces the CT number and this reduction may be associated with local control at 10 months. A two-component model is consistent with lung tumor number distribution and its response to radiation.

Acute pneumonitis following breast irradiation is a rare and transient phenomenon that can be easily managed by drugs. The aim of this study is to evaluate late sequelae on lung, after postoperative radiotherapy (RT) for breast cancer. We were concerned with investigating late radiological findings when very small lung volumes are involved in the irradiated volume. We studied 28 consecutive patients. They underwent clinical examination and all staging procedures before surgery, evaluation of pulmonary function with spirometry, postoperative chest x-ray and high resolution computed tomography (HRCT) of the lung before RT. Clinical examinations were usually performed every 3 months after RT. A second chest x-ray, HRCT and spirometry were carried out after nearly 7 months from the end of RT. We estimated the irradiated lung volume by measuring the area of the lung surface enclosed by the 50% isodose (LA50) in each profile. We found a significant correlation between LA50 and the score of radiological findings after RT. No correlations were found between other factors (i.e., adjuvant chemotherapy, age, weight, smoking) and lung fibrosis. No woman developed radiation pneumonitis syndrome or respiratory symptoms. Our results indicate that irradiation of the breast and/or chest wall is well tolerated if treatment planning is done accurately. The fibrosis likelihood is strongly correlated to the irradiated lung volume. The use of tangential fields limits radiological changes that can be detected only by HRCT examination and are not associated with clinical symptoms.

We recently reported the outcome of 168 patients treated with pelvic lymphadenectomy and definitive radiation therapy. This report is a subanalysis of those patients (pts) who were clinically without evidence of disease (NED) 10 years after a negative staging pelvic lymphadenectomy and definitive radiation therapy for prostate cancer. One hundred of our original cohort of 168 patients had at least ten year follow-up. 76 patients had pathologically negative lymph nodes and had not received hormonal therapy. Forty-two N0 patients with sufficient follow-up were alive and clinically NED 10 years post-operatively. Distribution by disease stage at diagnosis was: Stage A2: 12 pts; Stage B: 19 pts; Stage B2/C: 6 pts; Stage C: 5 pts. Median follow-up was 13.3 years, with a minimum follow-up of 10 years. Of the 42 patients clinically NED at 10 years, 5 pts died subsequently without PSA data, remaining clinically NED a median of 13 y 3 m postoperatively; 37 patients were alive and without evidence of disease off all therapy at 10 years post-operatively. Bone scans were performed on 8 of the 9 patients with PSA over 4.0 ng/ml or on hormonal therapy. These revealed a single patient with diffuse but asymptomatic bone metastases. Ultrasound-guided sextant biopsies were performed on one 78-year-old patient with elevated PSA 19 years post-operatively, revealing an asymptomatic local recurrence. Patients who survive clinically NED for 10 years have a low likelihood of clinical failure, even in the presence of PSA values between 4.0 and 10 ng/ml. In these patients, PSA trends are of greater utility than absolute values.

This report clarifies the prognostic factors for survival in localized non-Hodgkin's lymphoma (NHL) of the head and neck and defines optimal regimens for this disease. One hundred-seven untreated patients with Stage I or II NHL of the head and neck were treated with involved field radiation therapy for orbital, nasal, or paranasal lymphoma and extended field radiation for Waldeyer's ring or neck lymphoma. Radiation doses were 39-48 Gy. In the latter half of the study, adjuvant chemotherapy was administered. Of 107 patients, 95 achieved complete response (CR). Of the 12 patients that did not achieve CR, 9 had nasal T-cell lymphoma (NTL) of the lethal midline granuloma type (LMG-NTL). Only one patient who obtained CR relapsed in a previously irradiated area. Age, sex, stage, bulky mass, number of involved sites, LMG-NTL, histologic subtypes, radiation dose, and adriamycin dose were analyzed for prognostic significance for disease-specific survival in NHL by multivariate analysis. LMG-NTL was the most significant prognostic factor (P < 0.001). Patients with higher age also experienced a higher relative risk than patients of > or =60 years of age (P = 0.0063). Dose of adriamycin reached the borderline significance (P = 0.0600). Radiotherapy is excellent for obtaining local control of head and neck NHL. Randomized trials are required to determine the appropriate radiation field and dose in patients previously treated with chemotherapy. LMG-NTL and age were the significant prognostic factors for disease-specific survival.

The purpose of this study was to investigate the feasibility and the efficacy of administering tirapazamine by a slow-releasing polymer disc that was implanted interstitially into a U251 (human glioblastoma multiforme) tumor grown in nude mice. Tumor-bearing animals, with a tumor nodule 0.8 cm3 in size, were distributed to groups receiving combinations of empty or drug-containing polymer implants in the tumor or contralateral leg, intraperitoneal (i.p.) drug, and/or irradiation. The drug (i.p.) alone (14 mg/kg x6) or in combination with tumor drug implant (2 mg) did not significantly increase the tumor volume doubling time compared to that of control animals. Given with 12 Gy of irradiation in twice a day 2-Gy fractions, combined i.p. drug and tumor drug implant significantly delayed tumor growth compared to irradiation alone, which was not achieved with either drug treatment alone added to irradiation. Toxicity, as manifested by transient weight loss, was primarily seen in animals receiving radiation and i.p. tirapazamine. These results indicated that a slow-releasing tirapazamine disc can be produced and the addition of an interstitially implanted tirapazamine disc further increased the effectiveness of i.p. tirapazamine.

We report our experience with consolidative 32P after second-look laparotomy. Forty-three patients received consolidative 32P after platinum-based chemotherapy and a negative (39 patients, 91%) or positive (4 patients) second-look laparotomy. Thirty-one patients (72%) initially had stage III (30 patients) or stage IV (1 patient) disease; 28 patients (65%) had grade 3 tumors. Patients had follow-up from 3.5 to 14.9 years (median, 7.7 years); no patient was lost to follow-up. The 5-year rates of control of disease within the abdomen (local control) for the overall group and the subset of patients with stage II-IV disease and a negative second-look laparotomy were 65% and 69%, respectively. The corresponding 5-year survival rates were 78 and 81%, respectively. Multivariate analyses revealed that tumor found at second-look laparotomy significantly influenced the likelihood of local control and cause-specific survival. Acute side effects included cellulitis (1 patient) and ileus (3 patients). Two patients (5%) experienced severe late complications; both experienced small bowel obstruction that necessitated surgical intervention. Consolidative 32P appears to reduce the risk of recurrence and improve survival after negative second-look laparotomy. The risk of significant complications is low.

Clinical modulation of radiosensitivity via combined fractionated high dose rate and continuous ultra-low dose rate irradiation (ULDR) holds promise for the radiosensitization of human malignant gliomas. We measured both the in vitro and in vivo responses of a human malignant glioma cell line to combined continuous ULDR and high dose rate treatments. For in vitro ULDR treatments, U251 human malignant glioma cells were cultured in media containing tritiated water to yield a continuous dose rate of 0.03 Gy/hr. After exposures of 24, 48, or 72 hr, cells were acutely (1.1 Gy/min) irradiated, replated, and scored for colony formation. In vivo, U251 flank xenografts in nude mice had 125-iodine (125-I) seed brachytherapy at a dose rate of 0.05 Gy/hr. For whole-body continuous ULDR (0.03 Gy/hr), a 137-Cs source was mounted a fixed distance above the cages of animals bearing xenografts. After 3 days' continuous exposure, xenografts were acutely irradiated (2 Gy x 8 vs. 5 Gy x 2 daily fractions), and the regrowth delay in tumors was measured. In vitro, exposure to ULDR (0.03 Gy/hr) alone caused only modest killing and reduced the surviving fraction by approximately 0.2 logs after 72 hr exposure. The highest (10 Gy) dose of acute irradiation alone reduced survival by 1 log. However, U251 cell killing increased to 2.5 logs after combined HDR and ULDR treatments. Linear-quadratic modeling showed comparatively greater increase in the beta than the alpha coefficients of the linear-quadratic model for cell killing. In vivo, the 125-I seed brachytherapy treatments delayed tumor growth but resulted in no regression. The HDR treatments (5 Gy x 2 or 2 Gy x 8 daily fractions) caused growth delays (in days) of 17+/-2 or 16+/-2 (P=NS) days, respectively. The combined seed and 5 Gy x 2 or 2 Gy x 8 daily fractions regimen resulted in striking prolongation of regrowth delay (52.3+/-8.7 vs. 59.5+/-7.7 days) (P < 0.001 vs. HDR treatments alone). External ULDR alone caused no regression and minimal growth delay. Combined continuous external ULDR and the 5 Gy x 2 vs. 2 Gy x 8 daily fraction regimens resulted in prolongation of growth delay (33+/-0.9 (P=0.01 vs. 5 Gy x 2 daily fractions alone) vs. 35+/-0.7 (P=0.049 vs. 2 Gy x 8 daily fractions alone). We conclude that continuous ULDR increases the effect of HDR treatments of experimental malignant glioma. This increased effect may prove clinically important in the treatment of human malignant brain tumors.

Our purpose was to examine the role of radiotherapy in the management of phyllodes tumor of the breast. Eight patients were treated with adjuvant radiotherapy for nonmetastatic phyllodes tumor of the breast at the M.D. Anderson Cancer Center between December 1988-August 1993. Tumors were classified as benign (n=2), borderline (indeterminate; n=1), or malignant (n=5). Median follow-up was 36.5 months. Primary surgery consisted of either lumpectomy in 2 patients or mastectomy in 6 patients. Seven patients received adjuvant radiation therapy to the breast or chest wall to a dose of 60 Gy. One patient received 50 Gy to the breast, followed by an interstitial boost of 20 Gy for a total of 70 Gy. Radiotherapy was administered for a combination of reasons, including bulky tumor volume, positive margins, recurrence, and/or malignant histology. There were no local or distant failures. This retrospective review suggests that adjuvant radiotherapy may be underutilized in the treatment of phyllodes tumor of the breast, particularly in patients with adverse features. Although treatment to the breast or chest wall (not the lymphatics) to a dose of 60 Gy appears effective, a dose-response has not been established, and lower doses (50-60 Gy) may be equally effective.

The purpose of this pilot study was to determine the feasibility and toxicities of an accelerated treatment program by using a concomitant stereotactic radiotherapy boost given weekly during a course of standard external-beam irradiation (EBXRT) in patients with malignant gliomas. Twelve patients underwent biopsy or subtotal resection of a malignant glioma and were enrolled on the protocol, which delivered 44 Gy-EBXRT and a 12-Gy stereotactic radiotherapy boost given on 3 consecutive weeks of treatment for a total dose of 80 Gy over 33 days. Three patients with anaplastic astrocytoma and nine patients with glioblastoma multiforme had median survival times of 33 months and 16 months, respectively. All of the tumor recurrences were within or were closely adjacent to the region of high-dose irradiation. None of the patients required a treatment break, and there were no acute complications. Two patients developed seizures in the follow-up period, and four patients were diagnosed with radionecrosis at the time of the second operation. The treatment program was found to be feasible and was well tolerated, and it resulted in a rate of late complications similar to those of radiosurgery or interstitial brachytherapy.