Phase II trial of brachytherapy alone after lumpectomy for select breast cancer: toxicity analysis of RTOG 95-17.

PURPOSE: Accelerated partial breast irradiation (APBI) can be delivered with brachytherapy within 4-5 days compared with 5-6 weeks for conventional whole breast external beam radiotherapy. Radiation Therapy Oncology Group 95-17 is the first prospective phase I-II cooperative group trial of APBI alone after lumpectomy in select patients with breast cancer. The toxicity rates are reported for low-dose-rate (LDR) and high-dose-rate (HDR) APBI on this trial. METHODS AND MATERIALS: The inclusion criteria for this study included invasive nonlobular tumors < or =3 cm after lumpectomy with negative surgical margins and axillary dissection with zero to three positive axillary nodes without extracapsular extension. The patients were treated with either LDR APBI (45 Gy in 3.5-5 days) or HDR APBI (34 Gy in 10 twice-daily fractions within 5 days). Chemotherapy (> or =2 weeks after APBI) and/or tamoxifen could be given at the discretion of the treating physicians. RESULTS: Between August 1997 and March 2000, 100 women were enrolled in this study, and 99 were evaluated. Of the 99 women, 33 were treated with LDR and 66 with HDR APBI. The median follow-up for all patients was 2.7 years (range, 0.6-4.4 years) and was 2.9 years for LDR and 2.7 years for HDR patients. Toxicities attributed to APBI included erythema, edema, tenderness, pain, and infection. Of the 66 patients treated with HDR APBI, 2 (3%) had Grade 3 or 4 toxicity. Of the 33 patients treated with LDR, 3 (9%) had Grade 3 or 4 toxicity during brachytherapy. Late toxicities included skin thickening, fibrosis, breast tenderness, and telangiectasias. No patient experienced late Grade 4 toxicity; the rate of Grade 3 toxicity was 18% for the LDR and 4% for the HDR groups. CONCLUSION: Acute and late toxicity for this invasive breast radiation technique was modest and acceptable. Patients receiving chemotherapy, a nonprotocol therapy, had a greater rate of Grade 3 toxicity. The study design did not allow for this to be tested statistically.

Megavoltage portal films using computed radiographic imaging with photostimulable phosphors.

Conventional portal films taken with high-energy x rays are severely impaired by poor image quality, and many attempts have been made to overcome this problem. A new technology, computed radiographic imaging, has been investigated as a means of producing images taken with 6-and 10-MV x rays. The computed radiographic imaging (CRI) system is based on the principle of laser-stimulated luminescence induced in an image receptor plate exposed to ionizing radiation, and direct conversion of the light into digital form. Image processing using contrast enhancement and unsharp masking yields images at least as good as the best portal films obtainable with conventional commercial radiotherapy cassettes. Additionally, CRI offers advantages of reduced image size and digital storage. The system is capable of producing normal film densities over an extremely wide range of exposure.

Performance evaluation of a new quality control dose monitor for radiation therapy.

The performance of a new quality control dose monitor for radiation therapy with respect to precision, stability, temperature coefficient, and radiation damage has been extensively evaluated. The results of routine use at several centers are reported.

Treatment of adjoining field areas with electron beams of different energy using a single central axis.

The use of a single central axis causes the divergence of radiation at the abutting boundaries to be parallel, even in cases for which the abutting boundary does not coincide with the beam central axis. Lateral diffusion of scattered electrons from an area treated with one energy into the neighboring area is reciprocated to provide a smooth change from the dose at4 any given depth near the center of one area to that near the center of the other. This allows treatment of deep levels of tissue in one portion of a field, while sparing deep level structures in an adjacent portion of the field.