Postmastectomy CT-based electron beam radiotherapy: dosimetry, efficacy, and toxicity in 118 patients.

PURPOSE: To evaluate the technique, dosimetry, acute and late toxicity, local control (LC), and overall survival (OS) with the use of computed tomography (CT)-based postmastectomy electron beam therapy (PMEBT) in high-risk patients. METHODS AND MATERIALS: From 1990 to 2000, 118 patients with pathologic stage I-IIIB breast cancer underwent PMEBT of the chest wall (CW) (n = 3), CW and supraclavicular fossa (SCV) (n = 63), CW, SCV, and internal mammary lymph nodes (IMN) (n = 51), and SCV+IMN (n = 1). Radiation therapy was delivered with an en face electron beam with a custom cutout. Treatment plans were all CT-based. The plans of 16 patients were retrospectively reviewed to analyze dosimetry data. A retrospective chart review was conducted to assess acute and late complications, LC, and OS. RESULTS: At a median follow-up of 43 months, 5-year LC and OS were 91% and 61%, respectively. Sixty-one patients developed acute grade 3-4 skin toxicity, necessitating treatment breaks in 33 patients. Fifteen patients experienced a worsening of lymphedema, and 2 patients developed cardiac injury thought to be unrelated to radiotherapy. No patients developed symptomatic pneumonitis. Dosimetric analysis revealed heart and lung normal tissue complication probabilities of zero. Analysis of other clinically relevant dosimetric parameters revealed PMEBT to be comparable to previously reported techniques. CONCLUSION: Postmastectomy electron beam therapy is an effective way to deliver radiation to the postmastectomy chest wall and adjacent nodal sites. It offers acceptable acute and late toxicities and a high degree of local control given the high-risk population to which it is offered.

Tolerance of tissue transfers to adjuvant radiation therapy in primary soft tissue sarcoma of the extremity.

PURPOSE: Treatment of extremity sarcomas occasionally requires tissue transfer in the form of pedicle flaps, free flaps, or skin grafts to repair surgical defects. These tissues are often subject to radiation (RT) and are therefore at risk for wound breakdown requiring reoperation. This study reviews a single center's experience with tissue transfer and postoperative RT. METODS AND MATERIALS: Between 1983 and 2000, 43 adult patients (>16 years old) with primary high-grade soft tissue extremity sarcomas underwent limb-sparing surgery and reconstruction of their surgical defects, followed by adjuvant RT. The reconstructions were as follows: pedicle flaps (n = 14), free flaps (n = 10), skin grafts (n = 4), or a combination (n = 15). Postoperative external beam radiation therapy (EBRT) (median dose: 63 Gy) alone was given to 27 patients (63%). Adjuvant brachytherapy (BRT) was given to 16 patients (37%); BRT alone (median dose: 45 Gy) was given to 12 patients and combined with EBRT for 4 patients (EBRT: 45 Gy; BRT: 20 Gy). Comorbid conditions such as diabetes, hypertension, tobacco use, and obesity (calculated using body mass index >or=30) were present in 30 patients (70%). Tumor characteristics were as follows: 26 were >5 cm in size, 37 were deep, and 30 were in the lower extremity. The median follow-up time, calculated from the date of operation, was 32 months. Five of 43 patients suffered wound complications necessitating reoperation; however, 3 patients developed complications before initiation of RT and were therefore excluded from the analysis. Two of 43 patients (5%) required reoperation for wound complications after RT; 1 of these patients ultimately required amputation for necrosis. The 5-year overall wound reoperation rate was 6% (95% confidence interval: 0-14%). The influence of patient and tumor characteristics, as well as the type of RT, on the wound reoperation rates is as follows: BRT vs. EBRT (17% vs. 0%, p = 0.06); upper vs. lower extremity (0% vs. 8%, p = 0.41); 5 cm (8% vs. 4%, p = 0.9); comorbidity vs. no comorbidity (3% vs. 13%, p = 0.8); age 50 (8% vs. 4%, p = 0.8). CONCLUSION: Based on this review, most tissue transfers (95%) tolerated subsequent adjuvant radiation therapy well. Although more wound complications necessitating reoperation were seen in patients who received BRT, whether this is because of the inherent susceptibility of flaps and skin grafts to breakdown in the immediate postoperative period vs. the direct result of BRT needs further investigation.