Background: Sarcomas are a rare complication of radiotherapy for breast carcinoma and patients have a poor prognosis. The incidence, histology, and management of patients with sarcomas were reviewed in the current study.
Methods: The authors reviewed the records of 16,705 patients with breast carcinoma. Of these, 13,472 (81%) were treated with megavoltage radiotherapy and 3233 were treated without at the Institute Curie (Paris, France) between 1981 and 1997. Median doses of 50-55 grays (Gy) in 25-27 fractions were delivered to the whole breast over a period of 5-5.5 weeks (2 Gy/day, 5 weekly fractions) followed, when indicated, by a 16-26-Gy boost to the tumor or tumor bed. Treatment of radiation-induced sarcomas (RIS) consisted mostly of radical surgery and chemotherapy.
Results: Overall, 35 patients developed sarcomas. Of these, 27 fulfilled the Cahan criteria. The median follow-up was 9.3 years (range, 1-22.4 years). The latency period ranged from 3 years to 20.3 years. Thirteen sarcomas were located in the breast, 5- in the chest wall, 3 in the sternum, 2 in the supraclavicle, 1 in the scapula, and 3 in the axilla. Histologic evaluation identified 13 angiosarcomas, 3 osteosarcomas, 5 undifferentiated sarcomas, 1 malignant fibrous histiocytoma, 2 leiomyosarcomas, 1 fibrosarcoma, 1 rhabdomyosarcoma, and 1 myosarcoma. The cumulative RIS incidence was 0.07% (+/- 0.02) at 5 years, 0.27% (+/- 0.05) at 10 years, and 0.48% (+/- 0.11) at 15 years. Standardized incidence ratios were 10.2 (95% confidence interval, 9.03-11.59) for irradiated patients and 1.3 (0.3-3.6) for nonirradiated patients. Of the 27 patients, 15 died of sarcoma within 1 month to 14.5 years (mean, 34.2 +/- 0.7 months). The 5-year actuarial survival rate after diagnosis of RIS was 36% (+/- 0.11).
Conclusions: The current study confirmed the rarity of RIS. However, it showed that the risk increased with time. Therefore, careful, long-term follow-up of patients treated with radiotherapy is needed for early detection and efficacious treatment of these malignancies.