Abstract
Background: The late effect of ionizing radiation on the development of sarcomas within the field of radiation is referred to as Post Irradiation Sarcoma (PRS).
Methods: A retrospective study from the Scottish Bone Tumor Registry (1940–2000) of PRS of the upper limb. The diagnostic criterion of Cahan was strictly followed and all patients followed up for 5 years.
Results: 11 female patients with previous history of radiotherapy (XRT) for carcinoma breast were identified as having PRS. The mean age at diagnosis was 68.7 years (51–80y). The latent period between irradiation and diagnosis ranged from 8 to 36 years (mean 15.6 y). All lesions occurred on the same side as breast malignancy. 6 lesions involved the proximal humerus and 5 the scapula. Histologically there were 7 osteosarcomas (65%), 1 chondrosarcoma, 1 spindlecell sarcoma and 2 dedifferentiated sarcomas. 2 humeral lesions underwent forequarter amputation, 2 excisions and endoprosthesis and 2 chemotherapy. Cumulative 5 year survival for humeral lesions was 33%. Survival was better with patients who achieved complete surgical margins. Majority of scapular lesions presented with either pulmonary/chest wall secondaries and were unresectable. Cumulative survival was poor ranging from 1 to 12 months (mean 6.2 months). De-differentiated lesions had the worst prognosis. Both orthovoltage and megavoltage XRT were implicated. It was not possible to analyze the relationship between total irradiation dose, individual fraction dose and incidence of PRS.
Discussion: PRS is an uncommon tumor with an incidence less than 1%, for patients who survive 5 years after XRT. Delay in diagnosis, aggressive nature, truncal location making extirpative surgery difficult and elderly patients all make the prognosis worse than that of primary sarcomas. As treatment of carcinoma of the breast evolves towards greater breast conservation it will be important to monitor the frequency of this complication more closely.
Correspondence should be addressed to BOOS at the Royal College of Surgeons, 35 - 43 Lincoln’s Inn Fields, London WC2A 3PN
