PURPOSE: We tried to find the patients characteristics of parasternal recunence, to classify the parasternal recunence according to the radiological and clinical features, and to evaluate the efficacy of local radiotherapy. MATERIALS AND METHODS: Between August 1987 and April 1997, twenty one patients with parastemal recurrence of breast cancer after surgery with or without adjuvant chemotherapy were treated with radiotherapy. Age distribution at initial operation was ranged from 31 to 79 years(median 48 years). Sixteen(76.2%) cancers were in the right breast and five(23.8%) were in the left. The pathologic types were infiltrative ductal carcinoma in 18 patients and medullary carcinoma in 3 patients. Eight patients had stage I, three had stage IIa, six had stage IIb, one had stage IIIa diseases and we had no information about the initial stage of the other 3 patients. Parasternal recurrence were diagnosed by biopsy in 7 patients, and the other 14 recurrences were diagnosed by clinical and radiologic findings such as chest CT, whole body bone scan. All the patients were treated with radiation for the parasternal recurrent tumors. In addition, five patients also received chemotherapy(FAC or Taxol based protocol) and one patient also received partial resection before radiotherapy. Radiotherapy was delivered with Co-60 gamma-ray or 4~6 MV X-ray or electron beam to both supraclavicular lymph nodes and parasternal areas with total doses of 3000~6480 cGy(median 6100 cGy). RESULTS: The range of interval between curative resection and parasternal recurrence were 4~110 months(median 34 months). The main symptoms of the parasternal recurrence were a painless mass(n=10). The duration of symptom before diagnosis ranged from one to 36 months(median 7 months). Among 21, five patients(23.8%) presented distant metastses at the diagnosis of parasternal recurrences. The parasternal recurrences were classified into three groups according to radiologic and clinical findings; the recurrent tumors originated from sternum and invaded into adjacent tissues(Group 1, n=5), tumors originated from intemal mammary lymph nodes and invaded into sternum or parasternal tissues(Group 2, n=6), tumors originated from medial chest wall and invaded into sternum or parasternal tissues(Group 3, n=10). In nineteen patients(19/21; 90.5%) there was complete response of parasternal recurrence following radiotherapy. Although the follow up period was relatively short(3~78 montbs, median 14 months), there were no local recurrence in radiation field in 19 patients with complete response. Among the 16 patients without distant metastases at diagnosis of parasternal recurrence, nine patients were alive without any evidence of disease. CONCLUSION: Chest CT scan is necessary and effective in patients with parastemal discomfort, pain, swelling or palpable mass after mastectomy. And we found that radiotherapy was very effective for the local treatment of parasternal recunence in terms of symptom palliation and local control of tumor. Although we classified the parasternal recurrence into three groups, we could not reach any conclusive results because of short follow up duration and insufficient patients number.