Is there an increased risk of local recurrence under the heart block in patients with left-sided breast cancer?
UNLABELLED: Tangential radiotherapy for left-sided breast cancer may be cardiotoxic. Shaping the field with a heart block reduces cardiac exposure but may under-dose the breast and/or chest wall. We compared the incidence and location of local recurrences in patients irradiated with and without a heart block. METHODS AND MATERIALS: Between 1994 and 1998, 180 patients irradiated to the left breast and/or chest wall were retrospectively reviewed. The local recurrence rates in patients treated with and without a heart block were compared using a 2-tailed Fisher exact test. An in-depth dosimetric analysis was performed in 23 patients to assess the percentage of breast tissue under-dosed by inclusion of the heart block. RESULTS: Overall, the local recurrence rates in patients with or without a heart block were similar. In postlumpectomy patients with inferiorly located tumors, the rates of local recurrence with and without a heart block were 2 of 6 patients versus 0 of 19 patients, respectively. In the dosimetric analysis, the average percentage of breast tissue under-dosed by the inclusion of a heart block was 2.8% (range, 0%-11%). DISCUSSION: A heart block is a reasonable method to limit cardiac dose but should be used cautiously following a lumpectomy in patients with inferiorly located tumors. Additional study with larger numbers of patients is warranted.
Raj, KA; Evans, ES; Prosnitz, RG; Quaranta, BP; Hardenbergh, PH; Hollis, DR; Light, KL; Marks, LB
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