Analysis of the prognosis of minimal and occult breast cancers

Of 296 occult breast cancers diagnosed at Kaiser-Permanente Medical Center, Los Angeles, in the last ten years, 80 were classified as minimal and 167 as nonminimal. Minimal cancers were intraductal, lobular in situ, or invasive and 0.5 cm or less in diameter. In the occult-minimal group, no woman had axillary node metastases, and there were no recurrences. In the occult-nonminimal group, 26% of the patients had axillary nodal involvement, with a recurrence rate of 13% and a mortality of 11.6%. Occult breast cancers differed significantly between minimal and nonminimal tumors in both treatment and prognosis. Nonminimal cancers should be treated as any palpable carcinoma. More conservative approaches could be considered for the minimal group, but prospective controlled studies should be done to determine the long-term risks of such treatment.