[Breast cancer without palpable tumor revealed by microcalcifications. Prognosis and treatment]

Routine screening mammography has greatly increased the number of breast cancers detected in the form of clumped microcalcifications without a palpable tumour.

From 1964 to 1989, 315 breast cancers revealed by microcalcifications without contralateral cancer, treated at the Institut Curie. Cancers were observed in 40% of the microcalcifications excised. Treatment was conservative in 57.5% of cases and mutilating in 42.5% of cases; these rates have changed only very slightly with time. Histologically, 50% of the tumours were intraductal cancers, 25% were microinvasive, 24% were infiltrating and 1% were lobular in situ carcinomas. The therapeutic indication can be defined on the basis of the histological result of the initial tumour excision, as the initial examination underestimated the lesions in only 5.6% of cases. Lymph node invasion was observed in 1.8% of intraductal cancers, 5.3% of microinvasive cancers and 14.8% of invasive cancers.

The overall survival was 99% at 5 years and 89.9% at 10 years. The prognosis of invasive cancer was less favourable than that of intraductal and microinvasive cancers (p = 0.03). Survival was not influenced by the radical or conservative nature of treatment. The presence of lymph node invasion severely worsened the prognosis. The 5 year recurrence rate was 4.2% for intraductal, 4.6% for microinvasive and 6.1% for invasive. The incomplete nature of the resection increased the local recurrence rate: 11.9% at 5 years instead of 5%.

Conservative treatment of cancers revealed by microcalcifications without a palpable tumour therefore appears to be justified provided the lesion is radiologically localized, with a histologically satisfactory resection and in the absence of residual microcalcifications on postoperative mammography.