Treatment and survival of female patients with nonpalpable breast carcinoma

Since 1971, 151 nonpalpable breast cancers (100 invasive carcinomas, 39 in situ ductal carcinomas, and twelve lobular carcinomas in situ) have been diagnosed and treated at the St. Radboud University Hospital. Of the 100 clinically occult invasive carcinomas, 53 had pathologic diameters of more than 10 mm, 29 were of sizes between 6 and 10 mm, and 18 were tumors of 5 mm or less. Residual tumor outside the "excisional" biopsy cavity was encountered in 76 of the 118 mastectomy specimens (64.4%) fully capable of evaluation. Invasive residual tumor would have been left behind in 34 of 86 mastectomy specimens (39.5%). Of 27 axillas studied, no patient with in situ carcinoma had evidence of axillary lymph node metastases. Invasive carcinoma, however, showed axillary lymph node involvement in 7.7% of mastectomy specimens when the size of the primary tumor was not more than 5 mm, in 12.5% when the size was between 6 and 10 mm, and in 29.5% when the primary tumor was more than 10 mm in diameter. The 10-year recurrence-free survival (RFS) of patients with clinically occult invasive carcinomas greater than 10 mm in size was 71.9% and differed significantly from the 90.9% for patients with the invasive tumors less than or equal to 5 mm, as well as from the 100% RFS of patients with invasive tumors of between 6 and 10 mm and noninvasive tumors. Although the 10-year RFS was 92.6% for the patients with negative axillary nodes and 80.0% for the patients with positive axillary nodes, this difference did not reach statistical significance. However, the disease-specific overall survival after 10 years was significantly different between node-negative patients (96.4%) and node-positive patients (78.8%). Multivariate analysis disclosed that the relationship between size of the primary tumor and RFS was independent of the presence of axillary lymph node metastases. In conclusion, the validity of the concept of minimal breast cancer has been re-enforced. However, the results of this study suggest that the upper limit of the original definition of minimal breast cancer is too narrow and should be extended, so that, apart from the noninvasive tumors--regardless of their size--all invasive tumors having a maximum diameter less than or equal to 10 mm should be regarded as minimal breast cancers.