Radical mastectomy versus radical mastectomy plus internal mammary dissection. Five year results of an international cooperative study

From 1963 to 1968, the international group collected 1580 cases of breast cancer, randomized into two therapeutic groups: radical mastectomy and extended mastectomy. The data were processed on the UNIVAC 1107 computer of the I.N.S.E.R.M. Computing Center. No significant difference was observed between the two groups in the overall five year survival rate. However, a more detailed analysis, according to certain prognostic features, showed that extended mastectomy improved the results in one subgroup: cancers of inner or medial quadrants, axillary N+. Within this group the difference was highly significant for a smaller subgroup (190 patients) including only tumors T ₁ and T ₂. In conclusion, there is no indication for extended mastectomy in any cancers of the outer quadrants or in those of the inner or medial quadrants without axillary involvement. A limited indication for extended mastectomy may be provisionally retained for T ₁ and T ₂ cancers of the inner or medial quadrants with axillary involvement.