[A multivariate analysis of en bloc extended radical mastectomy versus conventional radical mastectomy in operable breast cancer].
We made clinical trials of en bloc extended radical mastectomy (EXT) of a new type in 118 patients from 1980 through 1985. Conventional radical mastectomies (RDL) were also performed in 105 patients from 1973 through 1985. A multivariate analysis was performed to compare the results of EXT and RDL. As the result, the 5-year survival rates of 91 +/- 2.6% and 83 +/- 3.7% were achieved for the EXT and RDL groups, respectively (Cox P value for comparison of survival curves = 0.16). Adjusted Cox regression analysis revealed a significantly favorable result of EXT (P = 0.03). This difference was most remarkable in patients with one to three metastatic axillary lymph nodes, although it was not statistically significant because of too small number of patients available (P = 0.18). The results are thus not definite, but suggest that EXT may be advantageous over RDL especially in patients with a few metastatic axillary lymph nodes.