The degree of lymphiod infiltration (LI) seen in primary lesions of breast cancer was classified into three ranks, LI (-), LI (+) and LI (++). With the aim of clarifying the influence of LI on the prognosis, the relation between LI, the prognostic factors and disease-free survival rate was investigated. As a result, it was clarified that LI was closely related to the hormone receptors, nuclear grade and nuclear DNA content, representing the grade of malignancy of breast cancer. Moreover, cases of LI (++) showed a lower positive rate of hormone receptors, and seen in cases with a high nuclear grade and cases of types other than the diploid type on the histogram of the nuclear DNA content with the significantly high frequency. The disease-free survival rate was lowest in cases of LI (++).
These results suggest that as far as cumulative disease-free survival rate is concerned, lymphoid infiltration in cases of breast cancer cannot be a host response resulting in an uneventful prognosis but simply a histologic finding reflecting the grade of malignancy of primary lesions.