Some international differences in histology and survival in breast cancer

Survival rates for patients with breast cancer have been reported to be higher in Japan than in the United States. It has also been reported that histologic features associated with more favorable survival are more frequent in Tokyo than in the United States. In this report data are presented on the question of whether differences in breast cancer histology could account for the differences in survival rate between Tokyo and two western areas–Boston, USA, and Glamorgan, Wales. Intraductal carcinoma was found to be most frequent in Tokyo and least frequent in Boston, but survival differences between the two cities were found when non‐invasive cases were excluded. Low (relatively malignant) nuclear grade was observed most often in Glamorgan; there was little difference in frequency of this characteristic between Boston and Tokyo. Since nuclear‐grade specific survival ratios were highest in Tokyo, this histologic feature also does not account for the better survival experience of Japanese patients. Tumors of medullary histologic type and those with high degrees of lymphoid infiltration were most frequent in Japan and least frequent in Boston. However, the relationships of histologic type and lymphoid infiltrate to survival were not consistent in the three areas, and the higher survival ratio of the Japanese patients could not be related to these characteristics.