Abstract
With vivipara 811 breast cancer patients and 1, 239 control cases as the materials, I have studied the relation of the lactation periods to the growth of breast cancer, and now think to have reached the following conclusion: (The matter of the longest lactation period is not regarded instrumental to the growth of breast cancer).
In the 30-39 age-group, the total lactation periods little affect the growth of breast cancer, but their relation appears conspicuous in the groups over 40 and above years of age. As a general trend, it is observed that a close relation exists between the shorter total lactation period and the increased growth of breast cancer on one band and the longer total lactation period and the decreased growth of breast cancer on the other. But this relation differently appears in degree in accordance with the variety of groups on age and districts, urban and rural.
The number of live births and the total lactation periods hold an inseparable relation, and I have got a valuable suggestion that the smaller number of live births with shorter total lactation periods may be instrumental to the growth of breast cancer.
