[Menstrual cycle and surgery of breast cancer. Point of time for the surgery of primary breast cancer in connection with menstrual cycle is without prognostic significance]. / Menstruationscyklus og operation for mammacancer. Tidspunktet for operation for primoer mammacancer i forhold til menstruationscyklus er uden prognostisk betydning.

From 1977 to 1989 6488 patients under fifty years with primary breast cancer were registered in the nationwide Danish Breast Cancer Cooperative Group (DBCG). Among these information on last menstrual period prior to surgery was available in 1635 cases which constitute the study group of the present analysis. The group was representative of the total group with regard to prognostic factors and survival. In the study group time of surgery in relation to last menstrual period was found to have no influence on five- and ten year survival.