Observations on growth rate of breast carcinomas and its possible implications for lead time.

Doubling times were estimated for 15 breast carcinomas in 13 patients, and were found to be between 42 and 397 days with the average at 211 days. The mean lead time at mean growth rate from the average size of 44 preclinical to the average size of 118 clinical tumors was estimated to be 3 years. This period may be considered the probable time gained through screening for mammary carcinomas by the methods used in our studies, particularly single-view mammography. However, the wide range of observed growth rates and tumor sizes and probably measurement errors decreases the validity of this study.