May 9, 2008 -- Breast cancers tend to grow faster in younger women, Norwegian researchers report.
On average, breast cancer tumors took 1.7 years to double in diameter from 10 millimeters (mm) to 20 mm.
Breast cancer growth rate varied widely. The fastest-growing tumors, which made up 5% of the tumors studied, doubled in diameter from 10-20 mm in about a month. The slowest-growing tumors, which accounted for another 5% of the tumors, took roughly six years to reach that size.
Age mattered, "with faster growth among younger women," write the researchers, who included Harald Weedon-Fekjaer of the Cancer Registry of Norway.