Small Number of Breast Cancers May Double in Size in 30 Days

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A large study looked at information on tumor size and growth from more than 400,000 women age 50 to 69 in Norway who were diagnosed with breast cancer. The scientists used a mathematical formula to estimate the growth of each breast cancer.

The researchers found that about 5% of the breast cancers grew very rapidly, doubling in size in just 1 month. Rapidly growing breast cancers were more likely to be found in younger women.

Slower growing breast cancers were more likely to be found in older women.

Mammograms, along with regular breast self-exams (BSE) and examinations by a medical professional, are the best ways to diagnose breast cancer early, when it's most treatable. Other research has shown that regular mammograms mean more women survive breast cancer. Still, some researchers and public health officials have suggested that annual mammograms should start later -- at age 50 instead of the current recommended age of 40 -- or that mammograms don't need to be done every year.

The results of this study show that a breast cancer can double in size in just 1 month in some women, especially younger women. These results are an important reason why current mammogram recommendations shouldn't change. These results also show how important it is for every woman age 40 and older to get a mammogram every year.

Visit the breastcancer.org Screening and Testing section to learn more about breast self-exam, mammograms, and other techniques used in breast cancer screening and diagnosis.

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