Breast cancer continues to rise among younger women, US study finds

NEW YORK – Rates of breast cancer – the second leading cause of cancer deaths in US women – climbed 1 per cent a year from 2012 to 2021, and even more sharply among women younger than 50 and among Asian American/Pacific Islander women of all ages, according to an American Cancer Society report published on Oct 1.

The biennial report is among the most comprehensive and detailed studies of breast cancer occurrence over recent years. One in 50 US women will develop invasive breast cancer by age 50, the authors said, based on National Cancer Institute calculations.

The sharpest increases in young adults by age during the decade were among women in their 20s, whose rate increased about 2.2 per cent a year, though their absolute risk remains very low, at about 6.5 per 100,000 women.

Among Asian American/Pacific Islander women, who historically also have had a low prevalence of the disease, rates increased 2.7 per cent a year among those younger than 50 and 2.5 per cent a year among older women.

Cancer is generally considered a disease of ageing, and that has not changed: the vast majority of breast cancer cases and deaths still occur among older women. But the new study is one of several documenting a troubling uptick in malignancies among younger Americans.

These so-called early-onset cancers pose special challenges. Striking in early adulthood or midlife, they tend to be aggressive yet are often missed because they are not expected, and routine screenings are aimed at older adults.

In 2024, the US Preventive Services Task Force lowered the age for initiating mammography to 40 from 50, reversing an earlier decision to raise the screening age. The American Cancer Society recommends starting annual mammography screening at 45 for women at average risk, with the option of starting at 40.

Despite the rise in incidence, deaths from breast cancer have plunged, dropping about 10 per cent in the last decade and 44 per cent in the past three decades because of improved screening and treatments.

But the benefits have not accrued equally to all women, according to the report, which was published in CA: A Cancer Journal For Clinicians.

Survival rates did not change at all for Native American and Alaska Native women. Breast cancer continues to be the leading cause of cancer deaths among black women, who have a 38 per cent higher death rate than white women. NYTIMES