Deadly rare cancer impacting young adults at escalating rates
In this DML Report…
Invasive lobular carcinoma (ILC), a rare but deadly type of breast cancer accounting for over 10 percent of all cases, grows in dispersed patterns that evade detection by traditional mammograms and physical exams, leading to challenges in early identification and treatment. Between 2012 and 2021, ILC incidence rose at an average annual rate of 2.8 percent in women aged 50 and older and 2.9 percent in those under 50, outpacing the 0.8 percent increase for all other breast cancers combined; from 2016 to 2021, the rise accelerated to 3.4 percent annually across all age groups. This uniform trend across demographics contrasts with other breast cancers that vary more by age. The disease spreads differently, often later and to unusual sites, without being inherently more aggressive in metastasis but complicating management.
Racial disparities show the steepest ILC increase among Asian American/Pacific Islander women at 4.4 percent per year, while White women maintain the highest overall rate of nearly 15 cases per 100,000, compared to 11 per 100,000 for Black women and about seven for AAPI women, with risks peaking between ages 70-79. Survival rates match other breast cancers at five years but decline long-term, with a 10-year rate of 12.1 percent for distant-stage ILC versus 19.6 percent for ductal carcinoma; beyond seven years, ILC outcomes are significantly worse, and early-stage advantages fade over time. Hormonal and lifestyle factors drive the surge, including excess body weight, earlier menarche, fewer or later births, later menopause, and rising alcohol use, all extending estrogen exposure; unlike other types, ILC links more strongly to hormone therapy, as evidenced by case drops post-menopausal use decline.
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Lead researcher Angela Giaquinto of the American Cancer Society noted, “Although lobular breast cancer accounts for a little over 10 percent of all breast cancers, the sheer number of new diagnoses each year makes this disease important to understand,” and emphasized, “survival rates beyond seven years are significantly lower for lobular breast cancer than the most common type, highlighting the pressing need for prevention and early detection strategies.” Senior researcher Rebecca Siegel added, “Invasive lobular breast cancer is very understudied... at 10 years, these women with metastatic disease are half as likely to be alive as their counterparts with ductal cancer, probably because of the unique spread and resistance to therapy,” calling for more genetic studies and clinical trials. The study, published in Cancer, analyzed national data using specialized software to compare ILC trends, characteristics, and survival against ductal cancers from 2007-2021, urging targeted research due to ILC's detection difficulties and chemotherapy resistance.