Age at breast cancer screening in women with intellectual disability.

Abstract

Dear Editors, Current guidelines for breast cancer screening in women with intellectual disability (WIDs) do not differ from those for women in the general population. However, research suggests that WIDs are younger and have more advanced disease at breast cancer diagnosis than women in the general population. Three studies conducted in France showed breast cancer appearing earlier (Table 1). A hospital survey in central France included 11 breast cancer cases in WIDs discovered at a mean age of 55.6 years, 7 years earlier than in the control cohort (62.4 years). Five of the 11 malignancies (45%) were discovered in women before the age of 50. The cases in WIDs however were at a more advanced stage than in the control cohort (American Joint Committee on Cancer: AJCC1, OR=3.2, p=0.010). A study including 1519 randomly selected institutions dedicated to disabled adults across the whole of France identified 13 breast cancer cases in WIDs (with age known). These were diagnosed at a mean age of 47.8 years, 15 years earlier than in the French population during the corresponding period, and eight (61%) were in women under 50 years at diagnosis. The third was a population-based study conducted in the south of France which analyzed breast cancers in 21 WIDs. The mean age at diagnosis was 7 years earlier (54.7 years vs 61.8 years) than for controls in the regional Cancer Registry. Seven tumors (33%) were diagnosed before 50 years of age. There was also a trend to greater tumor volume (more advanced T stage) (Jacot et al., article submitted). A literature search conducted by one of us (MN) on Japanese publication sources, using “Japan Medical Abstract Society” (ICHUSHI) which includes medical conference reports, with key words “breast cancer” and “intellectual disability” yielded five articles and abstracts published 2003–2018.Thefive Japanesewomen concerned were aged 38–61 (mean 46.6). According to the data of “Cancer Statistics”, Cancer Information Service, National Cancer Center, Japan (National Cancer Registry, Ministry of Health, Labor and Welfare)” in recent years (2016–2018), the mean age at diagnosis of female breast cancer in Japan is 62.4 years. Three of the five WIDs were younger than 50 years at diagnosis. In a US nationwide study of data collected during 2010, 384 breast cancers among 602 reproductive cancers in WIDs were treated almost seven years earlier, at a mean age of 61, compared to 67.8 years for women without intellectual disability. Mass screening is a precious opportunity to treat breast cancer early in WIDs. First, breast cancer which has a similar incidence compared to women in the general population is the most frequent malignancy in WIDs. Second, WIDs have greater risk factors such as being more frequently overweight or obese, less involved in physical exercise, more frequently nulliparous and rarely breast feeding. Third, many WIDs do not practice breast self-palpation and have difficulties expressing their pain and symptoms. Fourth, and importantly, breast cancer is discovered at a later stage in WIDs. The current age to begin breast cancer screening is 50 in most countries. Screening before this age has been considered less conclusive because breast cancer is less frequent before 50 in the general population. However, this may not be true for the particular subgroup of WIDs. Breast cancer diagnosis delay is associated with more advanced stages and lower survival. As life expectancy in WIDs is increasing, and as breast cancer incidence does not decrease after 50 years of age, a well-adapted surveillance strategy is urgently needed. We acknowledge that the current lack of data on absolute incidence of breast cancer in WIDs by age is a limitation of our message. This information should be established from large cohorts and different countries to evaluate if guidelines used for women in the general population are appropriate for this particular subgroup of vulnerable persons. Already, a greater breast awareness is necessary after the age of 40 years in this group of women.