Abstract
Background: cancers are as common in individuals with intellectual disabilities as in the general population (GP). For the subgroup of people with profound and multiple disabilities (PMD) who present with both severe intellectual disability and major motor disorders, the frequency and distribution of cancers are currently not known, preventing proper cancer surveillance. Methods: we carried out a systematic and synthetic review of the medical literature, including a focused search of Japanese data. Results: the total risk of cancer in individuals with PMD is thought to be lower than in the GP, possibly due to a shorter life expectancy. They have reduced exposure to cancer risk factors, such as alcohol, tobacco, sunlight, human papillomavirus infection, occupational toxins, and being overweight. On the other hand, individuals with PMD present a greater frequency of gastroesophageal reflux disease, Helicobacter pylori gastritis, chronic cystitis, and cryptorchidism, which increase the risk for cancer of the esophagus, stomach, urinary bladder, and testes. In addition, certain genetic disorders underlying compromised motor and cognitive functions are associated with higher risk of childhood cancers. An analysis of 135 cancers in persons with PMD in Japan suggested that they present a particular tumor profile, with certain cancers rarer than in the GP, whereas cancers of the digestive tract are frequent. Cancers of the digestive tract occurred significantly earlier than in the GP (colon: average age 48.3 years vs. 71.3 years in the GP, esophagus: 39 years vs. 72 years in the GP). An increasing number of therapeutic successes in children and adults with PMD have been reported in different countries when cancers are discovered early. Conclusion: individuals with PMD must be appropriately monitored for cancer. Screenings for breast and colon cancer, as well as regular monitoring of the esophagus, stomach, urinary bladder, and testicles, are necessary. Population-based epidemiological studies are needed to better understand risk factors, frequency, and distribution of cancers in the PMD population.