A study by the American Cancer Society has found that deaths from rectal cancer are increasing among younger adults in their 30s and 40s, a trend that researchers say is not fully understood. The study, published in the journal, found that colorectal cancers, once more common in older adults, are increasingly diagnosed in younger people and are often more advanced at detection. This trend could lead to rectal deaths surpassing those of colon cancer by 2035, according to the researchers. The reasons for this rise in younger adults are unclear. Researchers suggest possible links to diet, obesity, environmental exposures, and lifestyle factors as well as changes in the gut microbiome.