Adults under age 50 have been developing breast cancer and colorectal cancer at increasingly higher rates over the last six decades, and alcohol use may be one factor driving the trend, according to a scientific report published on Wednesday.

The report, by the American Association for Cancer Research, highlights scientific breakthroughs that have led to new anticancer drugs and improved overall survival.

But the authors also described a troubling pattern: Even as cancer death rates have declined, the overall incidence of several cancers has been rising inexplicably, with an especially alarming increase among younger adults in cancers of the gastrointestinal system, like colorectal cancer.

The report estimates that 40 percent of all cancer cases are associated with modifiable risk factors. It recommends reducing alcohol consumption, along with making lifestyle changes such as avoiding tobacco, maintaining a healthy diet and weight, exercising, avoiding ultraviolet radiation and minimizing exposure to pollutants.

The authors called for raising awareness through public messaging campaigns and adding cancer-specific warning labels to alcoholic beverages.

The recommendations come amid a radical rethinking of the putative health benefits of moderate alcohol consumption, which for years was considered to be protective against heart disease.