Rates of secondary blood-related cancers that develop due to chemotherapy or radiation may be rising

Some therapies used to treat cancer may increase the risk of later developing cancers that affect the blood. A population-based study in Japan has revealed a gradual increase in the rates of therapy-related acute myeloid leukemia (tAML) in recent years, especially after breast cancer treatment. The findings are published in Cancer.

tAML is an aggressive cancer of the blood and bone marrow that develops after prior chemotherapy or radiation for an earlier, primary cancer, likely arising in part due to DNA damage from these treatments. To assess whether tAML is increasing as a post-cancer therapy complication as the number of cancer survivors increases, investigators analyzed data from the Osaka Cancer Registry pertaining to patients in Japan who were diagnosed with AML between 1990 and 2020.

Among 9,841 patients with AML, 636 (6.5%) had tAML. The annual tAML incidence increased from 0.13 per 100,000 population in 1990 to 0.36 per 100,000 population in 2020. The proportion of tAML cases in overall AML cases almost doubled.

The most common primary cancer that was treated before tAML developed was another form of blood cancer (23.1%), followed by breast cancer (14.6%), colorectal cancer (11.5%), and gastric cancer (8.7%). The distribution of primary cancers changed over time, with a prominent increase in breast cancer and a decrease in gastric cancer.

“The study provides an important step toward better understanding how the nature of tAML is changing with the increasing number of cancer survivors,” said lead author Kenji Kishimoto, MD, Ph.D., of the Osaka International Cancer Institute.