Rise in Therapy-Related Blood Cancers Among Survivors: Key Study Findings

A population-based study from Japan has identified a steady increase in cases of therapy-related acute myeloid leukemia (tAML), an aggressive form of blood and bone marrow cancer that develops following exposure to certain cancer treatments.

The research, published in the journal Cancer of the American Cancer Society, indicates that while life-saving chemotherapy and radiation therapies have significantly improved survival rates, they may also carry delayed risks that are becoming more visible as more patients live longer after their initial treatment.

Trends in tAML Incidence

Investigators analyzed data from the Osaka Cancer Registry for patients in Japan diagnosed with acute myeloid leukemia (AML) between 1990 and 2020. Out of 9,841 patients with AML, 636, or 6.5%, were found to have tAML.

The study observed a gradual rise in the annual incidence of the condition, which increased from 0.13 per 100,000 population in 1990 to 0.36 per 100,000 population in 2020. This represents a nearly threefold increase in incidence over the 30-year period.

the proportion of tAML cases relative to overall AML cases almost doubled during this timeframe.

Primary Cancers Linked to tAML

The study examined the types of primary cancers most commonly associated with the subsequent development of tAML. The most common primary cancer treated before tAML developed was another form of blood cancer, accounting for 23.1% of cases.

Other significant primary cancers included:

• Breast cancer: 14.6%
• Colorectal cancer: 11.5%
• Gastric cancer: 8.7%

Researchers noted a change in the distribution of these primary cancers over time, specifically observing a prominent increase in cases following breast cancer treatment and a decrease in those following gastric cancer treatment.

Clinical Implications and Risks

tAML is believed to occur due to damage caused to genetic material by radiation therapy or chemotherapy drugs. Because of this underlying DNA damage, tAML tends to be more difficult to treat than primary forms of leukemia and is often associated with poorer clinical outcomes.

The clinical relevance of therapy-related acute myeloid leukemia is increasing as the number of cancer survivors increases,

Kenji Kishimoto, lead author and researcher at the Osaka International Cancer Institute

The findings emphasize the necessity of long-term monitoring for cancer survivors. However, the study notes that the overall benefits of the primary cancer treatments still outweigh the risks of developing tAML.

The research provides a critical step in understanding how the nature of tAML is shifting as medical advancements allow more patients to survive their initial cancer diagnoses, thereby increasing the population susceptible to these delayed therapy-related complications.