Life-saving cancer treatments may, in some cases, lead to long-term complications, a population-based study from Japan has found, pointing to a steady increase in therapy-related acute myeloid leukemia (tAML). Therapy-related acute myeloid leukemia is an aggressive cancer of the blood and bone marrow that develops after exposure to certain cancer treatments. It is believed to occur due to damage to genetic material caused by chemotherapy drugs or radiation therapy. Although relatively uncommon, it tends to be more difficult to treat than primary forms of leukemia and is often associated with poorer outcomes.
The rise is particularly noticeable among patients who had earlier undergone treatment for cancers such as breast cancer, noted the study, published in the journal Cancer of the American Cancer Society. This highlights a growing concern in oncology as survival rates improve and more patients live longer after treatment. While advances in chemotherapy and radiation have significantly improved outcomes, they may also carry delayed risks that are only now becoming more visible.
“The clinical relevance of therapy-related acute myeloid leukemia is increasing as the number of cancer survivors increases,” said lead author Kenji Kishimoto of the Osaka International Cancer Institute. The study, he added, aimed to examine how the incidence and patterns of this condition have changed over a 30-year period.
To understand long-term trends, researchers analysed data from the Osaka Cancer Registry, focusing on patients diagnosed with acute myeloid leukemia between 1990 and 2020. The dataset included 9,841 patients, of whom 636 — or about 6.5% — were identified as having therapy-related disease.
The study found a clear increase in incidence over time. The annual rate of tAML rose from 0.13 per 100,000 population in 1990 to 0.36 per 100,000 in 2020. In addition, the proportion of therapy-related cases among all acute myeloid leukemia diagnoses nearly doubled during the study period, indicating a gradual but consistent shift.
Experts said this rise must be understood in the context of improved cancer care. With better screening, earlier diagnosis, and more effective treatment, survival rates have increased across many cancers. As a result, more patients are living long enough for late complications, including secondary cancers, to emerge.
The study also examined the types of primary cancers most commonly associated with tAML. Blood-related cancers accounted for the largest share, followed by breast cancer, colorectal cancer, and gastric cancer. Together, these conditions made up a significant proportion of cases where therapy-related leukemia developed.
Interestingly, the pattern has changed over time. Cases of tAML following breast cancer treatment have shown a noticeable increase, while those linked to gastric cancer have declined. Researchers suggest that this shift may reflect changes in treatment approaches, differences in survival rates, and evolving patterns in cancer incidence.
The findings underline the importance of long-term monitoring in cancer care. Patients who have undergone chemotherapy or radiation may benefit from periodic follow-up, even years after completing treatment. Early detection of secondary complications can help improve outcomes and guide timely intervention.
At the same time, experts have emphasised that these findings should not discourage patients from undergoing recommended cancer therapies. The benefits of treatment — including improved survival and quality of life — continue to outweigh the risks in the vast majority of cases. Instead, the study highlights the need for more personalised approaches that balance effectiveness with long-term safety.
There is also growing interest in developing treatment strategies that minimise long-term harm. This includes refining drug regimens, reducing unnecessary exposure to radiation, and improving risk assessment for individual patients. Advances in precision medicine may play a key role in achieving this balance, said the researchers.
