Evaluating the risk of developing secondary cancer after treatment for follicular lymphoma

This study investigated the risk of developing secondary cancer in patients with follicular lymphoma (FL). This study concluded that this risk was low after first-line treatment, but increased with multiple lines of treatment.

Chemoimmunotherapy regimens involving rituximab (Rituxan) remain the standard of care for patients with FL. However, many patients eventually experience relapse (cancer recurrence). These patients then need more treatment. This can lead to developing secondary cancer years later.

Secondary cancers can be more aggressive, especially in patients with a prior history of cancer. Previous studies have suggested that the risk of developing secondary cancers may increase with more cycles of chemotherapy. The frequency of this complication in patients with FL remains under investigation.

This study had 1028 patients with FL. More than half (64.2%) of all patients had 1 line of treatment. 22.7% of patients had 2 lines of treatment, and 13.1% had 3 or more lines of treatment. Treatments included chemotherapy, radiation therapy, and stem cell transplantation. Patients were followed-up for an average of 67 months.

Overall, 96.7% of all patients were still alive 1 year later, with 89.5% not having tumor growth or spread. 5 years later, 84.2% of all patients were still alive, with 52.7% not having tumor growth or spread.

Overall, 14 patients were diagnosed with a secondary cancer. At an average of 62.5 months, this included 7 patients. 5 years after treatment, the risk of developing another cancer was 1.1% for all patients. At 10 years, this risk was 2.7%.

The risk of developing another cancer significantly increased with multiple lines of treatment. 5 years after first-line treatment, this risk was 0.5%. After second-line treatment, this risk was more than doubled (1.6%). At 10 years, this rate was 5.5%.

Overall, having 3 or more lines of treatment was significantly associated with a 5.0-fold higher risk.

For patients treated with chemotherapy containing anthracyclines, the risk of developing a second cancer was 1.3% (5 years later) and 3.7% (10 years later). This type of treatment was also significantly associated with a higher risk of developing acute myeloid leukemia (AML). This is a cancer of the bone marrow that can be difficult to treat.

This study concluded that the risk of patients with FL developing secondary cancer after first-line treatment was low. However, this risk increases with multiple lines of treatment. The authors suggest that low-risk patients may be treated with immunotherapy only to lower this risk.

This study was retrospective, meaning it looked back in time to analyze data. Data were collected from patient records. This may limit the conclusions that can be drawn from these results. More studies with a longer follow-up are needed to further evaluate the long-term complications of treatments for FL.