Occurrence of new cancers after rituximab treatment for patients with diffuse large B-cell lymphoma

The authors examined whether rituximab was associated with the development of a second cancer after treatment for diffuse large B-cell lymphoma. The authors concluded that the number of patients with certain cancers has increased after rituximab was introduced.

Diffuse large B-cell lymphoma (DLBCL) is a very common type of non-Hodgkin lymphoma. It was difficult to treat before the late 1990s when rituximab was introduced. It led to a 30% decrease in death in patients with DLBCL. Rituximab is a form of biological treatment that targets CD20 antibodies on cancer cells. This allows the immune system to attack the cancer cell.

Now that DLBCL patients are living longer, it is important to look at long term outcomes. More research is needed on the effect rituximab has on the development of new cancers.

This study looks at the rate and type of new cancers occurring in patients with DLBCL. The medical records of 23,879 patients were reviewed. The patients were split into those who received treatment before 2001 (pre-rituximab) and those who received treatment in 2001 or later (post-rituximab). The average length of follow-up was 3.6 years pre-rituximab and 4.5 years post-rituximab.

Overall, there was a slight but significant increase in the occurrence of new cancers in the post-rituximab era. Pre-rituximab, 9.67% of patients were diagnosed with a new cancer 10 years after being treated for DLBCL. Post-rituximab, 10.47% of patients were diagnosed with a new cancer 10 years after being treated for DLBCL.

Thyroid cancers were much more common in patients treated in the post-rituximab era (after 2001). Acute myeloid leukemia was twice as common in patients treated after 2001. The occurrence of melanoma was also slightly increased in patients who were treated after 2001. 

The study concluded that the rate of certain cancers has increased after the introduction of rituximab as a treatment of DLBCL.

This research did not take into account other cancer risk factors, such as smoking, or other treatments received by the patients. Future research needs to take these factors into account.

Discuss with your doctor the benefits and risks associated with rituximab treatment, as well as appropriate cancer screening.