A review of chemotherapy alone or chemotherapy plus radiation therapy to treat adult patients with Hodgkin lymphoma

This paper is a review of the effectiveness of chemotherapy alone or chemotherapy plus radiotherapy for treating adult patients with early stage Hodgkin lymphoma. The review concluded that, for the same chemotherapy regimen, RT may increase progression free survival, but has little effect on overall survival for patients.

Hodgkin lymphoma (HL) is largely considered a curable disease. However, some treatment has been linked to future negative outcomes. One of these treatments is radiotherapy (RT). RT can potentially cause secondary cancers or heart problems many years after the completion of HL treatment. Modern treatment research focuses on reducing the intensity of treatment while also curing the patient. It is important to make sure that the patient is cured of HL but also has a low risk of later negative effects. A comprehensive review of chemotherapy (chemo) alone or chemotherapy plus RT is needed.

Seven randomized controlled trials (RCTs) were included in this review. 2,564 patients participated in the trials. Each trial compared chemo alone to chemo plus RT. Some trials used the same chemo regimen in both parts and others used different chemo regimens for chemo alone or chemo plus RT.

Five trials used the same regimen in both chemo alone and chemo plus RT. 1388 patients were involved in these trials. Overall there was no difference in overall survival (OS, time from treatment until death from any cause). The odds of longer progression-free survival (PFS, time from treatment until disease progression) were significantly higher (58%) with chemo plus RT. When two studies that were thought to have some bias were removed from the analysis, including RT significantly increased the OS. In these three trials, patients who received RT had a 69% lower risk of death. 

Two trials used different numbers of chemo cycles in the chemo alone group versus the chemo plus RT group. 1176 patients were involved in these trials. Patients who received chemo alone were given more cycles. One trial found that chemo alone increased OS compared to chemo plus RT. Patients were twice as likely to have a longer OS if they received more cycles of chemo alone. The other trial found no difference between chemo alone and chemo plus RT for many outcomes, including PFS and future negative outcomes. 

The review concluded that RT may increase progression free survival, but has little effect on overall survival for patients treated with the same chemotherapy regimen. 

There were too few studies that compared the chemo alone vs chemo plus RT with different cycles of chemo. Conclusions about overall survival and progression free survival could not be made.