Avoiding consolidation radiotherapy in advanced Hodgkin lymphoma with large nodes after ABVD chemotherapy

The study evaluated the impact of consolidation radiotherapy (cRT) on patients with advanced Hodgkin lymphoma (HL) who had large nodal mass (LNM) and currently in complete metabolic response (CMR) after receiving ABVD chemotherapy. The authors found that cRT could be safely avoided in such patients.

CMR defines the disappearance of cancerous metabolic abnormalities detected by positron emission tomography (PET) scan. Residual masses (RM) are lumps of tissues left after anti-cancer therapies. Recently, patients with HL who had PET-negative RMs after chemotherapy needed no further treatment. Whereas, RMs that tested positive on PET-scan required cRT.

ABVD is a combination of doxorubicin (Adriamycin), bleomycin (Blenoxane), vinblastine (Velban), and dacarbazine (DTIC-Dome). It is unclear whether cRT is truly needed for patients with advanced HL who previously had LNMs and are currently in CMR after receiving ABVD.

The study included 296 adult patients with advanced HL. They achieved CMR after undergoing 2 (PET-2) or 6 (PET-6) ABVD cycles. Lymph-node tumors with a diameter of 5cm or more were called LNMs. Patients had LNMs at baseline (before chemotherapy). 148 patients received cRT on LNMs and the rest 148 received no further treatment (control group). Patients were followed up for 5.9 years on average.

92% of patients on cRT and 90% with no further treatment survived for 6 years without cancer progression. 10 patients on cRT and 13 in the control group experienced progression or relapse. 6-year progression-free survival (PFS) rates were also similar under cRT or control among patients with different sizes of LNMs.

Overall survival (OS) rates for 6-years were 99% on cRT and 98% in the control group. Disease-free survival (DFS) defined the time from complete remission (CR) to relapse. CR means the absence of all cancer symptoms. The 6-year DFS rate was 94% for cRT and 91% for the control group

A total of 260 patients developed RMs after ABVD. Among them, the relapse rate for those treated with cRT was 7% compared to 9% in the control group. 

The study concluded that cRT caused no major improvements compared to no further treatment in patients with advanced HL with LNMs at baseline, who were in CMR after ABVD chemotherapy. 

This was the first study to show the lack of benefits of cRT in PET-negative patients after ABVD. Studies on larger populations may be needed to further prove it.