Hodgkin’s Lymphoma Patients With Negative PET May Need No Further Treatment

Positron emission tomography after chemotherapy could help to guide further treatment decisions in patients with stage IA or IIA Hodgkin’s lymphoma

medwireNews: Early-stage Hodgkin’s lymphoma patients with a negative positron emission tomography (PET) scan after chemotherapy have a good prognosis with or without additional radiotherapy, research suggests.

“Although the noninferiority margin was exceeded in this study, the results suggest that radiotherapy can be avoided for patients with negative PET findings”, says the team led by John Radford, from the University of Manchester and the Christie NHS Foundation Trust in the UK.

A total of 571 patients with stage IA or IIA Hodgkin’s lymphoma underwent a PET scan after three cycles of chemotherapy with doxorubicin, bleomycin, vinblastine and dacarbazine in the phase III RAPID noninferiority trial. And those with negative PET findings were randomly assigned to either receive no further therapy or radiotherapy.

After a median follow-up of 60 months, disease progression occurred in 9.5% of the 211 patients in the no further treatment group and in 3.8% of the 209 participants in the radiotherapy group.

Four deaths – two each with and without disease progression – occurred in the no further treatment arm, while eight patients died in the radiotherapy arm, five following progressive disease and two without. The researchers point out that five of the deaths in the radiotherapy group occurred in participants who had not actually received radiotherapy, and that one death could be attributed to Hodgkin’s lymphoma.

Patients who did not and did receive further radiotherapy had a comparable 3-year progression-free survival rate, at 90.8% and 94.6%, respectively, giving an absolute risk difference of –3.8 percentage points. Although this was within the maximum allowable difference of 7 percentage points, the 95% confidence interval included a possible difference of up to 8.8 percentage points, leading to the trial failing to demonstrate noninferiority of the no further therapy strategy, explain the researchers.

“Nevertheless, the results of RAPID suggest a rationale for taking a more individualized approach to the treatment of early-stage Hodgkin’s lymphoma”, they say in The New England Journal of Medicine.

The authors emphasise, however, that a longer follow-up period is needed to assess whether this response-adapted approach “leads to fewer second cancers, less cardiovascular disease, and improved overall survival, as compared with a strategy incorporating radiotherapy for all patients.”

In an accompanying editorial, Dan Longo, deputy editor of the NEJM, and James Armitage, from the University of Nebraska Medical Center in Omaha, USA, note that both approaches work, and question whether such a small percentage-point difference in the relapse rate merits the added risk of radiotherapy-related toxic effects.

“Should 100 patients be exposed to radiation therapy to keep 4 from relapsing with no evidence of long-term survival benefit?”, they write, concluding that “[t]he patient should be involved in making that decision after being fully informed of the risks and the benefits.”

References

Radford J, Illidge T, Counsell N, et al. Results of a Trial of PET-Directed Therapy for Early-Stage Hodgkin’s Lymphoma. N Engl J Med 2015; 372: 1598–1607. doi:10.1056/NEJMoa1408648

Longo DL, Armitage JO. Controversies in the Treatment of Early-Stage Hodgkin’s Lymphoma. N Engl J Med 2015; 372: 1667–1669. doi:10.1056/NEJMe1502888

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