Lower-intensity radiation regimens for patients with early-stage Hodgkin lymphoma (HL) did not shorten progression-free survival (PFS), according to a long-term analysis. Further, for patients with unfavorable early-stage disease, a more intense chemotherapy or radiation regimen conferred no survival benefit.
The German Hodgkin Study Group included patients with early-stage HL who had both early-stage favorable HL and early-stage unfavorable HL. Stephanie Sasse, MD, and her study group colleagues published long-term follow-up findings from multiple trials, conducted from 1993 to 2003, that evaluated risk-adapted treatment strategies to reduce radiation field size and chemotherapy intensity, “aiming at achieving sufficient tumor control while potentially reducing treatment-associated toxicity,” wrote Dr. Sasse and her colleagues of the University Hospital of Cologne (Ger.) (J Clin Oncol. 2017 Apr 18. doi: JCO2016709410).
Trials in favorable HL
Of the 627 patients in the HD7 trial in patients with favorable HL, combined-modality therapy resulted in better rates of PFS (73%) over a 15-year period, compared with extended-field radiotherapy (RT) alone (52%) (hazard ratio, 0.5; 95% confidence interval, 0.3-0.6; P less than 0.001). Another study, called HD10, was in early-stage favorable HL patients. It compared a lower-intensity regimen of two cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) plus 20 Gy involved-field RT with a four-cycle ABVD regimen combined with 30 Gy involved-field RT. The 1,190-patient study achieved a median follow-up of 98 months, finding that the less-intense regimen was not inferior with an identical 10-year PFS of 87% in both arms (HR 1.0; 95% CI 0.6-1.5). Overall survival (OS) was nearly identical as well, at 94% in each arm (HR 0.9; 95% CI, 0.5-1.6).
Both trials HD7 and HD10 tracked the incidence of secondary neoplasias and detected no significant differences between groups, though there was a nonsignificant trend toward more secondary neoplasias for the HD7 patients who received extended-field radiotherapy. These analyses “strongly support the current risk-adapted treatment strategy in early-stage favorable HL,” wrote Dr. Sasse and her coinvestigators.
Trials in unfavorable HL
The HD8 trial enrolled 1,064 patients and followed them for a median 153 months to compare the efficacy of involved-field RT with extended-field RT, finding involved-field RT noninferior for PFS (HR, 1.0; 95% CI, 0.8-1.2). However, the overall 15-year PFS rate of 74% and OS rate of 82% “leave room for improvement,” said the investigators.
Finally, trial HD11 compared two different chemotherapy regimens and two different radiation doses. Patients received four cycles of either ABVD or bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, and prednisone at baseline dosage (BEACOPPbaseline), followed by 20 or 30 Gy involved-field RT. The study, which followed 1,395 patients for a median of 106 months, had a 2x2 factorial design.
Following the HD11 cohort longitudinally showed that BEACOPPbaseline did not confer a PFS advantage over ABVD for patients receiving the 30 Gy RT regimen (HR 1.1; 95% CI, 0.7-1.5). Nor did patients who received 20 Gy RT have significantly longer PFS with the more intense BEACOPPbaseline chemotherapy regimen (HR 0.8; 95% CI, 0.6-1.1).
Overall survival and the incidence of secondary neoplasias did not differ between trial arms in HD11, said Dr. Sasse and her coinvestigators.
To further explore whether more intense chemotherapy might result in better PFS rates for patients with early-stage unfavorable HL, Dr. Sasse and her colleagues are following long-term results from more recent trial, HD14, that combined two cycles of BEACOPPescalated and two cycles of ABVD. More short-term toxicity was seen, but patients in this trial arm have significantly better 5-year PFS rates than do those receiving four cycles of ABVD. “The improved tumor control is a relevant outcome parameter for patients,” wrote Dr. Sasse and her colleagues.
The investigators are reserving judgment about whether more radiation exposure and higher doses of alkylating agents and etoposide may eventually result in higher rates of secondary neoplasms. “Subsequent analyses with even longer follow-up will have to confirm that the reduction of RT field size or dose indeed translates into a reduced risk of [secondary neoplasms],” they wrote.
Several of the authors reported multiple relationships with pharmaceutical companies. The study was funded by a grant from the German Cancer Aid.
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