Relative survival of patients with follicular lymphoma achieving a complete response (CR) at 30 months following initiation of immunochemotherapy was 100% compared with a gender- and age-matched general population, a retrospective study published in the British Journal of Haematology has shown.

Follicular lymphoma is associated with high response rates to immunochemotherapy (eg, rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone [R-CHOP]), followed by disease relapse/progression of disease in most patients. Although newer, active treatments have become available for follicular lymphoma, their associated safety profiles make it particularly important that those patients with a lower likelihood of long-term overall survival (OS) with first-line immunochemotherapy are identified as potential candidates for subsequent treatment with these newer therapies.

This retrospective study included 2 cohorts of patients with follicular lymphoma, representing a training set and a validation set for comparison. The main study end point, CR at 30 months following initiation of first-line treatment with a rituximab-containing regimen, was chosen, in part, as a potential surrogate for progression-free survival (PFS) and OS because it generally approximates the duration of first-line induction therapy followed by 24 months of maintenance therapy.

Of the 263 patients with follicular lymphoma treated with rituximab-containing regimens between January 2004 and January 2014 at 2 cancer centers in Spain, 188 patients achieved CR at 30 months. Factors associated with this achievement included presentation with early-stage disease, no nodal involvement, no bulky disease, and a low-risk FLIPI score, as well as maintenance rituximab. Immunochemotherapy induction regimen was not a predictor of CR at 30 months. Although rituximab maintenance therapy was associated with an increased likelihood of achieving CR at 30 months, OS was lower in patients reaching CR during maintenance compared with the induction period. Median follow-up was 7 years.

Notably, compared with a gender- and age-matched general Spanish population, the decrease in life expectancy of patients with follicular lymphoma achieving CR at 30 months 0% vs 27% in those who did not achieve CR at 30 months (hazard ratio [HR] = 5.95; P <.00001). Similar results were also observed in an independent series of 693 rituximab-era patients with follicular lymphoma from the Spanish group of lymphoma and autologous stem cell transplantation (GELTAMO) cohort with a median follow-up of 6.7 years.

In commenting on these results, the authors wrote that “the most remarkable finding probably is not the difference in survival between early failures and maintained responders, but rather the huge magnitude of this difference.”

When accounting for confounding factors, only FLIPI score remained an independent predictor of OS in patients achieving CR at 30 months (HR = 6.45; P =.034).

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Study limitations noted by the authors included the relatively short follow-up periods which were constrained by including only those patients treated during the rituximab era.

“Future studies should be directed towards studying the biological profile of this group of patients with follicular lymphoma with good prognosis in order to allow for guidance on risk-adapted treatment strategies,” the authors concluded.

Reference

Magnano L, Alonso-Alvarez S, Alcoceba M, et al. Life expectancy of follicular lymphoma patients in complete response at 30 months is similar to that of the Spanish general population [published online February 22, 2019]. Br J Haematol. doi: 10.1111/bjh.15805