Abstract: Eight RCTs, conducted between 1974 and 2011, and involving 2636 patients were included in this meta-analysis. All trials included therapy-naive patients. Rituximab was used in one trial only. Follow-up was between three and five years in most trials (range three to 18 years). All trials were published in peer-reviewed journals. Five trials compared similar chemotherapeutic regimens, except for the anthracycline. In three studies reporting overall survival specifically in FL patients, there was no statistically significant difference between ACR and non-ACR arms (HR 0.99; 95% CI 0.77 to 1.29; I2 = 0%). ACR significantly improved disease control (HR 0.65; 95% CI 0.52 to 0.81; four trials). Progression or relapse at three years were reduced (RR 0.73; 95% CI 0.63 to 0.85). Anthracyclines did not significantly increase rates of complete response (RR 1.05; 95% CI 0.94 to 1.18) or overall response (RR 1.06; 95% CI 1.00 to 1.12), but heterogeneity was substantial. Overall, ACR were more often associated with cytopenias, but not with serious infections or death related to chemotherapy. Cardiotoxicity, albeit rare, was associated with anthracycline use (RR 4.55; 95% CI 0.92 to 22.49; four trials). Three trials added anthracycline to one arm of two different regimens. None showed benefit to ACR regarding OS, yet there was a trend in favor of anthracyclines for disease control. Results were heterogeneous. We judged the overall quality of these trials as moderate as all are unblinded, some are outdated and are not uniform in outcome definitions. The use of anthracyclines in patients with FL has no demonstrable benefit on overall survival, although it may have been mitigated by the more intense regimens given in the control arms of three of five trials. ACR improved disease control, as measured by PFS and RD with an increased risk for side effects, notably cardiotoxicity. The current evidence on the added value of ACR in the management of FL is limited. Further studies involving immunotherapy during induction and maintenance may change conclusion.

Plain-language summary: We found eight randomized controlled trials, of which five compared similar chemotherapy regimens in both trial arms, except for the anthracycline. Even among these five trials, three included more intense chemotherapy in the control arm. Most trials were conducted in the 1980s and 1990s. Only one of them included rituximab as part of the chemotherapy regimen. Almost all patients were treatment-naive with advanced disease. Follow-up ranged between three and five years in most trials. The main results from this set of trials are. 1. There is no evidence that OS is prolonged with the use of anthracyclines, although it may have been hampered by the more intense regimens given in the control arms of three of five trials. 2. Anthracyclines improved disease control. Concordantly, less patients progressed or relapsed within three years of treatment with ACR. 3. There is no statistically significant difference in complete or overall response rates. 4. Qualitatively, more side effects were reported with ACR, myelotoxicity and cardiotoxicity included. This evidence is limited, mainly due to disparities in regimens between control and study arms, but also since most included trials were conducted over one to two decades ago, and only one employed rituximab. Importantly, results from this study were in agreement with pooled-outcomes from trials of the pre-rituximab era. It is essential to find the optimal chemotherapeutic regimen in conjunction with rituximab and other novel agents, and understand the role of anthracyclines in this combination, especially with current methods that are able to reduce their toxicity. With longer follow-up periods we may better understand whether improved disease control will eventually translate to an increase in survival.