Top Line: Is there enough data to choose something other than 45 Gy in 30 BID fractions or 66 Gy in 33 daily fractions for locally advanced small cell lung cancer (LA-SCLC)?
The Study: We’ve previously seen two randomized phase II trials that found potential improvement in treatment outcomes with either a) 60 Gy in 40 fractions BID or b) 65 Gy in 26 daily fractions. The studies are intriguing and even made the NCCN guidelines, but are they sufficient to implement in routine practice? Enter this recent Oncology Scan from the Red Journal where a group of experts reviewed and weighed in on the topic. What were their takeaways? With respect to the 65 Gy / 26 hypofractionation trial, improved tumor control and PFS were intriguing, but they felt the numbers were too small to declare this regimen a new standard. With respect to the 60 Gy / 40 trial, the improvement in overall survival (a whopping 48→ 74% at 2 years) without corresponding improvement in the rate of disease progression (63% v 64%) or PFS (median 18.6 v 10.9 months) or local control and no increase in toxicity were a little conspicuous. On the one hand, dose escalation using BID fractionation makes sense when the standard is BID treatment, and this trial showed a clear improvement in overall survival. Would Pharma be so critical of a positive survival outcome? On the other hand, many feel that combination of outcomes might be too good to be true. Ultimately, this review concluded that we need larger and more solid data to stand on before moving away from the standard 45 Gy in 30 BID fractions or the real-world “standard” of 66-70 Gy in 33-35 fractions. At the same time, they stoke enthusiasm for larger trials exploring accelerated fractionation as a means of improving outcomes for LA-SCLC.
TBL: Much of the discussion surrounding dose-escalated BID fractionation and hypofractionation for LA-SCLC seems to favor waiting for larger trials before routinely employing these regimens in standard practice. | Robinson, Int J Radiat Oncol Biol Phys 2022