A few comments. I think 45Gy / 30 is great. Constraints are easier to meet, looks to works as well or better than conventional fractionation. Patients deserve to be offered this if interested. I serve a very rural and poor population as part of my practice and they are categorically unwilling to travel for BID, so I am left to utilize alternatives for those patients. Maybe your pitch is better than mine, but they have no means to temporarily live closer to clinic, no interest in hanging out for 6 hours each day, and no local support organizations that can resolve these issues.
For those patients willing to do BID, I'm just not sure I'm willing to make the jump to 60Gy yet. I made a provocative statement earlier about "dragging" patients in for this, as I wanted to see what the defenders had to say. Would love for the effect to be real, and maybe it is. The PFS/OS thing is strange though and I just can't fully explain it away with what has been said so far.
When I pore over this study, I feel like there are a lot of small imbalances in the study that start to stack up.
In the 45Gy arm, there are more patients >70, worse ECOG, more current smokers, more with >5% weight loss.
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I think this likely translated some to the treatment delivery side where you see less chemotherapy given, more dose reductions, more carbo given, and less people completing their radiation in the 45 Gy arm.
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And then in the survival curves, you had a fairly immediate separation in survival, again I surmise due to some of these imbalances manifesting well before the treatment effect would be likely to manifest.
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I think these imbalances undoubtedly magnified any benefit. Median survival in the 45Gy arm was 22.6 months, which compares unfavorably with CONVERT (30 months) and RTOG 0538 (29 months) (yeah yeah, cross trial comparison bad...). Also is a very small study at 170 pts and susceptible to a few outliers driving results. However, there does seem to be something going on here than can't be fully explained away either. Having had some time to think about it more, if a highly motivated healthier younger patient wanted to try it, I think there is enough there that I would be willing to discuss and perhaps include it as part of my standard initial consultation discussion. I can't say many of my small cell patients fit that bill, but always nice to have options as we attempt to maximize survival in a horrible disease. Ironically, these patients will be the most likely to have private insurance with higher probably of unpleasant evilcore interactions.
All this small cell talk probably needs another thread so we can keep appropriately gawking at radoncrocks twitter nonsense.