All due respect, but it is relatively common knowledge that radiotherapy works for many months after it has been delivered. One must not conflate pCR, especially short term pCR, after radiotherapy as a surrogate for LC or residual tumor. This has been well demonstrated across many disease sites.
For reference, MISSILE cut at 10 weeks s/p RT while SABR-BRIDGE cut at 4.5 mo post-SBRT (range 2-17.5 mo).
Take anal cancer, for example. When biopsied at 3 months, if positive, 3/4 of patients with positive biopsy converted to negative biopsy by 6 months. Of course, the whole specimen was not removed, so there is a potential there could be "residual," but robust data supports very high cure rates in the long term (~85%, generally speaking) with CCRT alone for anal SqCC.
Receipt here:
pmc.ncbi.nlm.nih.gov/article…
Take prostate cancer, for example. Post treatment biopsies are essentially not recommended until two years after radiotherapy.
Receipt here:
pubmed.ncbi.nlm.nih.gov/3355…
Take RCC, for example, where routine post-treatment biopsy is not recommended as it is not predictive of patient outcome.
Receipt here:
pubmed.ncbi.nlm.nih.gov/3818…
So, why should lung cancer be any different? Similarly to RCC, if post-treatment biopsies after lung RT do not predict outcomes, is this meaningful to patients or multidisciplinary discussion? Radiotherapy can also induce cellular senescence, where the cell will no longer divide but can still make proteins at low levels. We must not perpetuate misinformation suggesting short-term pCR is predictive of patient outcomes after RT, as it harms existing biases against radiotherapy.
I have seen this fallacy posted repeatedly on X, so I felt it was time to address this head-on.
Unfortunately, MISSILE and SABR-BRIDGE didn't show the same w/ full pathology...clearly we need more research and effects may be tumor/site specific!