onc brain

The longer read

The central position here is not new. Trimodal therapy as a curative peer of radical cystectomy for select cT2-4aN0M0 muscle-invasive disease has driven the RTOG and NRG bladder-preservation program since the first TMT trials of the 1980s. What changes is who signs it. The task force included medical and urologic oncologists, ASCO, EAU and ESTRO sent representatives, and the final document carries an EAU endorsement. For a radiation oncologist whose TMT volume depends on the urologist in the room, a urology society backing a strong, high-QoE call for TMT as an alternative to RC matters more than the grade itself.

Read the strength and quality-of-evidence columns separately, because they diverge often. ASTRO's system lets a strong recommendation sit on low or expert-opinion evidence when the panel judges the benefit clear, and this guideline uses that latitude in the node-positive and neoadjuvant territory where practice is least settled. TMT or RC for cN1M0 after neoadjuvant therapy, neoadjuvant or induction systemic therapy before TMT for cT3-4 or N1-3 disease, and maximal TURBT are all strong calls on low QoE. The text concedes the neoadjuvant trials were not powered for small (5%) OS differences, and that most RT-treated pts in the key trial got no concurrent chemotherapy. The neoadjuvant recommendation is panel judgment extrapolated from trials where RT mostly ran without radiosensitization, not a tested TMT sequence.

The technique section is more interesting for what it declines to settle. Partial tumor boost keeps a strong endorsement even though both RCTs testing it against whole-bladder RT showed no statistically significant reduction in adverse events. The justification is failure pattern (most post-TMT recurrences arise at the original tumor site) plus bowel sparing in unfavorable anatomy, which is rationale rather than outcome. Elective pelvic nodal RT stays conditional because the comparative data conflict: an NCDB analysis found no OS advantage, a Canadian IPTW series found cancer-specific and OS benefit, and the one RCT that tried to answer it carries acknowledged concerns. The dose table puts 5500 cGy in 20 fractions level with 6400-6480 cGy in 32-36 fractions, both strong with high QoE, which ends any argument that the shorter course is a compromise in the bladder-alone case.

Two things could move this document before its first annual review. The first is the systemic partner. Perioperative chemo-immunotherapy and ADC-immunotherapy are entering care for pts going to RC, with no comparative TMT data, so the parity argument now rests on a surgical comparator whose systemic backbone is strengthening. If RC plus modern perioperative therapy pulls ahead and TMT cannot safely borrow the same agents, the alternative-to-RC framing weakens. SWOG/NRG 1806, adding atezolizumab to TMT chemoradiation, is the trial that tests whether it can. The caution about checkpoint inhibitors with moderately hypofractionated whole-pelvis chemoradiation or >400 cGy per fraction bites here, because the 20-fraction whole-pelvis option offered as an implementation remark is exactly that combination. The second is fractionation itself: NCT07097142 randomizes adaptive 5-fraction ultrahypofractionated RT against moderate hypofractionation, both with concurrent chemotherapy, and a positive result would rewrite the dose table this guideline just published.