onc brain

Individual patient data meta-analysis from the MARCAP Consortium, 12 eligible trials, 10,853 patients, median follow-up 11.4 years (IQR 9.0-15.0). Three intensification questions analyzed separately: ADT use, neoadjuvant ADT prolongation, adjuvant ADT prolongation.

Localized prostate cancer treated with definitive radiotherapy, stratified by NCCN prognostic risk group. The RT ± ADT comparison ran 2,557 control vs 2,579 experimental (NCCN high 32.6% vs 32.8%, intermediate 47.6% vs 48.7%); the adjuvant-prolongation comparison was high-risk enriched at 71.5% vs 71.1% NCCN high across 1,900 vs 1,874 pts.

Dose was analyzed as a binary ≥74 Gy vs <74 Gy split, with the companion HEAT analysis using 64 to <74 Gy vs ≥74 Gy and escalation up to 79.2 Gy. Brachytherapy boost is discussed as an escalation route alongside external-beam dose.

ADT addition improved MFS HR 0.83 (0.77-0.89) and OS HR 0.86 (0.80-0.92). Adjuvant prolongation improved MFS HR 0.84 (0.78-0.91) and OS HR 0.85 (0.78-0.94); neoadjuvant prolongation did neither (MFS HR 0.95, OS HR 0.95). 10-yr MFS 61% (59-63) with ADT vs 52% (50-54) without; 10-yr OS 65% (63-67) vs 57% (55-59).

The 2022 HEAT network meta-analysis (13 trials, 11,862 pts) found dose escalation improved biochemical RFS but not MFS or OS, and named high-dose RT plus long-term ADT the best strategy. PROG 05/09 and GETUG-18 are invoked to explain the gap: a 21% 5-year biochemical benefit in low risk where metastasis is rare, versus 3% in high risk where it is not.

The pooled trials span 30+ years of practice, so the RT technique behind the <74 Gy stratum is not the technique a reader delivers today. The stated optimal durations (closer to 12 months high risk, 24+ months very high risk) come from DHARMA, accepted but unpublished, so that specific number is not yet auditable.

The framing claim is that dose escalation and ADT are not interchangeable levers: escalation buys biochemical control, ADT buys metastasis-free and overall survival, and the two do not substitute. The dogma that dose escalation obviates ADT is named as widely repeated and never demonstrated.

IPD meta-analysis of randomised trials, large N, long f/u. Reinforces ADT intensification over dose escalation; no new randomisation, and duration guidance rests on unpublished DHARMA.

Randomized, non-blinded phase III, 1:1, N=698 (MH-IMRT 345, SBRT 353), stratified by Gleason score, PSA, and rectal manipulation. The trial's oncologic primary endpoint sits elsewhere; this analysis reports the patient-reported secondary endpoints.

Localized intermediate-risk prostate cancer, median age 68 (IMRT) and 69 (SBRT). Two patients were ineligible (one high-risk, one PSA out of window). Baseline EPIC domains were balanced across arms, all p≥0.093.

SBRT 36.25 Gy in 5 fractions delivered 2-3 per week, PTV expansion 5mm except 3mm posteriorly and anteriorly, PTV max capped at 38.78 Gy unless the urethra was visualized and contoured (acceptable variation 43.5 Gy). MH-IMRT 70 Gy/28 fx or 60 Gy/20 fx, PTV expansion 8mm except 5mm posteriorly. CTV was prostate ± 1cm proximal seminal vesicles. Rectal manipulation was common: SpaceOAR in 55% overall.

EPIC-26 at baseline, 12 and 24 months. MCID thresholds: >5 points urinary irritative/obstructive, >6 urinary incontinence, >10 sexual, >4 bowel and hormonal. Individual MCID rather than group mean scores was the analytic unit, with an exploratory longitudinal linear model adjusted for baseline score, arm, stratification factors, T-stage, age, and race.

The arm-level MCID and toxicity comparisons are tabulated above. Longitudinal modeling of urinary incontinence gave a least square mean difference of 2.91 (95% CI 0.85-4.97, p=0.0058) favoring SBRT, while sexual and hormonal domains showed no significant treatment effect.

Investigator-reported toxicity favored SBRT across the board: grade ≥3 GU 0.6% vs 2.5% (p=0.04), any-grade rectal hemorrhage 10.5% vs 17.3% (p=0.01), any-grade fatigue 39.2% vs 50.8% (p=0.0025). The GU finding is the one that most often runs the other way in ultrahypofractionation series, so it is worth reading as the trial's own answer to the pre-trial toxicity concern.

PACE-B is the other large randomized SBRT vs moderate hypofractionation comparison, and both trials show lower urinary incontinence decline with SBRT despite differing MCID definitions. Prior patient-level meta-analysis had suggested less clinically meaningful bowel and urinary irritative/obstructive decline at two years with SBRT, and the 1-year bowel result here is directionally consistent.

Differential attrition ran against the IMRT arm: 22 IMRT patients (6.4%) died or withdrew before year 1 versus 4 SBRT patients (1.1%), and 22 IMRT patients never received the assigned RT after withdrawal versus 1 in the SBRT arm. Completion was 79.9% (IMRT) and 84.0% (SBRT) at year 1. The domain-by-timepoint pattern (bowel and sexual at 1yr, incontinence at 2yr) is the kind of scattered significance that multiplicity should temper.

The trial was designed when the open question was whether five fractions cost the patient something. The PRO answer is that it does not, and the investigator-reported toxicity answer is that it may cost less. What the QoL data cannot do is settle whether SBRT is oncologically non-inferior, which is the primary endpoint and is not reported in this source.

Prespecified PRO secondary analysis of a phase III trial, non-blinded with patient-reported endpoints; aligns with PACE-B rather than establishing a new position. Oncologic primary endpoint not reported here.