For patients with rectal cancer, the prospect of avoiding total surgical removal of the rectum — and the lifelong functional consequences that follow — has long been a clinical priority. The STAR-TREC trial offers the most rigorous comparative data yet on whether a compressed, five-fraction radiation regimen can match the organ-preservation rates achieved by the longer standard chemoradiotherapy approach, without sacrificing cancer control.
This international phase 2/3 trial enrolled patients across five European countries with early-to-intermediate rectal adenocarcinoma (tumors ≤40 mm, staged mrT1–T3bN0, ECOG 0–1). In the phase 2 component, participants were randomized 1:1:1 among long-course chemoradiotherapy-based organ preservation (LCCRT-OP: 50 Gy in 25 fractions plus capecitabine 825 mg/m² twice daily), short-course radiotherapy-based organ preservation (SCRT-OP: 25 Gy in five fractions), or primary total mesorectal excision (TME). Phase 3 shifted to a partially randomized patient-preference design, allowing participants to self-select organ preservation versus TME, with those choosing preservation then randomized between the two radiotherapy arms. The primary feasibility endpoints — recruitment thresholds at 12 and 24 months — were met, validating the trial's design for the larger phase 3 comparison.
The STAR-TREC findings are noteworthy for several reasons beyond their immediate clinical scope. The "watch-and-wait" paradigm for rectal cancer has gathered momentum since Habr-Gama's landmark Brazilian cohort work, but comparative data between radiation schedules in a randomized setting have been sparse. SCRT's logistical advantages — fewer hospital visits, lower patient burden, reduced healthcare cost — make it an attractive alternative if oncological equivalence holds at longer follow-up. The 12-month data presented here represent an interim window; definitive organ-preservation and disease-free survival rates will require the full phase 3 analysis. Key limitations include the open-label design, heterogeneous national treatment cultures across five countries, and the patient-preference element in phase 3 introducing potential selection bias. This trial is best characterized as confirmatory of feasibility and directionally promising — paradigm-shifting conclusions await mature survival data.