Rectal cancer organ preservation: long-course chemoradiotherapy kept more patients free of surgery than short-course

Design

International, open-label, partially randomised phase 2/3 trial

Population

409 patients with rectal cancer up to 40 mm, mrT1-T3b N0

Primary outcome

12-month TME-free survival (interim implementation analysis)

Effect

78.5% LCCRT vs 60.6% SCRT; HR 1.90 (1.29 to 2.81)

STAR-TREC, an international phase 2/3 trial in The Lancet Oncology (August 2026), enrolled patients with small early to intermediate rectal cancers (up to 40 mm, mrT1-T3b N0). In a partially randomised design, those choosing organ preservation were randomised to long-course chemoradiotherapy (50 Gy with capecitabine) or short-course radiotherapy (25 Gy in five fractions), followed by response-adapted surveillance; others had primary total mesorectal excision (TME).

In 331 patients choosing organ preservation, 12-month TME-free survival was 78.5% with long-course chemoradiotherapy against 60.6% with short-course (HR 1.90, 95% CI 1.29 to 2.81). Grade 3-4 gastrointestinal serious adverse events were 2% and 4% with the two radiotherapy options and 8% with primary TME; one patient died after an anastomotic leak following TME.

These are 12-month results reported early on the monitoring committee's advice; the 30-month organ-preservation endpoint and oncological outcomes are awaited.

For patients with small rectal cancers who want to avoid major surgery, long-course chemoradiotherapy appears the more effective route to keeping the rectum.

• Discuss organ preservation with patients who have small, node-negative rectal cancers
• Where organ preservation is chosen, long-course chemoradiotherapy kept more patients surgery-free at 12 months than short-course
• Commit patients to intensive MRI and endoscopic surveillance if they choose organ preservation
• Explain that surgery may still be needed if response is incomplete or disease regrows

Why it matters

It gives the first randomised comparison of the two radiotherapy routes to avoiding rectal surgery.

Don't overread it

These are early 12-month results; long-term oncological safety of organ preservation is not yet shown.

The statistics, in plain English

The HR of 1.90 compares the rate of needing TME: short-course patients needed surgery at nearly twice the rate of long-course patients over 12 months.

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