KEY POINTS
- The propensity-score-weighted analysis included 1,568 patients with locally advanced rectal cancer and pathological nodal assessment after neoadjuvant treatment: 238 received chemoradiotherapy, 1,256 received conventional total neoadjuvant therapy, and 74 received immunotherapy-based TNT within the prospective TORCH trial.
- Chemoradiotherapy comprised 50 Gy in 25 fractions with concurrent capecitabine. The TNT cohort received long-course chemoradiotherapy plus oxaliplatin- or irinotecan-based consolidation, while immunotherapy-based TNT used 25 Gy in five fractions followed by six cycles of XELOX plus toripalimab 240 mg every three weeks.
- After inverse-probability weighting, residual node-positive disease occurred in 44.1% after chemoradiotherapy, 34.0% after TNT, and 13.4% after immunotherapy-based TNT. Corresponding ypN2 rates were 13.3%, 7.6%, and 3.3%.
- Among ypT0 tumours, weighted node-positive rates were 16.8% after chemoradiotherapy, 11.2% after TNT, and 0% after immunotherapy-based TNT. For ypT1 disease, the corresponding rates were 26.4%, 19.2%, and 0%, although the immunotherapy cohort contained only four ypT1 cases.
- Nodal disease was not eliminated when the residual primary tumour was more advanced. After immunotherapy-based TNT, weighted ypN-positive rates remained 24.0% for ypT2 and 40.5% for ypT3–4 disease.
- Within the immunotherapy cohort, ypT2 disease was associated with higher nodal risk (OR 20.45, 95% CI 1.04–402.15; p=0.008), as were ypT3–4 disease (OR 65.0, 95% CI 3.3–1,281.53; p<0.001), persistent mesorectal-fascia involvement, and extramural venous invasion. Baseline cT, cN, cMRF, and cEMVI were not significant.
- Only three near-complete responders in TORCH underwent local excision. Two remained recurrence-free at four years; one developed a solitary liver metastasis that was treated. The analysis excluded 48 clinical complete responders managed with watch-and-wait and provides no comparative long-term evidence for local excision versus total mesorectal excision.
CLINICAL TAKEAWAY
The absence of pathological nodal disease in ypT0–1 tumours provides a biological rationale for testing local excision after immunotherapy-based TNT in carefully selected near-complete responders. It does not yet establish local excision as safe: the relevant subgroup was small, treatment cohorts were non-contemporaneous, and long-term pelvic control remains unknown.