Retrospective analysis of risk of distant metastasis after organ preservation in rectal cancer

Organ preservation has become an attractive alternative to surgery (total mesorectal excision,TME) among patients with rectal cancer who achieve a clinical complete response (cCR) after neoadjuvant therapy. Nearly 30% of these patients will develop local regrowth (LR). Retrospective analysis of two prospectively maintained databases compared risks of distant metastasis (DM) between patients with LR after watch and wait and patients with near-complete pathologic response (nPCR) managed by TME at the time of reassessment of response. The DM rate was significantly higher among LR patients than among TME patient (22.8% versus 10.2%; p<0.001). Three-year DM-free survival was 75% versus 87% (p=0.001). When stratified for pathologic stage, patients with LR did significantly worse through all stages. The authors conclude that patients with LR appear to have a higher risk of subsequent DM than patients with nPCR managed by TME at restaging irrespective of final pathology. Leaving the primary undetectable tumor in situ until development of LR may result in worse oncologic outcomes.