Watch it.

MSKCC reports the largest US case series to date (n=113) on watchful waiting in lieu of surgery for patients with a complete clinical response to neoadjuvant treatment for locally-advanced rectal cancer. Very much in line with a previously reported large Dutch national database, a local failure occurred in less than 20% at a median time within a year. All these patients underwent salvage surgery, typically 4-6 weeks from time of detection—11 via APR, 9 via LAR, and 2 with local excisions. This all translated to an organ preservation rate of 82% at a median follow-up of 3.5 years. Sounds great until reading on to see, when compared to institutional surgical controls with pathologic complete responses, 5-year rates of distant mets (8 vs 4%) and disease-specific survival (90 vs 98%) fell short of ideal. But this non-randomized series comes with some obvious selection bias: Not surprisingly, the watch and wait cohort was older at 67 versus 57 years and had lower tumors at 5.5 versus 7.5 cm from anal verge. TBL: There may be some degree of oncologic trade-off for rectal preservation in the form of slightly decreased distant control and survival, but this also may be solved with improved selection criteria. | Smith, JAMA Oncol 2019