www.thelancet.com/oncology Vol 20 February 2019 189 Perspectives Declaration of interests ER and ROP declare no competing interests For more on the Brazilian experience on watch-and-wait see Ann Surg 2004; 240: 711–18 For more on the meta-analysis on watch-and-wait see Articles Lancet Gastroenterol Hepatol 2017; 2: 501–13 For more on salvage surgery after watch-and-wait see Dis Colon Rectum 2017; 60: 335–45 For more on organ preservation for rectal cancer see Articles Lancet 2017; 390: 469–79 For more on mortality after total mesorectal excision see Dis Colon Rectum 2015; 58: 159–71 For more on the International Watch-and-Wait study see Lancet Articles 2018; 391: 2537–45 For more on the pooled analysis see Ann Surg 2018; 268: 955–67 Opening opinion: Surgery Eric Rullier Department of Colorectal Surgery, Haut-Lévèque Hospital, Pessac, France; University of Bordeaux, Bordeaux, France eric.rullier@chu-bordeaux.fr Chemoradiotherapy followed by total mesorectal excision is the standard of care in rectal cancer. Watch-and-wait was first tested by a Brazilian team, who showed a complete clinical response in a subgroup of patients treated with chemoradiotherapy for rectal cancer. After 57 months follow-up, 5-year overall survival and disease-free survival did not differ between patients with complete pathological tumour response treated by total mesorectal excision or watch-and-wait. The first meta-analysis on studies of patients with rectal adenocarcinoma managed by watch- and-wait after complete clinical response to neoadjuvant chemoradiation includes mainly retrospective studies (19 [83%] of 23) with a few patients (15 studies had data for less than 30 patients). The pioneers of watch-and-wait must be congratulated for pushing surgeons to improve the quality of life of some patients with rectal cancer who can avoid surgery. Although there is no doubt that watch- and-wait will be part of the future management of patients with rectal cancer, the literature shows that treatment without surgery cannot be recommended as a new standard of care in this setting in 2018. The first limitation of a watch-and-wait approach is the absence of a correlation between complete clinical response, assessed by clinical, endoscopic, or radiological examinations, and pathological complete response, which explains local recurrence in 16–28% of patients after chemoradiotherapy due to the heterogeneity of responders, many of whom present with residual scars formed mainly by fibrotic tissue and a low concentration of tumour cells that can only be detected by histology. The second limitation of a watch-and-wait approach is relying on salvage surgery, required in a third of patients who did not have upfront surgery. Although salvage surgery has been reported as feasible in 80–90% of these cases, local recurrence occurs more frequently after salvage than upfront surgery (three [3%] of 98 vs 0 of 136 patients; p=0·04). Regarding other endpoints, the meta-analysis showed that disease-free survival improved with surgery compared with watch-and-wait, but there was no difference in terms of recurrence and cancer- specific mortality. However, the small number of patients included in this analysis warrants cautious interpretation. To date, there are no data on morbidity and functional outcomes after salvage surgery, however definitive colostomy is required in 50% of patients who undergo salvage surgery. The third limitation of watch-and-wait is the absence of prospective evidence regarding this approach. There is no standardisation in patient selection, neoadjuvant therapy regimen, diagnostic technique for clinical response assessment, definition of local recurrence, and follow-up protocols. The meta-analysis shows that most patients selected for watch-and-wait were treated for locally advanced tumours (67% had T3 rectal tumours) and watch-and-wait was incidentally chosen due to high-risk characteristics or patient’s refusal to surgery. Considering patients with localised disease, eligible for organ preservation as an alternative to total mesorectal excision, surgery might achieve better outcomes than observation after neoadjuvant treatment. The GRECCAR 2 trial randomly assigned patients with stage T2T3 lower rectal tumours, of maximum size 4 cm, who had a good clinical response to neoadjuvant chemoradiotherapy (residual tumour ≤2 cm) to local excision (n=74) or total mesorectal excision (n=71). As per protocol, a third of patients with pT2 or pT3 stage tumours in the local excision group received a completion total mesorectal excision due to the theoretical risk of lymph node micrometastases. The high frequency of side effects observed in the local excision group, mainly due to the high crossover to total mesorectal excision, did not permit to demonstrate the benefit of local excision compared to total mesorectal excision. However, the fact that completion total mesorectal excision was not necessary in 90% of cases because only 8% of patients had positive lymph nodes suggests good disease control with local Spotlight Surgery or a watch-and-wait approach for rectal cancer? Science Photo Library