Discussion
tumor, colorectal cancer, ischemia, cancer, dehydration, anastomotic dehiscence, anastomotic, stoma, leaks, tumors
ANASTOMOTIC LEAKS, TUMOR, RECURRENCE, COLORECTAL CANCER, DISEASE PROGRESSION, POSTOPERATIVE COMPLICATIONS, ISCHEMIA, MINOR, CANCER, ANASTOMOTIC COMPLICATION, DEHYDRATION, TUMORS, RECTAL CANCER, COMPLICATIONS, ILEUS
This phase II multicenter North American trial is the most recent large prospective trial to confirm the procedural safety, favorable pathologic outcomes, and low rates of conversion achieved with taTME when performed by experienced surgeons using a 2-team hybrid approach. The 2% abdominal open conversion rate is consistent with the 0–5.1% conversion rates reported in large taTME series of patients, and was achieved despite a predominantly male cohort with the highest proportion of patients with BMI ≥ 30 reported to date (33%) and in whom 67% of tumors were located ≤ 6 cm from the AV [The primary endpoint of the trial was mesorectal TME grade, an important pathologic endpoint and strong predictor of local recurrence and disease-free survival that also serves as an accurate marker of surgical quality [There is a paucity of data regarding the impact of delayed time to TME following completion of NRT on TME grade, and this has not been described in prior taTME series or trials. The 2015 TIMING phase II trial assigned patients with locally advanced tumors into 4 groups treated with CRT: CRT followed by 2, 4, or 6 cycles of mFOLFOX6, effectively increasing the interval to TME by 6 up to 20 weeks [In the Spanish laparoscopic vs taTME RCT where a 0% rate of incomplete TME was reported in the taTME arm, a similar proportion of patients were treated with NRT (69.1% vs 69%) but the NRT-to-TME interval was not specified. The difference in rate of incomplete TME may reflect a higher level of technical difficulty during transanal dissection based on differences in median tumor height (8.0 cm vs 5.8 cm), and in the proportion of cases where ISR was performed (0% vs 36%) in the Spanish vs North American taTME cohorts, respectively [Regarding other pathologic endpoints, our 1.5% positive CRM and 1.5% positive DRM rates compare favorably with the 1.4–12.7% CRM and 0–2.5% DRM-positive rates published in large taTME series [This prospective trial is unique in that it provided extended capture of early and late postoperative complications following taTME, including outcomes of all anastomoses until primary stoma closure or permanent stoma creation. Overall, 71 complications among 49 patients and 82 complications among 56 patients were reported at 30 and 90 days, respectively, which is relatively high relative to other taTME publications; but the majority were minor, with severe (CD ≥ 3) complications only reported in 14 and 17 patients at 30 and 90 days, respectively. Ileus and stoma-related dehydration accounted for 35% of 30-day complications and 47% of readmissions, and were a direct consequence of loop ileostomy creation. Although published rates of diversion following sphincter-preserving taTME vary from 55.7 to 100% [Anastomotic complications accounted for 10% of the trial 30-day morbidity. Given the lack of agreement with standardized definitions and diagnostic criteria for anastomotic leaks, we opted to report all anastomotic complications identified and treated throughout the trial clinical follow-up period. This broader framework for reporting early and late anastomotic complications, which also incorporates stoma closure and non-closure rates, has been used by other groups when reporting outcomes of restorative proctectomy from large colorectal cancer registries, clinical trials, institutional series, and the international taTME registry [This trial highlighted emerging trends in the management of anastomotic complications among North American rectal cancer practices, including the use of transanal rescue approaches to manage early symptomatic and asymptomatic leaks, and anastomotic revision with coloanal anastomosis for refractory anastomotic complications that failed initial interventions. Among early anastomotic complications, given that all anastomoses had been diverted, some leaks were diagnosed in patients who were otherwise asymptomatic. One leak was suspected based on CRP elevation and another diagnosed on CT scan with rectal contrast performed to evaluate for possible early ileostomy closure. Whether symptomatic or not, early leaks were managed within 30 days with transanal repair attempted in 75% of reoperations. Early re-intervention led to resolution and ileostomy reversal in 80% patients with ≤ 1 additional re-intervention. All anastomotic complications diagnosed > 30 days postoperatively were managed with 0–1 major surgical intervention, and stoma reversal was achieved in all cases. Overall, 2 patients with anastomotic complications were converted to permanent colostomy due to colonic conduit ischemia and refractory anastomotic dehiscence in the setting of disease progression, respectively. There was no mortality related to anastomotic complications and 89% stoma-free rate was achieved at 2 years in patients with anastomotic complications. The trial’s overall 93% 1-year and 98% 2-year stoma reversal rates are higher than those in other trials that report long-term outcomes of sphincter-preserving TME with or without a primary fecal diversion [A limitation of the trial concerns strict inclusion and exclusion criteria for enrollment. Similar to the two recent RCT’s of lap vs taTME, cT3b tumors with predicted positive CRM, sphincter invasion or cT4 tumors on preoperative staging were excluded, even when downstaging was achieved with neoadjuvant treatment and restaging. While this was necessary in order to establish the feasibility and safety of taTME on a homogenous cohort of resectable cancer cases, our cohort does not entirely reflect current practice where taTME has become the preferred approach for tumors with incomplete response or tumor regrowth following neoadjuvant treatment. While ongoing RCTs will validate the long-term oncologic safety of taTME and evaluate functional results relative to laparoscopic TME, it will become important to understand the role that taTME plays in contemporary rectal cancer practices in the era of robotic surgery, TNT and an increased demand for sphincter preservation among young patients.