Minimally Invasive Approaches to Rectal Cancer and Diverticulitis

Abstract

Several advances have occurred in the field of colorectal surgery over the past 25 years, but 3 areas of noticeable progress relate to appreciating an anatomical operative approach to rectal cancer, understanding the natural course of diverticular disease, and adopting minimally invasive strategies for large bowel disorders such as colon cancer and ulcerative colitis.1,2 The high local recurrence rates customarily accepted after curative resection of rectal cancer were challenged when an association between the circumferential resection margin (CRM) and local recurrence was recognized. In the current era, careful sharp dissection within the anatomical planes leads to excision of an intact mesorectum with uninvolved margins and local recurrence rates as low as 5%.3 Similarly, recent evidence refutes historical dogma that maintained 2 episodes of uncomplicated diverticulitis warranted an elective operation, and peritonitis secondary to complicated disease requires a Hartmann procedure (ie, resection of perforated sigmoid colon, closure of distal bowel, and creation of colostomy). Surgeons now commonly counsel against an elective colectomy for recurrent uncomplicated diverticulitis and often perform urgent resection with diverted anastomosis for complicated disease with peritonitis.4 Just as knowledge has evolved, so has technology. More than half of elective operations performed for colorectal cancer at National Comprehensive Cancer Network centers from 20105 and for diverticulitis in the Nationwide Inpatient Sample database from 20096 were minimally invasive in their approach. In this issue of JAMA, 3 clinical trials7-9 focus on outcomes associated with minimally invasive operations for colorectal disorders. The studies by Fleshman et al7 and Stevenson et al8 describe results from randomized, multicenter clinical trials from North America (American College of Surgeons Oncology Group [ACOSOG] Z6051 trial) and Australasia (Australasian Laparoscopic Cancer of the Rectum Randomized Clinical Trial [AlaCaRT]), respectively, investigating the noninferiority of minimally invasive compared with open pelvic dissection for patients with rectal cancer. In both studies, only surgeons accredited after video review of relevant operations were allowed to participate, and the primary outcome was defined as the adequacy of surgical dissection as assessed by completeness of the total mesorectal excision (TME), uninvolved CRM, and uninvolved distal resection margin. The North American study included patients (N = 486) with clinical stage II or III rectal cancer treated with neoadjuvant therapy followed by minimally invasive (n = 240) or open (n = 222) proctectomy.7 The Australasian study enrolled patients (N = 475) with clinical stage I-III rectal cancer who underwent laparoscopic (n = 238) or open (n = 235) pelvic dissection; 50% received preoperative radiotherapy.8 The technical quality of surgery in both trials was high as demonstrated by few laparoscopic conversions, high sphincter preservation rates, and low rates of anastomotic leakage and other complications in these study groups that included high-risk overweight patients, the majority of whom were male. Likewise, the composite pathologic success rate based on meeting all 3 surgical dissection criteria was very high in the North American (84%) and Australasian (85%) trials. However, in both studies, the adequacy of surgical dissection tended to be lower in theminimally invasive group compared with the open resection group despite comparable low rates of distal margin involvement. The ACOSOG Z6051 trial reported an adequate composite surgical dissection in 82% of patients undergoing minimally invasive surgery and 87% undergoing open proctectomy (difference, −5.3%; 1-sided 95% CI, −10.8% to , P for noninferiority = .41). This difference did not meet the prespecified noninferiority margin of 6%. The ALaCaRT trial found the laparoscopic and open success rates to be 82% and 89% (difference, −7.0%; 1-sided 95% CI of −12.4% to ; P for noninferiority = .38). Similarly, this difference did not meet the prespecified noninferiority margin of 8%. Earlier randomized, multicenter trials from South Korea (COREAN trial)10 and Europe (COLOR II trial)11,12 included patients undergoing laparoscopic or open proctectomy for clinical stage II-III rectal cancer after neoadjuvant chemoradiotherapy and stage I-III rectal cancer, respectively. The COREAN trial demonstrated a complete or nearly complete TME in 92% and 88% (P = .55) of patients undergoing laparoscopic and open proctectomy, respectively, and an uninvolved CRM (>1 mm) in 97% and 96% (P = .77) of cases, respectively.10 The 3-year local recurrence rates were comparable at 2.6% for laparoscopic and 4.9% for open surgery, with similar disease-free and overall survival rates. Similarly, the COLOR II trial found a complete TME in 88% of laparoscopic and 92% of open resection cases (P = .25), an Related articles pages 1346, 1356 and 1364 Opinion