Extended Perineal Resection of Distal Rectal Cancers: Surgical Advance, Increased Utilization of Neoadjuvant Therapies, Proper Patient Selection or All of the Above?

Abstract

With the introduction of improved surgical techniques such as total mesorectal excision and autonomic nerve preservation during the last two decades, a corresponding decrease in local recurrence rates and increase in overall survival of patients with rectal cancer has been observed. Despite the broad implementation of these techniques, local recurrence and survival after an abdominoperineal resection (APR) have not improved to the same degree as that seen after an anterior resection. This difference has been attributed, in part, to relative smaller tissue volumes around the tumor and higher rates of cancer at circumferential resection margins (CRM) after an APR compared with an anterior resection. Because of this, a number of investigators have called for a change in the technical approach of the APR. Since the late 1990s, surgeons at the Karolinska University Hospital have used an extended posterior perineal approach with gluteus maximus flap reconstruction of the pelvic floor in patients with extensive primary or locally recurrent rectal cancer infiltrating the pelvic floor or with coccygeal or sacral involvement. In the retrospective review by West et al in this issue of Journal of Clinical Oncology, standard APR specimens are compared with those obtained with a cylindrical approach. Specifically, they compare the amount of tissue removed around potentially curable primary rectal adenocarcinomas as well as rates of CRM and intraoperative perforations. In addition, an effort is made to document the impact of such a change in surgical approach on a single surgeon’s practice. The authors must be commended for their long-standing efforts and contributions addressing the importance of surgical technique and pathologic assessment of adequacy of the resected specimen. In this article, the authors report the superiority of the cylindrical relative to the standard APR approach in terms of CRM and perforation rates. We agree with their final concluding sentence: “Use of this operation in combination with new preoperative neoadjuvant therapies should further improve results without the risk of increasing perforation rates.” However, we would add that the incorporation of a more extensive APR approach to the surgical armamentarium will necessitate further emphasis on the need for improved patient selection, given that it is not clear whether all distal rectal adenocarcinomas requiring an APR will benefit from a cylindrical approach as much as from preoperative neoadjuvant therapies. Though the authors demonstrate an apparent superiority of the cylindrical APR approach, their analysis should be interpreted with caution. It is retrospective and based on a small sample size, especially for the cylindrical group, with just 27 combined reported experiences between the two institutions. Therefore, due to the small sample size, statistically significant differences cannot be detected among patients undergoing a standard and a cylindrical APR, but it appears that there is a trend toward more preoperative therapy utilization (97% v 67%) and less stage III disease (30% v 43%) in the cylindrical group compared with the standard APR group. Would the results, therefore, have been the same if the rate of preoperative therapy had been similar between both surgical approaches? Similarly, although the authors demonstrate that a highly experienced, senior surgeon can learn and adopt the cylindrical APR approach, the data do not fully support their conclusion “that adoption of the cylindrical technique can lead to an immediate improvement in CRM positivity and perforation rates for an individual surgeon.” First, this conclusion is based on a single surgeon’s experience with only eight patients who were treated with the cylindrical approach. Second, it is unclear how many of these patients received preoperative chemoradiotherapy. Was the rate of preoperative chemoradiotherapy use similar between the standard APR and cylindrical APR groups? The data from Table 1 in West et al suggest that preoperative therapy was used much more frequently in the cylindrical than in the standard APR group. Furthermore, given that the Leeds group adopted the Karolinska approach in 2005, is it possible that—in addition to performing a cylindrical APR—they also began to use preoperative chemoradiotherapy more liberally? The Karolinska standard practice has been to use neoadjuvant radiation or chemoradiotherapy for “all patients with low rectal cancer requiring an APR.” In fact, in the published Karolinska experience, nearly 70% of patients received neoadjuvant 50 Gy of radiation. Therefore, are the reported improvements in CRM and perforation rates solely due to a more extended APR, to increased use of neoadjuvant therapies, or a combination of both? JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 26 NUMBER 21 JULY 2