Understanding the Philosophy, Anatomy, and Surgery of the Extra-TME Plane of Locally Advanced and Locally Recurrent Rectal Cancer; Single Institution Experience with International Benchmarking

Abstract

Pelvic exenteration surgery has become a widely accepted procedure for treatment of locally advanced (LARC) and locally recurrent rectal cancer (LRRC). However, there is still unwarranted variation in peri-operative management and subsequently oncological outcome after this procedure. In this article we will elaborate on the various reasons for the observed differences based on benchmarking results of our own data to the data from the PelvEx collaborative as well as findings from 2 other benchmarking studies. Our main observation was a significant difference in extent of resection between exenteration units, with our unit performing more complete soft tissue exenterations, sacrectomies and extended lateral compartment resections than most other units, resulting in a higher R0 rate and longer overall survival. Secondly, current literature shows there is a tendency to use more neoadjuvant treatment such as re-irradiation and total neoadjuvant treatment and perform less radical surgery. However, peri-operative chemotherapy or radiotherapy should not be a substitute for adequate radical surgery and an R0 resection remains the gold standard. Finally, we describe our experiences with standardizing our surgical approaches to the various compartments and the achieved oncological and functional outcomes.

Keywords: R0 resection; locally advanced and recurrent rectal cancer; neoadjuvant treatment; pelvic compartments; pelvic exenteration; radical surgery.

Figure 1

(A–D) Distribution patterns of local recurrence along extramesorectal plane following TME surgery. (A) demonstrates normal pelvic anatomy with intact mesorectal plane prior to surgery. The areas shaded in red demonstrate where local recurrences occur; along the pelvic floor muscles, the seminal vesicles and prostate and anteriorly along the pelvic floor muscles towards the membranous urethra. Posterior the presacral fascia (and sacrum) can be involved. MU = membranous urethra, SF = sphincter, AC = anal canal, SV = seminal vesicles. Green = TME plane, blue = presacral fascia, shaded red = extramesorectal plane of recurrence following TME excision. (B) demonstrates a typical local recurrence pattern with spread in the extramesorectal plane after previous APR involving pelvic floor, bladder, prostate, seminal vesicles and membranous urethra. The red line demonstrates the surgical resection margin which includes a distal (S4) sacrectomy and complete soft tissue exenteration with penile urethrectomy. The differences between a standard urological approach for urethrectomy and a perineal urethrectomy is demonstrated. (C) demonstrates a local recurrence at the level of anastomosis following a low anterior resection. The tumour extends to the presacral fascia at the level of S1 and S2 (red) and anteriorly the seminal vesicles are involved (red). This patient underwent a complete soft tissue exenteration with a high anterior cortectomy at the level of S1 and S2. (D) demonstrates a local recurrence at the rectal stump following a Hartmann’s procedure. The tumour extends along the presacral fascia from the level of S2 to S4. This patient underwent a posterior pelvic exenteration with high abdominolithotomy sacrectomy (S2).

Figure 2

Evolution of R0 margins for the various compartments in pelvic exenterations for locally recurrent rectal cancer over the last 25 years.