The modern abdominoperineal excision: the next challenge after total mesorectal excision

Abstract

Objectives: Examine the cause of local recurrence (LR) and patient survival (S) following abdominoperineal resection (APR) and anterior resection (AR) for rectal carcinoma and the effect of introduction of total mesorectal excision (TME) on APR.

Methods: A total of 608 patients underwent surgery for rectal cancer in Leeds from 1986 to 1997. CRM status and follow-up data of local recurrence and patient survival were available for 561 patients, of whom 190 underwent APR (32.4%) and 371 AR (63.3%). Also, a retrospective study of pathologic images of 93 specimens of rectal carcinoma.

Results: Patients undergoing APR had a higher LR and lower survival (LR, 22.3% versus 13.5%, P = 0.002; S, 52.3% versus 65.8%, P = 0.003) than AR. LR free rates were lower in the APR group and cancer specific survival was lowered (LR, 66% versus 77%, log rank P = 0.03; S, 48% versus 59%, log rank P = 0.02). Morphometry: total area of surgically removed tissue outside the muscularis propria was smaller in APR specimens (n = 27) than AR specimens (n = 66) (P < 0.0001). Linear dimensions of transverse slices of tissue containing tumor, median posterior, and lateral measurements were smaller (P < 0.05) in the APR than the AR group. APR specimens with histologically positive CRM (n = 11) had a smaller area of tissue outside the muscularis propria (P = 0.04) compared with the CRM-negative APR specimens (n = 16). Incidence of CRM involvement in the APR group (41%) was higher than in the AR group (12%) (P = 0.006) in the 1997 to 2000 cohort. Similar results (36% and 22%) were found in the 1986 to 1997 cohort (P = 0.002).

Conclusions: Patients treated by APR have a higher rate of CRM involvement, a higher LR, and poorer prognosis than AR. The frequency of CRM involvement for APR has not diminished with TME. CRM involvement in the APR specimens is related to the removal of less tissue at the level of the tumor in an APR. Where possible, a more radical operation should be considered for all low rectal cancer tumors.

Figures

FIGURE 1. Distribution of tumors in the 1997–2000 cohort into APR and AR groups according to TNM stages T1–T4.

FIGURE 2. Digital image of representative slices of rectum showing the measurements made using computer-assisted morphometry. White line around the edge of the specimen = circumferential margin (CRM); dotted white line outlines the edge of tumor; solid black line outlinles the border of muscularis propria; inner solid white line outlines the lumen. m, distance of tumor to CRM; a, anterior measurement of the distance from the muscularis propria to the CRM; l, lateral measurement of distance from the muscularis propria to CRM; P, posterior measurement of distance from the muscularis propria to the CRM. The scale is in centimeters.

FIGURE 3. Absence of local recurrence and cancer-specific survival by operation type (1986–1997).

FIGURE 4. Views of both surfaces of 4 APR specimens, 2 from Leeds and 2 from the Karolinska Hospital. One of each has been shown formalin fixed. A, Fresh standard APR specimen from our hospital showing the natural coning of the low mesorectum and the creation of the CRM on the sphincter muscles. B, Formalin-fixed standard APR specimen showing similar features to A. C, The perineal approach in a fresh APR creating a CRM outside the levators giving wider clearance. The coccyx has also been removed. D, Formalin-fixed APR with levators and coccyx attached. These wider APR resections were performed by Dr. T. Holm of the Karolinska Hospital, Stockholm.