Although efforts have been made to attempt restorative resections in rectal cancer wherever possible, and although APR rates have fallen over the past twenty years, excisional surgery with a permanent stoma is still commonly performed in up to 25% of cases of rectal cancer (Harling 2004, Tekkis 2005).

A recent report from the USA noted a permanent stoma rate in patients with rectal cancer of over 60% (Ricciardi 2007). There is increasing evidence that the adequacy of excision is poorer for cases undergoing APR. Using circumferential margin involvement as a surrogate marker for adequacy of surgical excision, several studies have shown an increased positive rate in patients undergoing an APER (Tekkis 2005, Marr 2005, CRO7 reference, Nagtegaal 2005). It seems likely that the anatomical limitations within the pelvis and at the outlet, particularly in male patients, may limit the margin of tissue that can be excised. Good results can be achieved from individual units (Dehni 2003) but others have demonstrated inferior results with APER (Law 2001). The current view is that the coning that can occur as the mesorectal plane is followed down to the anorectal junction inevitably means that the margin is close to the rectum in the very area where the tumour is located. It is therefore important that the decision to perform an APR is taken early during the operation so that a different approach to the dissection within the low pelvis is undertaken. Efforts should be made to obtain a wider clearance and a cylindrical specimen (Holm 2007).

The perineal phase of the operation can be performed in the prone position but one problem encountered with the wider clearance is adequate closure of the perineal wound. This can be performed with a rectus abdominis or gluteal flap or with insertion of a prosthetic mesh. It is likely that perineal herniae will become more of a problem with this form of major surgery unless such procedures are employed. Our own experience with prone dissection and efforts to obtain a more cylindrical specimen have led to a reduction in the perforation rate of the specimen, more tissue being removed and a lower circumferential margin involvement (West 2008 in press). The question of improving results from APR has been reviewed recently (Radcliffe 2006) Although there have been some surgical modifications to APR it is likely that most tumours that are low in the rectum, and are likely to be removed with an APR, will have some form of pre-operative chemoradiotherapy. There is increasing evidence that these low tumours have a high incidence of pelvic side-wall lymph node involvement ((Takahashi 2000). These nodes are not removed in the standard APR and, although the Japanese have practiced pelvic lymphadenectomy, this technique has not found favour in the Western world. There is increasing evidence that radiotherapy to the pelvis is an acceptable alternative to lymphadenectomy for these low tumours and the subject has recently been reviewed (Yano 2008).

References:

• Dehni N, McFadden N, McNamara DA et al. Oncologic results following abdominoperineal resection for adenocarcinoma of the low rectum. Dis Colon Rectum 2003; 46: 867-874
• Harling H, Bulow S, Kronborg O et al. Survival of rectal cancer patients in Denmark during 1994-99. Colorectal Dis. 2004; 6: 153-157
• Holm T, Ljung a, Haggmark T et al. Extended abdominoperineal resection with gluteus maximus flap reconstruction of the pelvic floor for rectal cancer. Br J Surg 2007; 94: 232-238
• Law WL, Chu KW Impact of total mesorectal excision on the results of surgery for distal rectal cancer Br J Surg 2001; 88: 1607-1612 Marr R, Birbeck K, Garvican J et al. The modern abdominoperineal excision: the next challenge after total mesorectal excision. Ann Surg 2005; 242: 74-82
• Nagtegaal ID, van de Velde JH, Marijinen AM et al Low rectal cancer: a call for a change of approach in abdominoperineal resection J Clin Oncol 2005; 36: 9257-9264
• Radcliffe A Can the results of anorectal (abdominoperineal) resection be improved: are circumferential resection margins too often positive? Colorectal Dis 2006; 8: 160-167
• Ricciardi R, Virnig BA, Madoff RD et al. The status of radical proctectomy and sphincter-sparing surgery in the United States. Dis Colon Rectum 2007; 50: 1119-127
• Takahashi T, Ueno M, Azekura K et al. Lateral node dissection and total mesorectal excision for rectal cancer Dis Colon Rectum 2000; 43: S59-S68
• Tekkis PP, Heriot AG, Smith J et al. Comparison of circumferential margin involvement between restorative and nonrestorative resections for rectal cancer. Colorectal Dis. 2005; 7: 369-374
• Yano H, Moran BJ. The incidence of lateral pelvic side-wall nodal involvement in low rectal cancer may be similar in Japan and the West. Br J Surg 2008;95: 33-49