[cancer of the rectum and rectosigmoid]

Abstract

It is the purpose of this thesis to examine this evidence, and also to consider the anatomical and technical factors governing the use of restorative resections, so as to determine the place that they may legitimately assume during this interim period in the treatment of rectal and rectosigmoid cancer.1. In this thesis an attempt has been made to ascertain how far sphincter conservation and restoration of continuity can be reconciled with the requirements of radical surgery in the treat - ruent of carcinoma of the rectum and rectosigaoid, and to decide which are the best technical methods of achieving this end.2. A study of 1500 combined excision specimens has disclosed the following facts: - (a) In approximately 40 of the combined excision cases the growth was situated in the anal canal or lower 1 /3rd of the rectum and the removal of the anal sphincters and related levator muscles was essential for radical treatment. (b) In the remaining 60%, however, in which the growth lay in the upper 2/3rds of the rectum or in the rectosignoid, it was not apparent that the sacrifice of the sphincter apparatus had in any way increased the prospects of eradication of the disease. It seemed that preservation of the anus and rectum from a level 1" below the lower margin of the primary tumour mass would not have adversely affected the chances of ultimate cure. The rare occurrence of retrograde venous and lymphatic extension below this level is not denied, but such cases, by reason of their wide spread in other directions, must be regarded as incurable by any operation. (c) The most important avenue of extension of carcinoma of the rectum and rectosignoid is by the upgoing lymphatics and veins accompanying the superior haeinorrhoidal and inferior mesenteric arteries. No operation for these conditions can be considered adequate unless it provides for removal of these vessels to a high level. Spread to the sigmoid paracolic glands only occurs when the growth arises in the rectosigmoid and they lie in sequence between it and the inferior mesenteric glands. Consequently all but the basal and possibly the lowest part of the sigmoid mesocolon and attached colon may always be safely preserved.3. An examination of the arrangement of the blood vessels to the rectum and distal half of the colon in 75 necropsy room bodies, supplemented by observations on living patients at operation, has established the following-points :- (a) The left colic and first sigmoid arteries generally spring conjointly from the inferior mesenteric trunk opposite the bifurcation of the abdominal aorta; in a combined excision the ligature on the inferior mesenteric vessels is generally placed immediately below this point. (b) With the main ligature so sited, it is, however, possible in practically every case to prepare a sufficiently long well vascular - ized piece of sigmoid colon to permit of endto-end union with an anorectal stump after resection. One method of preparation provides for a direct blood supply to the end of the sigmoid stump through the first sigmoid branch; if this stump should not be long enough additional length may be secured by preserving the intersigmoid marginal artery and colon for 2 or 3" below the first sigmoid, or by severing the latter branch and relying on the descending division of the left colic artery. Our preference is for the latter method whenever possible. (c) When an abdomino -anal "pull through" type of operation is contemplated a very much longer sigmoid stump is required. In our experience this can also be provided by a combination of methods in the great majority of cases, though not in all. (d) When the entire si :g,aoid colon has to be sacrificed, as for example in some cases of double carcinoma, restoration of continuity may still be possible by resetting up to the splenic flexure or middle of the transverse colon and swinging down the remainder of this to the anorectal stump or anus. Occasionally a graft taken from the lower ileum with its blood supply intact may be useful in this type of case. (e) The blood supply to the anorectal stump after resection with division of the superior, and often the middle, haemorrhoidal vessels is surprisingly abundant. It would appear to be derived not only from the inferior haemorrhoidal arteries but also from numerous unnamed branches in the levator ani muscles.4. The highest point at which the superior haemorrhoidal or inferior mesenteric vessels can be tied through a sacral approach is usually 3 or 4" lower than the site generally chosen for this ligature in a combined excision. Sacral resections are therefore condemned as pathologically inadequate, and the recorded results support this condemnation.5. An abdominal phase, to permit of high division of the inferior mesenteric vessels and proper preparation of the colon stump, is an essential part of any radical resection operation. The steps of the abdominal dissection are described in detail. The operation may be carried out entirely through the abdomen or completed as an abdomino-sacral or abdoinino-anal resection.6. Our experience has been chiefly with abdominal resection and it has been found possible to remove nearly all growths, that are suitable for resection, by this method. An "open" suture technique has been used for making the anastomosis in the bowel. We have not been able to reach any firm conclusion as to the advantage of establishing a preliminary or simultaneous transverse colostomy. Post- operative septic complications and fistulae have not been common. There have been 5 hospital deaths in 45 cases. The functional results have been uniformly excellent.7. For some low growths in the middle 1 /3rd of the rectum in individuals with narrow pelves an abdoinino- sacral or abdoin ino -anal techni4ue of resection may be advisable. We have had no personal experience of the former, but hAve used abdomino -anal resection of Maunsell -Weir type in 21 cases with one operative death. All the survivors possessed good rectal function, but troublesome stenosis at the suture line was a frequent sequel.S. Most of our-resection operations have been performed recently and no full account of the late results is yet possible. But in a few cases further growth has appeared in the region of the anastomosis in the bowel or in the rectal stump. It is suggested that this may have been due to:- (a) incomplete removal at the original operation, (b) the development of a fresh primary carcinoma, or (c) the occurrence of metastases by implantation. The latter two seem the more likely explanations, and measures calculated to minimise these dangers are described.9. In view of these unfavourable results an optimistic assessment of the value of resection procedures in the treatment of rectal or recto - sigmoid cancel is not at the present stage justified.