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The Basis for Choice of Operation for Cancer of the Rectum
The Basis for Choice of Operation for Cancer of the Rectum JESSIE C. GRAY, M.D., F.R.C.S. (c.), F.A.C.S.*
THE basic surgical concept of an acceptable operation-for-cure of carcinoma in any organ of the body entails two factors. One factor is that the local lesion must be resected with an adequate margin of apparently normal tissue all around it. The other factor is that as extensive a resection of the field of lymphatic drainage of that carcinoma as is surgically and anatomically practical must be carried out. When these two factors are applied to carcinoma of the rectum, an adequate excision of the local lesion entails the resection of at least 5 cm. of apparently normal bowel beyond both margins of the growth, and the removal of as much of the perirectal tissue as is anatomically feasible at the level of the growth. Thus, if the carcinoma is at the level of the levator ani muscles, a wide margin of these muscles must be resected. If, on the other hand, the tumor is at the rectosigmoid junction, the resection of an adequate depth of tissue at the level of the tumor might entail the removal of whatever may be adherent to the growth, such as the uterus, a segment of the urinary bladder wall, or a loop of small bowel. The other factor, namely the resection of an extensive segment of the field of lymphatic drainage of the carcinoma, will also be affected by the anatomical level of the growth in the rectum because there are differences in the direction of lymphatic drainage from the various portions of the rectum. The exhaustive studies of many reliable investigators have proved beyond reasonable doubt that the lymphatic drainage of tumors whose lower border is 3 cm. or more above the upper border of the levator ani muscles occurs in an upward direction only, along the superior hemorrhoidal vessels, until complete occlusion of nodes occurs allowing retrograde permeation downward of the malignant cells in the blocked lymph vessels. At the other extreme of the rectum, malignant tumors extending below Hilton's line have long been known to have access to the lymphatic drainage of the anal region outward to the inguinal
* Clinical Teacher, Department of Surgery, and Associate Professor in Surgery, Faculty of Dentistry, University of Toronto; Surgeon-in-Chief, Women's College Hospital, Toronto, Ontario. 1331
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Jessie C. Gray
lymph nodes. The lymphatic drainage of the intermediate portion of the rectum, between Hilton's line below and the demarcation line 3 cm. above the levators above, is known to occur not only upward via the lymphatics accompanying the branches of the superior hemorrhoidal vessels, but also in a lateral direction in lymph channels in and on the levator ani muscles draining to obturator nodes and lymph nodes in the ischiorectal fossae. The resection of an adequate segment of the lymphatic field of drainage of the rectum in an upward direction is never a difficult matter surgically provided some operation is being done which entails the opening of the abdomen. The upward lymphatic drainage is associated anatomically with the blood supply of the colon and rectum, and the extent of resection of the field of lymphatic drainage is associated with the sacrifice of arteries of supply. Thus the extent of the resection of the field of lymphatic drainage inevitably leads to the decision as to what length of bowel in an upward direction from the growth must be removed in order to have an adequate blood supply to the segment to be retained. For example, if the lymph node involvement is proved by frozen section to extend to the site on the inferior mesenteric artery where it gives off the left colic branch, an adequate excision of the lymphatic field of drainage for cure would entail division of the inferior mesenteric artery well above the level at which it gives off the left colic artery. For reasons of blood supply, therefore, the resection of the bowel would have to be carried around into the transverse colon in order to have a good blood supply from the middle colic artery ensuring the viability of the terminal segment of colon being retained. It is generally conceded that for any carcinoma of the rectum the inferior mesenteric vessels should be divided at least 5 cm. above the promontory of the sacrum in order to insure an adequate resection of the field of proximal lymphatic drainage. The burning question in the choice of operation for any case of carcinoma of the rectum is always whether or not some procedure which preserves the anal sphincters and permits of restoration of bowel continuity, thus obviating the necessity of a permanent colostomy, is advisable. Of all the factors which influence the decision on this crucial question, by far the most important is the anatomical level of the growth in the rectum. It has been shown that the internal sphincters are microscopically invaded by malignancy in a high proportion of cases where the lower edge of the tumor extends down to within 3 cm. of the upper border of the levator muscles. Therefore it can be stated unequivocally that no operation designed to preserve the sphincter mechanism should be even remotely considered for carcinomas extending down to this level if there is any hope of more than palliation. This demarcating line of 3 cm. above the levator ani muscles is approximately 6 cm. from the anal margin when the patient is being examined in the knee-chest position.
Basis for Choice of Operation for Cancer of the Rectum
1333
At the other extreme of the rectum occur the carcinomas whose lower borders are 15 cm. or more above the anal margin when seen through the sigmoidoscope with the patient in the knee-chest position. These growths are a full 12 cm. above the level of the levator muscles .and their lymphatic drainage will be entirely in an upward direction unless they are so advanced as to have developed gross occlusion of lymph nodes. Therefore carcinomas at this high level can always be resected adequately by some operation which preserves the sphincters unless the tumor is so extensive that the surgeon feels there is a real possibility of retrograde lymphatic permeation downward. When considering only the anatomical level of the growth, the debatable cases in reference to sphincter preservation are those in which the lower border of the carcinoma is more than 6 cm. but less than 15 cm. from the anal margin as measured on the sigmoidoscope with the patient in the knee-chest position. These are the patients in whom factors other than the anatomical level of the tumor may influence the choice of operation. When a carcinoma is found to occur within the debatable region, the next factor which most strongly influences the choice of operation and the decision as to whether or not the sphincters may be preserved is the gross extent of the tumor and its pathological type. If the growth is advanced and fixed and particularly if it is of the scirrhous infiltrating type, nothing less radical than the combined abdominoperineal resection of the entire rectum and lower sigmoid colon can possibly give that patient the best chance of being cured of his disease. When the carcinoma appears to be relatively early, as gauged by its gross extent and mobility, it is very tempting to carry out :a, procedure which will preserve the sphincters. This is particularly true when the growth is 10 cm. or more from the anal margin and is thus sufficiently high in the bowel as to r:mder an apparently adequate anterior resection with end-to-end anastomosis of upper sigmoid colon to the rectal stump technically easy. These early cases, however, are the very ones in which local recurrence following a sphincter-preserving operation is such a tragedy, as the surgeon always bitterly regrets not having been more radical at the initial operation. Consequently a good conservative rule, when operating for cure, is to reserve sphincter-preserving procedures for growths in the debatable region which are not only relatively mobile and early in app@arance, but also are of the somewhat less malignant polypoid type, and preferably occur 12 cm. or more from the anal margin on sigmoidoscopic examination in the knee-chest position. Occasionally factors other than anatomical level of growth and its extent and gross pathological type may influence the choice of operation. In very aged patients, or patients with such serious concomitant disease as to render them very poor operative risks as well as to shorten materially their life expectancy, and certainly in patients who already have
1334
Jessie C. Gray
hepatic metastases which make them incurable, procedures which permit preservation of the sphincters are frequently indicated, even though they fail to meet our usual standards of what is necessary to give maximum insurance against local recurrence. Without question, much of the apparent divergence of opinion in the literature as to what level of lesion permits sphincter-preserving procedures stems from a failure to use a constant standard of measurement in describing the actual level of the tumor. If a carcinoma is still mobile there may be great differences in its apparent level depending upon the position in which the patient is examined. It will have been noted, in discussing the anatomical level of growths in the rectum, that constant reference has been made to the distance of the lower border of the lesion from the anal margin as measured on the sigmoidoscope with the patient in the knee-chest position. This has been done intentionally. This is the measurement usually obtained at the time of the first examination of the patient when the diagnosis is established by the taking of a biopsy. It is not the perfect constant because a carcinoma 12 cm. from the anus in a patient 5 feet tall is obviously relatively higher in level than a growth the same distance from the anal margin in an individual 6 feet 4 inches tall. Nevertheless, as a standard measurement, the distance of the carcinoma from the anal margin as measured on the sigmoidoscope with the patient always in the knee-chest position has been selected deliberately as one of the most practical. The technique, advantages, limitations and indications of various specific operations for carcinoma of the rectum will not be discussed here. However, a few generalizations about choice of operation might not be out of place. Any patient with a carcinoma of the rectum which is within reach of the finger on digital examination, and for whom there is hope of cure, should be subjected to a combined total excision of the rectum if his general condition will permit. Whenever the lower border of the carcinoma is 15 cm. or more from the anal margin as measured in the knee-chest position, there is good evidence that the percentage of survivals is just as high following a radical anterior resection as after total excision, and that in these cases preservation of the lower rectum with restoration of continuity avoiding a permanent colostomy is quite justified. Where the lower border of the growth lies between 10 and 15 cm. from the anal margin, the comparative results following resection and anastomosis from above are good if the growth is of the favorable type. But carcinomas at this level which are extensive, fixed and of the invasive type are better subjected to some type of combined procedure if operation is being undertaken for cure. Most of the intermediate procedures between the total combined excision and anterior resection with restoration of continuity either pre-
Basis for Choice of Operation for Cancer of the
Rec~um
1335
serve the levator ani muscles and are therefore no more radical than anterior resection from the aspect of cure, or they resect the levators and in so doing impair the nerve supply of the preserved sphincters so that subsequent anal continence is a matter of doubt. Generally speaking, most of these intermediate procedures are applicable to lesions extending down to within 6 to 15 cm. of the anus. In the lower portion of this range they are employed as palliative operations when it is known that even a total combined excision could not cure the patient. In the upper portion of this range they are sometimes employed for cure in an attempt to avoid a permanent colostomy where excision of the levators is essential to an adequate local excision. In the vast majority of cases where the growth is too low or too extensive for a radical anterior resection to offer a satisfactory chance of cure, a combined total excision will be found to be the operation of choice. 170 St. George Street Toronto, Ontario, Canada
THE basic surgical concept of an acceptable operation-for-cure of carcinoma in any organ of the body entails two factors. One factor is that the local lesion must be resected with an adequate margin of apparently normal tissue all around it. The other factor is that as extensive a resection of the field of lymphatic drainage of that carcinoma as is surgically and anatomically practical must be carried out. When these two factors are applied to carcinoma of the rectum, an adequate excision of the local lesion entails the resection of at least 5 cm. of apparently normal bowel beyond both margins of the growth, and the removal of as much of the perirectal tissue as is anatomically feasible at the level of the growth. Thus, if the carcinoma is at the level of the levator ani muscles, a wide margin of these muscles must be resected. If, on the other hand, the tumor is at the rectosigmoid junction, the resection of an adequate depth of tissue at the level of the tumor might entail the removal of whatever may be adherent to the growth, such as the uterus, a segment of the urinary bladder wall, or a loop of small bowel. The other factor, namely the resection of an extensive segment of the field of lymphatic drainage of the carcinoma, will also be affected by the anatomical level of the growth in the rectum because there are differences in the direction of lymphatic drainage from the various portions of the rectum. The exhaustive studies of many reliable investigators have proved beyond reasonable doubt that the lymphatic drainage of tumors whose lower border is 3 cm. or more above the upper border of the levator ani muscles occurs in an upward direction only, along the superior hemorrhoidal vessels, until complete occlusion of nodes occurs allowing retrograde permeation downward of the malignant cells in the blocked lymph vessels. At the other extreme of the rectum, malignant tumors extending below Hilton's line have long been known to have access to the lymphatic drainage of the anal region outward to the inguinal
* Clinical Teacher, Department of Surgery, and Associate Professor in Surgery, Faculty of Dentistry, University of Toronto; Surgeon-in-Chief, Women's College Hospital, Toronto, Ontario. 1331
1332
Jessie C. Gray
lymph nodes. The lymphatic drainage of the intermediate portion of the rectum, between Hilton's line below and the demarcation line 3 cm. above the levators above, is known to occur not only upward via the lymphatics accompanying the branches of the superior hemorrhoidal vessels, but also in a lateral direction in lymph channels in and on the levator ani muscles draining to obturator nodes and lymph nodes in the ischiorectal fossae. The resection of an adequate segment of the lymphatic field of drainage of the rectum in an upward direction is never a difficult matter surgically provided some operation is being done which entails the opening of the abdomen. The upward lymphatic drainage is associated anatomically with the blood supply of the colon and rectum, and the extent of resection of the field of lymphatic drainage is associated with the sacrifice of arteries of supply. Thus the extent of the resection of the field of lymphatic drainage inevitably leads to the decision as to what length of bowel in an upward direction from the growth must be removed in order to have an adequate blood supply to the segment to be retained. For example, if the lymph node involvement is proved by frozen section to extend to the site on the inferior mesenteric artery where it gives off the left colic branch, an adequate excision of the lymphatic field of drainage for cure would entail division of the inferior mesenteric artery well above the level at which it gives off the left colic artery. For reasons of blood supply, therefore, the resection of the bowel would have to be carried around into the transverse colon in order to have a good blood supply from the middle colic artery ensuring the viability of the terminal segment of colon being retained. It is generally conceded that for any carcinoma of the rectum the inferior mesenteric vessels should be divided at least 5 cm. above the promontory of the sacrum in order to insure an adequate resection of the field of proximal lymphatic drainage. The burning question in the choice of operation for any case of carcinoma of the rectum is always whether or not some procedure which preserves the anal sphincters and permits of restoration of bowel continuity, thus obviating the necessity of a permanent colostomy, is advisable. Of all the factors which influence the decision on this crucial question, by far the most important is the anatomical level of the growth in the rectum. It has been shown that the internal sphincters are microscopically invaded by malignancy in a high proportion of cases where the lower edge of the tumor extends down to within 3 cm. of the upper border of the levator muscles. Therefore it can be stated unequivocally that no operation designed to preserve the sphincter mechanism should be even remotely considered for carcinomas extending down to this level if there is any hope of more than palliation. This demarcating line of 3 cm. above the levator ani muscles is approximately 6 cm. from the anal margin when the patient is being examined in the knee-chest position.
Basis for Choice of Operation for Cancer of the Rectum
1333
At the other extreme of the rectum occur the carcinomas whose lower borders are 15 cm. or more above the anal margin when seen through the sigmoidoscope with the patient in the knee-chest position. These growths are a full 12 cm. above the level of the levator muscles .and their lymphatic drainage will be entirely in an upward direction unless they are so advanced as to have developed gross occlusion of lymph nodes. Therefore carcinomas at this high level can always be resected adequately by some operation which preserves the sphincters unless the tumor is so extensive that the surgeon feels there is a real possibility of retrograde lymphatic permeation downward. When considering only the anatomical level of the growth, the debatable cases in reference to sphincter preservation are those in which the lower border of the carcinoma is more than 6 cm. but less than 15 cm. from the anal margin as measured on the sigmoidoscope with the patient in the knee-chest position. These are the patients in whom factors other than the anatomical level of the tumor may influence the choice of operation. When a carcinoma is found to occur within the debatable region, the next factor which most strongly influences the choice of operation and the decision as to whether or not the sphincters may be preserved is the gross extent of the tumor and its pathological type. If the growth is advanced and fixed and particularly if it is of the scirrhous infiltrating type, nothing less radical than the combined abdominoperineal resection of the entire rectum and lower sigmoid colon can possibly give that patient the best chance of being cured of his disease. When the carcinoma appears to be relatively early, as gauged by its gross extent and mobility, it is very tempting to carry out :a, procedure which will preserve the sphincters. This is particularly true when the growth is 10 cm. or more from the anal margin and is thus sufficiently high in the bowel as to r:mder an apparently adequate anterior resection with end-to-end anastomosis of upper sigmoid colon to the rectal stump technically easy. These early cases, however, are the very ones in which local recurrence following a sphincter-preserving operation is such a tragedy, as the surgeon always bitterly regrets not having been more radical at the initial operation. Consequently a good conservative rule, when operating for cure, is to reserve sphincter-preserving procedures for growths in the debatable region which are not only relatively mobile and early in app@arance, but also are of the somewhat less malignant polypoid type, and preferably occur 12 cm. or more from the anal margin on sigmoidoscopic examination in the knee-chest position. Occasionally factors other than anatomical level of growth and its extent and gross pathological type may influence the choice of operation. In very aged patients, or patients with such serious concomitant disease as to render them very poor operative risks as well as to shorten materially their life expectancy, and certainly in patients who already have
1334
Jessie C. Gray
hepatic metastases which make them incurable, procedures which permit preservation of the sphincters are frequently indicated, even though they fail to meet our usual standards of what is necessary to give maximum insurance against local recurrence. Without question, much of the apparent divergence of opinion in the literature as to what level of lesion permits sphincter-preserving procedures stems from a failure to use a constant standard of measurement in describing the actual level of the tumor. If a carcinoma is still mobile there may be great differences in its apparent level depending upon the position in which the patient is examined. It will have been noted, in discussing the anatomical level of growths in the rectum, that constant reference has been made to the distance of the lower border of the lesion from the anal margin as measured on the sigmoidoscope with the patient in the knee-chest position. This has been done intentionally. This is the measurement usually obtained at the time of the first examination of the patient when the diagnosis is established by the taking of a biopsy. It is not the perfect constant because a carcinoma 12 cm. from the anus in a patient 5 feet tall is obviously relatively higher in level than a growth the same distance from the anal margin in an individual 6 feet 4 inches tall. Nevertheless, as a standard measurement, the distance of the carcinoma from the anal margin as measured on the sigmoidoscope with the patient always in the knee-chest position has been selected deliberately as one of the most practical. The technique, advantages, limitations and indications of various specific operations for carcinoma of the rectum will not be discussed here. However, a few generalizations about choice of operation might not be out of place. Any patient with a carcinoma of the rectum which is within reach of the finger on digital examination, and for whom there is hope of cure, should be subjected to a combined total excision of the rectum if his general condition will permit. Whenever the lower border of the carcinoma is 15 cm. or more from the anal margin as measured in the knee-chest position, there is good evidence that the percentage of survivals is just as high following a radical anterior resection as after total excision, and that in these cases preservation of the lower rectum with restoration of continuity avoiding a permanent colostomy is quite justified. Where the lower border of the growth lies between 10 and 15 cm. from the anal margin, the comparative results following resection and anastomosis from above are good if the growth is of the favorable type. But carcinomas at this level which are extensive, fixed and of the invasive type are better subjected to some type of combined procedure if operation is being undertaken for cure. Most of the intermediate procedures between the total combined excision and anterior resection with restoration of continuity either pre-
Basis for Choice of Operation for Cancer of the
Rec~um
1335
serve the levator ani muscles and are therefore no more radical than anterior resection from the aspect of cure, or they resect the levators and in so doing impair the nerve supply of the preserved sphincters so that subsequent anal continence is a matter of doubt. Generally speaking, most of these intermediate procedures are applicable to lesions extending down to within 6 to 15 cm. of the anus. In the lower portion of this range they are employed as palliative operations when it is known that even a total combined excision could not cure the patient. In the upper portion of this range they are sometimes employed for cure in an attempt to avoid a permanent colostomy where excision of the levators is essential to an adequate local excision. In the vast majority of cases where the growth is too low or too extensive for a radical anterior resection to offer a satisfactory chance of cure, a combined total excision will be found to be the operation of choice. 170 St. George Street Toronto, Ontario, Canada