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CONTROVERSIES AND ADVANCES IN SURGERY DF RECTAL CANCER
Dr. A. K. Khanna Reader, Department of Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi-221005, India

INTRODUCTION:
Even at the end of the millennium it is frustrating to note that rectal cancer is a dismal disease and in the last 25 years probably there has not been much change in the overall outlook of this disease but data is appearing by using a multimodality management for a better outcome of the disease. The biggest change In the management of rectal cancer is more and more cases of rectal cancer are being treated with sphincter saving procedures rather than lassical abdomino perineal resection (APR) with a life long permanent colostomy. In Japan, in the year 1960. 90% of patients with rectal cancer had APR while in 1996, the rate of APR Is reduced to less than 10% and most cases are being treated by sphincter saving procedures2. Most of the patients with cancer of the upper 1/3 of rectum can be managed by sphincter saving procedures but decision on choosing the treatment for lower 2/3 Is difficult and more so ever for lowest 1/3 of rectum. The patients with rectal cancer face a challenge of their quality of life by the change in bladder and bowel habits as well as sexual habits. Though rectal cancer is a disease of elderly but many young patients are also afflicted with this disease so one has to be more particular about the sexual habits.

CONTROVERSIES:
So what are the controversies in surgery of rectal cancer. There are many controversies In the. treatment of rectal cancer starting from choosing the patient for sphincter saving procedures and once decided to do surgery then how the trowel should be prepared for surgery, what surgical prophylaxis should be given, what operation has to be performed, where to place the colostomy, should pelvis be drained or not, should the pelvic peritoneum be stitched or not, should lavage be done or not. Then how much should be the extent of surgery? What should be the distal margin of clearance, how much lateral excision should be done? How much mesorectum should be excised? How one can save the pelvic nerves to minimise the sexual problems, how much should be the lateral pelvic node dissection? Should the posterior vaginal wall be excised in females? What is the status of radio-immuno-guided surgery especially in recurrent cancers? What is the state of laparoscopic surgery? What should be done in synchronous cancers, cancers with predisposing factors like inflammatory bowel diseases, polyposis of colon etc.? What should be done especially in obstructed cancers and what are the various options available for It? How successful is the local operations and microsurgery for rectal cancers^ What is the role of colonic pouch reservoirs? The list goes on like this.

The biggest change in concept in surgery for rectal cancers came with the anatomical concept that the distal microscopic intramural spread of rectal cancers is rare occurring in less than 7% cases So a reduction in the distal mural margin from 5cms to 2 cms came in concept and that is why more and more low rectal cancers can be treated by sphincter saving procedures.

In the recent years few surgeons have come out with a concept of Total mesorectal excision (TME), also known by some as CCME (Complete Circumferential Mesorectal excision) and MRE (Mesorectal excision) which means excision of the mesorectum along with the primary operation. Anatomically the mesorectum is surrounded by a thin layer, the visceral layer of the pelvic fascia. The mural structures like pelvic autonomic nerves and plexus are covered t the parietal layer of pelvic fascia. The plane called as "Holy Plane" between two layers is the anatomic foundation of the concept mesorectal excision. The TME Is excision of the mesorectum in toto under sharp dissection so that the pelvic nerves are not damaged. The technique of TME is supposed to be associated with low local recurrence up to 5-8% on as compared to 20-25% in conventional surgery. In radical resection without TME, positive lateral margin is seen in 25% cases an 80% local recurrence I because of positive lateral margin. TME has the advantage as all dissection is done under vision, the mesorectum is removed in a block, complet haemostasis is maintained, nerves are preserved and all this is associated with low local failure and les sexual and urinary problems. The good results are because of improved lateral clearance, removal of potential site of tumor deposit and decreased risk of spillage from disrupted mesorectum. Further because of low local recurrence there is chance of increased disease free survival. The patients who undergo TME are more likely to undergo the sphincter preservation rather than APR and also the impotence rate is only 15% in TME as compared lo 50% in conventional surgery. This operation is associated with 5-8% local failure and the various reasons for failure are supposed to be the distal mesorectal spread, undetected pathologic evidence of Involvement of lateral margins, 5-7% chance of lateral spread to internal iliac and or obturator nodes. Japanese have advised to undertake the clearance of internal iliac and obturator nodes but it is associated with an increased morbidity. TME is not an operation which can be performed by occasional surgeon and in certain Scandinavian countries this operation has been accepted as the optimal treatment for rectal cancer.

In the recent years much emphasis has been laid on the local excision procedures, in the same line Endoscopic Transanal Resection (ETAR) and Transanal Endoscopic Microsurgery (TEM) has been developed. But for carrying out the local excision, very strict criteria should be followed especially in selection of the patient for local excision. T1 -2 tumors less than 3 cms size, Involving less than one quadrant, well differentiated with no lymphovascular invasion without perineural invasion.

There are many centres which consider that rectal cancer surgery should be performed only by the specialist surgeons and there is now plenty of data to suggest better outcome of the disease from the centres which specifically deals with individual disease and it is very much related to the experience of the specialist surgeon. A study performed at Glasgow looking Into 1128 patients operated by 15 surgeons showed that hazard ratio for the curative resection varied from 0.54-1.46 and one can say that half of the surgeons were doing a good job and another half were having more complications, The similar figure is for the palliative resection also with a hazard ratio of 0.32-1,57. Another important parameter is the volume of surgery carried out by a surgeon and the surgeons carrying out less operations have more chance of anastomotic leak. Another study published in Disease of Colon and rectum In 1997 showed that apart from the patient factors, tumour factors one of the Important factor was the patients who did not undergo surgery by a colorectal surgeon specialist even after the adjustment for the patient and tumour factors. If we look at the Scotland series of 3000 cases In 12 hospitals, one can find a great variability In the presentation of the patients like the mean % of emergency cases was 34% but it varied from hospital to hospital like 23-42% and from surgeon to surgeon 9-83%, Similar are the figures for the Dukes stage, curative resection varied from surgeon to surgeon 36-87%, palliative resection from 7-46%. The figure of anastomotic leak is interesting that varied from 0-33% amongst the surgeons both in elective as well as emergency situation and the similar was the figure for mortality". So what does all these figures suggest that the experience in colorectal surgery is needed for the better outcome of the disease and preferably as has been rightly said that the right thing can be achieved if It is carried out by aright person, at the right lime, in the right manner and on the right patient. So differences in outcome among surgeons do appear to exist and volume of work makes the difference. Colorectal surgery, especially the rectal surgery where there are so many new advancement which are technically demanding, it should be carried out by the specialist and it is not only important from the patient outlook but also from the surgical training.

So there are many advances in the treatment of rectal cancer and more and more controversies are appearing on the scenario.