Results of the Treatment

One of characteristics of rectal cancer is a predisposition to local recurrence and distant metastases. Evaluation and comparison of the results of treatment presented by various centres are not easy because of differences in number of patients, interpretation of various statistical methods, and in the first place -lack of standard criteria for qualification of the patients. Numerous prognostic factors affect survival rate: stage of the disease, tumour localisation, complications (bowel obstruction, tumour perforation, haemorrhage), tumour morphology, histological findings, mucous secretion and (recently brought into discussions more and more often) quality of treatment connected with the surgeon's experience.

A modern surgical treatment of rectal cancer that leads to an improvement in results was introduced by

Dixon in the Mayo Clinic. In 1940 he performed partial anterior resection of rectum. A further improvement in the results of treatment was observed in 1977, when Turnbull introduced the "no-touch" isolation technique, which was the basis for the oncological aseptic technique during the operating procedure [62, 63]. The real revolution in surgical treatment was the introduction of the TME technique presented in 1980 by Heald et al. [64].

Studies comparing results of treatment utilising TME with the conventional technique clearly show benefits of the TME technique. Local recurrence rate in curative resection, during a 3-5-year period with TME is 3-11% [65-72] compared to 23-30% with the conventional technique [66, 68, 69]. Five-year survival rates after TME are 68-80%, and after conventional operations only 45% [73, 74]. Metastasis appearance is 23-25% after TME and 60-65% after conventional treatment. The above facts show the clear-cut position of TME as the golden standard in the treatment of rectal cancer. The next factor improving results of treatment of colorectal cancer is pre-operative RT, which is discussed separately.

We must remember that results presented are only average numbers, not taking into consideration various prognostic factors, which can influence results of the treatment of the rectal cancer. Basically, the most important and undisputed prognostic factor is the tumour stage, precisely described by the TNM system. Five-year survival rates in an analysed group of 15 000 patients were: stage I, 70%; II, 55%; III, 46%; and IV, 9% [75, 76]. Lymph node metastases as well as local cancer invasion in blood and lymphatic vessels cause further worsening of five-year survival. Positive resection margin always leads to the recurrence of the cancer.

Worse results of the treatment are usually described in younger patients, below 40 years of age [77-79]. An important fact is that in younger patients we are dealing with poorly differentiated and mucous secretion tumours more often. Other facts are the more aggressive and fast course of the disease and -unfortunately - late diagnosis, with large tumour and advanced stage of disease.

The influence of sex on survival remains uncertain. A statistically significant worsening of 5-year survival rate in men compared to women was observed in many studies [79-81]. But worse prognosis for men was observed mainly in Dukes B and C stages. Numerous recent studies do not show a significant influence of sex on survival rate or recurrence of the disease [82, 83].

Complications of rectal cancer, like bowel obstruction, haemorrhage or perforation, that usually are indications for immediate surgical treatment, correlate with crucial deterioration in treatment results. The complete 5-year survival rate is significantly lower, and cancer recurrences are more frequent than in uncomplicated cases. A worsening of the prognosis is connected with a low percentage of operative tumours, due to the advanced stage of the disease, as well as with the possibility of intraperi-toneal spread of cancer cells, which have a capacity for implantation and growth [84, 85]. Another factor that affects results of treatment is an unintended tumour perforation during the scheduled operation of an uncomplicated tumour [86].

Histological grading of tumour has unquestionable influence on treatment results. Poorly differentiated tumours are characterised by aggressive and dynamic growth. This is connected with a significant decrease in survival rates [87], increased rate of total cancer recurrences [88] and local recurrences as well [78].

Tumour morphology is another factor that may affect recurrence prognosis. Raised tumours cause local recurrence less often then ulcerative tumours, coring into bowel wall [79]. The reason for this situation may be significantly lower cancer infiltration outside the bowel wall and lower rate of lymph node infiltration and distal metastases, in cases of rising type of growth tumours. Circular type of tumour growth is also connected with worsening of the prognosis [89]. Bad results are also proven in cases of mucous-secreting tumours [80], which appear in younger patients (less than 40 years) more often.

Recent studies show unquestionable influence of treatment quality and surgeon's experience on the results of treatment. Low-volume hospitals have significantly lower survival rates compared to high-volume centres. Surgeons well experienced in pelvic surgical procedures, as well as in bowel resections, have better results, lower recurrence rates and better long-term survival rates [78, 90].

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