In most Western societies rectal carcinoma is uncommon. However, as the number of surgeries performed on men with prostate cancer increases, in turn the number of men, particularly older men, will present with rectal cancer. Rectal carcinoma is usually a late manifestation of a more aggressive disease but it is also relatively radioresistant and so may be treated by the same curative modalities used to treat prostate cancer.
Approximately 14% of patients with stage III or IV rectal carcinoma die per year. This information will be useful at time of diagnosis when the doctor and the patient decide on options, including surgery, chemo- and radiation therapy, and palliative care. Survival seems to be similar across histopathologic differentiation of rectal carcinoma in the United States.
Rectal carcinomas may be treated with surgical resection alone. If the tumor infiltrates the margins of the surgical resection specimen, additional treatment with radiotherapy may be recommended. For tumors with positive nodes, systemic chemotherapy may be considered.
Rectal bleeding, a painful or bleeding stool, an unintentional weight loss, or rectosigmoid colon cancer that has spread may warrant consideration for pre-operative imaging. In a recent study, findings may be signs of an unresectable tumor. Lateral rectal cancer is associated with a higher percentage of lymph node involvement and lymph node involvement of distant metastases, a poor prognosis and would be considered an indication to perform a total mesorectal excision (TME). On CT scan, the most specific abnormality is a well-defined solid mass that does not have a shadow effect around it.
Results from a recent paper indicates that trauma, particularly from childhood, is an important etiological factor. More specifically, trauma after anorectal surgery is an important risk factor. The lack of correlation with colonic polyploidy may be a result of the relatively low prevalence of rectal cancer in our population of patients with polyploidy.
Rectal cancer cannot be cured. However, the stage of the cancer determines the outcome. The 5-year survival rate for T1 and T2 cancers is high with proper treatment; however, in advanced T3 tumors the 5-year survival rate is only 40%, which has led to the inclusion of concurrent chemotherapy with radiation therapy with curative intent in the treatment protocol. The use of modern chemotherapy combined with radiation therapy has increased the five-year survival rate from 40% to 85-90%. The 5-year survival rate increases to 100% when combined with careful, pre-operative, surgical staging and adequate post-operative radiotherapy.
We believe that the use of yttrium-90 radioembolization may be a safe procedure that could lead to better outcomes in patients with unresectable liver or extrapalna cancer. However, more complete data need to be obtained on this interesting treatment.
Results from a recent clinical trial suggest that the most common risk factor for rectal carcinoma is chronic inflammation induced by a persistent infection with a bacteria known to cause chronic rectal disease. These studies suggest that screening for chronic rectal disease may decrease the incidence and the death rate from rectal carcinoma.
The new drugs being explored are likely to be successful, as many are already approved for breast carcinoma. Further study should be on the potential of other treatment modalities that have not yet been tested in rectal cancer.
As a non-invasive intervention, [(90)Y] RIT is effective in controlling cancer load but must be assessed in clinical trials using standardized protocols to prove its safety and effectivity as a monotherapy or in combination with systemic therapy.
A common adverse effect following treatment with Y90-based radioembolic therapy is transient bowel or bladder spasm, which can be a significant problem in patients with severe comorbidities, even if the procedure can be performed on an outpatient basis. In our experience, post-treatment computed tomographic imaging should be performed in all such patients as soon as practical after treatment to prevent bowel wall spasm and other complications.
The current study may help guide oncologists and patients to understand the risks and the benefits of clinical trials to help with the decision-making process. For those [with a stageT3N0M0(0) or T3N0M0(+) tumour pattern] and/or a high BMI (> or =25), the inclusion in a clinical trial may not be necessary.