Results of Radiation Therapy in Primary Operable Rectal and Anal Cancer

Abstract

RESULTS following the use of roentgen and radium rays in primary operable rectal and anal cancer depend largely upon selection of cases for this type of treatment and upon dosage and technic of application of the physical agents. Experience has proven that radiation therapy is suitable for a fair percentage of operable cancers as well as for the inoperable stages of disease. It should be recognized that at the present time irradiation is not a suitable method for routine employment in all operable cases. Until there is additional improvement in the technic of application of the physical agents, surgical resection will be required in over 50 per cent of the operable cases, largely because of inaccessibility and extent of the local disease. Patients with operable tumors may be separated, as to the type of treatment, into three main groups: (1) cases suitable for radiation therapy alone, colostomy being occasionally required for relief of obstructive symptoms; (2) cases suitable for radical surgery by one of the proven methods of technic, and (3) cases most benefited by the combined use of irradiation and radical surgery. The combined treatment has its greatest field of usefulness in advanced operable stages of disease. Treatment of the latter two groups need not be considered in this communication. Selection of cases for clinical cure by irradiation is of vital importance. Early recognition, while the cancer remains small and the disease localized, is the greatest asset to successful radiation therapy. A high percentage of the very small lesions can be successfully treated by this method. A number of medium and large-sized tumors may also be favorably influenced, but the percentage of suitable cases with well-established or far-advanced operable disease will be lower than in the group of early lesions. The degree of infiltration into the submucous and adjacent tissues must be carefully considered in all cases. Increased difficulty in adequately applying radon is encountered when infiltration is extensive, diffuse, and poorly localized. Cancers, to be favorable for this type of treatment, must be sufficiently accessible for approach with a suitable instrument so that the size, shape, degree of infiltration, etc., can be estimated in relation to radium applications. Badly infected tumors or those with miliary or large abscesses are to be avoided. Severe local and constitutional reactions with sloughing of the tumor mass may occur when a large amount of radon is inserted into a badly infected tumor. Various methods of applying the physical agents have been advocated. The method which appears most suitable for operable rectal and anal cancer consists of external irradiation in all cases, in combination with the use of either (1) gold-filtered non-removable radon seeds, or (2) local applications administered by way of the rectum with specially constructed applicators.