Telecobalt Therapy of Early Malignant Tumors of Vocal Cord

Squamous-cell carcinoma limited to movable vocal cords is highly radio-curable. There have been many fine presentations on this subject (1–3), with the reporting of material for glottic, sub-glottic, and supraglottic lesions. All these have been broken down into their respective stages, and the cure rate for the early cord lesion is approximately 90 per cent. We wish to present an analysis of our first 100 cases of carcinoma of the vocal cords treated by telecobalt therapy, beginning with our first patient, in whom therapy was completed in 1958, and including those treated up to one and a half years ago. The method of analysis will be one discussed by the American Joint Committee for Cancer Staging and End Result Reporting (4) and is called the actuarial or life-table method. This utilizes all survival information accumulated up to the closing date of the study and describes the manner in which the patients were depleted during the total period of observation. Classification The clinical staging of our patients was developed by the Joint Committee for Cancer Staging and End Results Reporting (5). In all, the lesions were limited to one or both vocal cords and in some the antenor commissure was also involved. These would mainly be T1, NO, MO lesions, but those with both cords involved would be T2, NO, MO. This would correspond in Lederman's classification to Stage I and part of Stage II. As will be demonstrated subsequently, we have included all of these in our report because we have found no significant difference in the effectiveness of treatment in the two groups. Materials and Methods All 100 patients included in this study have been followed for at least one and a half years. More than half have been followed for three years and some for six. The ages range from thirty-three to seventy-five years, with the usual male to female sex distribution. In recent years, the number of patients entering this study has been approximately 30 per year. a great increase over the earlier period. All patients were treated with telecobalt therapy, using lateral, parallel opposing, 6 × 6 cm fields measured at the midline. The dose range varied between 6,000 and 7,000 rads, the total being somewhat dictated by the patient's individual tissue reaction. Early in this study the maximum dose was set at 7,000 rads, but this has been reduced to 6,500 rads with no apparent failures due to the reduction. Treatments were administered at the rate of 1,250 rads per week for a total treatment time of approximately five and a half weeks. The source-tumor distance was 75 cm. Each patient was examined frequently, particularly near the end of the course of therapy. Results Out of the entire group of 100 patients, 8 were subjected to laryngectomy for persistent disease, and they are included in this study as treatment failures.