THE ROLE OF RADIOTHERAPY IN INSITU CARCINOMA OF THE LARYNX

Twenty patients with in situ carcinoma of the vocal cord treated with radical radiotherapy over a 16-year period have been assessed for local control and survival. Seventy-one patients with Stage T1 invasive carcinomas treated in the same period have been similarly assessed and the results are compared. All patients were treated with megavoltage wedge pair techniques using fields of mean size 4.5 × 4.5 cm. Patients were treated to radical intent, the Tis group receiving a mean nominal standard dose (NSD) of 1759 ret and the TI invasive group a mean NSD of 1743 ret. In the Tis group, radiotherapy resulted in local control in 70% ( 14 20) of patients with an ultimate local control, after surgery, of 90% ( 18 20). This is not statistically different to the primary local control rate for T1 invasive lesions of 83% ( 59 71) with an ultimate control rate, after surgery, of 94% ( 68 71), χ2 P > 0.2. Five and 10-year actuarial survival rates were 100% in the Tis group and 96.8% and 92.6%, respectively, in the T1 invasive group χ2 p = 0.275). Five and 10-year actuarial recurrence-free survival rates were 78.8% and 69% for the Tis group and 86.1% and 78.4% for the T1 invasive group (χ2 p = 0.548). Analysis of failures suggests that extent of disease, field size, and total dose given are not contributory factors to local control or survival in this group of patients. There is no indication that in situ lesions respond to radiotherapy less favorably than T1 invasive lesions and we would support the use of radiotherapy as a therapeutic option in this condition. © 1990.