Local control of oropharyngeal carcinoma after two accelerated hyperfractionation radiation therapy schemes.

In October 1979 we started an accelerated hyperfractionation program consisting of 1.6 Gy/fraction, 2 fractions/day for 12 days or 38.4 Gy. Due to acute toxicity, the patients were then given a 2-week break and resumed once daily radiation therapy with 1.8 Gy/fraction up to 65 Gy, designated as the b.i.d.-q.d. program. In August 1982, the program was changed and the latter part of the treatment was continued on the twice daily program with 1.6 Gy/fraction for a total of 64 Gy, designated as the b.i.d.-b.i.d. program. We evaluated the local control rates of 140 patients with squamous cell carcinomas arising from the oropharynx, that is faucial tonsil and base of tongue. After these treatment regimens, the 36 month actuarial local rates for the T1-4 lesions were 56% for b.i.d.-q.d. (52 patients) and 85% for b.i.d.-b.i.d. (88 patients) with a p value of 0.0013. For the T1-2 lesions the corresponding rates were 81% (13 patients) and 97% (44 patients) with a p value of 0.53. The difference was marked for the T3-4 lesions, that is 47% vs 77% respectively with a p value of 0.017, and those patients without nodal metastases, that is 46% vs 93% with a p value of 0.00043. The improvement was probably due to marked shortening of the overall treatment course following b.i.d.-b.i.d. accelerated program--in this case 1 1/2 weeks. Our preliminary data suggests that the b.i.d.-b.i.d. program is superior to the b.i.d.-q.d. program. The seemingly improved local control rates for the treatment of oropharyngeal carcinomas requires a clinical prospectively randomized trial for confirmation, that is b.i.d.-b.i.d. versus b.i.d.-q.d. versus standard fractionation (q.d.) program.