Does 'up front boost' accelerated hyperfractionated radiation therapy affect local control of T3 carcinomas of the head and neck?

Purpose/objective: With fraction sizes of 1.6 Gy given two times daily (BID) for carcinoma of the head and neck, the acute mucosal effects frequently require a mid-course pause or 'break' after a dose of 38.4 Gy before the entire treatment course can be completed. An attempt was made to reduce the mucosal toxicity by using a small initial portal so that the dose to normal mucosal membranes would be limited. This program should improve the mucosal tolerance with increased dose delivered before the mid-course break. To test this hypothesis, we started a modified BID program (MBID) with an 'up front boost' technique 6 years ago for the treatment of advanced carcinomas. This paper presents an analysis of local control for T3 carcinomas related to pre-break doses, duration of treatment gap, total treatment time and total dose after the modified accelerated fractionation. Materials and methods: >From 1979 to 1994, total of 213 patients with T3 squamous cell carcinoma of the oropharynx and larynx treated by accelerated hyperfractionated radiation therapy with fraction size of 1.6 Gy/f twice-daily were available for statistical analysis. Of these, 144 were treated with BID and 69 with MBID programs. Their records were reviewed, and the radiation treatment dates, up front boost doses, total doses, duration of treatment gap and total treatment time were entered into the database for computerized statistical analysis. There were 150 males and 63 females. There were 32 patients with carcinoma of the base of the tongue, 39 with carcinoma of the tonsil, 38 with glottic and 104 with supraglottic carcinomas. Results: The treatment parameters of the BID and MBID radiation therapy are as following: The 5-year actuarial local control and disease specific survival rates after BID were 67% and 64% respectively and the corresponding rates after MBID were 83% and 84%. These rates of local control and DSS were compared with Log-Rank test and the differences were statistically significant with p=0.04 and 0.003, respectively, as shown in the attached figures. Conclusion: Our data indicate that: (1) the MBID program allows higher doses prior to treatment break and improves local control of T3 carcinomas of the oropharynx and larynx. The initial pre-break doses are still limited to 48-50 Gy in approximately 3(1(2)) weeks, which probably represents the maximal tolerant limit of the mucosa of the oropharynx without acute and late sequelae. (2) The MBID program did not prolong the duration of the gap or the total treatment time, and yet the total dose was increased to 72 Gy without great difficulties. (3) In spite of further escalation of the pre-break treatment dose and total doses, no significant late detrimental effects have been observed