The feasibility of high-dose multiple daily fractionation and its combination with anoxic cell sensitizers in the treatment of head and neck cancer a pilot study of the Radiotherapy Group of the EORTC (European Organisation for Research on Treatment of Cancer)

From 1978 to the end of 1980, 179 patients with advanced head and neck tumors were accrued in a multicenter pilot study of the EORTC Radiotherapy Group, investigating the feasibility of high dose multiple daily fractionation (MDF) and its combination with misonidazole. The irradiation scheme consisted of three daily fractions of 1.6 Gy (four hour intervals) to a total dose of 48 Gy in two weeks, followed 3 to 4 weeks later by a boost to a total of about 70 Gy in 6 to 7 weeks. Misonidazole was given in daily doses of 1 g/m² (total 13 or 14 g/m²) to 53 patients, thus sensitizing every radiation session. All patients had large head and neck tumors, with a poor prognosis. Acute reactions were well tolerated. Skin reactions were very moderate; mucosal reactions started at day 10 to 12. All patients had a confluent mucositis that lasted for one to two weeks. When the whole oral cavity was irradiated, reactions lasted somewhat longer. The boost caused no significant symptoms. The radiosensitizer did not modify the reaction pattern. Tumor regression was very impressive, so that palliation was obtained quickly. Nine patients died from treatment related causes. It is difficult to assess local control at this time, but at the time of analysis (August 1981), the actuarial control rate was 48% at 20 months, with misonidazole 57%. This difference, however, is not statistically significant. Survival of the total group is 31% at 20 months. In these patients with a heavy tumor burden the early results were considered a success by all participants. For patients with sufficient follow-up, late reactions can be evaluated. Some edema and fibrosis is seen, but did not exceed a degree which could be expected with single daily fractionation to the same dose. This study demonstrates the possibility of giving highly concentrated treatments to total doses equal to those used in conventional fractionation. For assessment of a possible benefit in local control and ultimate survival, a randomized study is necessary. Such a study is now underway in the EORTC Radiotherapy Group, comparing single daily radiotherapy with multiple daily fractionation with or without misonidazole.