NEUTRON VS PHOTON RADIATION-THERAPY FOR INOPERABLE REGIONAL NONSMALL CELL LUNG-CANCER - RESULTS OF A MULTICENTER RANDOMIZED TRIAL

Purpose: To determine, with a prospective, multicenter randomized stud y, whether fast neutron radiation therapy improves the outcome for pat ients with non-small cell lung cancer, as compared to conventional pho ton radiotherapy. Methods and Materials: From September 1986 to March 1991, a total of 200 patients with inoperable regional non-small cell lung cancer were randomized to 20.4 Gy in 12 fractions with neutrons v ersus 66 Gy in 33 fractions with photons. Inoperable patients with Rad iation Therapy Oncology Group Stages I, II, III, or IV(MO) disease, Ka rnofsky Performance Score greater-than-or-equal-to 70, and who had rec eived no previous therapy for their non-small cell lung cancer were el igible for the study. Of the 200 patients randomized, a total of 193 p atients, 99 on the neutron arm and 94 on the photon arm, were eligible for analysis. The two treatment groups were balanced with regards to prognostic factors. At the time of this analysis, the median at-risk f ollow-up was 33 months, with a minimum follow-up of 16 months. Results : No difference in overall survival was observed; however, there was a statistically significant improvement in survival for patients with s quamous cell histology (p = 0.02), and a trend toward improved surviva l for those with favorable prognostic factors (i.e., patients who were not T4, N3, and had no pleural effusion or weight loss > 5% from base line) (p = 0.15), favoring the neutron-treated group. With the excepti on of skin and subcutaneous changes, acute and late toxicity was simil ar in both arms. Conclusion: In selected patients with inoperable regi onal non-small cell lung cancer (e.g., squamous cell histology, favora ble prognostic factors), fast neutron irradiation provides a therapeut ic benefit over conventional photon radiotherapy.