Purpose: A prospective phase II trial was conducted by the Institute of Oncology, istanbul University in December 1994 on patients with locally-advanced non-small cell lung cancer to assess acute toxicity and the feasibility of a combination of radiosensitizer and accelerated radiotherapy with concomitant boost. Materials and methods: Patients were irradiated using 'large' fields (primary tumour and locoregional lymph nodes) with 1.8 Gy per fraction, five fractions a week. Reduced 'boost' fields (primary and involved nodes only) were also irradiated twice-weekly 1.8 Gy per fraction in ten fractions concomitantly 6 h after the administration of large field. Total radiation dose was 63 Gy in 5 weeks (45 Gy 'large' fields and 18 Gy 'boost'). The maximum allowed dose to the spinal cord was 3750 cGy. Cisplatinum, 6 mg/m(2) was given daily just before 'large' field irradiation, Results: As of January1997, 15 patients were evaluated (median follow-up of 12.5 months with a range of 5.5-23 months). The overall acute toxicity rate was 38% and Grade 3 acute toxicity was 8%. Grade 4 or greater acute toxicities were not observed. The overall rate of cisplatinum-induced nausea and vomiting was 80% (severe in 60%), but all were easily treated with antiemetics. Complete response rate (clinical and radiological) was 40% and an overall response rate was 73%. Median survival was 16 months and progression-free survival was 5.5 months (range of 2.5-21 months). Conclusions: Toxicity was well tolerated and no treatment-related death occurred with this combined treatment regimen. Although it appears that better local control rates can be achieved, additional phase II/III studies are needed. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.