THE ADDITION OF CARBOGEN AND NICOTINAMIDE TO A PALLIATIVE FRACTIONATION SCHEDULE FOR LOCALLY ADVANCED BREAST-CANCER

Tumour cell hypoxia is a recognized cause of resistance to radiotherap y. Using clinically relevant dose-fractionation schedules in a mouse t umour model, the addition of carbogen and nicotinamide to overcome chr onic and acute hypoxia results in a marked increase in radioresponsive ness with a lower degree of sensitization in normal tissue. Carbogen a nd nicotinamide were added to the palliative radiation treatment given to six patients with locally advanced breast cancer. The aim of the p ilot study was to determine if patients tolerated the addition of carb ogen and nicotinamide and to assess if there was any increase in radio sensitivity of the skin. Patients received 30 Gy prescribed to the int ersection dose in six fractions over 17/18 days with full skin bolus t o the tumour. All patients were given 6 g of nicotinamide orally 90 mi n before radiation treatment. Carbogen breathing was started 5 min pri or to treatment and continued during it. Patients tolerated the treatm ent well, with vomiting in one patient being the only side effect that could be related to the nicotinamide, and this settled with an anti-e metic. No increase in skin reaction was noted with the addition of car bogen and nicotinamide, and good tumour regression was achieved.