#260 Gamma Linolenic Acid is a Radiation Response Modifier of the Human Nervous System and May be Clinically Important. PN Plowman; St. Bartholomew’s Hospital, London, UK Our previous laboratory data demonstrated that gamma linolenic acid (GLA: and omega 6 essential fatty acid) modifies the damage to rat spinal cord affected by a single dose radiation (Brit J Radiol 1996; 69:374-5). In a clinical study of radiosurgery for large brain AVM (more than 15cc target volume), there was, amongst 34 patients treated without GLA (median follow-up 27 months, range 11-65), an obliteration rate of 41% and a complication rate of 20%. However, when we treated the nest cohort of 28 similar patients (median follow-up 24 months, range 13-45) on the same radiosurgical protocol and followed by 4 months of GLA the obliteration rate was reduced to 5%(p=0.02) and the complication rate to 0% (p=0.05); (Brit J Neurosurg 2000-in press). GLA was non-toxic. We concluded that there was no improvement in the therapeutic ratio for AVM (i.e. vascular damage). However the implications of these observations for neuro-oncology are far reaching for what we have described is a "post-hoc" radiation response modifier for the human nervous system: 1. The routine use of this agent after radiation accidents is recommended. 2. The use of GLA, during/after radiation prophylaxis for childhood ALL, oat cell cancer and whole brain radiation therapy for metastases or chemo-radiation therapy protocols must be studied for neuropsychological risk reduction. 3. It may well be possible to increase the dose of radical radiation therapy for primary brain tumors in conjunction with this radiation response modifier (thus leading to an improved therapeutic ratio) and perceived standard radiation tolerance levels of the human CNS may need to be modified upwards. Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.