VARIATIONS IN THE NATURAL-HISTORY AND SURVIVAL OF PATIENTS WITH SUPRATENTORIAL LOW-GRADE ASTROCYTOMAS

DATA FROM 55 consecutive patients with low-grade astrocytomas treated between 1982 and 1990 were analyzed to determine specific outcome fact ors, including time to recurrence, incidence of anaplastic transformat ion, and survival. Gender, type of symptoms, contrast enhancement, and timing of radiation therapy were not significant in determining outco me. Patients who had symptoms for >2 years and underwent gross-total r esection of the tumor, with age as a continuous variable, were associa ted with significantly longer time to recurrence and survival. Within the population of patients with low-grade astrocytomas, patients with chronic epilepsy clearly had the best prognoses. There were no tumor r ecurrences or deaths in 27 patients with chronic epilepsy, regardless of the extent of surgery and without the use of radiotherapy. Ten-year survival was 100% for 31 patients who underwent gross-total tumor res ection, regardless of the length of preoperative symptoms. Immediate p ostoperative radiotherapy did not prolong the time to recurrence, redu ce the incidence of transition to more malignant tumors at recurrence, or increase the length of survival when compared with delayed radioth erapy. Because recurrence with a high-grade lesion caused 92% of the m ortality in our series, the benefit in patients who underwent aggressi ve surgery seems to result from a significant decrease in the risk of recurrence when compared with patients who underwent anything less tha n gross-total resection. Our data also suggest that variability in the natural history of low-grade astrocytomas has a strong influence in d etermining survival and that tumors associated with chronic epilepsy a re much less likely to become more malignant over time.