Progress in long-term survival in adult patients with supratentorial low-grade gliomas: a population-based study of 993 patients in whom tumors were diagnosed between 1970 and 1993.
OBJECTIVE
The goal of this study was to document and compare long-term survival during the periods 1970 through 1981 and 1982 through 1993 in all adult patients in Norway with histologically verified supratentorial low-grade gliomas (LGGs).


METHODS
Nine hundred ninety-three patients 15 to 69 years of age were found to have a primary supratentorial diffuse astrocytoma, oligodendroglioma, oligoastrocytoma, or pilocytic astrocytoma. Survival time was analyzed in all patients and, in a subset of 451 patients, the influence of new imaging methods on the time from symptom onset to imaging diagnosis was estimated. Overall median survival was 6.4 years (95% confidence interval [CI] 5.7-7.1 years). Survival times for patients in whom a diagnosis was made between 1970 and 1981 (397 patients) and between 1982 and 1993 (596 patients) were 4.1 years (95% CI 3.3-4.9 years) and 9.2 years (95% CI 7.9-10.6 years), respectively (p < 0.0001). Survival also improved in the later period within each histological subgroup. In patients in whom a biopsy was performed the median length of survival was 6.4 years (95% CI 3.1-9.7 years); in patients treated with subtotal tumor resection it was 6.8 years (95% CI 5.8-7.7 years); and in those treated with gross-total tumor resection it was 7.6 years (95% CI 5.5-9.7 years), a nonsignificant difference (p = 0.59). A considerable age-dependent variation in overall survival was demonstrated. The availability of computerized tomography (CT) scanning and/or magnetic resonance (MR) imaging as a diagnostic tool reduced the median period of symptoms prior to diagnosis by 6 months.


CONCLUSIONS
Long-term overall survival significantly improved, but age-related differences in prognosis persisted. The increased sensitivity of the diagnostic method due to the availability of CT scanning and/or MR imaging may partly, but not entirely, account for the observed magnitude of improvement in overall survival. Thus local tumor treatment improved during the study period.
Johannesen
Tom B
TB
Norwegian Cancer Registry, Institute of Population-Based Cancer Research, Oslo, Norway. tomj@trollnet.no
Langmark
Frøydis
F
Lote
Knut
K
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005910:Glioma / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D011159:Population Surveillance; D012720:Severity of Illness Index; D015173:Supratentorial Neoplasms / Q000175:diagnosis / Q000401:mortality* / Q000628:therapy; D015996:Survival Rate; D013997:Time Factors; D014057:Tomography, X-Ray Computed