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The
conditional probabilities of survival in patients with anaplastic astrocytoma or
glioblastoma multiforme
Lin CL, Lieu AS, Lee KS, Yang YH, Kuo TH, Hung MH, Loh JK, Yen CP, Chang CZ,
Howng SL, Hwang SL
Division of Neurosurgery, Kaohsiung Medical University Hospital,
Kaohsiung, Taiwan.
Background. By the use of conditional probabilities of survival,
we studied the yearly survival rates for individual tumor survivors.
Methods. Conditional survival rate was estimated in 114
consecutive patients with anaplastic astrocytoma or glioblastoma
multiforme.
Conditional probabilities of surviving some years given survival to a specific
period of time after craniotomy and 95% confidence intervals were calculated in
the individual tumor survivors.
Results. The estimated median survival was 30 months for 45
patients with anaplastic astrocytoma and 12 months for 69 patients with
glioblastoma multiforme.
The conditional probabilities of surviving next one year given survival to 1
year, 2 years, 3 years, 4 years, or 5 years after craniotomy for anaplastic
astrocytoma were 86.2%, 75.0%, 85.9%, 77.8%, or 85.7%, respectively; for
glioblastoma multiforme 64.8%, 58.7%, 85.7%, 80.0%, or 75.0%,
respectively.
The conditional probability of surviving to 5 years given survival to 2 years
after craniotomy for anaplastic astrocytoma, i.e., surviving an additional 3
years, was 50.1%, which was better than observed 5-year survival rate (28.6%);
for glioblastoma multiforme it was 40.2%, which also was better than observed
5-year survival rate (12.4%).
Conclusions. The conditional probability of survival was a
good method to clinically predict yearly survival rate for individual tumor
survivors.
In addition, the method can estimate the probabilities of surviving next some
years given survival to a specific period of time after craniotomy.
It also showed a more encouraging result than observed survival rate in patients
with supratentorial malignant astrocytomas.
PMID: 14572960 [PubMed - indexed for MEDLINE]
 Abstract
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