This article is more than 5 years old. Information may no longer be current.
Chemotherapy plus radiation failed to extend OS in adults with low-grade glioma
Click Here to Manage Email Alerts
The addition of chemotherapy to radiation improved PFS but did not extend OS in adults with low-grade glioma, according to study results.
A post-hoc analysis of patients who survived beyond 2 years began to show a survival advantage among patients who underwent the combination regimen, however.
Edward G. Shaw, MD, professor of radiation oncology at Wake Forest School of Medicine, and colleagues enrolled 251 patients between 1998 and 2002. All patients had WHO grade 2 astrocytoma, oligodendroglioma or mixed oligo-astrocytoma.
The patients were randomly assigned to radiation therapy alone (n=126) or procarbazine, lomustine and vincristine (PCV) chemotherapy plus radiation (n=125).
All patients received the same radiation therapy — 54 Gy given in 30 fractions of 1.8 Gy each during 6 weeks.
The chemotherapy regimen consisted of six cycles of postradiation procarbazine (60 mg/m2 orally per day on days 8 through 21 of each cycle), lomustine (110 mg/m2 orally on day 1 of each cycle) and vincristine (1.4 mg/m2 IV on days 8 and 29 of each cycle). Each cycle lasted 8 weeks.
The primary endpoint was OS. Secondary endpoints included PFS and grade 3 or higher toxicity. Researchers compared survival using modified Wilcoxon and log-rank tests.
At the time of data collection, 88 (35%) of the patients had died. Median follow-up for all patients still alive was 5.9 years.
Patients assigned to radiation therapy alone demonstrated similar 2-year OS (87% vs. 85%) and 2-year PFS (75% vs. 74%), according to study results.
However, the OS and PFS curves separated significantly after 2 years.
Five-year OS was 72% among patients in the combination arm vs. 63% for patients assigned to radiation therapy alone (HR=0.72; 95% CI, 0.47-1.10), according to study results.
Five-year PFS was 63% among patients in the combination arm vs. 46% among patients assigned to radiation alone (HR=0.6; 95% CI, 0.41-0.86).
Among the 211 patients who survived at least 2 years, the probability of an additional 5 years of OS was 74% among those assigned to the combination regimen vs. 59% among those assigned to radiation therapy alone (HR=0.52; 95% CI, 0.3-0.9).
Patients assigned to the combination regimen reported higher rates of hematologic toxicity (51% vs. 8% for grade 3; 15% vs. 3% for grade 4; P<.001).
“In the post hoc subset analysis, the addition of [chemotherapy] to radiation therapy conferred an advantage to both OS and PFS, reducing the risk of death by 48% and progression by 56%,” Shaw and colleagues wrote. “These data suggest a possible delayed survival benefit for chemotherapy.”
Disclosure: Dr. Shaw reports no relevant financial disclosures.
Collapse
Click Here to Manage Email Alerts