The prognostic impact of histology and 1p/19q status in anaplastic oligodendroglial tumors

Abstract

BACKGROUND.It has been reported previously that the combined loss of chromosomal arms 1p and 19q is a significant predictor of outcome for patients with anaplastic oligodendroglial (AO) tumors and that such chromosomal loss correlates with classic histology in AO. The authors sought to determine whether histology was an equivalent or superior predictor of outcome compared with 1p/19q status in 131 patients with AO tumors. METHODS.The status of 1p and 19q was determined using real-time, quantitative polymerase chain reaction analysis and/or fluorescence in situ hybridization.Clinical features (response to adjuvant therapy and tumor location) and molecular genetic abnormalities (9p and 10q deletions, overexpression of p53 and epidermal growth factor receptor) were determined on available specimens. Histologic assessments for classic oligodendroglial features were performed by five neuropathologists. RESULTS.Classic histology was associated closely with 1p/19q loss, as reported previously. Patients who had tumors that were considered classic by at least four of the five neuropathologists showed significantly increased progression-free and overall survival compared with the patients who had less classic tumors. The authors also tested the correlation between 1p/19q status and outcome in subsets of patients stratified according to classic tumor features. The association of 1p/19q status with survival was related closely to the presence of classic histology. Loss of 1p/19q was predictive of improved outcome only among patients who had tumors with classic histologic features. CONCLUSIONS.The current results suggested that, in addition to 1p/19q status, histologic features contribute information to the prediction of outcome in patients with AO. Loss of 1p and 19q appeared to be a prognostic marker only in the subset of patients who had AO tumors with classic histologic features. Cancer 2005;104: 1468 -77.

Identification of genomic aberrations associated with shorter overall survival in patients with oligodendroglial tumors

“…20,[30][31][32][33][34][35] With respect to the prognostic significance of genetic alterations, previous reports have mostly focussed on 1p/19q deletions, which were found to be significantly associated with longer survival of patients with oligodendroglial tumors. 10,12,[14][15][16][17]36 In line with these data, we found that combined 1p and 19q losses were associated with a better prognosis in our patients (increase in median patient survival of around 70 months, i.e. 5.8 years).…”

“…6,9 Several of the genetic aberrations in oligodendroglial tumors have been associated with patient outcome. Most importantly, a number of retrospective [10][11][12][13][14][15] as well as recent prospective studies 16,17 have identified 1p/19q deletion as a powerful molecular marker of prolonged survival. Relatively few studies have addressed the prognostic role of other genomic alterations in oligodendroglial tumors.…”

Oligodendrogliomas: Molecular Biology and Treatment

“…However, the outcome of patients with non-1p/19q codeleted tumors but with typical histological appearance was reported to be equally favorable in a large prospective U.S. trial [17]. Another study reported loss of 1p and 19q to be related, in particular, to outcome in patients with tumors with classic histologic features [27].…”

“…The 1p/19q codeletion is present in 61%-89% of AOD cases, but in only 13%-20% of patients with AOA [6,27]. Of note, McDonald et al [27] confirmed the close association between CFO and 1p/19q codeletion, with a higher likelihood of 1p and 19q loss if more pathologists judged the tumor to be CFO.…”

“…However, if 1p and 19q loss was accompanied by unfavorable alterations, the prognosis was poor. Others have reported that the prognostic impact of 1p and 19q loss is mainly present in tumors with classic AOD morphology, but not in oligodendroglial tumors with atypical features or in mixed AOAs [6,27].…”