The effects of tumor size and postoperative radiotherapy for patients with adult low-grade (WHO grade II) infiltrative supratentorial astrocytoma/oligodendroglioma: A population-based and propensity score matched study

A systematic review and meta-analysis informing the role of adjuvant radiotherapy (RT) in Grade 2 and 3 oligodendroglioma

BACKGROUND AND PURPOSE

Evidence and clinical guidelines support the use of adjuvant RT in high-risk low-grade gliomas. However, patients with oligodendroglioma have a more indolent disease course and delaying or avoiding RT is often considered to reduce treatment-related toxicities. As the optimal adjuvant management for oligodendroglioma is unclear, we aimed to assess the effect of adjuvant RT on overall survival (OS) and progression-free survival (PFS).

METHODS

MEDLINE, EMBASE, CENTRAL and CINAHL were searched from January 1990 to February 2023 for studies comparing adjuvant RT versus no adjuvant RT for patients with oligodendroglioma.

RESULTS

This review found 17 eligible studies including 14 comparative retrospective studies and 3 randomized controlled trials. Using random-effects model, the results suggested that adjuvant RT improved OS by 28 % (HR 0.72, 95 % CI (0.56-0.93), I2 = 86 %), and PFS by 48 % (HR 0.52, (95 % CI 0.40-0.66), I2 = 48 %) compared to patients without adjuvant RT. Subgroup analysis showed that upfront adjuvant RT improved OS and PFS compared to salvage RT. There were no significant differences in OS and PFS between adjuvant RT versus adjuvant chemotherapy. There was improvement in PFS but not OS for adjuvant chemoradiotherapy versus adjuvant chemotherapy alone. Adjuvant RT improved OS in WHO Grade 3 but not WHO Grade 2 oligodendroglioma.

CONCLUSION

Overall, adjuvant RT improved OS and PFS in patients with oligodendroglioma. In patients with low-risk features (e.g. Grade 2, gross total resection), alternative approaches and individualization of management such as adjuvant chemotherapy alone may be reasonable considering the lack of survival benefit. Future efforts should prospectively investigate these treatment regimens on molecularly-classified oligodendroglioma patients (defined by presence of IDH mutation and 1p/19q co-deletion), balancing between maximizing survival outcomes and reducing RT-related toxicities.

Nomogram to Predict the Prognosis of Oligodendroglioma Patients Undergoing Postoperative Adjuvant Chemoradiotherapy

OBJECTIVE

The aim of this study was to develop a prognostic nomogram for predicting the prognosis of oligodendroglioma patients receiving combined chemoradiotherapy (CRT) after surgery.

METHODS

The study used data from the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2019. The patients were randomly divided into a development cohort (700 patients) and a validation cohort (244 patients) in a 7:3 ratio. The Cox hazards regression model was used to identify predictors, and a nomogram was constructed to visualize the prognosis. The performance of the prognostic nomogram was evaluated using the consistency index (C-index), clinical net benefit, and calibration.

RESULTS

The nomogram included 5 variables: age, marital status, tumor size, site of lesions, and surgery type. The C-index of the training set and validation set were 0.77 and 0.68, respectively. The calibration plots showed that the nomogram was in good agreement with the actual observation. The clinical decision curve indicated that the nomogram had a good clinical net benefit in oligodendroglioma patients receiving CRT after surgery.

CONCLUSIONS

This study established and verified a prognostic nomogram for a large cohort of oligodendroglioma patients receiving CRT after surgery based on the SEER database. The nomogram may help clinicians provide personalized treatment services and clinical decisions for patients.

Prognosis of Oligodendroglioma Patients Stratified by Age: A SEER Population-Based Analysis

Purpose

Glioma may affect patients of any age. So far, only a limited number of big data studies have been conducted concerning oligodendroglioma (OG) in diverse age groups. This study evaluated the risk factors for OG in different age groups using the Surveillance, Epidemiology, and End Results (SEER) database built by the National Cancer Institute, which is part of the National Institutes of Health.

Patients and Methods

A total of 5437 cases within the SEER database were included. These patients were divided into seven age groups. The Kaplan-Meier method was employed for survival analysis. The independent risk factors for the survival of OG patients were identified using the Cox regression model. A nomogram was drawn with R software based on the independent risk factors. The X-tile software was adopted to find the optimal age group at diagnosis.

Results

The all-cause mortality and the tumor-specific mortality increased with age. The univariate analysis showed that the patients' age, gender, primary lesion location, side affected by the primary lesion (left or right), surgery for the primary lesion, and tumor size were correlated with survival (P<0.05). Multivariate Cox regression analysis showed that age was an independent risk factor for the survival of OG patients (P<0.05). The optimal cutoff value of age in terms of overall survival (OS) and cause-specific survival (CSS) were identified as 48 and 61 years and 48 and 59 years, respectively.

Conclusion

The older the age, the worse the survival would be. That's, the mortality increased with age. In the clinic, healthcare professionals should be fully aware of the variability in the prognosis of OG patients in different age groups. Therefore, individualized treatments are recommended to OG patients in different age groups to optimize the prognosis.

Clinical Characteristics and Overall Survival Prognostic Nomogram for Oligodendroglioma: A Surveillance, Epidemiology, and End Results Population-Based Analysis

OBJECTIVE

Oligodendroglioma is a rare primary malignant brain tumor that has highly variable clinical outcomes. The aim of this study was to investigate demographics, outcomes, and prognostic factors of all oligodendroglioma cases from the Surveillance, Epidemiology, and End Results database to build a clinical prognosis model to predict survival time of patients with oligodendroglioma.

METHODS

Cases diagnosed between 1975 and 2016 were selected from the Surveillance, Epidemiology, and End Results database. Age, sex, race, insurance, year of diagnosis, marital status, tumor location, tumor size, summary stage, surgery method, and use of radiotherapy and chemotherapy were evaluated with respect to overall survival by univariate and multivariate analysis. A nomogram predicting 5- and 10-year survival probability for oligodendroglioma was constructed and validated.

RESULTS

After data cleaning, 4568 patients with oligodendroglioma were included. At the time of last follow-up, mean survival times among grade II and grade III oligodendrogliomas were 74 and 39 months, respectively. In multivariate analysis, radiotherapy, age, tumor site, summary stage, and surgery demonstrated independent associations with survival in both cohorts. Race and radiotherapy demonstrated independent associations with survival in grade II oligodendroglioma. Sex and chemotherapy demonstrated independent associations with survival in grade III oligodendroglioma. Independent factors in either cohort were selected to build a clinical nomogram. The C-index for the nomogram was 0.738 (95% confidence interval 0.718-0.757). The calibration curves of 5- and 10-year survival rates showed good agreement between the nomogram predictions and actual observations.

CONCLUSIONS

This study was the first to develop a nomogram for predicting overall survival of patients with oligodendroglioma to help clinicians predict patient prognosis accurately and conduct further treatment.

The effects of tumor size and postoperative radiotherapy for patients with adult low-grade (WHO grade II) infiltrative supratentorial astrocytoma/oligodendroglioma: A population-based and propensity score matched study

Background

The update of 2018 NCCN guidelines (central nervous system cancers) recommended the risk classification of postoperative patients diagnosed as adult low‐grade (WHO grade II) infiltrative supratentorial astrocytoma/oligodendroglioma (ALISA/O) should take tumor size into consideration. Moreover, the guidelines removed postoperative radiotherapy (PORT) for low risk patients. Our study aimed to explore the specific tumor size to divide postoperative patients into relatively low‐ or high risk subgroups and the effect of PORT for ALISA/O patients.

Methods

We conducted a retrospective study choosing 1277 postoperative ALISA/O patients from the Surveillance, Epidemiology, and End Results database. The X‐tile analysis provided the optimal cutoff point based on tumor size. The differences between surgery alone and surgery +RT groups were balanced by propensity score‐matched analysis. The multivariable analysis and the nomogram evaluated multiple prognostic factors based on cancer‐specific survival (CSS) and overall survival (OS).

Results

X‐tile plots defined 59 mm (P < 0.001) as the optimal cutoff tumor size value in terms of CSS, which was verified in multivariate analysis (P < 0.001). The Kaplan‐Meier analysis showed that the surgery alone had higher CSS and OS than surgery +RT, while the low risk group had no statistical significance after propensity score match. Multivariable analysis showed that surgery +RT was independently associated with diminished OS and CSS for high risk group, which had no statistical significance for low‐risk group.

Conclusions

Our study suggested that tumor size of 59 mm was an optimal cutoff point to divide postoperative patients into relatively low‐ or high risk subgroups. PORT may not benefit patients, while the effects of PORT for low risk patients need further research.