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Prognostic factors associated with survival in patients with diffuse astrocytoma

Original author: Liu S, Liu X, and Zhuang W (2021) (DOI: 10.3389/fsurg.2021.712350)



Content writer – Clinical

February 08, 2023


Astrocytomas are the most common primary tumors in the central nervous system (CNS). These tumors arise from astrocytes—star-shaped cells that make up the “glue-like” or supportive tissue of the brain. The diagnosis is based primarily on histopathological criteria defined by the World Health Organisation (WHO) that grades astrocytomas as pilocytic astrocytoma (grade I), diffuse astrocytoma (grade II), anaplastic astrocytoma (grade III), and glioblastoma (grade IV).

Diffuse astrocytomas (DA) are grade II astrocytomas also known as low-grade astrocytomas.  DA consists of fibrillary astrocytoma, protoplasmic astrocytoma, and gemistocytic astrocytoma. Diffuse astrocytoma is a slow-growing brain tumor. They are infiltrating tumors with ill-defined borders. Although diffuse astrocytoma is a relatively slow-growing tumor with a median survival time of 5-8 years, they have a high recurrence rate due to diffuse infiltration of brain tissue and an inherent malignant potential to transform into high-grade astrocytomas. Clinical symptoms of DA vary depending on the location of the tumor. Seizures, headaches, and focal neurologic deficits are the most frequent presenting symptoms.  The histopathological diagnosis of a diffuse astrocytoma can be challenging due to its pronounced heterogeneity. Hence, the tumor characteristics and the factors associated with the prognosis are inadequately understood. However, studies about the clinicopathological characteristics of DA are scarce in the literature at present. Factors influencing the prognosis of DA are also unclear. Thus, identifying the factors associated with prognosis and survival rate in DA patients is necessary.


Given this, a population-based cohort study was conducted, utilizing prospectively extracted data from the Surveillance, Epidemiology, and End Results (SEER) database. The patients were collected from the SEER database, documented from 1973-2017. In this retrospective study, the patients diagnosed with primary tumor as DA, according to the International Classification of Diseases for Oncology, Third Edition (ICD-O-3), were identified. The demographic features as well as the clinicopathological characteristics of the patients were also collected. The age of the patient at diagnosis, race, sex, marital status, primary tumor site, histological type, tumor size, surgical treatment, survival duration in months, and survival status were collected in this study. Patients with unclear information on any of the collected variables were excluded.

Kaplan–Meier analysis was used to assess the cancer-specific survival (CSS) stratified by each factor. The clinicopathological factors and CSS were analyzed using Cox proportional hazards model. Statistically significant variables in univariate Cox analysis were further included in multivariate Cox analysis. For each patient, significant prognostic factors were further utilized to prepare a nomogram and then put into the nomogram calculator to get a predicted survival rate at 5- and 10 years. The C-index and receiver operating characteristic (ROC) curve were utilized to evaluate the accuracy of the nomogram. R software (version 3.5.0) was utilized to perform the statistical analysis.


A total of 799 participants with DA were included, consisting of 95.9% fibrillary astrocytoma and 4.1% protoplasmic variants. The average age of participants was 41.9 years, with 57.2% being male. The majority of the population was white (87.5%). More than half (53.9%) of the patients were married. DA arose mostly in the cerebrum (63.8%). Around 71.6% of the population had received surgical treatment. The overall 1-, 3-, 5-, and 10-year survival rates were 73.7, 55.2, 49.4, and 37.6%, respectively. Kaplan–Meier analysis showed that age at diagnosis, marital status, primary tumor site, tumor size, and surgery was possibly associated with cancer-specific survival (CSS) (p < 0.05). Multivariate Cox proportional hazard analysis indicated that surgery was a protective factor whereas older age, larger tumor size, and tumors in the brainstem were harmful factors for patients with DA. Moreover, a nomogram predicting 5- and 10-year survival probability for DA was developed.


In conclusion, the authors proposed that the present study is the largest one to date to investigate the clinicopathological characteristics and survival of patients with DA. They concluded that age, primary tumor site, tumor size, and surgery were associated with the survival of patients with DA. Thus, these outcomes may contribute to the future management of DA patients.

Impact of the research

  1. Help in systematic treatment planning

  2. Predict the prognosis and better treatment outcomes

  3. Personalized or individualistic approach to the management of DA patients

  4. The survival rate of the patients

  5. All the above factors will impact the quality of life of DA patients

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