What is the pathophysiology of a brain tumor?

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Last updated: April 3, 2025View editorial policy

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From the Guidelines

A brain tumor is a mass of abnormal cells that grow uncontrollably in the brain, leading to increased pressure, damage to surrounding tissue, and interference with normal brain function, with symptoms depending on the tumor's location, size, and growth rate. The development of a brain tumor is a complex process that involves genetic mutations, uncontrolled cell division, and disruption of normal brain function [ 1 ]. Brain tumors can be benign or malignant, primary or metastatic, and their symptoms can vary widely depending on the specific characteristics of the tumor [ 1 ].

Key Characteristics of Brain Tumors

  • They can be benign (non-cancerous) or malignant (cancerous)
  • They begin when genetic mutations cause cells to divide rapidly and continue living when healthy cells would normally die
  • As the tumor grows, it can increase pressure within the skull, damage surrounding brain tissue, and interfere with normal brain function
  • Brain tumors can develop from brain cells (primary tumors) or spread from cancers elsewhere in the body (metastatic tumors)

Symptoms and Treatment

  • Symptoms include headaches, seizures, vision problems, balance issues, personality changes, and cognitive difficulties
  • The specific symptoms depend on the tumor's location, size, and growth rate
  • Treatment typically involves surgery, radiation therapy, chemotherapy, or a combination of these approaches, with the goal of removing or shrinking the tumor while preserving brain function [ 1 ]
  • Surgical options include stereotactic biopsy, open biopsy, subtotal resection, or complete resection (gross total resection), and radiation oncologists use several different treatment modalities, including brachytherapy, stereotactic fractionated RT, and stereotactic radiosurgery (SRS) [ 1 ]

Prognosis and Quality of Life

  • The prognosis for brain tumor patients varies widely depending on the type and grade of the tumor, as well as the patient's overall health and response to treatment [ 1 ]
  • Glioblastoma is the most lethal brain tumor, with only a third of patients surviving for 1 year and fewer than 5% living beyond 5 years [ 1 ]
  • Anaplastic oligodendrogliomas have a much better prognosis than anaplastic astrocytomas and glioblastomas due to their marked sensitivity to chemotherapy [ 1 ]

From the Research

Brain Tumor Overview

  • Brain tumors are common and require a basic understanding of their diagnosis and management 2
  • The most prevalent brain tumors are intracranial metastases from systemic cancers, meningiomas, and gliomas, specifically glioblastoma 2

Treatment Options

  • Bevacizumab, temozolomide, and radiotherapy are three therapeutic methods used to treat brain tumors, with the combination of these methods still under investigation 3
  • Temozolomide has shown promise in treating malignant gliomas and other difficult-to-treat tumors, with a per os imidazotetrazine second-generation alkylating agent that enters the cerebrospinal fluid and does not require hepatic metabolism for activation 4
  • Immunotherapy efficacy in brain tumors is being investigated, with different doses and timing of immunotherapy following temozolomide treatment being studied to eradicate tumor cells and alter tumor mutational burden 5

Treatment Outcomes

  • Adding bevacizumab to standard therapy improved progression-free survival in patients with newly diagnosed glioblastoma, with a pooled 6-month progression-free survival rate of 79% vs. 56% 3
  • Temozolomide treatment outcomes have been studied, with clinical trials showing that standard of care, dose-intensive, and metronomic temozolomide regimes are not able to completely eradicate glioblastoma 5
  • A phase II trial of pembrolizumab in combination with bevacizumab for untreated melanoma brain metastases showed a brain metastasis response rate of 54.1% and a median overall survival of 4.3 years 6

Adverse Events

  • Adverse events occurred in 62% of bevacizumab-treated patients, with common complications including fatigue, thrombocytopenia, and thromboembolic events 3
  • Grade 3 treatment-related adverse event rates from bevacizumab and pembrolizumab were 10.8% and 18.9%, respectively 6

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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