Brain Metastases: An Overview

Introduction

The growth of abnormal cells in an uncontrolled way is called cancer. Cancer is named depending on the site it occurs. For example, cancer occurring in the lungs is lung cancer, one occurring in the breast is breast cancer, and so on. When cancer travels from the site at which it first occurred to another site, it is called metastasis. When it travels to the brain, it is called brain metastases. It is a critical condition in which the quality of life and the patient's life span is minimized. Certain diagnostic methods can detect the presence of metastases. They also help in determining the treatment plan. Supportive care and surgical and radiotherapies are provided to increase the patient's life span. Proper diagnosis is a must for a better outcome of the treatment.

What Are Metastases?

The place at which certain cancer develops is called its primary site. Metastases are a process of developing cancer at a site other than the primary site. Cancer is categorized into stages based on the severity of the effects of cancer. A metastasized cancer can be stage four cancer, an advanced stage. One should make a note that even the presence of a large tumor without any metastasis can also be called advanced cancer. Brain metastases are causedwhen cancer cells from the primary site break off, they move to another site, and start to develop in that area.

What Is Brain Metastases?

When cancer from the primary site moves to the regions of the brain, it is called brain metastases. Nearly half of the patients having cancer tend to develop brain metastases. Lung, breast, and melanomas cancers frequently metastasize to the brain. However, in general, any cancer subtype can metastasize to the brain.

What Are the Types of Brain Metastasis?

Brain metastases can be categorized into two types

Based on the Number of Lesions:

• Single Lesions - Brain metastases can occur in the presence of a single lesion.

• Multiple Lesions - Multiple lesions can be present in brain metastases.

Based on the Location of Lesions:

• Cerebellum - A part of the brain located at the backside of the neck.

• Cerebral Hemispheres - The major part of the brain that controls body functions.

• Basal Nuclei - The part of the brain that controls major motor functions, emotions, and behavior.

What Are the Symptoms of Brain Metastases?

Following are the symptoms of brain metastases.

• Intra Cranial Hypertension - A buildup of pressure around the brain.

• Seizures - Uncontrolled disturbances in brain activity that changes body behavior and movements.

• Focal Neurological Deficits - It is an abnormality with the nerve, brain function, or spinal cord.

  • Hemiparesis - Partial paralysis or muscle weakness on one side of the body.

  • Aphasia - A disorder that affects the person's ability to communicate.

  • Hemianopia - Loss of one-half of vision.

• IntraTumoral Hemorrhage - Continuous bleeding inside the tumor.

• Transient Ischemic Shock - Short-term disruption of blood supply to a part of the brain causes a short-lived stroke.

• Altered Mental State - Patients are conscious yet do not respond correctly to emotions.

• Cognitive Slowing - Thinking of the patient is affected.

How Can Brain Metastases Be Diagnosed?

• MRI (Magnetic Resonance Imaging) - It is a diagnostic method in which the pattern, size, site, and maximum number of lesions are detected.

• Contrast Enhanced MRI - It eliminates the presence of any smaller lesions and offers a better treatment approach.

• Computed Tomography (CT Scan) - It cannot precisely visualize all the lesions to that of MRI present but can localize a tumor's hemorrhage and identify bone lesions.

• Contrast Enhanced Chest/ Abdomen CT - A patient detected with a single lesion on an MRI, and no history of cancer is made to undergo these diagnostic methods.

What Is the Management Protocol for Brain Metastases?

The three main principles that are followed in the treatment of brain metastases include to stabilize brain metastases, to control toxicity and to limit the symptoms. The treatment is carried out in two phases simultaneously by providing

Supportive Care - Supportive care involves dealing with cancer symptoms and increasing the body's immunity which includes -

• Steroids- Steroids play a major role in treating patients with brain metastases. In patients with intracranial pressure, low doses of steroids are more effective than higher doses. Hence steroids are the first line of treatment for patients with or without symptoms, and the dosage varies based on the patient's clinical condition.

• Anti-epileptic drugs- They are administered to control seizures.

Definitive Care- Definitive care is provided based on the characteristics of the brain metastases.

• Treatment of single brain metastases.

• Treatment of multiple brain metastases less than three.

• Treatment of multiple brain metastases of more than three.

Following are the approaches elected based on the patient's clinical condition.

• Surgical Resection - A total resection of the lesion is carried out to resume the brain's normal functioning. The extent of the tumor resection (the spread of the lesion and its borders are identified to carry out the resection), intraoperative image guidance (imaging techniques like MRI and ultrasound are performed during the operation to guide the resection) as well as intraoperative monitoring (monitoring of the patient is also done throughout the surgical process).

• Stereotactic Radiosurgery - Gamma rays are used to be projected on the target area. It is a minimally invasive high, precision process. It gives a chance for minor side effects as compared to other approaches.

• Stereotactic Radiotherapy - It is a type of radiation therapy that positions the patient in a certain way using equipment and delivering the radiation to the target. The total radiation is divided into certain small doses and is given at intervals for several days.

• Whole Brain Radiotherapy - It is a process that is least carried out due to advancements in radiotherapy and the toxic effects of the treatment.

What Are the Postoperative Risks Involved in the Treatment of Brain Metastases?

The risks that occur after treating brain metastases can be divided based on the occurrence.

• Acute Toxicity - Acute toxicity is caused shortly after the treatment process, which includes fatigue, severe headache and cerebral herniation (change in location of brain tissue).

• Early Delayed Toxicity - When symptoms of risks occur after four to six months of treatment, they are termed early delayed toxicity, including neurologic deficits (abnormalities with the nerves).

• Late Toxicity - These are critical symptoms that occur during the terminal stage. It includes dysarthria (inability to speak), seizures (tremors), and even death.

Conclusion

Brian metastases is a critical condition in which the patient’s need immediate treatment to prolong their lifespan for nearly ten months to one year, depending on the clinical condition after treatment. Prophylactic treatments are also available to prevent the spread of tumors to the brain. Combating the post operative risks also forms an important part of treatment. Consulting an oncologist at the earliest and getting the right treatment shows better positive outcomes.