Dr Aditya Gupta
Cancer spread to the brain is one of the feared complications of cancer that poses significant mortality and morbidity in the patients with advanced cancer. This occurs when the cancer cells travel through the blood stream or the lymph system from the original tumour and metastasize (spread) to the brain. This is known as metastatic cancer. For example, breast cancer that has spread to the brain would be referred to as metastatic cancer and not primary cancer.
According to Globacan 2020 report, issued by the International Association of Cancer Registries (IARC) associated with World Health Organization (WHO), over 28,000 new brain tumour cases are reported annually in India. Around 24,000 patients lost their lives battling such deadly and cancerous tumours.
Mostly people ignore the initial symptoms of this disease which include headaches, vomiting seizures etc. As they often get confuse about the exact location of the tumour. This leads to misdiagnosis which may results in death of the patient. However, the numbers are now gradually declining with the improved treatment methods of such deadly tumours and are allowing patients survival.
How to identify?
The following can be the symptoms of brain metastasis but many patients may experience additional complications caused by the original tumour and its related manifestation.
• Increased pressures within the skull- In most of the cases symptoms are caused by the expansion of lesions and increased ICP (Increased Cranial Pressure). The most common symptoms of ICP are headaches, vomiting, and disturbance in consciousness.
• Headache- Headache is the initial symptom in more than half of the cases of brain tumour and this is faced by the most of the patients at some point in their life.
• Vomiting- This is an occasional accompaniment with the headaches. It is far more common in children. In children, this can be dramatic and forceful so much it may be labelled as projectile in nature.
• Seizures- It is a uncontrolled and electrical disturbance in the brain. It causes changes in the mental behaviour, movements and level of consciousness. These are almost associated with 35% cases of brain tumours.
• Specific Neurological symptoms- Whereas headaches alters mental status and seizures may be seen with the tumour that occur in any part of the brain, some symptoms are associated with the tumours that occurs in a specific location. These symptoms affect the side of the body opposite from the side where tumour resides and may include different modalities of sensation such as tingling and motor changes.
What are its causes?
Virtually any systemic malignancy can metastasize to the brain, but there are some which have greater tendency to do so, Melanoma (A type of skin cancer) has a tendency metastasize to the brain. Other cancerous tumours in skin, breast renal and colon can also metastasize the brain. Some differences are seen in the types of primary malignancies responsible for metastasis of the brain in both the genders. In males, lung cancer is the most common source of brain metastasis whereas breast cancer is the most common source in females.
Diagnosis of brain metastasis
Brain metastasis can be diagnosed with the following tests:
• CT/CAT scan- It can be done with or without injecting intravenous contrast and includes different views of the brain. CT scans are initial diagnostic tests utilized.
• Magnetic Resonance Imaging (MRI)- It makes a clear picture of the brain using powerful magnets and radio waves. With the addition to intravenous contrast agent, this is the gold standard testing that provides information about the location, size, characteristics and pressure effects of tumour.
• PET Scan- Positron emission tomography (PET) scans can show up a cancer, reveal the stage of the cancer, show whether the cancer has spread, help doctors decide on the most appropriate cancer treatment, and give doctors an indication on the effectiveness of ongoing chemotherapy. They are also useful in finding out how effective current treatment is. The biggest advantage of a PET scan, compared to an MRI scan or X-ray, is that it can reveal how a part of the patient’s body is functioning, rather than just how it looks. Medical researchers find this aspect of PET scans particularly useful. A CT or MRI scan can assess the size and shape of body organs and tissue, but cannot assess its function, which a PET scan does. In other words, MRI or CT scans tell you what an organ looks like, while a PET scan can tell you how it is working.
Tissue diagnosis is crucial and may have already occurred if the patient has a previously known malignancy. It may be obtained by a biopsy or removal at the site of the primary cancer. Besides this on other occasions, a biopsy of the, metastatic brain tumour is performed if the size is larger and causing significant pressure effects. The tumour may be removed entirely to relieve the pressure while providing the adequate tissue for diagnosis.
Once a clear diagnosis of the tumour is obtained, staging of the systemic cancer is completed and the patient’s medical condition is stabilized, a multidisciplinary team of physicians will try to treat the tumour within the brain with best possible treatment methods.
Why Cyberknife M6 over other traditional methods of treatment?
The treatment varies with the size and type of tumour. The primary sites of malignancy are extent to both locally and in rest of the body, the general individual health and presence of other medical problems. The goals of the treatment involves improve body functioning, controlling the cancer and its satellite its tumour within the brain.
Cyberknife M6 is performed in a non-invasive manner with a higher brain surgery recovery time done on outpatient basis. The characteristics of M6 to pinpoint the exact location of the tumor in real time using 3-D imaging techniques during the treatment of brain tumor and ablating the tumor without any cut marks has proven outcomes to overtake the traditional methods of treatment. With the flexibility of the treatment to be done in 1 to 5 sessions each of 30 minutes duration provides comfortability to the patient and the maximum level of restricting the tumor from spreading further.
The main advantage of cyberknife radiation therapy is that it directly alters the individual deposits inside the brain without affecting the brain functioning.
Easily upto 5 deposits can be treated with Cyberknife, and in fact upto 10 small sized metastatic deposits are being treated with Cyberknife with excellent results. Deposits in the brainstem are also much better treated with Cyberknife radiosurgery. Additionally, Cyberknife radiation therapy can be given for repeated lesions whereas this is not possible with WBRT as the amount of radiation in WBRT already reached the threshold tolerance of the brain.
Also Whole Brain Reserve Therapy (WBRT) is reserved for those unfortunate patients who have too many deposits that cannot be treated with cyberknife or those with very advanced disease and limited survival possibility.
For treatment of metastasis such as melanoma, radiation therapy (cyberknife) may be the only good option.
(The author is Director Neurosurgery and Cyberknife Centre, Artemis Hospital, Gurugram)