The tumors that affect the brain and its coverings can be affected by a wide variety of tumors which includes both benign and malignant tumors. Among the malignant tumors a significant percentage would be metastatic (tumors that have spread to the brain from malignant tumors elsewhere in the body).
The vast majority of brain tumors, the type of tumor can be accurately diagnosed based on the radiology ( CT and MRI scan) but for management we need to know the exact type of tumor that is present this is especially true for malignant tumors which would require chemotherapy and radiotherapy in addition to surgery.
If the tumor is benign (not a cancer) then most of these will require surgery to remove it and this then cures the patient completely. In some cases like small meningioma’s in difficult to reach locations or some other small tumors we may offer radiation (stereo tactic radiosurgery) without offering surgery.
Primary malignant brain tumors would require some form of surgery it may be in the form of a guided biopsy or complete tumor removal in almost all cases. This is required because firstly the removed tumor can be subjected to tests to determine the nature of further treatment and also because the outcomes of treatment are better when the majority if not the entire tumor has been removed surgically. Only in very rare primary malignant brain tumors radiation/ chemotherapy offered without undertaking a biopsy.
In metastatic tumors where the primary tumor is known, in some patients we may be able to treat the tumor without removing it. However in some metastatic tumors surgery may still be required prior to giving the other modalities of treatment.
To summarize management of brain tumors needs to be tailored to the type of tumor and also to the individual patient. Majority of patients with brain tumors (other than metastatic) will require some form of surgery or biopsy. The management for the same type of tumor may be different in different patients with the age, how was it detected and the symptoms it is causing. A small incidentally detected meningioma in an 80 year old can be followed up but a same sized tumor with seizures in a 30 year old will be offered surgery.