Newly Diagnosed With a Brain Tumor: First Steps

The label covers dozens of tumors that behave nothing alike. Some are cured with surgery. Some are watched for years. Some need radiation fast.

SEER estimates 24,740 new brain and nervous system cancers in the United States for 2026. It estimates 18,350 deaths. That is 1.2% of new cancer diagnoses and 2.9% of cancer deaths. Five-year relative survival, across all types combined, is 32.9%.

Brain tumors make up 85% to 90% of all primary central nervous system tumors. Two groups dominate. Anaplastic astrocytomas and glioblastomas account for 38%. Meningiomas and other mesenchymal tumors account for 27%. After those come pituitary tumors, schwannomas, CNS lymphomas, oligodendrogliomas, ependymomas, low-grade astrocytomas, and medulloblastomas.

One reassuring fact gets lost. Primary brain tumors rarely spread to other parts of the body. They can spread within the brain and along the spine.

General signs include headaches, seizures, and vision changes. Appetite loss with nausea and vomiting is common. So are shifts in personality, mood, thinking, and concentration.

Seizures deserve their own paragraph. They are the first sign in about 20% of people with tumors above the tentorium. The tentorium is the membrane between the upper brain and the cerebellum. In slow-growing tumors, seizures can come months or years before the diagnosis.

Over the whole course, 70% of people with primary brain tissue tumors develop seizures. So do 40% of those whose tumors spread there from elsewhere. Ask whether an antiseizure medicine is planned, and what to do if one happens at home.

Both get used, for different reasons.

CT is fast, which matters when someone is unstable. It is better at showing calcium deposits and skull lesions. It also shows hyperacute bleeding, meaning blood less than 24 hours old.

MRI has far better soft-tissue detail. It picks up lesions that blend into normal tissue on CT. It shows contrast uptake and swelling. It detects every phase of bleeding except the hyperacute one. For spinal cord lesions, high-quality MRI is the study of choice.

After treatment, SPECT and PET scans can help sort tumor regrowth from radiation necrosis. Radiation necrosis is dead tissue caused by the radiation itself. That call is hard on standard MRI, and it changes what happens next.

Imaging can mislead. A mass on a scan has to be told apart from an abscess, a tangle of abnormal blood vessels, and an old stroke. All three can look and act similar.

So biopsy confirmation is treated as critical. It comes either from a needle biopsy before surgery or from tissue taken during removal. CT- or MRI-guided technique can place a needle accurately in almost any part of the brain.

There is one exception. When the clinical and imaging picture clearly points to a benign tumor, watching without a biopsy may be right. That is common with small, symptom-free low-grade meningiomas. Most show minimal growth.

For diffuse gliomas, which include astrocytoma, oligodendroglioma, mixed glioma, and glioblastoma, three genetic findings shape both prognosis and management.

IDH1 or IDH2 variants. Tumors without an IDH variant, called IDH wild-type, had the worst prognosis regardless of which treatment they received.

1p/19q codeletion. Loss of parts of chromosomes 1 and 19 together, in a tumor that also has an IDH variant, carried the best prognosis in the same analysis.

MGMT promoter methylation. This is a chemical switch that silences a DNA repair gene, leaving the tumor less able to undo chemotherapy damage.

The combinations matter. One analysis covered 318 patients with low-grade glioma. Those with an IDH variant but no 1p/19q codeletion did better on radiation than on temozolomide. Progression-free survival was significantly longer, hazard ratio 1.86. For the other groups, treatment type made no significant difference.

MGMT methylation was present in all 45 of the IDH-variant, codeleted tumors. It was present in 62 of 72, or 86%, of IDH-variant tumors without codeletion, and in 5 of 9, or 56%, of IDH wild-type tumors.

Beyond molecular results, the NCI lists eight features that carry a poorer outlook. They are age over 40, progressive disease, tumor larger than 5 cm, and tumor crossing the midline. The rest are contrast uptake on MRI, a WHO performance status of 1 or worse, neurological symptoms, and less than a gross total resection.

That last item is worth reading twice. How much tumor the surgeon removes is itself a prognostic factor. That is why where the operation happens is a real decision, not a formality.

The regimen most people encounter comes from a trial of 573 patients run by the EORTC and the National Cancer Institute of Canada.

Radiation went to the tumor volume plus a 2 to 3 cm margin. The total was 60 Gy, in 2 Gy daily fractions over 6 weeks. One group got radiation alone. The other got the same radiation plus temozolomide capsules by mouth daily, for up to 49 days. Then came a 4-week break. After that, up to six cycles of temozolomide, five daily doses every 28 days, at a higher amount than during radiation, stepped up again after the first cycle if it is tolerated. All of these are calculated from body size and adjusted to blood counts, so take what your own prescription states.

The hazard ratio for death with the combination was 0.6. Three-year overall survival was 16.0% with chemoradiation against 4.4% with radiation alone.

A companion study explains part of the spread. MGMT promoter methylation was an independent favorable factor, hazard ratio 0.45. Median overall survival was 18.2 months in methylated tumors. It was 12.2 months in unmethylated ones.

Adding bevacizumab to radiation and temozolomide did not improve overall survival.

These are biodegradable wafers containing 3.85% carmustine. Up to eight are laid into the cavity lining during open removal. Each delivers about 7.7 mg, for a maximum of 61.6 mg. The drug is released over 2 to 3 weeks.

One trial enrolled 240 patients with malignant glioma, 207 of them with glioblastoma. Median survival was 13.8 months with wafers and 11.6 months with placebo wafers. The hazard ratio was 0.73. A systematic review combining two trials estimated a hazard ratio for overall mortality of 0.65.

The catch is timing. This decision is made before surgery, because the wafers go in during the operation. Both trials had an upper age limit of 65.

• A first seizure, or a seizure lasting more than 5 minutes
• A sudden, severe headache unlike your usual one
• New weakness on one side, facial droop, or trouble speaking
• Vomiting with a worsening headache, above all in the morning
• New confusion, or trouble waking someone
• New vision loss or double vision
• Fever after a recent craniotomy, or drainage from the incision

• What is the exact tumor name and WHO grade on the pathology report
• Have IDH, 1p/19q, and MGMT results come back, and what were they
• Was the resection gross total, subtotal, or biopsy only
• Is a second surgery being considered, and would that change the molecular result
• Who is on the tumor board reviewing this, and when do they meet
• What antiseizure medicine am I on, and for how long
• What steroid dose am I on, and what is the plan for reducing it

Steroids control swelling, but they bring their own problems over weeks. The taper plan should exist from the start, not be improvised later.

https://www.cancer.gov/types/brain/hp/adult-brain-treatment-pdq https://seer.cancer.gov/statfacts/html/brain.html