Secondary cancer after a brain tumour

Some treatments for brain tumours carry a small risk that a new tumour will develop. This risk is higher than in the general population, but it is still quite low. Not all secondary brain tumours are cancer. The most common type of secondary brain tumour is called a meningioma, which is benign. Benign tumors do not spread to other parts of the body but can still cause problems if they grow too big.

The risk of a new tumour or cancer depends on the type of treatment, the child’s age at treatment, the child’s sex, and the presence of genetic conditions that may increase a person’s chance of getting cancer.

What causes a secondary cancer?

Several different factors can contribute to the risk of developing a new cancer.

• Radiation therapy can cause changes in normal cells. Over time, this may increase the risk of cancer cells developing. In general, a higher dose of radiation leads to a greater risk. The risk is higher for children treated at a younger age.
• Chemotherapy can cause changes in normal cells. Over time, this may increase the risk of cancer cells developing. In particular, alkylating agents can increase the risk of developing leukemia (cancer of the blood) in the first 10 years after completing therapy. This category of drugs includes cyclophosphamide, ifosfamide, lomustine (CCNU), carmustine (BCNU), nitrogen mustard, thiotepa, and temozolomide. Another chemotherapy agent, etoposide, also increases the risk of developing leukemia, but usually only for the first 6 years after completing therapy. In general, higher doses lead to a greater risk.
• Certain genetic conditions in families are connected to brain tumours. These may increase the chance of developing a second tumour.

How will secondary cancer be screened?

Children who have had brain tumours will need regular check-ups throughout their lives. Although the chance of developing a new tumour is very small, this can provide reassurance and help detect any problems early. Additionally, children who have had brain tumours, especially those treated with radiation, often have periodic scans of their brain (and sometimes spine) to monitor for new tumours.

What can be done to treat a secondary cancer?

If a new tumour or cancer does develop, then a new treatment plan will need to be made. The plan will depend on the type of tumour or cancer.

How will this affect your child’s future?

Because of the small increase in cancer risk, it is important to make healthy lifestyle choices to help prevent other cancers in adulthood. The general advice given to adults to prevent cancer is:

• Get regular check-ups, at least once per year.
• Eat a healthy diet, including daily fruits and vegetables.
• Exercise several times a week.
• Maintain a healthy body weight.
• Avoid smoking tobacco or cannabis products and avoid exposure to second-hand smoke. Do not chew tobacco. Long-term risks of vaping are not currently known, but vaping should be avoided as well.
• Alcohol should be consumed in moderation.
• Avoid direct exposure to the sun and always use sunscreen, particularly on irradiated skin.
• Get vaccinated: Some cancers are associated with preventable infections. Vaccines for hepatitis B and human papillomavirus (HPV) are safe and effective at protecting against these cancer-causing viruses.