Five-year survival rates for patients with childhood brain tumors increased from 54 percent in 1976 to 70 percent in 1998, resulting in an increasing number of child survivors who are potentially susceptible to later complications. In 2000, an estimated 350,000 people of all ages in the United States were alive who had once received or were still undergoing treatment for a brain tumor. Most previous research has been single-institution case studies without a comparison group to investigate relative risk, thus limiting conclusions because of vulnerability to selection and referral biases.

The current study was a multicenter, long-term follow-up study conducted as part of the Childhood Cancer Survivor Study; its American team investigated 1,607 young adult survivors and 3,418 randomly selected siblings to determine the relative risk of endocrine and cardiovascular adverse events, as well as associations between these conditions and treatment.

Treatment data were collected from medical records. A follow-up questionnaire was completed by survivors whose survival was five or more years and by randomly selected siblings. The questionnaire collected data on demographic details, health habits, and medical conditions including endocrine and cardiovascular diseases and symptoms. Data were then analyzed to calculate the incidence of an adverse medical outcome, to compare rates between survivors and siblings, and to compare through relative risk ratios the development of an adverse outcome in relation to treatment. Treatment was categorized as surgery alone, surgery and radiation, or surgery, radiation, and chemotherapy.

One or more adverse endocrine conditions were reported by 43 percent of survivors. Compared with siblings, the survivors were 14.3 times more likely to develop hypothyroidism, 277.8 times more likely to develop growth hormone deficiency, 86.1 times more likely to require medications to induce puberty, and 24.7 times more likely to develop osteoporosis five years or more after treatment.

Almost one of every five survivors (18 percent) reported one or more cardiovascular adverse events. Although cardiovascular outcomes were not common, risk was clearly elevated compared with risk for siblings: Survivors were 42.8 times more likely to have a stroke, 5.7 times more likely to develop a blood clot, and 2.0 times more likely to develop angina-like symptoms associated with cardiovascular disease. There was no increased risk of developing arrhythmias.

When patients treated with chemotherapy, radiation, and surgery were compared with those who were treated with surgery and radiation or surgery only, the triple-modality patients were at the highest risk for developing complications, followed by patients who received surgery and radiation. Surgery alone was associated with the lowest frequency of complications.

When treatment with surgery and radiation was compared with triple-modality therapy, adjuvant chemotherapy was associated with an increased relative risk to develop hypothyroidism (2.4), growth hormone deficiency (2.7), osteoporosis (3.1), medications to induce puberty (1.8), stroke (3.0), blood clots (3.6), and angina-like symptoms (2.4).

The authors state that these results suggest that lifetime medical surveillance and follow-up for potential endocrine and cardiovascular late effects is necessary for this population. They also recommend "aggressive conformity to a healthy lifestyle that includes a prudent diet, abstinence from smoking, regular exercise and monitoring for hypertension and hyperlipidemia" to help prevent cardiovascular-related diseases.