(ChemotherapyAdvisor) – Long-term survivors of retinoblastoma with bilateral disease and an inherited germline mutation have an elevated risk for second cancers compared with those with a de novo germline mutation; specifically, melanoma, a study published in the Journal of Clinical Oncology online February 21, 2012, has found.
“This is the first report, to our knowledge, to estimate the risks for second cancers by retinoblastoma mutation classification (inherited or de novo) taking treatment and other factors into account,” the investigators wrote.
They examined a cohort of 1,852 patients with bilateral (n=1,036) or unilateral (n=816) retinoblastoma who had survived at least one year. Medical records and self-reports were used to determine second cancers, which were confirmed by pathology reports. Laterality of retinoblastoma and positive family history of the disease were used to classify RB1 germline mutation, inherited or de novo.
A relative risk (RR) of 1.37 was observed for second cancers in bilateral survivors of retinoblastoma that was associated with a family history of the disease, adjusted for treatment, age, and length of follow-up. “Risk for melanoma was significantly elevated for survivors with a family history of retinoblastoma (RR, 3.08), but risks for bone or soft tissue sarcomas were not elevated,” they wrote.
Cumulative incidence of second cancers 50 years after diagnosis of bilateral retinoblastoma was significantly higher for survivors with a family history (47%) than survivors without a family history (38%; P<0.004).
“All bilateral survivors, especially those with a family history of retinoblastoma, and their affected family members should be alert to the risk of melanoma, especially that posed by excessive sun exposure,” they concluded.