Retinoblastoma is a rare cancer of the retina that primarily affects children and is most often diagnosed before age 1. The disease can often be cured; 97 percent of retinoblastoma patients survive 5 years after diagnosis. However, patients with hereditary retinoblastoma are at a high risk of developing another cancer, including soft tissue sarcomas. The increased risk of soft tissue sarcomas is attributed both to the mutation in the RB-1 gene that causes retinoblastoma and to the radiation treatment that most retinoblastoma patients received when treated decades ago. Radiation is used less frequently today because of the risk of second cancers.
Ruth A. Kleinerman, of the National Cancer Institute in Bethesda, Md., and colleagues studied a group of 963 1-year hereditary retinoblastoma survivors to better understand the risks for specific subtypes of soft tissue sarcomas. The patients were diagnosed between 1914 and 1984 at medical centers in New York and Boston and were followed for an average of 25.2 years. More than half of the patients were younger than 1 year old when diagnosed, and most (88.2 percent) of the patients were treated with radiation.
A total of 69 soft tissue sarcomas were diagnosed in 68 hereditary retinoblastoma patients. The most common subtype was leiomyosarcoma, a cancer of smooth muscle cells that was diagnosed in 23 of the patients. Other frequently diagnosed sarcomas were fibrosarcoma (13 patients), malignant fibrous histiocytoma (12), rhabdomyosarcoma (8), and liposarcoma (3). The authors calculated that there was a 184-fold
Source:Journal of the National Cancer Institute