Second primary tumors in neurofibromatosis 1 patients treated for optic glioma: substantial risks after radiotherapy.
OBJECTIVE
Optic pathway gliomas (OPGs) are the most common CNS tumor in neurofibromatosis 1 (NF1) patients. We evaluated the long-term risk of second tumors in NF1-related OPGs after radiotherapy.


METHODS
We reviewed 80 NF1 OPG patients from two NF1 clinics to evaluate the long-term risk of developing subsequent nervous system tumors, with or without radiotherapy.


RESULTS
Fifty-eight patients were assessable for second tumors. Nine (50%) of 18 patients who received radiotherapy after their OPGs developed 12 second tumors in 308 person-years of follow-up after radiotherapy. Eight (20%) of 40 patients who were not treated with radiotherapy developed nine tumors in 721 person-years of follow-up after diagnosis of their OPGs. The relative risk of second nervous system tumor after radiotherapy was 3.04 (95% CI, 1.29 to 7.15).


CONCLUSIONS
There is a significantly increased risk of second nervous system tumors in those NF1 patients who received radiotherapy for their OPGs, especially when treated in childhood. Thus radiotherapy should only be used if absolutely essential in children with NF1.
Sharif
Saba
S
Department of Clinical Genetics, St Mary's Hospital, Manchester, United Kingdom.
Ferner
Rosalie
R
Birch
Jillian M
JM
Gillespie
James E
JE
Gattamaneni
H Rao
HR
Baser
Michael E
ME
Evans
D Gareth R
DG
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D000075202:Contraindications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D016609:Neoplasms, Second Primary / Q000209:etiology*; D009456:Neurofibromatosis 1 / Q000150:complications*; D020339:Optic Nerve Glioma / Q000209:etiology / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects; D018570:Risk Assessment; D012307:Risk Factors