Puberty and plexiform neurofibroma tumor growth in patients with neurofibromatosis type I

To assess the relationship between pubertal progression and change in plexiform neurofibroma (PN) burden over time in pediatric and young adult patients with neurofibromatosis type 1 and PNs.

Analyses accounted for sex, age, race, and chemotherapy. Forty-one patients with neurofibromatosis type 1 (15 female and 26 male patients) were studied at the National Institutes of Health. Tanner stage, testosterone, progesterone, estradiol, insulin-like growth factor -1, luteinizing hormone, and follicle-stimulating hormone were assessed. Tumor volume was measured using magnetic resonance imaging and lesion detection software developed locally. Patients were divided into 2 groups based on whether they were actively progressing through puberty (n = 16) or were peripubertal (n = 25) and were followed for an average of 20 months. Tumor growth rates in the puberty and peripubertal group were analyzed for a subset of patients.

There was no statistically significant difference in tumor burden change over time (cm(2)/kg per month) between the pubertal and peripubertal groups (-0.16 ± 0.34 vs 0.03 ± 1.8, P = .31) and in the PN growth rates before and during puberty (P = .90). Change in tumor volume/patient weight/time did not correlate with testosterone change/time in males or estradiol change/time in females.

These findings support that hormonal changes of puberty do not accelerate PN growth. Additional long-term follow-up of patients is necessary to further characterize the interaction between puberty and tumor growth.