[Growth hormone treatment in childhood cancer survivors]

Growth hormone (GH) deficiency is one of the most frequent endocrine problems occurring in cancer survivors, particularly when there is a previous history of central nervous system (CNS) tumour and submission to radiotherapy (RT).

We retrospectively assessed pediatric cancer survivors with GH deficiency, submitted to GH treatment from 1988 to 2010 in a tertiary level hospital. We analised the following data: sex, age, oncologic diagnosis, oncologic treatment, auxology, Tanner puberty stage, final height, target height and other associated endocrine problems. We determined the height z-score difference between the beginning and the end of GH treatment (for patients who ended treatment), and between the beginning of GH treatment and the last observation (for patients who are currently on treatment), which was defined as the dependent variable. SPSS® version 17.0 was used for statistical analysis.

A sample of 18 patients was obtained, 12 male, with a median age of cancer diagnosis of six years old. The diagnostics were CNS tumors (n=15) and hematologic neoplasia (n=3). Cancer treatment modalities were craniospinal RT (n=9), cranial RT (n=4), chemotherapy (n=14) and CNS surgery (n=15). The median of time between cancer treatment and beginning of GH treatment was 4 years and 8 months. Height z-score difference was positive in 12 patients. Statistical significant differences between medians and centiles of height z-score difference occurred in patients submitted to craniospinal RT (-0.08), cranial RT (0.59) and no RT (1.56) (p=0.003, IC 95%). The biggest differences between final height and target height (-10 and -11.5 cm) occurred in two patients submitted to craniospinal RT, with associated precocious puberty.

Our results are consistent with previous studies, which point to a lesser efficacy of GH treatment when there is a past history of RT, namely craniospinal RT, and in association with precocious puberty.