Dynamics of pituitary hormone levels in adolescents with acute lymphoblastic leukemia before and after chemotherapy

Background. Acute lymphoblastic leukemia (ALL) is the most common malignant neoplasm in children. Modern treatment protocols have achieved high survival rates, increasing the significance of investigating early and late therapy-related complications, including endocrine disorders. Dysfunction of the hypothalamic-pituitary axis may develop both during antitumor therapy and prior to its initiation; however, data on the dynamics of pituitary hormone levels in adolescents with ALL remain limited.

Aim. To assess blood levels of pituitary hormones – including luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin, growth hormone (GH), adrenocorticotropic hormone (ACTH), and thyroid-stimulating hormone (TSH) – in adolescents with ALL before treatment initiation and after completion of therapy.

Materials and methods. The study included 40 adolescents of both sexes with ALL (median age 14.55 (11–17) years). The control group consisted of 40 age- and sex-matched apparently healthy children (median age 15.25 (11–17) years). Pituitary hormone levels (LH, FSH, prolactin, GH, ACTH, and TSH) were measured in blood samples before treatment and after the third consolidation phase using standard radioimmunoassay and enzyme-linked immunosorbent assay kits. Mean hormone levels obtained from the control group were used as reference values. Statistical analysis was performed using Statistica 10 software.

Results. In girls before treatment, the levels of LH, FSH, and TSH, as well as the LH/FSH ratio, were within the reference range (p > 0.05). Prolactin level was elevated 2.9-fold (p < 0.05), whereas GH and ACTH levels were reduced 2.5- and 1.8-fold, respectively (p < 0.05). After the third consolidation phase, LH and FSH levels increased relative to both the baseline and reference values: LH by factors of 2.1 and 1.6, and FSH by factors of 2.3 and 2.2, respectively (p < 0.05). The LH/FSH ratio remained within the reference range. Prolactin level remained elevated, exceeding the reference range by a factor of 2.0 (p < 0.05). GH level increased 1.5-fold compared to the baseline (p < 0.05) but remained 1.6-fold lower than the reference range (p < 0.05). ACTH levels increased 2.1-fold (p < 0.05) and reached the reference values. TSH levels remained within the reference range.

In boys, LH levels were reduced 1.5-fold before treatment (p < 0.05), while FSH levels and the LH/FSH ratio were within the reference range. Prolactin level was elevated 1.8-fold (p < 0.05), and GH level was elevated 3.0-fold (p < 0.05). ACTH and TSH levels showed 1.7-fold decrease each (p < 0.05). After the third consolidation phase, LH levels normalized, increasing 1.6-fold (p < 0.05). FSH level increased 1.8-fold relative to the baseline (p < 0.05) and remained within the reference range. The LH/FSH ratio remained normal. Prolactin level increased 1.6-fold compared to the baseline (p < 0.05) and exceeded the reference range by a factor of 2.9 (p < 0.05). GH level decreased 4.3-fold relative to the baseline (p < 0.05) and was 1.4-fold below the reference values (p < 0.05). ACTH and TSH levels increased by factors of 2.2 and 1.8, respectively (p < 0.05), reaching the reference values.

Conclusion. ALL in adolescents is associated with dysfunction of the adenohypophysis and an imbalance of tropic hormones, with the direction and magnitude of changes depending on sex and treatment stage. Antitumor therapy rarely results in complete normalization of pituitary hormone levels, which is attributable to both the disease itself and the cytotoxic effects of treatment. These findings support the need for dynamic monitoring of LH, FSH, prolactin, GH, ACTH, and TSH levels in adolescents with ALL at all stages of therapy for early detection and timely correction of endocrine disorders.