Endocrine Abstracts

Introduction: Acute lymphoblastic leukaemia (ALL) is the most common childhood malignancy and accounts for 25% of all childhood cancer. The survival rate is now 85% which emphasis the importance of long-term treatment complications. ALL patients treated with cranial radiotherapy (CRT) and chemotherapy are particularly at risk for GH deficiency (GHD), but little is known about central adrenal deficiency. Partial ACTH deficiency is often asymptomatic, but it may lead to deleterious consequences during stress.

Methods: Out of 44 (21 women) ALL patients (median 25 years, range 19–32), treated with 24 Gy CRT (18–24) and chemotherapy, 37 were tested with an insulintolerance test (ITT) to evaluate GH and cortisol secretion. All were GHD based on the GH response (<3 μg/l). The normal cortisol cut-off level was ≥500 nmol/l. Basal serum ACTH- and cortisol-levels were investigated in all 44 ALL patients and 44 matched population controls.

Results: Fourteen out of 37 (38%) ALL patients had subnormal cortisol response to an ITT (257–478 nmol/l) while there was no significant difference in basal serum cortisol levels between 44 patients and controls (P>0.3). ALL patients had significantly lower serum ACTH levels compared to their controls (P=0.04), being significantly lower among the women (P=0.03), only. There was a significantly positive correlation between peak serum cortisol after ITT and basal cortisol (P<0.001, r=0.6), and the GH peak after ITT (r=0.3, P=0.04).

Conclusion: Thirty-eight percent of former ALL patients with GHD, treated with CRT, have central adrenal insufficiency 20 years after ALL diagnosis. About 500 ALL survivors have been subjected to this therapy in Sweden (pop. 9 millions), and with the corresponding numbers in other countries. This is of great concern, particular as GHD masks the presence of a hidden central adrenal insufficiency.