Hyperparathyroidism in Adult Childhood Cancer Survivors Treated with Radiotherapy: Data from a Tertiary Oncology Centre

Abstract

Objectives

Adult Childhood Cancer Survivors (ACCS) who receive radiotherapy (RT) to the neck are at ongoing risk of hyperparathyroidism (HPT). This study explores HPT risk factors and potential screening recommendations.

Methods

The clinical records of 12 ACCS diagnosed with HPT aged between 15 and 39 and followed at BC Cancer were reviewed. Patients were treated with RT between 1971 and 2001. Previous cancer treatment, HPT and associated thyroid disease details were collected.

Results

Twelve ACCS were identified; 58.33 % females and 41.66% males. Median age at diagnosis for the original cancer was 2.5 years. ACCS received RT for different childhood malignancies; leukemia 25% (3/12), rhabdomyosarcoma 25% (3/12), Wilms tumor 16.66 % (2/12), neuroblastoma 16.66 % (2/12), Hodgkin lymphoma 8.33% (1/12) and ependymoma 8.33% (1/12). Patients received RT to the brain 25% (3/12), craniospinal axis 8.33% (1/12), head and neck 16.66 % (2/12), chest (1/12), whole lungs 16.66 % (2/12) and total body RT 25% (3/12). The median latency period to develop HPT was 37.60 years from time of RT. HPT in almost all patients was diagnosed with routine blood work showing elevated serum calcium (median 2.68 mmol/l) which prompted PTH levels which were elevated (median 14.52 pmol/l). Patients were further investigated and all had parathyroid adenomas. Out of 12 ACCS; 25% developed renal stones (3/12) and 50% had osteoporosis (6/12) as complications of HPT. Patients were evaluated by surgeons and 66.66% (8/12) underwent surgical resection. ACCS with HPT also had hypothyroidisim 50% (6/12), thyroid nodules 66.66% (8/12) and 2 patients had pathology proven papillary thyroid cancer.

Conclusion

HPT is a very late complication of RT to the neck. Serum calcium levels should be checked in ACCS in long-term follow-up as HPT is associated with morbidities (renal stones and osteoporosis).