Chromosomal aberrations, the consequence of refractory hyperparathyroidism: its relationship with biochemical parameters.

BACKGROUND: It has been shown that refractory hyperparathyroidism (HPT) correlates biologically with a monoclonal true neoplasm, but the chromosomal changes and their relationship with biochemical variables such as high levels of phosphate, low levels of calcium (Ca), and calcitriol deficiency are still in need of a deeper analysis. METHODS: Comparative genomic hybridization was used to scan for DNA copy number changes in two groups of samples: 57 glands from refractory secondary HPT and 28 glands from refractory HPT after kidney transplantation. Biochemical HPT-related parameters from these patients were collected and analyzed. RESULTS: Sixty-one percent of the glands from dialysis patients and 53.6% of the glands from transplanted patients suffering severe secondary hyperparathyroidism had clonal chromosomal imbalances. Losses were far more common than gains. The most recurrent changes were losses of 1p (71%), monosomies of chromosomes 19 and 22 (45%), and losses of 20q (44%) and 16p (42%). The most frequent gains were 5q, 6q, and 13q. Biochemical parameters suggested that Ca excess is related to the development of these chromosomal aberrations, although it is not known if it is by playing a role in producing the alterations or merely as a reflection of HPT severity. Phosphate levels, despite their known effect in increasing the proliferation of the parathyroid glands, were not related to the chromosomal aberrations found in severe secondary HPT. CONCLUSION: Clonal recurrent chromosomal changes are present in more than half of the glands from patients with refractory HPT, which undergo extreme biochemical levels in hyperparathyroidism effectors. These changes support the idea of the monoclonal neoplastic nature of this disorder.

Parathyroidectomy: whom and when?

Hyperparathyroidism (HPT) is common in patients on dialysis, and parathyroidectomy (PTx) is often required. We present a retrospective, descriptive analysis of data corresponding to 148 patients on dialysis undergoing PTx due to severe refractory HPT (PTH 1401 +/- 497 pg/mL, Ca 10.6 +/- 0.8 mg/dL, P 6.9 +/- 1.7 mg/dL). Demographic data were compared with those recorded in 309 patients on dialysis not subjected to PTx who were managed at the same hospital. In the PTx group, the factors age (49.3 +/- 14 years), male gender (48.6%), and diabetes (0.7%) were significantly lower than in the non-PTx group (61.5 +/- 14.9 years, male gender 59%, diabetes 19.4%), while time on dialysis was longer (8.6 +/- 5.8 vs. 5.5 +/- 5.4 years). In 129 of the study patients (87.4%), four or more glands were identified, and total PTx plus autotransplantation (AT) in the forearm was performed. In the remaining 19 patients, two to three glands were identified, and AT was not undertaken. Four of the 19 patients were successfully operated on again for persistent HPT, seven showed PTH levels <250 pg/mL, and eight maintained severe HPT. Perioperative complications included one death due to cardiac insufficiency, two repeat operations due to bleeding, and one patient with chronic hoarseness. Hospital stay was prolonged in 20% of patients due to a hungry bone syndrome. Among those patients with PTx and AT, HPT recurred in 21 patients (16.2%) at 3.1 +/- 2.3 years. In 13 of these patients, autograft was removed at 7.5 +/- 2.9 years. Serum calcium and phosphate levels improved after PTx, and these results were maintained for 5 years (9.6 +/- 0.8 and 4.2 +/- 1.2 mg/dL, respectively). In conclusion, PTx with AT is a safe option for the treatment of severe HPT that is accompanied by low morbidity and mortality and a good outcome. Medical treatment should not be prolonged at the expense of long repeated bouts of hypercalcemia and/or hyperphosphatemia with their irreversible consequences.