Survival in breast cancer patients after the first episode of hypercalcaemia

Kristensen B, Ejlertsen B, Mouridsen HT, Loft H (Copenhagen University Hospital, Copenhagen, Denmark). Survival in breast cancer patients after the first episode of hypercalcaemia. J Intern Med 1998; 244 : 189–98.

Objectives

.To investigate hypercalcaemia (serum ionized calcium (S-Ca²⁺) > 1.35 mmol L^?1) in breast cancer patients before and after the introduction of bisphosphonates and the effect of disease- and treatment-related factors on survival.

Design

.Prospective and retrospective registration of covariates.

Setting

.A department of oncology in a university hospital.

Subjects

.A consecutive cohort of 212 hypercalcaemic patients never treated with bisphosphonate was identified prospectively (period 1) and 193 patients with metastases were classified into three groups: mild (S-Ca²⁺ < 1.48; n= 102), moderate (1.48 ≤ S-Ca²⁺≤ 1.60; n= 41), and severe hypercalcaemia (S-Ca²⁺ > 1.60 mmol L^?1; n= 50). Fifty-one patients with severe hypercalcaemia all treated with bisphosphonate except one were identified retrospectively (period 2).

Results

.For period 1 median survival was 6.7 months. Survival was significantly decreased in the two groups with the highest initial S-Ca²⁺ (P < 0.0001). Median survival times in severely hypercalcaemic patients from periods 1 and 2 were 1.4 (95% confidence interval 0.8–2.1) and 2.2 (95% confidence interval 1.3–3.1) months, respectively. In a Cox model for period 1 significant covariates were: WHO performance, extent of metastases, whether systemic anticancer treatment could be given, and haemoglobin, but not S-Ca²⁺.

Conclusion

.Prognosis is poor in hypercalcaemic breast cancer patients with WHO performance 3–4 and advanced metastatic disease when effective systemic treatment can no longer be offered. Bisphosphonate treatment does not seem to improve survival in severe hypercalcaemia. Antihypercalcaemic treatment of mild malignancy-associated hypercalcaemia appears not to be vital. Therapeutic efforts should be aiming at patients with moderate hypercalcaemia.