Background: Pain is the most frequent symptom experienced by cancer patients, its intensity dependent on the site of the tumour. Tumours that compromise bone or nervous structures due to the bone destruction process are the most painful. There are several treatments to deal with pain (and other symptoms) caused by bone metastasis. The hormone, calcitonin, has the potential to relieve pain, and also retain bone density, thus reducing the risk of fractures.
Objectives: To assess the effectiveness of calcitonin in controlling metastatic bone pain and reducing bone complications (hypercalcemia, fractures and nervous compression) in patients with bone metastases.
Search strategy: Electronic searches were performed in MEDLINE (1966-2001), EMBASE (1974-2001), the Cochrane Central Register of Controlled Trials (Issue 2, 2001), specialised registers of the Cochrane Cancer Network and of the Cochrane Pain, Palliative and Supportive Care Group. Registers of clinical trials in progress were also searched.
Selection criteria: Studies were included if they were randomised, double-blind clinical trials of patients with metastatic bone pain, treated with calcitonin, where the major outcome measure was pain, assessed at four weeks or longer.
Data collection and analysis: Study selection and data extraction were performed by two independent reviewers. Only two studies (90 patients) were eligible for inclusion in the review and therefore meta-analysis of the data was not possible. Intention-to-treat analysis was performed by imputing all missing values as adverse outcomes.
Main results: Of the two small studies included in the review, one study showed a non-significant effect of calcitonin in the number of patients with total pain reduction (RR 2.50; CI 95%, 0.55 to 11.41). The second study provided no evidence that calcitonin reduced analgesia consumption (RR 1.05; CI 95%, 0.90 to 1.21) in patients with painful bone metastases. There was no evidence that calcitonin was effective in controlling complications due to bone metastases; for improving quality of life; or patients' survival. Although not statistically significant, a greater number of adverse effects were observed in the groups given calcitonin in the two included studies (RR 3.35, CI 95%, 0.72 to 15.66).
Reviewer's conclusions: The limited evidence currently available for systematic review does not support the use of calcitonin to control pain from bone metastases. Until new studies provide additional information on this treatment, other therapeutic approaches should be considered.