Zoledronic acid is used in cancer patients who have high calcium levels, and those whose cancers have spread to the bones.
“Bone metastases occur in 20-40% of patients with lung cancer, making them one of the most frequent sites for metastases from lung cancer. However, because early stage bone disease may be asymptomatic, bone metastases often go undiagnosed,” said researcher Dr Rossella Calderone from Istituto Nazionale dei Tumori in Milan, who presented the findings. “So the real number of patients with bone metastases could be higher than we know at the moment.”
In lung cancer, the zoledronic acid is currently used to treat high calcium levels. Bone metastases are not actively sought in patients with lung cancer unless they have pain in their bones. This means that in general, bone metastases in lung cancer patients are often undiagnosed or diagnosed late, when patients are more unwell.
Dr Calderone and colleagues at the Royal Marsden Hospital in London retrospectively studied 114 lung cancer patients whose cancer had spread to the bone (i.e. stage IV disease), 49 of whom had received zoledronic acid, and 75 who did not. All patients were treated with standard platinum-based chemotherapy.
The results showed that patients who received the zoledronic acid had survived on average 34 weeks, compared to 19 weeks for those who did not get the drug.
“In my audit, patients treated with the zoledronic acid appeared to have better overall survival. This has not previously been suggested in lung cancer although we do know the zoledronic acid can help bone pain,” Dr Calderone said. “It is possible that either the zoledronic acid may enhance the effectiveness of the chemotherapy, or that treating the bone metastases with zoledronic acid actually does prolong life.”
“This retrospective audit supports the view that all patients with symptomatic bone metastates should be treated with zoledronic acid. It is not an expensive drug compared to the cost of some of the new treatments. If it can prevent bone problems then that is a saving for the patient and the health service,” Dr Calderone said.
“We have no evidence that zoledronic acid can improve overall survival in patients with lung cancer without bone metastases, but all patients with lung cancer should be screened for bone metastases and more research should be done in the group with asymptomatic bone mets. More research is needed on the interaction between chemotherapy and zoledronic acid,” she said.