Management of Painful Bone Metastases: The Interaction between Radiation Therapy and Zoledronate

Abstract

Background: Advanced cancers frequently metastasize to bone, and the presence of bone metastases is the most common cause of cancer-related pain. Pain management requires a multidisciplinary approach that involves the use of analgesics, bisphosphonates, radiotherapy, chemotherapy, surgery. The aim of our study was to evaluate the enhancement of radiotherapy on painful bone metastases in patients treated also with bisphosphonates. Materials and Methods: We analyzed the differences in benefit on pain and on quality of life comparing two groups of treatment. The first group comprised 104 patients treated with Radiotherapy (RT), the second one included 50 patients treated with radiotherapy associated to zoledronic acid (RT + Z). All patients completed before, during and after treatment, a questionnaire that rated the grade of pain, the pharmacological type of analgesic therapy and patient’s performance status. For each patient a total score was calculated, from a minimum value of 0% to a maximum of 20%, then expressed as a percentage. Patients were classified as responder if at the follow-up reported a reduction of over 20% of the initial score, no-change if there was a reduction of between 0% and 20%, progression if there was an increasing of the score. Results: In the group RT + Z we found fewer patients that started radiation therapy with severe pain (16% vs 32%), no patient had pain of grade 10, and a higher proportion of asymptomatic patients (12% vs 4%) was observed. In the RT alone group a higher percentage of patients started treatment assuming strong opioid more than once a day (26% vs 24%) and a reduction in number of these patients was about 14% compared with the reduction of 23.6% observed in the group RT + Z. Furthermore an increased total score was calculated only in the 6% of patient belonged to group RT alone. Finally, in the group RT + Z responder patients are 52%, compared to 36% of the RT group, non-responder were 36% versus 60% in the RT. The risk of adverse events (Pz) in the RT + Z was Pz = 0.36, with an odds (Oz) equal to 0.56, while the risk of adverse events (Pc) in the RT group was Pc = 0.60 with an odds (OC) of 1.5. The odds ratio was OR = 0.37, showing a value in favor of treatment RT + Z. Conclusions: In our retrospective observational study it is relevant a clear potentiation of benefit effects related to palliative radiation therapy in patients receiving also bisphosphonate therapy, so obtaining a better control over pain, a decreased need for pain relief and consequently an improved quality of life.