New Roles for Bisphosphonates in Cancer Therapy

Bisphosphonate-associated osteonecrosis of the jaws: the limits of a conservative approach

BACKGROUND

An increasing number of cases of osteonecrosis of the jaws (ONJ) in patients treated with bisphosphonates has been reported in the literature. ONJ significantly affects the patients' quality of life and its management is still extremely difficult.

METHODS

A woman with ONJ secondary to therapy with zoledronic acid came to our attention for recurrent oral infections and orocutaneous fistula unresponsive to antibiotic therapy combined with minor surgical debridements. The patient underwent major surgery to remove the fistula and clean the necrotic bone and soft tissues; a lobed skin platysma flap was used to close the defect. The treatment outcome was good.

CONCLUSION

When ONJ fails to respond to antibiotic therapy and surgical debridements, a more invasive surgical approach may be necessary to guarantee a better quality of life for the patient.

Pharmacological management of metastatic boney pain

Many malignancies metastasise to the skeleton. This often results in a relatively unique pain process, which dramatically affects a patient's quality of life. With one in three members of the population likely to develop cancer at some stage in their lives, the prevalence of bone metastases is high. Despite the large financial investment on therapies for these patients, treatment is still suboptimal. In this article, the various treatments available are reviewed. Opiates and bisphosphonates, the mainstays in current practise, are covered in detail, and evolving therapies that may shape future management are also discussed.

Pharmacotherapy of cancer-related episodic pain

Episodic pain is a transient increase in pain intensity over background pain. Episodic pain occurs commonly in cancer patients; it is a heterogeneous phenomenon that is incapacitating, debilitating and can have a significant impact on quality of life. Episodic pain can be difficult to manage; it is often unpredictable, typically of fast onset, of short duration and feels similar to background pain except that it may be more severe. The successful management of episodic pain can only be achieved following a thorough assessment. The subsequent management usually involves both pharmacological and non-pharmacological strategies integrated into the overall care and appropriate for the stage of the patient's disease. Pharmacological management includes the implementation of primary therapies (e.g., chemotherapy for the underlying aetiology of the pain, optimising the scheduled medication (e.g., analgesics and adjuvant analgesics) and specific pharmacological interventions for the episodic pain (e.g., rescue medication).

Current strategies for pain control

Pain is the most feared symptom for patients diagnosed with cancer. Although our understanding of cancer pain and its management has greatly improved in the past decade, an unacceptably large proportion of patients still do not receive adequate pain relief. Before commencing any form of treatment, patients must receive a thorough assessment in order to define the pain, causes and severity. The recommendations for progressing a patient from step 2 to step 3 of the WHO analgesic ladder are discussed here as well as the choice of strong opioid substitution. An overview of the benefits of considering alternative routes of administering strong opioids, such as the transdermal delivery of fentanyl (TTS fentanyl), and the use of opioid substitution in patients intolerant to the adverse effects of morphine are also included. Finally, newer approaches to relieving refractory pain, such as neuropathic and bone pain, are considered.

New approaches to pain control in patients with cancer

Pain affects most patients with malignant disease, and the prevalence of severe pain increases in the advanced stages of the condition. One in 5 patients with cancer has uncontrolled pain, even after 10 years of the use of the World Health Organization programme for cancer pain control and its 'three-step ladder' for the rational use of analgesics including morphine. Morphine has long been the 'gold standard' for the treatment of severe cancer pain. However, its side-effects, particularly sedation, cognitive impairment and myoclonus at high doses, have provoked the use of 'opioid rotation' to alternatives such as methadone and hydromorphone. The new 72-h transdermal patch for fentanyl also offers advantages of reduced side-effects and increased convenience over oral morphine. Intravenous strontium-89 and bisphosphonate therapy are effective for both short- and long-term control of metastatic bone pain. The spinal N-methyl-D-aspartate (NMDA) receptor is important in modulating the plasticity of the central nervous system and in aggravating chronic pain through the phenomenon of 'wind-up'. The NMDA antagonist ketamine, an anaesthetic, can be used at low doses for the management of refractory and neuropathic pains. Among adjuvant drugs, ketorolac has emerged as a potent non-steroidal anti-inflammatory drug. Palliative care is gaining acceptance as a new discipline in healthcare. Its strategic role is being reviewed as an adjunct to cancer therapy at all stages and its use is no longer confined to the terminal phase of disease after curative treatment has failed. Pain control and other aspects of symptom control are, therefore, viewed as an integral part of cancer management.