Advances in cardiovascular care have led to improvements in longevity. Public health experts have predicted that in the next several years cancer will likely supplant cardiovascular disease as the primary killer in our country. As the disease burden imposed by various cancers increases, so too will the painful challenges associated with them.
Cancer pain can originate from a number of causes. The mechanical effects of tumor growth can displace and exert pressure on virtually any organ system. Nerves may be directly invaded by tumor or displaced by them resulting in an excruciating pain experience. Our therapies too, may inadvertently harm patients. Chemotherapeutic agents been associated with some of the most refractory pain conditions ever documented.
Destructive bone pain also presents a unique challenge with certain cancer types. Specifically, cancers of the breast, prostate, lung, kidney, and thyroid are known to have a penchant for bony metastasis. Metastases to bone can result in pathologic fractures or can simply be painful because of localized destruction.
Historically, first line therapy to address pain associated with bony lesions has consisted of NSAID therapy followed by opiate therapy. Mechanistically it makes sense that NSAIDs should be particularly effective at addressing bony pain. Unfortunately clinical studies are lacking to support this notion. Opiates too can be associated with lackluster response in certain populations. Moreover, the sedating qualities of opiates can leave patients who want to live productively quite frustrated. The shortcomings associated with these initial therapies has forced providers to search for other avenues of treatment. We have indeed made progress….
External beam radiation
Radiation oncologists should become early involved with patients suffering from bone-related cancer pain. There is clear data supporting the pain-reducing benefits of targeted external beam radiation. While the therapy is beneficial, there are limitations when lesions are widely disseminated or multiple. Moreover, there may be long-term drawbacks to radiation in patients with a favorable long-term prognosis.
Bisphosphonates - This class of medication too has been associated with pain reduction with erosive lesions. At least part of this pain benefit is related to the slowed erosion of bone by tumor, however, there is evidence to suggest that multiple beneficial mechanisms may be at play. Given the overall favorable side effect profile of bisphosphonate therapy, these medications should be an early consideration in treatment.
Radioisotopes - Drug companies have developed targeted isotopes complexed with phosphonates. These compounds are delivered intravenously and preferentially are delivered to cancerous lesions with high bone turnover. These medications are useful when lesions are multiple or widely disseminated. Moreover, pain reduction can last several months. Therapy can be repeated. The primary drawback to these therapies is the potential for transient myelosuppresion.
Intrathecal therapy - Refractory patient populations may benefit from intrathecal drug delivery. Providers can use opiate medications, local anesthetics, or a combination thereof to deliver medications into the intrathecal space. Many times this allows for a profound reduction of pain symptomatology, improved functionality, and avoidance of medication-induced side effects. Typically these systems are managed by pain medicine specialists with knowledge of cancer care.
Bone pain in cancer populations can dramatically worsen quality of life and impair functionality. While we are fortunate that a number of advanced treatment modalities have become available, application of these therapies requires close coordination between a given patient’s primary care specialist, oncologist, radiation oncologist, and pain medicine specialist. Regular communication is imperative for favorable outcome.
Steven M. Harrison, MD, is Board Certified in Pain Management and Anesthesiology. He is the Director of the University of Central Florida School of Medicine Anesthesiology Clerkship and an Assistant Professor of Anesthesiology at the University of Central Florida. He can be reached at Steven.Harrison@shcr.com
