Spine Pain and Metastatic Prostate Cancer: Defining the Contribution of Nonmalignant Etiologies

In patients with metastatic prostate cancer (MPC), the contribution of nonmalignant etiologies to morbidity is often overlooked.

We retrospectively reviewed the documented specialist assessments of back pain in men with MPC in a joint medical oncology and physiatry clinic at our tertiary cancer care center. Data on cancer disease extent, hormonal status, sites of spread, pain characteristics, physiatric examination findings, imaging, and recommended management were reviewed, extracted, and codified. For those with back pain at a site of known disease, pain etiology was classified as malignant, nonmalignant, or mixed.

Ninety-three men were collaboratively assessed for back pain, 24 (26%) with a biochemical recurrence and 69 (74%) with MPC of whom 53 (77%) reported pain in an area of known spinal metastases including 35 (66%) metastatic castration-resistant disease and 34 (64%) a precancer history of back pain. The presenting pain symptoms of the 53 patients were activity-related in 22 (42%), radicular in eight (15%), transitional movement-related in seven (13%), biologic in five (9%), and multifactorial in 11 (21%). Overall, pain was deemed malignant in 20 (38%; five castration-sensitive, 15 metastatic castration resistant prostate cancer), nonmalignant in 12 (23%; four castration-sensitive, eight CRPC), and of mixed etiology in 21 (40%; nine castration-sensitive, 12 CRPC).

Nonmalignant etiologies contributed significantly to back pain at sites of metastatic spread for 33/53 (62%) patients with MPC assessed by medical oncology and physiatry. We recommend multidisciplinary care for patients with MPC and back pain to address nonmalignant etiologies that contribute to functional compromise.