Pain Control Worse for Non-Whites with Metastatic Breast Cancer


CHAPEL HILL, N.C., Nov. 26 -- For reasons that are not clear, non-Caucasian women with metastatic breast cancer experience more severe pain than white women, despite similar medication regimens, researchers here found.Over the period of a year, during which all patients received standard analgesic treatment, non-white women reported pain that was more than twice as bad as that of white women, Liana D. Castel, Ph.D., of the University of North Carolina, and colleagues reported in the Jan. 1, 2008 issue of Cancer.
Action Points
Explain to patients that, although all breast cancer patients in this study received similar drug treatment for pain, severe pain was worse for the non-white patients.
Explain that further research is needed to discover the probable multiple reasons for this disparity.
That finding emerged from a secondary analysis of an international randomized, controlled, head-to-head trial of two bisphosphonate drugs for patients with multiple myeloma and breast cancer. The majority of the non-white women were in the U.S. The trial (a Novartis protocol) was conducted from October 1998 through January 2001.
The authors of this study limited their analysis to 1,124 women with metastatic breast cancer and bone metastases, all of whom had received standard treatment in the original international clinical trial.
As a measure of pain, the researchers used the Brief Pain Inventory (BPI) test, based on a score of zero to 10 in pain severity. For a time-to-event hazards analysis, the test was given repeatedly over the course of a year to determine pain levels. A score of seven or higher designated severe (versus moderate or mild) pain.
Hazard models were fitted to identify baseline and time-dependent covariates as predictors of pain worsening within cumulative 80-day intervals during the year, as well as restricted performance, namely pain interference in daily activities.
Non-white women reached a pain level of seven or higher significantly earlier than white women, the researchers reported.
Increased severe pain hazards were associated with non-Caucasian race (hazard ratio [HR]: 2.52, 95% CI: 1.69 to 3.76, P0.0001) and restricted performance status (HR:1.73, 95% CI: 1.13 to 2.64, P=0.012).
Besides race, other predictors of greater pain were radiation therapy in a previous interval (HR:2.86, 95% CI: 1.61 to 5.09) and being inactive (HR: 1.73, 95% CI: 1.13 to 2.64). Chemotherapy was not a factor.
Estimated cumulative rates for not yet reaching a pain score of seven or above ranged from 0.79 (0.72 to 0.85) in the first interval to 0.64 (0.55 to 0.74) in the last interval for non-Caucasian women. This contrasted with higher rates ranging from 0.91 (0.89 to 0.93) to 0.84 (0.81 to 0.87) for Caucasian women.
These results confirm published clinical evidence that non-Caucasian women are more likely to experience severe pain and pain interference in daily activities, the researchers said.
The findings also support published studies showing that non-Caucasian women have the highest risk of being undertreated for pain, including inadequate dosing and poor access to analgesics, as well as greater breast cancer mortality, they said.
The researchers called for future research to investigate whether non-Caucasian women with metastatic disease are treated less aggressively with analgesics. If so, they said, the underlying sources of the problem should be identified.
Adequate analgesia depends in part on patients' accurate reporting, the researchers said, and patients are sometimes unwilling to report pain to their physicians because of social, cultural, or religious barriers, such as fear of being labeled a drug addict or feeling that suffering is deserved.
They noted study limitations that included the fact that not all pain events of interest were captured because of the timing of assessments.
The analysis was also limited by the criteria of the original clinical trial, so that no dosing and timing data on the analgesics were reported.
In addition, the sample size of non-Caucasian women was relatively small and consisted entirely of women in a clinical trial.
Clinicians should use information about known risk factors to provide more aggressive and earlier interventions among non-Caucasian women with metastatic breast cancer, Dr. Castel, and her colleagues concluded.
No financial conflicts were reported. Support for this work was provided by an AHRQ National Research Service Award Institutional Research Training Grant. Primary source: CancerSource reference: Castel LD, et al "Racial differences in pain during 1 year among women with metastatic breast cancer: a hazards analysis of interval-censored data" Cancer 2008; DOI: 101002/cncr.23133.