LOS ANGELES - In cancer patients who develop bone metastases, symptom clusters refer to a stable group of at least two interrelated and concurrent symptoms that are relatively independent of other clusters. These symptom clusters may have an effect on patient morbidity, therapeutic outcome, and treatment failures.
In a presentation this week at the American Society for Therapeutic Radiology and Oncology (ASTRO), Canadian investigators explored whether palliative radiotherapy positively affects symptom clusters.
For this research, Stephanie Hadi and colleagues accrued 348 patients from the Rapid Response Radiotherapy Program at the Odette Cancer Centre in Toronto. All patients had a proven, pathologic diagnosis of cancer and had radiographic evidence of bone metastases.
"Approximately 70% to 85% of cancer patients will develop bone metastases.... Radiotherapy is well-established to provide pain relief in 80% of these patients," wrote Hadi in her group's poster.
Of the 348 patients, lung cancer was the most prevalent (26% of the patients). The majority of the patients were treated with a single 8-Gy radiation therapy scheme (58%), delivered most often to the spine (31%).
Pain and functional interference were assessed with the 11-point Brief Pain Inventory, with patients providing their scores at baseline and four to 12 weeks after radiation treatment. A principal component analysis (PCA) with varimax rotation was performed on the worst pain ratings and functional interference ratings at each follow-up to determine interrelationships between symptoms pre- and postradiotherapy.
According to the results, two symptom clusters were identified: Cluster 1 included walking ability, general activity, enjoyment of life, and worst pain. Cluster 2 included relations with others, mood, and sleep patterns.
In patients who responded to radiotherapy, both symptom clusters disintegrated at four, eight, and 12 weeks after radiation treatment. In nonresponders, the cluster disappeared at week four, returned at week eight, then disintegrated at week 12. All symptom severity improved over time, the authors stated.
"Palliative radiotherapy decreases symptom severity, increases function, and can improve overall quality of life," Hadi and colleagues wrote. "The significant correlations between worse pain and the functional interference items reaffirm the importance of pain reduction as a treatment goal for palliative radiotherapy."
Finally, treating physicians should pay attention to symptom clustering as the treatment of one symptom may affect others within the same cluster, they stated.
By Shalmali Pal
AuntMinnie.com staff writer
November 2, 2007
Related Reading
PET/CT, whole-body MRI each has merits in metastatic breast disease, May 29, 2007
Repeated samarium dosing safe and effective for metastatic bone pain, March 15, 2007
Cryoablation reduces metastatic cancer pain, November 27, 2006
Copyright © 2007 AuntMinnie.com
