CHICAGO – A study of 119 cancer patients with solid tumors suggests that the complexity of some oral chemotherapeutic regimens can interfere with adherence to treatment.
Only one-third to one-half of patients on various intermittent regimens was fully compliant with their dosing schedules, reported Barbara A. Given, Ph.D., at the annual Chicago Supportive Oncology Conference.
Patients on simple regimens were much less likely to miss doses of oral drugs or to take doses on off days, according to Dr. Given, a registered nurse and associate dean of research in the college of nursing at Michigan State University in East Lansing.
The study assessed the feasibility of using an automated voice response (AVR) system to remind patients about their dosing schedules, to monitor adherence and medication side effects, and to identify patients in need of additional nursing support.
Investigators randomized patients with solid tumors (primarily of the breast and lung) who were treated with nonhormonal oral biologics to the following three groups:
• Weekly AVR calls during weeks 1-8 for evaluation of adherence and 15 symptoms.
• Weekly AVR calls for adherence and symptom evaluation, as well as nurse follow-up calls during weeks 5-8 if any symptom was above threshold or adherence was 80% or less.
• Weekly AVR calls for adherence evaluation only, with nurse assistance during weeks 5-8 for 80% or less adherence.
Patients were primarily women (82%) with a mean age of 61 years. All participants received a tool kit containing frequently asked questions and symptom self-management strategies. They were interviewed at baseline and at 10 weeks regarding symptom severity, depression, beliefs about oral agents, and cost of therapy.
Initially, 119 patients were enrolled in the study. Through attrition, the number of participants fell to 91 at 10 weeks. Investigators interviewed these patients about their satisfaction with AVR.
Adherence did not differ significantly among patients in any of the three arms, and neither symptom severity nor depression at intake was related to adherence. Symptom severity decreased in all three arms at 10 weeks, although symptom severity among lung cancer patients did not improve. At 8 weeks, 33% of patients had experienced adherence problems, with regimen complexity the major contributor.
"We would like to know what would happen at 12, 15, and 20 weeks, since some of [these patients] are on drugs for a long time," Dr. Given said.
Based on 100 patients assessed, the percentage who missed three or more doses was 12% among those on a consistent regimen (28 days on medication), but was 60%, 67%, and 38% among those on an intermittent regimen (14 days on, 7 days off; 7 days on, 7 days off; and other regimens, respectively).
Only 2% of patients on a consistent regimen overadhered to treatment (that is, took medication on an off day); however, 48%, 67%, and 13% of patients on the respective intermittent cycles overadhered. "Patients who overadhered by the end of the study really had worse symptoms, which then gave us another set of problems to deal with," Dr. Given said, reporting that patients who overadhered had an average score of 19 on the Symptom Experience Inventory, whereas those who did not overadhere scored 13.
Patients with breast tumors had a mean SEI score of 18.9 on intake and 12.8 at 10 weeks, whereas lung cancer patients scored a mean of 18.1 on intake and 18.4 at 10 weeks. Patients with other tumors had a mean score of 19.1 on intake and 12.4 at 10 weeks.
Full adherence was found in 88% of patients on the consistent cycle, but in only 36%, 33%, and 50% of patients on the respective intermittent cycles.
More than half of participants reported that AVR helped them manage their symptoms. A Web-based AVR system to help patients with adherence and symptom management "adds value" for patients, practitioners, and payers, and it can improve outcomes by allowing patients to be followed over time, Dr. Given said.
Specialty pharmacies also could help to educate patients, she added.
The Oncology Nursing Society funded the study. Dr. Given had no conflicts of interest.