Almost half of women treated for early-stage invasive breast cancer experience severe or very severe side effects that increase patient and caregiver burden, according to a new study published online January 24 in Cancer.
"This study shows that the likelihood of a toxicity considered severe or very severe in a patient who is being treated for breast cancer is higher than one might think," author Allison W. Kurian, MD, from Stanford University Medical Center in California commented to Medscape Medical News.
Before the study, no good benchmark existed about the extent of treatment toxicities in real-world clinical practice. Most data on patient-reported toxicities in breast cancer come from clinical trials, healthcare claims, and single-patient registries, which may not reveal the actual experiences of many women with breast cancer.
"This study was important in providing information from a population-based cohort of breast cancer patients about what their experience with toxicity with treatment really is," Dr Kurian said.
Side effects related to cancer therapy can have serious consequences, including treatment discontinuation and premature death. They also contribute to increased healthcare utilization and costs, as well as increased physical, emotional, and financial burdens on the part of patients and their families, according to background information in the article.
"This study is a real reminder to clinicians to be very much on the alert for the possibility of treatment toxicities. It's a lot better and more effective to prevent toxicity than to try to catch up and treat it once it's happened," Dr Kurian said.
In the study, called the iCanCare study, researchers mailed survey questionnaires to patients who were an average of 7 months out from receiving a diagnosis o early-stage invasive breast cancer. Participants were a diverse group of women who lived in Los Angeles County and Georgia between 2013 and 2014.
Surveys asked women to rate the severity of seven common breast cancer treatment side effects (nausea/vomiting, diarrhea, constipation, pain, arm swelling, shortness of breath, and breast skin irritation). Women also reported unscheduled clinic and emergency department visits and hospitalizations for treating side effects.
Overall, 71% of women responded to the surveys. The analysis included surveys from 1945 women. Of these, 93% reported at least one toxicity, and 45% reported at least one severe or very severe toxicity. The most frequently reported toxicities included severe/very severe pain (23%), constipation (14%), and breast skin irritation (13%).
Most patients visited a clinic for managing their side effects. Nine percent of respondents reported needing additional, unscheduled clinic visits, and 5% reported emergency department visits or hospitalizations.
Women who received systemic chemotherapy were twice as likely to report severe toxicity as those who did not (odds ratio [OR], 2.0; 95% confidence interval [CI], 1.7 - 2.4). Those who received both chemotherapy and radiation had 30% increased odds of higher toxicity than those who only received chemotherapy (OR, 1.3; 95% CI, 1.0 - 1.7). Being Latina was also associated with a 30% increased odds of higher toxicity compared with being white (OR vs whites, 1.3; 95% CI, 1.1 - 1.5).
Women who underwent double mastectomy were more likely to report higher toxicity than those who underwent unilateral mastectomy, but the results were not significant (OR, 1.2; 95% CI, 1.0 - 1.4).
The study didn't look at whether physicians treating these patients followed clinical guidelines. However, Dr Kurian pointed out that, for the high-frequency side effects such as nausea and gastrointestinal problems, clear guidelines and good treatment options exist.
"It's not clear to what extent all oncologists are following these guidelines. It's not clear to what extent, even if they follow them, they actually explain to patients what should be done under different circumstances," she said.
Dr Kurian emphasized the need for patient education and physician-patient communication going forward.
Patients need this information when they are experiencing and managing events, she said. They also need it when making treatment decisions, so that they can carefully weigh the risks and benefits. For example, women in this study who had a double mastectomy reported more pain than women who had less extensive surgery. That information could be important to some women who are deciding for or against a double mastectomy.
"We know that double mastectomy doesn't improve survival for a great majority of patients. Really educating women about side effects is important to help them make a truly informed decision," Dr Kurian said.
Also, some patients may not benefit from chemotherapy. Avoiding overtreatment and related side effects may be important in such patients.
"The better we can get at determining who really benefits, the better care I think we can deliver for our patients," she stressed.