TUESDAY, Aug. 15, 2006 (HealthDay News) -- The side effects and added costs of chemotherapy treatment for breast cancer patients are probably higher than thought, new research suggests.
A study in the Aug. 18 issue of the Journal of the National Cancer Institute found the number of adverse events related to chemotherapy, and the associated costs, may be underestimated when chemotherapy moves from clinical trial patients to the general population.
"When we looked at the rates of side effects commonly associated with chemotherapy, we found women experienced more hospitalizations or emergency room visits for these side effects than previous clinical trials would have estimated," said study author Dr. Michael Hassett, a clinical instructor in medicine at the Dana-Farber Cancer Institute, in Boston.
Breast cancer is the most common reason American women receive chemotherapy, according to the study. Hospitalizations due to chemotherapy side effects are thought to be rare, but the current study notes that only one study has been done to measure the side effects of chemotherapy in the general population.
"We wanted to understand how frequently these side effects occur in the general community, because what happens in the community may be different from what we observe in clinical trials," explained Hassett.
To better assess the incidence of side effects, Hassett and his colleagues gathered data from a pool of 12,239 women who had been recently diagnosed with breast cancer. All were under the age of 63. In this group, 4,075 women received chemotherapy.
The researchers looked at hospitalizations and emergency room visits in the year following the initial diagnosis for both women who received chemotherapy and those who did not.
Women on chemotherapy were much more likely to visit the emergency room or be hospitalized for any cause than women who didn't have chemotherapy -- 61 percent compared to 42 percent.
Fever and infection were the most common causes women were hospitalized or visited the emergency room. Low blood cell counts were the next most common reason, followed by dehydration or an electrolyte imbalance.
Women who received chemotherapy also had more than $1,200 in additional health-care expenditures related to chemotherapy and more than $17,000 in additional costs for ambulatory care than women who didn't receive chemotherapy.
When asked to explain the finding, Hassett said, "There are a number of possible explanations. Clinical trials may not detect all of the side effects that occur. People enrolled in clinical trials may be less likely than those treated in the general community to experience serious side effects of chemotherapy. Clinical trials may not have enough power to detect rare side effects. Or, our study could have overestimated the likelihood of experiencing serious side effects of chemotherapy, because we used hospital bills rather than medical records to identify these events."
"This study was a bit surprising, although it's been known for a time that following adverse events is very difficult, and the systems used are somewhat imperfect. This study really quantified in young women what the experience may be like," said Dr. John Erban, director of the breast cancer program at Tufts New England Medical Center, in Boston. Erban also co-authored an editorial in the same issue of the journal.
"Chemotherapy that's offered is likely to be very helpful," said Erban. "Women should not be afraid to take chemotherapy if they're offered it, but should ask questions about how much of a benefit to expect and what types of side effects they may experience. And women need to recognize that this information may be changing more and more as the drugs change. This is a very rapidly changing field, but it takes a long time to understand the ultimate risks and benefits of any one agent," he added.
"Hopefully, women with breast cancer who hear about this study will understand that deciding whether or not to have chemotherapy must be made on an individual basis," Hassett said. "Women should talk with their doctors about both the benefits and risks of chemotherapy. For women with small cancers, the benefits may not outweigh the risks. On the other hand, for women with larger or higher-risk cancers, the benefits usually outweigh the risks."
For more information on chemotherapy's side effects, visit the National Cancer Institute.