Breast cancer sufferers experience more side effects from chemo than previously thought

Women with breast cancer ages 64 and younger experience three to four times more serious side effects from chemotherapy than previously hypothesized, according to a study published in the Aug. 16 edition of the Journal of the National Cancer Institute, the AP/Philadelphia Inquirer reports.

One in six women undergoing chemotherapy for breast cancer who experience side effects require hospitalization or emergency department care because of the treatment, the study finds (Neergaard, AP/Philadelphia Inquirer, 8/16). Michael Hassett of Harvard Medical School and the Dana-Farber Cancer Institute and colleagues reviewed insurance claims from 1998 to 2002 for 3,526 women who underwent intravenous chemotherapy for breast cancer treatment (Richwine, Reuters, 8/15). The researchers examined the records to determine the frequency with which women with breast cancer under age 64 were hospitalized a year after their diagnosis and how often chemotherapy side effects were blamed for those hospitalizations. The study -- which was funded by the Agency for Healthcare Research and Quality -- finds that 16% of the women were hospitalized for at least one of eight side effects -- including infections, low blood counts, dehydration or nausea. The most common side effects are infection and fever, which occurred in 8% of the women, a rate that is four times what previous reports had predicted, the study finds (AP/Philadelphia Inquirer, 8/16). Other side effects also occurred more frequently than previously reported, Reuters reports. For example, 5.5% of women had low blood counts that could raise the risk of infection or bleeding compared with rates of 1% to 2% in clinical trials (Reuters, 8/15). In addition, 61% of women undergoing chemotherapy were hospitalized for some medical reason -- whether it was chemotherapy related -- compared with 42% of women with breast cancer who were not undergoing chemotherapy treatment (AP/Philadelphia Inquirer, 8/16). The researchers also reported that women undergoing chemotherapy who experienced side effects spent $16,000 more for outpatient care, $13,000 more for hospital care and $1,900 more for prescription drugs than women undergoing chemotherapy who did not experience such complications (CQ HealthBeat, 8/15). Hassett said, "Our results don't change the benefits of chemotherapy. ... We still think chemo can improve survival" for many women living with breast cancer (Reuters, 8/15). AHRQ Director Carolyn Clancy in a statement said, "It is important to know the impact of interventions such as chemotherapy, so that patients can make informed decisions about the risks and benefits of their treatment options" (CQ HealthBeat, 8/15).

Additional Comments

According to the AP/Inquirer, information about side effects come from clinical trials of medications, which can "underestimate toxicity" because they are designed to prove the medication's effectiveness. As a result, trials enroll only the best candidates instead of considering those who might be sensitive to the medication, the AP/Inquirer reports (AP/Philadelphia Inquirer, 8/16). In a related editorial, John Erban of the Division of Hematology-Oncology at the Tufts-New England Medical Center in Boston and Joseph Lau of the Institute for Clinical Research and Health Policy Studies at Tufts write, "The inability of our well-designed studies to detect uncommon (less than one in 1,000) acute, yet important, or even fatal, adverse effects serves as a reminder that clinical trials data are only an estimate of the worth of a drug and that healthy skepticism and diligent reporting of potential toxicities should continue even after an agent enters general use" (Erban/Lau, Journal of the National Cancer Institute, 8/16).