ASCO Breast: Hepatitis C Impacts Breast Cancer Treatment

SAN FRANCISCO, Sept. 10 -- Hepatitis C infection may impair breast cancer treatment and increase complications of chemotherapy, researchers found.

In a small retrospective study of breast cancer patients with HCV infection, there were chemotherapy dose delays or reduction in 27% of neoadjuvant therapy and in 30% of adjuvant therapy, according to P.K. Morrow, M.D., of the University of Texas M.D. Anderson Cancer Center in Houston, and colleagues.

"Hepatitis has wide-ranging effects on treatment of breast cancer," Dr. Morrow said at the American Society of Clinical Oncology Breast Cancer Symposium. Although the reason for the effect is not known, she postulated that it's because of poor metabolism of the drugs, and that HCV is causing myelosuppression.

In the study, HCV was also associated with 100% of grade 3/4 complications for taxane monotherapy, 30% for anthracycline-based chemotherapy, and 55% for women who got both.

"This study demonstrates the importance of close surveillance of patients with hepatitis C who are being treated for breast cancer," Dr. Morrow said.

"If you find someone with elevated liver enzymes, do a hepatitis panel on them," because hepatitis C is often found retrospectively once complications arise, she added.

A prior study had shown that breast cancer treatment for patients with hepatitis B increased likelihood of viral reactivation, early discontinuation of chemotherapy, and treatment delay.

However, the effect of HCV infection, which infects 2% of Americans, was little known, she said.

Dr. Morrow's group had previously studied their small cohort of patients with concurrent HCV infection who were treated at M.D. Anderson. But when the number of such patients more than doubled over only two years, the researchers decided to update their analysis.

They retrospectively reviewed their database and found a total of 43 women with invasive breast cancer who had been identified with previously-untreated HCV infection.

Because M.D. Anderson does not systematically screen patients for HCV, the study likely missed many HCV-positive women, said Dr. Morrow.

Those women who were included were age 49 on average. Their tumors were typically hormone receptor-positive (58%), stage II or III (33% and 35%, respectively), and HER-2/neu negative (60%).

For neoadjuvant treatment, 45% of the women received the combination of doxorubicin [Adriamycin], and cyclophosphomide [Cytoxan]), with or without fluorouracil [Adrucil]. Another 54% got sequential treatment with an anthracycline and a taxane.

The partial response rate was 36% whereas only 9% had a complete pathological response. Twenty-seven percent had no response or progression. Response was unknown for a 27%.

Furthermore, 45% of patients required growth factor support and 27% had dose delay or reductions. Complications of grade 3 or worse were seen among 55% of patients during neoadjuvant therapy. These rates included:

• 9% during taxane-based therapy.
• 27% during anthracycline-based therapy.
• 18% both while receiving a taxane and during anthracycline-based therapy.

During adjuvant therapy, 24% of patients were given combination therapy and 24% sequential chemotherapy including both a taxane and anthracycline. A third received antihormonal therapy, 15% got other chemotherapy regimens, and 3% received no therapy.

Among the patients in adjuvant therapy, 24% required growth factor support and 30% had dose delay or reductions. Grade 3/4 complications affected 48% of patients. The rates were:

• 21% during taxane-based therapy.
• 12% during anthracycline-based therapy.
• 3% during CMF chemotherapy (cyclophosphamide, methotrexate, and fluorouracil).
• 12% both during therapy with a taxane and with an anthracycline.

In total, 70% of patients who received both anthracyclines and taxanes in either setting developed grade 3 or greater complications. The most common were peripheral neuropathy (40%) and neutropenic fever or infection (40%).

Overall, 27% of patients with both hepatitis and breast cancer had delays or reductions in chemotherapy dosing and 5% of patients had to discontinue chemotherapy prematurely because of adverse events.

Although hepatitis C treatment often cannot be initiated until after chemotherapy, "get the hepatologist involved from the very beginning," Dr. Morrow recommended. The hepatologist can monitor the patient and do viral genotyping to prepare for treatment, she said.

However, Dr. Morrow noted that the response rates among the seven patients treated for concurrent hepatitis C in the study "weren't good either." Only one of the two patients treated with interferon alone responded, and none of the five treated with pegylated interferon plus ribavirin responded while 40% had complications from this therapy.