LOS ANGELESEarly data from a Breast Cancer International Research
Group (BCIRG) study showed that docetaxel (Taxotere)-based combination
therapy was significantly more effective than standard FAC
(fluorouracil/doxorubicin [Adriamycin]/cyclophosphamide [Cytoxan, Neosar])
for the treatment of early-stage breast cancer (ASCO abstract 141).
Reporting on behalf of BCIRG was its chairman Jean-Marc Nabholtz, MD,
professor of medicine at the University of California at Los Angeles and
director of Cancer Therapy Development at UCLA’s Jonsson Comprehensive
Cancer Center.
The phase III trial compared TAC (Taxotere
[docetaxel]/doxorubicin/cyclophosphamide (TAC) to FAC as adjuvant treatment
for node-positive breast cancer. Dr. Nabholtz said that interim data
analysis with a median follow-up of 33 months showed that TAC reduced breast
cancer recurrence risk by 32% (relative risk 0.68 vs FAC, P = .0011) and
reduced mortality for women with 1 to 3 positive nodes by 54% (P = .006).
"The observed early benefit that TAC provides over FAC in treatment
of node-positive breast cancer is large enough to be of clinical
significance, but final conclusions will require a longer period of
follow-up," Dr. Nabholtz said.
Relapse Risk Reduced
The primary study endpoint is disease-free survival (DFS), assessed by
Cox analysis. This showed a relative risk for TAC/FAC of 0.64 (CI 0.54-0.81,
P = .0002). "Seventy-four percent of patients were alive and
disease-free at 36 months on FAC and 82% on TAC," Dr. Nabholtz said.
There were 119 recurrences on TAC vs 170 on FAC. This constitutes a 32%
reduction in relapse risk (P = .0011), but planned subset analysis showed
that this improvement was accounted for entirely by better outcomes for
women with three or fewer positive nodes. TAC cut the risk of relapse in
half for these women but did not improve DFS for women with four or more
positive nodes.
Dr. Nabholtz said the investigators were surprised to find that TAC
reduced the risk of relapse almost equally in hormone-receptor positive
(HR+) patients and in those who were hormone-receptor negative (32%
reduction, P = .002, and 38% reduction, P = .005). "It was very
unexpected to see such a difference in a group of patients with positive
hormonal receptor status," he said.