Who Most Benefits from Adjuvant Chemo?
A landmark study presented at the San Antonio meeting suggests that post-menopausal women who have ER positive, node positive breast cancers are among those who derive the most benefit from chemotherapy. These women were treated with chemotherapy, followed by five years of tamoxifen.
Perhaps of most interest was the finding that the women who would most benefit from chemotherapy could be identified through the Oncotype DX gene test. This has been a ten year study, under the auspices of SWOG (the Southwest Oncology Group), and is an important contribution to the understanding of more individualized treatments. As you know, there is a move away from "one size fits all treatment" as we know more and more about the individual characteristics of specific tumors.
Here is a quote and then a link to read more:
December 18, 2009 (San Antonio, Texas) — Postmenopausal women with hormone-receptor-positive and node-positive breast cancer who are at especially high risk for recurrence might be the main beneficiaries of the addition of chemotherapy to tamoxifen to prevent recurrence. This suggestion comes from 10-year results of a landmark clinical trial published online December 10 in the Lancet.
Furthermore, a multigene assay might help rule out women who do not benefit from the added chemotherapy,according to a related study.
This second study, which uses a group of patients from the same landmark trial, was presented as a poster here at the 32nd Annual San Antonio Breast Cancer Symposium (SABCS).
The landmark trial, known as Southwest Oncology Group (SWOG)-8814, randomized 1477 patients. The new results from a 10-year follow-up show that chemotherapy added to tamoxifen (in both a concurrent and sequential fashion) provides statistically significantly better disease-free survival than tamoxifen alone (57% vs 48%; P = .002).
For the secondary end point of overall survival, chemotherapy added to tamoxifen is superior to tamoxifen alone, but not statistically significantly so (65% vs 60%; P = .043).
The chemotherapy regimen used was anthracycline-based CAF (cyclophosphamide, doxorubicin [Adriamycin], and fluorouracil), which was one of the "most commonly used regimens when this trial was designed," write SWOG investigators. Tamoxifen was taken daily for 5 years.
Despite the 5% improvement in overall survival from adjuvant chemotherapy, the
majority of the patients (95%) who received the chemotherapy did not derive any
additional benefit, notes an editorial that accompanies the study.