Tailored but heavy doses of chemotherapy given at shorter intervals do not seem to improve the chances of patients with early but high-risk breast cancer remaining cancer-free, compared to standard adjuvant chemotherapy, according to data from a recent clinical trial. Findings also showed that dense-dose chemotherapy appears to increase treatment-related side effects.
The study, “Effect of Tailored Dose-Dense Chemotherapy vs Standard 3-Weekly Adjuvant Chemotherapy on Recurrence-Free Survival Among Women With High-Risk Early Breast Cancer,” published in The JAMA Network, suggests that standard chemotherapy is a better overall treatment approach for these cancer patients.
Most chemotherapy agents are dosed for each patient based on body surface area, but considerable differences are seen in how patients respond to both the therapy’s effectiveness and its toxic effects. Patient-tailored and dose-dense treatments, which give the same total chemotherapy dose but over shorter periods, are being suggested as an alternative approach to improve the treatment’s efficacy.
Little is known about the approach’s outcomes in breast cancer patients, leading researchers at the Karolinska Institutet and University Hospital, Stockholm, to conduct a randomized, open-label clinical trial (NCT00798070) in patients with early but high-risk breast cancer in Europe.
The study assessed 2,017 women, randomly assigned to receive either tailored dose-dense chemotherapy (1,006 patients) or standard chemotherapy (1,011). All had previously undergone surgery for nonmetastatic node-positive, or high-risk node-negative, breast cancer.
After a median follow-up of 5.3 months, results showed that dose-dense chemotherapy did not significantly improve outcomes: the two groups had similar five-year overall survival rates (92% vs. 90%), five-year cancer recurrence-free rates (89% vs. 85%), and five-year metastasis-free survival rates (89% vs. 87%).
A significant difference was, however, found in “event-free survival” (defined as any complications or events that treatment is intended to prevent) between the groups. Dose-dense chemotherapy, compared to standard use, showed a five-year event-free survival rate of 87 percent, compared to 82 percent in the control group.
But this treatment approach was associated with higher rates of Grade 3 or Grade 4 nonhematologic toxic effects, like fatigue and pain, compared to the control group (53% vs. 37%).
Although these results suggest that dose-dense chemotherapy does not greatly improve outcomes for patients with early breast cancer, researchers suggest further studies address whether this treatment may benefit certain groups of patients, according to a press release.