medwireNews: Gemcitabine offers no survival benefit, but increases toxicity, when added to anthracycline and taxane-containing adjuvant chemotherapy in early breast cancer, results from the tAnGo trial show.
“Therefore, gemcitabine has not been added to standard adjuvant chemotherapy in breast cancer for any subgroup,” Helena Earl (University of Cambridge, UK) and co-researchers report in The Lancet Oncology.
In the phase III tAnGo trial, women with newly diagnosed, early-stage breast cancer of any nodal and hormonal status were randomly assigned to receive either four cycles of intravenous epirubicin 90 mg/m2 and cyclophosphamide 600 mg/m2 followed by four cycles of paclitaxel 175 mg/m2 infused over 3 hours or to the same chemotherapy regimen plus intravenous gemcitabine 1250 mg/m2 during the paclitaxel cycles.
During 10 years of follow-up, 1087 of the 3141 patients studied experienced locoregional or distant relapse or died without relapse.
This translated to a 10-year disease-free survival of 65% in both treatment groups, while 10-year overall survival was also similar between the groups, at 70% for the 1570 patients who received gemcitabine and 71% for the 1571 who did not.
The researchers note that the “frequencies of patients reporting grade 3 and 4 toxicities were as expected.”
Grade 3 neutropenia, myalgia and arthralgia, fatigue, infection, vomiting, nausea, neurosensory neuropathy, fever, diarrhea, constipation, anemia, and thrombocytopenia were all more common among the patients who received gemcitabine versus those who did not.
On the other hand, grade 3 dyspnea, deep vein thrombosis, and skin rash were similar between the groups, as was neutropenia, which was the only grade 4 event to occur in more than 1% of patients.
Dimitrios Mavroudis, from the University Hospital of Heraklion in Crete, Greece, comments that the findings, along with those of the NSABP B-38 trial, “leave no doubt that gemcitabine has no proven role in the adjuvant setting.”
He says that “the reasons for the negative findings are not obvious,” but suggests that the all-comers design will have affected the outcome because “our understanding of the heterogeneity of breast cancer at the molecular level” has “changed dramatically in the past 10 years.”
Mavroudis adds: “Results of high-quality studies such as tAnGo, even if negative, are important to the practising oncologists who can spare their patients and society undue medical toxicity and financial burden, and these studies could help researchers explore novel hypotheses by analysing the biological samples obtained from patients treated in a uniform manner.”
He concludes: “Publication of the tAnGo trial findings also heralds the end of an era of large-scale adjuvant studies. Future advances in adjuvant breast cancer therapy are likely to occur when the molecular heterogeneity of breast cancer is taken into account in the design of clinical trials testing the efficacy of novel therapeutics.”
By Laura Cowen
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