Researchers at The Institute of Cancer Research, London, and the Cancer Research UK Edinburgh Centre found that capecitabine resulted in patients experiencing fewer side effects and having a better quality of life, and it was as effective at preventing cancer's return as CMF.
Most patients experienced some side effects regardless of the treatment they were given. But those taking CMF were more likely to experience severe side effects including early menopause, nausea, infection, thrombosis, and anaemia.
During the trial, patients were followed up after 12, 18 and 24 months, and then yearly for at least 10 years, to see if their cancer had returned and to monitor side effects. More than 85 per cent of patients did not experience their cancer returning for at least five years.
Professor Judith Bliss, director of the Clinical Trials and Statistics Unit at The Institute of Cancer Research, London, who led the management of the trial said: "The TACT2 trial is the largest single study to look at the benefits of these different treatment approaches and schedules for chemotherapy to treat breast cancer.
"We've been able to show that capecitabine can be used as an alternative to CMF for part of the chemotherapy regime, giving patients a better quality of life without reducing their chances of survival."
The researchers also tested whether having an accelerated course of epirubicin - given every two weeks instead of three - was more effective or better tolerated by patients, but the results showed that it wasn't.
This trial was the first to look in detail at experience of accelerated chemotherapy from the patient's perspective, with some patients completing self-assessments of their symptoms and side effects.
Professor David Cameron, clinical chief investigator on TACT2, clinical director of the Cancer Research UK Edinburgh Centre and director of cancer services in NHS Lothian, said: "Using patient-reported data was extremely valuable because we could learn what patients find tolerable and where they struggle to cope during treatment.
"This new approach to chemotherapy may benefit a range of breast cancer patients, including younger women who want to preserve their fertility."
Professor Arnie Purushotham, Cancer Research UK's senior clinical adviser, said: "Treatment for many breast cancer patients is very successful and now it's important to research how to improve patient experience and minimise the adverse effects of treatment.
"The results of this trial will form an important part of the discussions doctors have with patients when deciding on the most appropriate chemotherapy."
Cameron D, Morden JP, Canney P, Velikova G, Coleman R, Bartlett J, Agrawal R, Banerji J, Bertelli G, Bloomfield D, Brunt AM, Earl H, Ellis P, Gaunt C, Gillman A, Hearfield N, Laing R, Murray N, Couper N, Stein RC, Verrill M, Wardley A, Barrett-Lee P, Bliss JM; TACT2 Investigators.
Accelerated versus standard epirubicin followed by cyclophosphamide, methotrexate, and fluorouracil or capecitabine as adjuvant therapy for breast cancer in the randomised UK TACT2 trial (CRUK/05/19): a multicentre, phase 3, open-label, randomised, controlled trial.
Lancet Oncol. 2017 Jun 6. pii: S1470-2045(17)30404-7. doi: 10.1016/S1470-2045(17)30404-7.