Chemotherapy dose intensification in breast tumours is being evaluated in many multicentre trials, its indication being based on a clinical response in high-risk patients, thus selecting for tumours with rapid proliferation and low resistance. However, results from randomized trials are still pending. Clinical and pathological responses to therapy are valuable surrogate endpoints following primary chemotherapy. They will make it possible to distinguish at an early stage between patients who still retain an apoptotic response to chemotherapy and those patients whose disease will progress rapidly due to resistance mechanisms. For practical purposes, patients at risk and capable of responding represent the population of choice for primary systemic chemotherapy. Thus, by investigating mechanisms of response and resistance during the first courses of treatment we may target chemotherapy at those patients likely to benefit most from this treatment. A number of immunotherapy and vaccination trials are being conducted in many different centres. There is a lot of anecdotal evidence that cancer vaccines could help patients, but little yet in the way of solid, reproducible clinical data. Best responses to clinical testing would ideally be expected in early-stage disease because there is less tumour bulk and the patient's immune system is still able to respond. Patients with early breast cancer who are at high risk of recurrence and who have failed to respond to primary chemotherapy might be given the option of participating in adjuvant vaccination trials following the completion of local therapy.