NEW APPROACHES TO ADJUVANT CHEMOTHERAPY FOR BREAST-CANCER

Adjuvant chemotherapy improves the disease-free and overall survival o f patients with resectable, early-stage breast cancer. However. the ef fect is modest, and we need means of increasing its impact. Retrospect ive and prospective studies on the effects of increased drug dosage ha ve demonstrated that within some dose ranges, increasing the dose inte nsity (total drug dose divided by total treatment time) improves the o utcome of treatment. Dose escalation to higher levels, sufficient to r equire growth factor and autologous stem cell support, is the subject of ongoing randomized study. Because there are both theoretical and pr actical limits on the potential effectiveness of single-cycle, high-do se chemotherapy researchers are developing alternative means of increa sing the effect of chemotherapy. One theoretically advantageous approa ch, predicted to be superior by kinetic models, is ''dose-dense'' chem otherapy administration. This approach consists of multiple cycles of escalated-dose chemotherapy administered at very short intervals. When administering presumed non-cross-resistant regimens or agents with ov erlapping toxicity, clinicians can increase dose density by using the sequential treatment plan. Furthermore, this plan can also facilitate the addition of new active drugs.