Taxotere-cyclophosphamide (TC) chemotherapy is commonly used as an adjuvant chemotherapy regimen in patients with resected early stage breast cancer. TC chemotherapy can cause febrile neutropenia (FN) which can be serious and associated with treatment delays and dose reductions, thereby compromising treatment efficacy. To reduce the risk of chemotherapy-induced FN,TC is administered with either one of two highly effective standard treatments; namely primary prophylaxis with either ciprofloxacin or granulocyte colony-stimulating factor (G-CSF). However, there are considerable cost differences between these strategies; subcutaneous daily G-CSF costs at least $12,000 over 4 cycles of treatment while oral ciprofloxacin costs about $100.

The investigators have therefore been performing a feasibility study to explore whether the "integrated consent model" involving oral consent is feasible in practice; and whether it can be used to increase the number of physicians and patients who take part in clinical trials. This feasibility study (REaCT-TC NCT02173262) has been an amazing success and the investigators are therefore now performing a definitive study comparing G-CSF with ciprofloxacin. This study will not be evaluating feasibility endpoints, but rather clinically important endpoints of hospitalizations and febrile neutropenia rates.

Inclusion Criteria:

• Histologically confirmed primary breast cancer
• Planned TC chemotherapy
• ≥19 years of age
• Able to provide verbal consent

Exclusion Criteria:

• Contraindication to either Ciprofloxacin or G-CSF

There is no plan to make IDP available.