Doxorubicin Hydrochloride, Cyclophosphamide, Docetaxel, and S-1 Before Surgery in Treating Women With Stage II or Stage III Breast Cancer

DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed invasive primary breast cancer

  * Clinical (radiologic) stage II or III disease
  * No T4d disease
  * No inflammatory breast cancer
* ErbB2-negative disease OR patient cannot receive trastuzumab treatment

  * ErbB2-positive disease defined as either immunohistochemistry 3+, or FISH- or CISH-positive; immunohistochemistry 2+ is to be determined according to FISH or CISH results

PATIENT CHARACTERISTICS:

* Mobile
* ECOG performance status 0-1
* Normal cardiac function (LVEF \> 50%)
* Hemoglobin ≥ 10.0 g/dL
* Absolute neutrophil count ≥ 1,500/μL
* Platelet count ≥ 10 x 10\^4/μL
* Creatinine ≤ 1.5 times upper limit of normal (ULN) OR creatinine clearance ≥ 50 mL/min
* Total bilirubin ≤ 1.5 times ULN
* AST/ALT ≤ 2.5 times ULN
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* Able to swallow tablet whole with water
* No prior motor or sensory neurotoxicity CTCAE ≥ grade 2
* No other serious disease or medical condition
* No uncontrolled or serious cardiovascular disease, including any of the following:

  * Myocardial infarction within the past 6 months
  * New York Heart Association class III or IV heart failure
  * Uncontrolled angina pectoris
  * Clinically significant pericardial disease
  * Cardiac amyloidosis
* No history of symptomatic or therapy-requiring cardiac arrhythmia CTCAE grade 3 (e.g., multifocal premature ventricular contractions, bigeminy, trigeminy, ventricular tachycardia, uncontrolled atrial fibrillation)
* No asymptomatic sustained ventricular tachycardia
* History of atrial fibrillation or cardiac arrhythmia controlled by medication allowed
* No uncontrolled infection, unstable peptic ulcer, uncontrolled diabetes, or any other contraindication to corticosteroid administration
* No history of infection or any other serious medical event which may cause any functional injury in the affected patient and consequently, interfere with continuing the study treatment
* No history of hypersensitivity to taxanes, fluorouracil, or S-1
* No significant gastrointestinal malfunction that will affect S-1 absorption
* No history of other cancer within the past 5 years except properly treated carcinoma in situ of the uterine cervix or basal cell or squamous cell carcinoma of the skin
* No severe psychological or neurological disorder or dementia that would preclude understanding of the informed consent
* No psychological, social, family, or geographical condition, or difficult circumstance that would preclude follow-up or compliance with the protocol

PRIOR CONCURRENT THERAPY:

* No prior systemic treatment for this cancer (e.g., radiotherapy, chemotherapy, hormone therapy, or biological therapy)
* No prior preoperative topical treatments (e.g., incomplete surgery or radiotherapy) for this cancer
* No concurrent drug(s) that may potentially cause changes in the pharmacological activity of S-1 formulation, including any of the following:

  * Allopurinol
  * Phenytoin