Inclusion Criteria:

To be eligible for inclusion in the study, each patient must fulfill each of the criteria
below.

- Have provided written informed consent prior to study-specific screening procedures,
with the understanding that the patient has the right to withdraw from the study at
any time, without prejudice.

- Be female and 18 years of age or older.

- Have histologically confirmed invasive breast cancer.

- High risk of breast cancer recurrence (> 25% within the first 5 years without
adjuvant therapy, > 35% within the first 10 years) with one of the following:

- Regional node positive disease (pN+; tumor cells or tumor cell clusters < 0.2 mm
in diameter are not counted as metastases);

- Pathological N0 and PgR- and tumor size > 20 mm.

Exclusion Criteria:

Patients who fulfill any of the following criteria will be excluded:

- > 65 years of age.

- ”Special type” histology (mucinous, papillary, medullary, or tubular breast cancer),
when pN0.

- ER, PgR and HER-2 status (via in situ hybridization or immunohistochemistry) not
determined.

- Presence of distant metastases.

- Previous chemotherapy in the neoadjuvant setting.

- Non-ambulatory or WHO performance status > 1.

- Pregnant or lactating women. Women of childbearing potential (menstruating within 6
months of study entry or with no hysterectomy and age < 55) with either a positive or
no pregnancy test at baseline.

- Women of childbearing potential unless using a reliable and appropriate contraceptive
method. (Post-menopausal women must have been amenorrheic for at least 6 months to be
considered of non-childbearing potential).

- More than 12 weeks between breast surgery and date of randomization.

- Organ allografts with immunosuppressive therapy required.

- Major surgery (except breast surgery) within 4 weeks prior to study treatment start,
or lack of complete recovery from the effects of major surgery.

- Participation in any investigational drug study within 4 weeks preceding treatment
start.

- Patients with a history of uncontrolled seizures, central nervous system disorders or
psychiatric disability judged by the investigator to be clinically significant
precluding informed consent or interfering with compliance for oral drug intake.

- History of another malignancy within the last five years except cured basal cell
carcinoma of skin or carcinoma in situ of the uterine cervix.

- Clinically significant (i.e. active) cardiac disease (e.g. congestive heart failure,
symptomatic coronary artery disease and cardiac arrhythmia not well controlled with
medication) or myocardial infarction within the last 12 months.

- Abnormal laboratory values:

- Hemoglobin < 10.0 g/dL, neutrophils < 1.5 x 10^9/L, platelet count < 120 x
10^9/L;

- Serum creatinine > 1.5 x Upper Limit of Normal (ULN);

- Creatinine clearance (calculated per Cockroft and Gault) < 50 mL/min;

- Serum bilirubin > ULN;

- ALAT > 1.5 x ULN;

- Alkaline phosphatase > 2.5 x ULN.

- Serious uncontrolled intercurrent infections or other serious uncontrolled
concomitant disease.

- Lack of physical integrity of the upper gastrointestinal tract or those who have
clinically significant malabsorption syndrome.

- Inability to swallow tablets.

- Life expectancy of less than 3 months.

- Unwilling or unable to comply with the protocol for the duration of the study.

- Requirement for concurrent use of the antiviral agent sorivudine or chemically
related analogues, such as brivudine.