Intervention: Celecoxib
Trial phase: Phase 3
ATC code: C08CA51 | G01AE10 | L01XX33 | M01AH01 | N02AJ16
SMILES: Cc1ccc(-c2cc(C(F)(F)F)nn2-c2ccc(S(N)(=O)=O)cc2)cc1
Sex: Female
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 1755
Group description: Patients in this arm will receive 400mg of celecoxib once daily. In addition, Hormone Receptor (+) patients will receive endocrine treatment according to local practice.

Celecoxib: Patients will receive 400mg of Celecoxib once daily for two years or until disease progression (if before the two years limit) or until development of unacceptable toxicities. In addition ER(+) patients will receive endocrine treatment according to local practice.
Eligibility criteria:
Inclusion Criteria:

Completely resected (greater or equal 1mm), histologically or cytologically proven unilateral breast cancer
Female greater or equal 18 years of age
If (neo) adjuvant chemotherapy received, patient must have received at least 4 cycles. Chemotherapy must be completed prior to study entry
Hormone Receptor negatives must have received prior chemotherapy
Study entry must be within any of the following timelines: 3 months of the end of definitive breast surgery OR between 3 weeks and 4 months after day 1 of the last cycle of adjuvant chemotherapy OR 6 weeks of the end of radiotherapy.
WHO performance status 0 or 1
Pre-treatment haematology and biochemistry values within acceptable local limits: Haemoglobin, white blood cell greater or equal to 3.0 x 109/l or absolute neutrophil count greater or equal to 1.51 x 109/l, Platelets greater or equal to 100 x 109/l, Serum bilirubin less than 1.5 x upper normal limit , Alkaline phosphatase less or equal to 1.5 x upper normal limit , Serum creatinine less than 1.5 x upper normal limit
Negative pregnancy test for patients with child-bearing potential
Normal baseline ECG and clinical cardiovascular assessment after completion of all (neo) adjuvant chemotherapy
No previous or current evidence for metastatic disease
Be accessible for and consent to long term follow-up
Written informed consent prior to commencement of specific protocol procedures must be obtained and documented according to the local regulatory requirements

Exclusion Criteria

Patients with node negative, T1, Grade 1 breast cancer
Unresectable, metastatic or bilateral breast cancer
Active or previous peptic ulceration or gastrointestinal bleeding in the last year
Active or previous history of inflammatory bowel disease
A past history of adverse reaction/hypersensitivity to NSAIDs, including celecoxib and salicylates, or sulphonamides
On current or planned chronic NSAIDs therapy (except low dose aspirin 100 mg four times per day or 325mg once daily).
Current or long-term use of oral corticosteroids
Known or suspected congestive heart failure (greater than New York Heart Association I) and/or coronary heart disease, previous history of myocardial infarction, uncontrolled arterial hypertension (ie BP greater than 160/90mmHg) under treatment with two anti-hypertensive drugs, rhythm abnormalities requiring permanent treatment.
Patients with diabetes controlled by diet and oral medication are eligible for the study however patients with insulin dependent diabetes are excluded
Past history of stroke/Transient ischaemic attack, symptomatic peripheral vascular disease or carotid disease
Previously entered into an adjuvant chemotherapy trial for which approval for entry into REACT has not been granted
ER receptor status unknown, Human epidermal growth factor receptor 2 or FISH positive, or Human epidermal growth factor receptor 2 status unknown

14. Hormone Receptor negative and not received (neo)adjuvant chemotherapy 15. Use of hormone replacement therapy within the last 6 weeks 16. Pregnant or lactating women or women of childbearing potential unwilling/unable to use non-hormonal contraception 17. No previous or concomitant malignancies except adequately treated squamous cell / basal cell carcinoma of the skin, in situ carcinoma of the cervix or ductal carcinoma in situ/lobular carcinoma in situ of the breast, unless there has been a disease-free interval of 10 years or more 18. Psychiatric or addictive disorders which could preclude obtaining informed consent 19. Clinical evidence of severe osteoporosis and/or history of osteoporotic fracture