Adjuvant Low Dose Aspirin in Colorectal Cancer

Inclusion Criteria: * Tumor with somatic alterations in PIK3CA, PIK3R1 or PTEN * Colon or rectal cancer tumor stage II-III * Radical surgery according to surgeon and pathologist * Karnofsky performance status ≥60% * Platelets ≥ 100 x 109 / L * Clean Colonoscopy or Computed Tomography (CT) colon within 3 months preoperatively or postoperatively but before randomization * Patient able to swallow tablets * Patient able to understand and sign written informed consent Exclusion Criteria: * Hereditary colorectal cancer linked to familial colonic polyposis or Lynch syndrome * Inflammatory bowel disease (Crohn's disease or ulcerative colitis) * Distant metastases * Other cancers (excluding colorectal cancer or other skin cancer than melanoma) within 3 years from screening * Known bleeding diathesis (such as hemophilia) * Concomitant antiplatelet therapy (eg clopidrogrel or ticlopidine) or anticoagulant therapy (warfarin or low molecular weight heparin). Post-operative treatment with low molecular weight heparin must be withdrawn before administration of study treatment * Active gastritis or peptic ulcer, or significant surgical post-op bleeding, within the previous three months assessed at screening and randomization * Ongoing regular use of corticosteroids, Nonsteroidal Anti-Inflammatory Drug (NSAID) * Uncontrolled hypertension according to Investigator's judgment * Clinically significant liver impairment according to Investigators judgment * Existing renal failure according to Investigator's judgment. Renal failure with decreased creatinine clearance \<60 should lead to consultation with a nephrologist. * Significant medical illness that would interfere with study participation * Pregnancy or breastfeeding females * Known allergy to NSAIDs or ASA * Current participation in another clinical trial that will be in conflict with the present study * Patients who are unlikely to comply with the protocol (e.g. uncooperative attitude, inability to return for subsequent visits) and/or otherwise considered by the Investigator to be unlikely to complete the study