Stomach and colorectal cancers are among the most common gastrointestinal malignancies worldwide. These cancers often develop gradually, progressing from precancerous changes to invasive disease over several years. Early-stage disease may be asymptomatic, highlighting the importance of screening and early detection.

Stomach cancer may present with persistent indigestion, abdominal pain, early satiety, unexplained weight loss, anemia, or vomiting. Colorectal cancer commonly presents with changes in bowel habits, rectal bleeding, abdominal discomfort, unexplained fatigue, or iron-deficiency anemia. Risk factors include age, family history, inflammatory bowel disease, lifestyle factors, and certain dietary patterns.

Diagnosis involves endoscopy or colonoscopy with biopsy, supported by imaging studies for staging and treatment planning. Early detection significantly improves treatment outcomes and survival rates.

Management requires a multidisciplinary approach involving gastroenterology, surgery, oncology, and radiology specialists. Treatment strategies depend on cancer stage, location, and patient factors. Long-term follow-up and surveillance are essential for recurrence prevention and survivorship care.