Colorectal cancer (CRC) is a malignant tumour that originates in the lining of the colon or rectum and ranks among the most common gastrointestinal cancers worldwide. Most cases develop gradually from benign polyps over several years, offering a valuable window for early detection and curative treatment.
Symptoms
Early-stage colorectal cancer often produces no symptoms, which is why routine screening is critical. As the disease progresses, patients may notice a persistent change in bowel habits such as diarrhoea or constipation, blood mixed in the stool, unexplained weight loss, abdominal cramping or bloating, a constant feeling of incomplete evacuation, and increasing fatigue due to chronic anaemia from slow internal bleeding.
Diagnosis
Colonoscopy is the gold standard investigation, allowing direct visualisation of the entire bowel lining and biopsy of any suspicious lesion. This is supported by CT scanning of the chest, abdomen, and pelvis to assess tumour spread, MRI of the pelvis for rectal cancers to determine depth of invasion, and a CEA blood tumour marker test to baseline disease burden and monitor treatment response.
Treatment
Surgery is the cornerstone of curative treatment, with laparoscopic (keyhole) colectomy being the preferred approach removing the affected bowel segment and surrounding lymph nodes with minimal incisions, faster recovery, and excellent oncological outcomes. For locally advanced rectal cancers, chemotherapy and radiotherapy are given before surgery to shrink the tumour. Post-operative adjuvant chemotherapy is recommended for Stage III disease to eliminate residual microscopic cancer and reduce recurrence. When detected early, colorectal cancer carries a 5-year survival rate exceeding 85%, making timely diagnosis and specialist surgical care the most critical factors in achieving a full recovery.