What are the signs of colorectal (colon) cancer?

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Last updated: February 14, 2025View editorial policy

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From the Guidelines

Colorectal cancer signs include alterations in bowel habit, abdominal pain, weight loss, weakness, iron deficiency, and anaemia. These symptoms are associated with relatively large tumours and/or advanced disease stages, and may not be specific for colon cancer 1.

Common Symptoms

  • Change in bowel habits
  • General or localised abdominal pain
  • Weight loss without other specific causes
  • Weakness
  • Iron deficiency
  • Anaemia These symptoms depend on the location and stage of the primary tumour, and their presence can indicate a worse prognosis 1.

Specific Signs

  • Rectal bleeding, particularly dark red rectal bleeding, can be a strong indicator of colon cancer, with a specificity of >95% 1.
  • Abdominal mass can also be a specific sign of colon cancer, with a specificity of >95% 1. It is essential to note that many patients with colorectal cancer do not develop symptoms until the cancer is advanced, highlighting the importance of screening for asymptomatic individuals 1.

From the Research

Signs and Symptoms of Colorectal Cancer

The signs and symptoms of colorectal cancer can vary, but some common presenting signs include:

  • Change in bowel habits
  • Alteration of fecal contour or consistency
  • Blood in stool
  • Fatigue
  • Weight loss
  • Rectal bleeding
  • Abdominal pain
  • Diarrhea
  • Iron deficiency anemia
  • Anemia
  • Occult bleeding 2, 3, 4, 5

Red Flag Signs and Symptoms

Red flag signs and symptoms that may indicate an increased risk of early-onset colorectal cancer include:

  • Abdominal pain
  • Rectal bleeding
  • Diarrhea
  • Iron deficiency anemia
  • Hematochezia (blood in stool)
  • Anemia 4, 5

Frequency of Presenting Signs and Symptoms

The frequency of presenting signs and symptoms among individuals with early-onset colorectal cancer includes:

  • Hematochezia (pooled prevalence, 45% [95% CI, 40%-50%])
  • Abdominal pain (pooled prevalence, 40% [95% CI, 35%-45%])
  • Altered bowel habits (pooled prevalence, 27% [95% CI, 22%-33%]) 5

Association with Colorectal Cancer Risk

Certain signs and symptoms are associated with a higher risk of early-onset colorectal cancer, including:

  • Hematochezia (estimate range, 5.2-54.0)
  • Abdominal pain (estimate range, 1.3-6.0)
  • Anemia (estimate range, 2.1-10.8) 4, 5

Time to Diagnosis

The time from sign or symptom presentation to diagnosis can vary, with a mean range of 6.4 (1.8-13.7) months and a median range of 4 (2.0-8.7) months 4, 5

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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