What are the symptoms of colon cancer?

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Symptoms of Colon Cancer

Common Symptoms of Colon Cancer

Rectal Bleeding

Rectal bleeding is one of the most specific symptoms of colon cancer, with a high specificity of 99.4% and a positive predictive value (PPV) of 4.0%. It is frequently reported among patients, with studies indicating that up to 58% of colorectal cancer patients experience this symptom. Rectal bleeding is more commonly associated with left-sided colon cancers.

Abdominal Pain

Abdominal pain is another prevalent symptom, reported by approximately 52% of patients with colorectal cancer. The pain can vary in location and nature, sometimes mimicking upper gastrointestinal issues. It is more commonly associated with right-sided colon cancers.

Change in Bowel Habits

Changes in bowel habits, including constipation, diarrhea, and changes in stool consistency, are reported by about 51% of colorectal cancer patients. These symptoms are less specific but still significant indicators of potential colorectal cancer.

Anemia and Occult Bleeding

Anemia and occult bleeding are common systemic symptoms, with anemia present in 57% of patients and occult bleeding in 77%. These symptoms often lead to the initial suspicion of colorectal cancer, especially in asymptomatic patients identified through screening.

Bloating and Distended Abdomen

Symptoms such as bloating and a distended abdomen are less specific but still reported among colorectal cancer patients. These symptoms can be indicative of gastrointestinal issues and warrant further investigation.

Less Common Symptoms

Weight Loss

Unexplained weight loss is another symptom associated with colorectal cancer, although it is less common than the symptoms mentioned above. Weight loss, along with rectal bleeding, has been shown to have a significant association with colorectal cancer.

Systemic Symptoms

Systemic symptoms such as fatigue, nausea, and vomiting are also reported among colorectal cancer patients. These symptoms are often indicative of more advanced disease and can complicate the clinical picture.

Pain in Unusual Locations

In rare cases, colon cancer can present with pain in unusual locations such as the thigh, waist, and back, often due to complications like retroperitoneal abscesses. These cases are easily misdiagnosed and require careful clinical evaluation.

Diagnostic Challenges

Variability in Symptom Presentation

The presentation of symptoms can vary significantly depending on the location of the cancer within the colon. For instance, rectal bleeding is more common in distal colon cancers, while abdominal pain is more frequently associated with proximal colon cancers . This variability can complicate the diagnostic process.

Importance of Clinical Vigilance

Given the wide range of symptoms and their varying specificity, it is crucial for healthcare professionals to maintain a high level of clinical suspicion when evaluating patients with gastrointestinal symptoms. Early referral for diagnostic tests such as colonoscopy is recommended, especially when symptoms persist or are accompanied by systemic signs like anemia .

Conclusion

Colon cancer presents with a variety of symptoms, the most common being rectal bleeding, abdominal pain, and changes in bowel habits. While some symptoms like rectal bleeding are highly specific, others such as bloating and systemic symptoms are less so. The variability in symptom presentation underscores the importance of thorough clinical evaluation and early diagnostic testing to improve outcomes for patients with suspected colorectal cancer.