Positive Predictive Value of Symptoms for Early-Onset Colorectal Cancer

Area of Science:

• Oncology
• Gastroenterology
• Public Health

Background:

• Colorectal cancer (CRC) diagnosis in individuals under 50 often relies on symptom evaluation.
• Limited data exists on the positive predictive value (PPV) of symptoms for early-onset CRC.
• Recent guidelines suggest initiating CRC screening at age 45.

Purpose of the Study:

• To determine the PPV of individual symptoms and symptom combinations for diagnosing CRC in patients aged 42-49.
• To evaluate the impact of fecal testing results on the PPV of symptoms for early-onset CRC.

Main Methods:

• Retrospective analysis of 28,198 patients aged 42-49 undergoing colonoscopy for diagnostic reasons between 2012-2020.
• Calculation of PPV for individual symptoms, common symptom combinations, and high-PPV symptom combinations.
• Stratification of PPV by symptom timing and fecal testing results.

Main Results:

• The PPV for blood loss was 2.4% (95% CI: 2.2%, 2.7%), and for positive fecal testing was 4.5% (95% CI: 3.3%, 5.9%).
• Combinations of blood loss, diarrhea, and abdominal mass showed PPV estimates exceeding 3% for CRC.
• Fecal testing results further refined the probability of CRC when symptoms were present.

Conclusions:

• Specific symptoms and their combinations can identify a subset of patients aged 42-49 with a ≥3% prevalence of CRC.
• Fecal testing can enhance the identification of high-risk individuals for early-onset CRC.
• Further research is needed to develop sensitive and specific strategies for early-onset CRC detection.