Effectiveness of screening colonoscopy in reducing the risk of death from right and left colon cancer: a large...

Area of Science:

• Gastroenterology
• Oncology
• Preventive Medicine

Background:

• Effectiveness of screening colonoscopy for colorectal cancer (CRC) mortality is debated, especially for right-colon cancers.
• Some countries do not recommend CRC screening colonoscopy due to unclear benefits.

Purpose of the Study:

• To determine if screening colonoscopy reduces mortality risk from both right-colon and left-colon/rectal cancers in average-risk individuals.
• To clarify the role of screening colonoscopy in community populations.

Main Methods:

• Nested case-control study with incidence-density matching within Kaiser Permanente members.
• Matched patients (55-90 years old) who died from CRC to controls based on age, sex, enrollment duration, and region.
• Excluded high-risk individuals; analyzed screening colonoscopy receipt in the 10 years prior to the reference date.

Main Results:

• Screening colonoscopy was associated with a 67% reduction in overall CRC mortality (aOR=0.33).
• A 65% reduction in mortality risk was observed for right-colon cancers (aOR=0.35).
• A 75% reduction in mortality risk was observed for left-colon/rectal cancers (aOR=0.25).

Conclusions:

• Screening colonoscopy offers substantial and comparable reductions in mortality risk for both right-sided and left-sided colorectal cancers.
• The findings support the use of screening colonoscopy in average-risk populations for reducing CRC deaths.