Validation of Advanced Colorectal Neoplasm Risk Categories in a Prospective Cohort in Mexico

Summary

Worldwide, there are 1,361,000 new cases of colorectal cancers (CRC) annually, with 694,000 deaths. However, the incidence varies by up to a factor of 10x between high and low incidence countries (eg. USA vs Mexico, incidence rate of 42.54 vs 7.44 / 100,000 inhabitants). Mexico is considered a low-incidence country, with 8,651 new cases and 4,694 deaths annually.

CRC is a preventable and detectable disease. Screening programs established in high-incidence countries have managed to reduce the incidence and mortality from this disease and it is considered a cost-effective strategy. In less developed countries where there are no screening programs for CRC, the highest number of deaths occurs despite having the lowest number of cases. It is recognized that a barrier to establishing a screening program in a country with low incidence and limited resources is cost-effectiveness.

The prevalence of Advanced Colorectal Neoplasia (ACN) detected by screening colonoscopy in a Mexican cohort of 1172 INNSZ patients was 2.9%. In the US the prevalence is 7.6%. The number of colonoscopies to be performed to detect ACN was estimated at 34 for Mexico and 13 for the US, which suggests that the cost-effectiveness of screening colonoscopy could be 3 times lower in our country.

In Mexico there is no national screening program for CRC. The eligible population (adults between 50 and 75 years old) for CRC screening is estimated in 20 million of Mexicans. It is recognized that Mexico does not have enough financial resources nor the infrastructure to screen the entire eligible population either by direct colonoscopy, or by FIT (fecal immunochemical test) followed by colonoscopy. With a 5% frequency of positive FIT, nearly 1,000,000 follow-up colonoscopies would be required annually in a population screening program.

An alternative could be to offer screening based on risk, which means only offering screening to the highest-risk population.

There are calculators to predict the risk of identifying ACN in a screening colonoscopy, however, none have been developed and validated in the Mexican population. The weight of the risk factors associated with ACN in the Mexican population could be different, so it is necessary to develop and validate an ACN risk calculator that allows the Mexican population to be stratified and to concentrate screening efforts on the population at highest risk.

Conditions

• Colorectal Cancer Screening

Interventions

DIAGNOSTIC_TEST

Fecal inmunochemical test

A fecal inmunochemical test will be performed prior to colonoscopy.

DIAGNOSTIC_TEST

Colonoscopy

A colonoscopy will be performed. Any polyp identified will be resected (polypectomy) and analyzed histologically. NOTE: The subject and colonoscopist will be blinded to FIT test results and risk category.

BIOLOGICAL

Optional collection of tissue, blood and urine for future biomedical research

Subjects may optionally participate in the collection of tissue, blood, and urine samples for future biomedical research. This procedure consists of taking a 15 ml sample of venous blood and 20 ml of urine. The tissue samples to be used will be those that have been taken for diagnostic purposes during the colonoscopy. Additional biopsies not required for medical care will not be taken. These samples will be used as long as they are no longer required to establish a diagnosis.

Sponsors & Collaborators

• Conquer Cancer Foundation

  collaborator OTHER

• Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran

  lead OTHER

Principal Investigators

• Fidel D Huitzil-Melendez, MS · Instituto Nacional de Ciencias Médicas y Nutrición

Eligibility

Min Age

50 Years

Max Age

75 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2019-08-01

Primary Completion

2024-12-30

Completion

2025-03-30

Countries

• Mexico

Study Locations