(Adds Exact Sciences CEO and analyst comments, USPSTF background)

By Ankur Banerjee

May 30 (Reuters) - The American Cancer Society on Wednesday recommended that people at average risk of colorectal cancer start regular screening at the age of 45 rather than at 50, at a time when studies show a rise in cases of the disease among younger individuals.

The new ACS guideline https://www.cancer.org/cancer/colon-rectal-cancer/detection-diagnosis-staging/acs-recommendations.html also recommends people, who are in good health and with a life expectancy of more than 10 years, should continue regular colorectal cancer screening through the age of 75.

The guideline suggests screening either through a high sensitivity stool-based test or visual examination such as colonoscopy that snakes a tiny camera through the rectum to view the colon to search for abnormal tissue growth.

Shares of diagnostic company Exact Sciences Corp, which makes Cologuard devices that helps detect colorectal cancer, jumped more than 10 percent after the guideline was revealed.

The move comes as a study https://onlinelibrary.wiley.com/doi/full/10.3322/caac.21457 showed that there has been a marked increase in colorectal cancer incidence, particularly rectal cancer, among younger individuals.

"While we commend the ACS for its forward thinking ... we do not believe this will necessarily be a big driver of Cologuard volume upside for Exact Sciences in the near term," William Blair analyst Brian Weinstein said.

Weinstein noted that Cologuard is currently approved for colon cancer screening for people between the ages of 50 and 84, adding that the company would need to run a separate trial for lower age groups.

Exact Sciences Chief Executive Officer Kevin Conroy said Cologuard is a cheaper way to screen younger people.

"First we need to do clinical work to establish the safety and efficacy of Cologuard in that population," Conroy told Reuters.

Colorectal cancer is the third-leading cause of cancer-related deaths in men and women in the United States and is expected to cause about 50,630 deaths during 2018.

American Cancer Society Cancer Action Network, a non-partisan advocacy affiliate of ACS, said it intends to officially recommend reconsideration of a guideline from U.S. Preventive Services Task Force (USPSTF).

Currently, USPSTF, a government-backed independent panel that assesses the evidence for medical procedures, recommends screening from the age of 50.

USPSTF's 2016 recommendation was based on a review of the available evidence on benefits and harms of colorectal cancer screening, USPSTF Chairwoman Sue Curry said.

"At the time of the Task Force's review, there was limited data on screening adults younger than age 50." (Reporting by Ankur Banerjee in Bengaluru; Editing by Shounak Dasgupta)