Cancer screening may not extend lives, new study suggests. But experts say it's flawed.

A new study recently seemed to cast doubt on whether screening for cancer actually saves lives.

But experts told Live Science we shouldn't jump to conclusions.

The study looked at 18 randomized clinical trials involving 2.1 million people.

Only one colorectal cancer screening test appeared to extend people's lives on average, by around three months .

There isn't enough data to suggest screening for some cancers, such as ovarian cancer, reduces deaths.

In some cases, the USPSTF says, there's not yet clear whether the benefits outweigh the risks of screening.

Overdiagnosis and overtreatment of cancer can result in serious side effects and psychological distress.