LA CROSSE, Wis. (WKBT) -

Every year, millions of women undergo mammograms as a way to screen for breast cancer. However, a new Canadian study suggests they may not be as advantageous as originally thought.

About 90,000 Canadian women between the ages of 40 and 59 participated in a 25-year-long study. In the study, published by The British Medical Journal, half of the women were randomly selected to receive mammograms, while the other half received only breast exams.

Researchers found that breast cancer death rates did not change depending on whether a woman received a mammogram or not. Researchers also concluded that there is no advantage to finding breast cancers when they were too small to feel.

So now the question stands: are they worth it?  Well, if you ask one La Crosse breast cancer survivor, she’ll tell you it saved her life.

About 10 years ago, Maureen Thompson’s life changed forever.

“I went in to have a routine mammogram, and through that mammogram, they found a small lump,” said Thompson. “They said, 'We want you to come over and have a biopsy,' and I kind of was like. OK.”

Thompson was diagnosed with breast cancer at the age of 53.

“I’ve always done a routine mammogram every yea,r so I was really surprised when it came back that there was something there,” said Thompson. “It’s very shocking because you don’t think it’s going to be you.”

However, this time it was. After a lumpectomy and 33 radiation treatments, Maureen has been cancer-free for 10 years, and she says she owes it all to a routine mammogram.

“If I hadn’t had the mammogram, I wouldn’t have known I had it,” said Thompson.

“Most cancers that are found by either a self-breast exam or a clinical breast exam are close to 2 centimeters in size. Most of the cancers we are finding on screening mammographies are less than a centimeter,” said Laurel Littrell, a breast radiologist with Mayo Clinic Health System.

Littrell looked at the last five years of screening results at the hospital and found that sometimes, self-breast exams are just not enough. However, the Canadian study suggests there is no advantage to finding undetectable tumors.

“I found that nearly 90 percent of our screen-detected cancers were less than a centimeter,” said Littrell. “I think we can all admit truthfully that finding a cancer at less than a centimeter is probably going to mean a better prognosis, a better outcome and better treatment options.”

“It’s really silly to say we are overdiagnosing,” said Littrell.

Littrell strongly believes early detection saves lives, and in Thompson’s case, it did.

“I was a perfect textbook case of why I should have a mammogram, because I couldn’t feel it; I had no idea when I went in there,” said Thompson.

That is why both of them believe mammograms are essential and worth the time every year.

“I think it is very safe. I think it saves lives, and I think every woman should give it some serious consideration,” said Littrell.

"It's not something that you should take lightly. Just have it done; it is something that is really painless, and it could make a difference in your life,” said Thompson.

Experts say there are some reasons why these results are unlike any studies published in previous years. The women involved in the Canadian study could have been more aware of breast cancer and its dangers than the women in earlier studies who were more likely to ignore lumps or perform self-examinations. Plus, there have been a lot of advancements in technology that need to be taken into account, too.