Nearly 322,000 new cases of invasive breast cancer are expected to be diagnosed in U.S. women in 2026.

Doctors say conflicting mammogram guidelines may be causing some women to delay getting screened.

While breast cancer mainly develops in middle-aged or older women, new cases in women younger than 50 have seen a slight uptick of about 1.4 percent in recent years.

Dr. Alyssa Cubbison of The Ohio State University Wexner Medical Center said, "There is a different recommendation out there depending upon what literature you're citing."

Doctors use those recommendations to guide decisions on when to suggest patients start screenings.

The U.S. Preventive Services Task Force recommends women start at age 40 and screen every other year.

The American Cancer Society suggests women at average risk have the option at age 40 to start annual screening, at age 45 have mammograms every year and at 55 start screening every other year or choose to continue annual screenings.

"Based on our guidelines for the American College of Radiology and the Society of Breast Imaging, we recommend starting at age 40 every year," said Cubbison.

Cubbison said the conflicting guidance may lead to delays in screening and cancers being detected at a later stage, when it's harder to treat.

She also said some women put off screening because no one in their family has had the disease.

"Most women that are diagnosed with breast cancer have no attributable family history of breast cancer," said Cubbison.

Cubbison suggests taking a risk assessment survey with a doctor around age 25.

"Knowing this can help know at what age it's most appropriate to start screening," said Cubbison.