While feeling a lump or mass on the breast is a sure sign you should go see a doctor, it is not the only way breast cancer can present itself.
Breast cancer remains the most common cancer -- aside from some skin cancers -- in women in the United States, with over 230,000 new cases expected in 2015, according to the American Cancer Society.
Experts say that while a lump is the classic warning sign, women should be aware of other, lesser-known symptoms of breast cancer, including swelling of all or part of a breast, skin irritation or dimpling, nipple inversion, nipple discharge other than breast milk, and a redness, scaling, or thickening of the nipple or surrounding skin.
"A lot of people think that you feel a lump and that triggers getting tested," Dr. Naoto Ueno, chief of Translational Breast Cancer Research at the University of Texas MD Anderson Cancer Center in Houston, told CBS News. "That's true, but there are breast cancers that present as half a lump or there may be no lump at all actually. It could just be a strange-looking skin appearance or skin being red or dimples."
Dr. Clifford Hudis, chief of Breast Medicine Service at Memorial Sloan Kettering Cancer Center in New York City, said that although we live in an era where the majority of women are screened for cancer regularly -- the American Cancer Society recommends annual mammograms for women 40 and older, while guidelines from the U.S. Preventive Services Task Force suggest mammography every other year starting at age 50 -- even routine screening has limits and people still need to be aware of warning signs.
"In between screening tests, patients still have to be alert to changes that might indicate cancer," he told CBS News. "It's a common misconception, but screening tests can't be expected to find every single cancer. They don't, and there's always the possibility of something happening between screens."
Women with a family history of breast cancer or others at higher risk may need more frequent screening starting at a younger age, and should be vigilant about checking any physical changes.
Lisa Royle of Manchester, England, recently brought the topic into the spotlight when she posted a selfie on Facebook that went viral showing the subtle warning signs of the breast cancer she had been diagnosed with.
"This is all that I found," she wrote before she underwent a mastectomy. "Very subtle dimples underneath that could easily be missed."
A survey of women in the UK shows that fewer than half of women over 70 could name a single symptom of breast cancer other than a lump, highlighting the lack of knowledge that exists in this area.
Doctors say it's important for women to be familiar with what's normal for their own bodies and pay attention to any changes that occur.
"What we're talking about here is a change in appearance," Hudis said. "Some people live their whole lives with their nipples inverted, for example. It's a change that we care about, not so much that it's always been that way."
And Hudis emphasized that while recognizing the different potential signs of breast cancer is important, having one or more of these symptoms does not automatically mean you have cancer. But a doctor visit to determine the cause is still necessary.
"If it's physically uncomfortable, you don't want to suffer with this longer than you need to," he said. "If it's an infection you need antibiotics. If it's cancer you need diagnosis and treatment. If it's some other illness then you need treatment, but you can't feel better until it's diagnosed."