What Causes Cervical Cancer? Plus, 6 Warning Signs Every Woman Should Know

About 13,000 American women will be diagnosed with cervical cancer this year, according to the Centers for Disease Control and Prevention (CDC). While that may not seem like a lot—especially when compared with the rate of breast cancer, which roughly one in eight women will develop in their lifetime—it's still the third most common gynecologic cancer in the United States, says Caryn St. Clair, M.D., gynecologic oncologist at New York-Presbyterian/Columbia University Irving Medical Center.

The good news: Thanks largely to the Pap smear, human papillomavirus (HPV) testing, and the HPV vaccine, there's been a significant decrease in cervical cancer risk in developed countries over the last 50 years, says Dr. St. Clair. What's more, experts anticipate the number of new cases of cervical cancer will continue to decline in women who have been vaccinated.

Now, for the not-so-great news: Signs of cervical cancer can be easily missed because its symptoms mimic those of many other conditions. And if it's not caught early, survival rates drop rapidly. Here's what you need to know.

In short, cervical cancer is (in almost all cases) the result of sexually transmitted disease, says Amanda Nickles Fader, M.D., associate professor and director of the Kelly Gynecologic Oncology Service at Johns Hopkins School of Medicine in Baltimore. Nearly all cervical cancers are caused by HPV (it's extraordinarily rare otherwise) , one of the most commonly transmitted infections, affecting hundreds of millions of women around the world. "The good news is that HPV and cervical cancer are preventable with the HPV vaccine, one of the safest, and most studied vaccines ever developed," says Dr. Fader.

It's important to know that not all strains of HPV cause cancer. There are about 200 subtypes of HPV that have been identified, and of those, about 40 or so are spread by sexual contact, says Dr. Fader. About 80-90 percent of cervical cancers are due to HPV 16 and 18, but some rarer types can also lead to cervical cancer, she notes.

There are three approved HPV vaccines, and all three effectively protect against HPV 16 and 18. "We can say that any HPV vaccine will protect against the vast majority of HPV-related cervical cancers, but none covers an absolute 100 percent," says Dr. Fader. This is why  regular screenings are still recommended for vaccinated patients, she adds.

Cervical cancer is most commonly diagnosed in women between the ages of 35 and 44, and rarely affects women under age 20, says Dr. Fader. About 15 percent of diagnoses are made in women older than 65, she adds (so share this with the women in your family too!).

If you're experiencing any of these symptoms, bring them to your doctor's attention. It may be nothing, or it may be something else (like another STD), but the key to survival is early diagnoses. "Yes, [cervical cancer] is one that we're beating, but not into submission," says Nicole Williams, M.D., F.A.C.O.G., a board-certified gynecologic surgeon and founder of The Gynecology Institute of Chicago. "If you haven't had a Pap smear in the last three to five years and have these symptoms, you need to be seen."

This doesn't feel like cramps, but more of a vague heaviness—like something just doesn't feel right, says Dr. Williams. "You might feel some pressure or even pulling, and things feel a lot heavier than they did before," she adds. Signs of cervical cancer tend to creep up over time, and that's what can make it tough to spot; you just don't feel well but may be unsure why, says Dr. Williams. 

You're not going to be able to feel it by pressing around on top of your stomach, but if you slide your finger into your cervix, it should feel smooth—"like a shiny, pink doughnut," says Dr. Williams. If you feel something rough instead, see a doctor ASAP.

Bleeding after sex is the most common symptom of cervical cancer. It doesn't have to be a lot of blood, but even a little irregular spotting should be brought up with your doctor, says Dr. Williams. You may also experience a dull, achy pain, particularly after sex. (That said, these symptoms can also be indicative of fibroids, STDs or vaginosis—that's why cervical cancer is "a great pretender," says Dr. Williams.) But if you're experiencing any of this, "it's generally not nothing," she adds, so see a doctor. (Read more about what it could mean to have pain during sex and pain after sex.)

If you're doing something that may alter the flow of or stop your period, such as taking a hormonal birth contol pill or if you use a hormone-containing IUD, it's normal to experience some irregular bleeding or spotting. Yet, if you're not doing any such thing and you're bleeding irregularly, that's something you should bring up to your doctor, as that could be an early warning sign of cervical cancer or something else, says Dr. Williams.  

An early sign of cervical cancer can be a persistent—and persistent is key here—vaginal discharge that is watery, mucous-like or pustulant, which can be quite smelly, says Dr. Williams. A very foul-smelling discharge (which occurs when a tumor starts to break down) is an indication of much more advanced disease. It's tough to tell the difference between discharge that's a sign of cervical cancer and the many other reasons you might have abnormal discharge (because remember, discharge is a natural, normal thing). Plus, discharge often changes throughout your menstrual cycle. This is yet another reason to get routine screening to rule out anything serious, says Dr. Williams.

Not everyone with cervical cancer has this symptom, but low back pain has been associated with some cervical cancer cases, says Dr. Williams. In advanced cases of cervical cancer, the cervix can become so large that it puts pressure on the lower back. Again, symptoms such as this could be indicative of lots of things, many of them much less serious than cancer—which can make it difficult to spot the signs of cervical cancer on your own.

One of the scariest things about cervical cancer, though, is that it is often asymptomatic—meaning you could have no symptoms at all, says Dr. St. Clair. "This speaks to the critical importance of good screening and prevention," she adds. (Read how one woman's cervical cancer scare changed her life.)

Cervical cancer is typically diagnosed during a pelvic exam by a doctor or during a routine Pap test or HPV screening, says Dr. St. Clair. Gynecologists follow screening guidelines set forth by organizations such as American Cancer Society and American College of Obstetrics and Gynecology to help them decide when to administer which tests; it has a lot to do with the patient's age and medical history, says Carey August, M.D., chair of the pathology department at Advocate Illinois Masonic Medical Center. For example, although a Pap test is currently recommended for women ages 21-29, the HPV test is not, since many women in this age group will have an HPV infection but their immune systems are able to get rid of it, says Dr. August. At the other end of the spectrum, if a woman is older than 65 and has never had cervical cancer or precancerous symptoms, she may not need to be screened at all, either by Pap test or HPV test. Every woman and her history and circumstances are different, so always consult your doctor ask for any tests you think you should be getting done.

"I can identify cells on the slide that look abnormal," says Dr. August. "While in rare cases, the abnormal cells mean that the patient already has cancer, the Pap test is also important because, using it, the pathologist can identify cells that are not already cancer cells but have the potential to become cancer. That's why regular screenings are so important." 

If your test comes back abnormal, you might need a cervical biopsy. That involves taking a tiny piece of cervical tissue, which is then examined by a pathologist under a microscope, says Dr. August. If the pathologist finds that the biopsy shows a precancer (a dysplasia or squamous intraepithelial lesion), the gynecologist will treat this part of the cervix—this can mean removing a larger piece of tissue in a procedure called a "cone" or "LEEP." Again, the pathologist will examine slides made from this procedure to be sure the precancer has been completely removed.

If a patient already has cervical cancer, a gynecologist can usually see the tumor during a pelvic exam but will need to take a biopsy from it. Using microscope slides from the tumor biopsy, the pathologist will confirm whether it's cancer and, from there, your doctor can begin planning treatment. 

When symptoms are caught early, cervical cancer is preventable, as doctors can treat them before they become a problem, says Jessica Shepherd, M.D., F.A.C.O.G., a board-certified ob-gyn in Dallas. "If all of us proactively got regularly screened and treated appropriately, we could get rid of cervical cancer in the U.S.," she adds. Yet despite this fact, one-third of U.S. women diagnosed with cervical cancer die from the disease, according to the American Cancer Society.

One reason for this concerning statistic is that many women are hesitant to discuss specific sexual health issues their health care provider, says Dr. Shepherd. What's more, it's crucial to get the HPV vaccine (psst—here's why your excuses not to are total B.S.), which drastically reduces your exposure to cervical cancer. Pap tests should start at the age of 21 and be done every three years, as recommended by the CDC. (See the complete guidelines here). For women ages 30-65, a combination of the HPV test and a Pap test can detect nearly all cervical cancers. "We need to think about this vaccine as a preventative measure that support a woman's overall health," says Dr. Shepherd. "Prevention is so important because it gives us the potential to eradicate the disease."