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Sunday, July 10, 2011

HPV, the most common STD, can cause cancer

The specialist: Dr. Michael Gaisa on HPV

The specialist: Dr. Michael Gaisa on HPV

An internist and infectious disease specialist at Mount Sinai HospitalDr. Michael Gaisa works with about 350 patients a year to help prevent HPV-related precancerous conditions from progressing to malignant, invasive cancer.

Who's at risk

HPV, the human papillomavirus, is the most common sexually transmitted disease in the U.S.

"HPV is a virus that is spread very easily," says Gaisa. "It's almost inevitable that people are going to be exposed, unless they're sexually celibate." 

About 20 million Americans are infected with HPV, and another 6 million are infected each year. 

At the current rates of infection, an estimated 50% to 90% of sexually active patients will acquire HPV at some point in their lifetime. "Anyone who is sexually active is at risk of acquiring HPV," says Gaisa. "The more you change sexual partners, the higher your risk." 

HPV is much more common than it's perceived to be, partly because so many patients don't have symptoms. One problem is that the virus is still transmissible although it may give no symptoms.

While healthy individuals can usually clear the virus within one to two years, there are certain high-risk subtypes of HPV that under certain conditions can establish chronic, latent infection and 
ultimately lead to cancer. 

"Cancer is the worst-case scenario of HPV infection," says Gaisa. "Cervical cancer is the most common HPV-related cancer, but we're also seeing increasing rates of anal cancer and others." 
People whose immune system is compromised, including HIV patients and organ-transplant recipients, are at an especially high risk of developing cancer as the result of HPV. 

"The Department of Health in New York was the first government body to recommend regular screening for HPV in HIV-positive patients," says Gaisa. 

HPV-related cancers progress according to a slow sequence from subtle precancerous lesions, called dysplasia, to invasive cancer, a process that usually takes many years. 

"What this means is that by screening for precancerous cells, we have a chance to treat the region and prevent invasive cancer from developing," says Gaisa. "While low-grade dysplasia may not progress to cancer, we can identify high-grade changes that put patients at high risk of cancer."

Signs and symptoms

Most people carrying the HPV virus do not have symptoms. 

"The lack of symptoms is part of the problem in preventing the spread of HPV," says Gaisa. "The one common symptom patients notice is genital warts." 

While the warts are unsightly, they aren't themselves dangerous and are usually caused by low-risk HPV types. They should nevertheless be evaluated in case they are a sign of simultaneous infection with a high-risk HPV type.

For the general population, there is no recommended HPV screening other than regular cervical PAP smears for women.

"The more vulnerable population of HIV-infected patients should be screened annually with both cervical and anal PAP smears," says Gaisa. "Not all HIV care providers are doing this yet, so be proactive about asking your doctor if you should get tested." 

While organ-transplant recipients are also likely to have increased risk, there are no official screening recommendations in place for that patient population.

Traditional treatment


When anal pap smear results come back positive, the next step is for the doctor to examine the affected area using a microscope, a procedure called high-resolution anoscopy. 

"Using a scope, we can evaluate the external surface of the skin around the anus and the mucous membranes within the anal canal where HPV causes potential problems," says Gaisa. "In the process, we often find abnormal areas and biopsy them." 

The procedure takes about 10-15 minutes, and most patients can go to work straight from the doctor's office. "It's a little uncomfortable, but patients usually say, ‘It's not as bad as I thought,' " says Gaisa.

If the doctor finds anything pre-cancerous, the next step is treating the area by using an infrared laser to burn off the superficial cell layers carrying the disease. 

"The laser procedure is done using the same local anesthesia a dentist would use in the mouth," says Gaisa. "It also lasts about 10-15 minutes, and patients usually go back to work the same day.

However, it's not necessarily a permanent fix. 

"There's still a chance of recurrence of both warts and precancerous lesions, because surrounding areas can harbor the virus without being exhibiting visible changes," says Gaisa. "It's like a visit to the dentist; after we pull the rotten tooth, you still have to come back for checkups." 

If patients persevere with thorough surveillance and regular anoscopies, doctors consider HPV-related cancers like anal cancer totally preventable.

Research breakthroughs

The biggest breakthrough in preventing HPV is the development of a specific vaccine. 

"The vaccine has been out now for a few years. It protects against the two most common cancer-causing and the two most common genital-wart-causing HPV subtypes," says Gaisa. "We're
predicting that rates of HPV infection and HPV-related cancers will go down dramatically in the coming decades as more young adults are vaccinated before they become sexually active."

Questions for your doctor


If you're immune-compromised, ask: "Should I be screened for HPV?"
If you're 26 or younger, or have  recurrent genital warts or precancerous changes, then ask, "Am I candidate for HPV vaccination?"


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