Cryotherapy deemed less effective option for keeping CIN at bay.

The risk of a woman dying of cervical cancer in the United States is low. The National Cancer Institute estimates that this year 11,270 women will be newly diagnosed and that 4,070 will die of the disease. Though the numbers are relatively low in comparison to other cancers, considering that the disease is almost 100 percent preventable, 4,070 are far too many deaths.

“It’s a scandal that anyone dies of cervical cancer in this country,” said Gary Leiserowitz, M.D., professor and chief, division of gynecologic oncology at the University of California Davis Cancer Center.

And a new study aims to lower that number. Led by Joy Melnikow, associate director of the UC Davis Center for Healthcare Policy and Research, the study analyzes a database of 37,142 women from British Columbia treated for cervical intraepithelial neoplasia (CIN), which is abnormal cervical cell growth. This group was followed for 18 years and was compared to a group of 71,213 women with normal pap smear results and no previous history of CIN.

Following CIN

One of the main issues the study addresses is the length of time a woman diagnosed with CIN should be followed. The study concludes that women who have been treated for CIN remain at risk for recurrence — and possibly cervical cancer — for at least 20 years. And that risk is based on the patient’s age, the grade of CIN and the treatment she has received.

Risk of recurrence in women who have had CIN may sound obvious in hindsight, but it wasn’t always the thinking, said Edward Wilkinson, M.D., professor and vice chairman of the department of pathology at the University of Florida College of Medicine, as well as editor-in-chief of the Journal of Lower Genital Tract Disease. He also wrote an editorial on the Melnikow study for the Journal of the National Cancer Institute.

For a long time, it was thought that if a CIN lesion were found and treated, the patient would not have much of an increased risk of cervical cancer in the future, Wilkinson said. “Now the thinking is that’s not true, that our treatment strategies may not be as good as we thought they were,” he said.

Treatment guidelines for the low- grade CIN 1 alone have changed in the last decade. In the 1990s, treatment of CIN 1 in the United States was common.  And a lot of OBGYNs are still opting to treat CIN 1.

The American Society for Colposcopy and Cervical Pathology (ASCCP) reports that adolescents and young women aged 13 to 20 have a very low immediate risk of cervical cancer but high rates of HPV, which can cause an abnormal pap smear.  Most of these cases resolve themselves with no treatment, ASCCP reports.

And so in 2006, ASCCP changed its guidelines to recommend that CIN 1 patients be followed, not treated.

Weighing cryotherapy

Another significant finding of Melnikow’s research was that women 40 years or older with an initial diagnosis of CIN 3 were much more likely to have recurrence of CIN 2/3 if they had been treated initially with cryotherapy — a method used to freeze the abnormal cervical cells.

In the first six years after treatment, 340/1,000 women in the 40-49 year-old age range who were diagnosed with CIN 3 and treated with cryotherapy had a recurrence of CIN 2/3, compared to 174/1,000 women treated with laser excision or ablation, 129/1,000 who were treated with loop electrosurgical excision procedure (LEEP), using a low voltage electrified wire loop to cut out abnormal tissue and only 85/1,000 who were treated with cone biopsy, which involves cutting a cone-shaped portion out of the cervix.

“What really raised my eyebrows was the high rate of disease ultimately found in women over 40 treated with cryotherapy,” said George Sawaya, M.D., director of the colposcopy and cervical displasia clinic at San Francisco General Hospital and one of the authors of the study. Sawaya uses cryotherapy frequently for CIN 2 and 3.

“My response to that observation was: ‘Is it real? Do we need more studies around that issue?’ Not: ‘I must change my practice immediately,’” he said.

But Jonathan Berek, M.D., professor and chair of the obstetrics and gynocology department at Stanford University School of Medicine would like to see a study done specifically posing the question of whether cryotherapy has any significant benefit at all.

“We know it’s not very effective,” he said. He argued that even if its use is reserved for low- grade CIN, recurrence of abnormal cells after cryotherapy appears to be only slightly lower than if no therapy was done.

“Does cryotherapy make any difference in the long run? Nobody knows that,” Berek said.

Leiserowitz said he was not surprised by cryotherapy findings, but nevertheless, he and other doctors say it’s still a useful procedure — particularly in younger women, as it is one of the least damaging procedures to the cervix. Other treatment procedures, like LEED, can lead to an incompetent cervix and the inability to maintain a pregnancy, Wilkinson said.

“Excisional treatments have more complications, like hemorrhaging, or incidence of preterm labor,” Melnikow explained.

Cryotherapy, on the other hand, is safe, cheap, and easier to learn how to do — very important attributes given that most women requiring treatment for CIN live in developing countries, Melnikow said.

According to Paula Hillard, M.D., chief, division gynecologic specialties at Stanford School of Medicine, the use of cryotherapy should be based on the patient’s age, her degree of CIN and her desire for bearing children in the future.

“In young women who want to have a pregnancy, we should not be slicing off their cervixes,” Hillard said.

For her part, Melnikow hopes the information in her research will be added to the body of evidence improving guidelines that help doctors and patients make the best decisions for cervical health – whether treatment or surveillance, cryotherapy or otherwise.

- By Lynn Graebner

Lynn Graebner is a freelance writer in Santa Cruz.