Ovarain Cancer and the Low-Dose Pill

Researchers looking at the risk of ovarian cancer in Pill users find an 81 percent risk reduction for women taking low-dose Pill brands (low levels of both estrogen and progestin):

NEW YORK (Reuters Health) - Oral contraceptives with low levels of estrogen and progestin reduce the risk of ovarian cancer even more than older versions of the "Pill," according to investigators at the University of Hawaii in Honolulu.

The benefits of oral contraceptive pills in protecting against ovarian cancer have long been recognized, Dr. Galina Lurie and her colleagues note in their report in the medical journal Obstetrics & Gynecology. However, over the last 30 years the doses of hormones in the pills have been decreased, to reduce side effects.

To see how this might have affected ovarian cancer risk, Lurie's group conducted a population-based study in Hawaii and Los Angeles involving 745 women diagnosed with ovarian cancer and a comparison group of 943 women matched by age and ethnicity and who were free of cancer.

Health information was collected by standard questionnaires, and interviewers used photo albums to help participants identify the specific oral contraceptive pills they had used.

Overall, women who had used any oral contraceptive had a 50 percent reduction in the risk of developing ovarian cancer than women who had never taken the Pill, the investigators report.

However, the risk was reduced by 38 percent for women who took high estrogen and high progestin pills, while the risk reduction was 81 percent for those taking pills with low levels of both hormones.

"Up to 42 percent of ovarian cancers might have been avoided if all women used some form of combined oral contraceptive pills," Lurie and her associates calculate.

Furthermore, they say, "An estimated 73 percent of ovarian cancers might have been avoided if all women used oral contraceptive pill formulation of low estrogen and low progestin."

One thing I'd like you to note is the methodology used:

Health information was collected by standard questionnaires, and interviewers used photo albums to help participants identify the specific oral contraceptive pills they had used.

There's nothing wrong with this method, but I want you to take a moment and think about its limitations [you should do that every time you read a study. It will help you better understand the conclusion.], and realize that this is not a definitive study.

For example, health info was collected via a questionnaire. What would've been a more accurate method? And what about showing the participants a photo album to identify Pill brands? What type of bias could this introduce?

Cervical cancer drops, but disparities persist

Interesting report on cervical cancer demographics (emphasis mine):

NEW YORK (Reuters Health) - In the United States, rates of invasive cervical cancer declined between 1998 and 2002, although significant racial, ethnic, and geographic differences persisted, according to pre-vaccine surveillance data covering 87 percent the population of women.

Altogether, 59,848 cases of cervical cancer cases were identified during the 5-year study period. The annual number of cases fell from 12,720 in 1998 to 11,071 in 2002.

The incidence rate declined from 10.2 per 100,000 women in 1998 to 8.5 per 100,000 in 2002, report Dr. Mona Saraiya from the Centers for Disease Control and Prevention, Atlanta....

For the period as a whole, the average annual incidence rate was highest among Hispanic women (14.8 per 100,000), followed by African American women (13.5 per 100,000). Rates among Asian or Pacific Islander women and white women were similar (8.9 per 100,000).

"We confirmed that in the United States there is a 50 percent higher incidence of cervical cancer among African-American (compared with white) and 66 percent higher incidence among Hispanic women (compared with non-Hispanic)," note the authors.

Cervical cancer rates rose with age for all groups. Among Hispanic women 40 years or older rates were 26.5 or more per 100,000; among African American women older than 50 years rates were 23.5 or more per 100,000 women.

"Our findings confirm the need to continue screening older women as recommended by guidelines and to find better strategies for access to screening of women of color," Saraiya and colleagues note.

There is evidence that suggests that the difference in cervical cancer incidence among African American, Hispanic, and white women may be due "in substantial measure, to differences, by race, in the follow up of abnormal Pap tests."

There were also geographic differences in cervical cancer rates, with higher rates of squamous cell carcinoma - the most common type of cervical cancer -- seen in the South than in other regions.

"Clearly, our approach to preventing cervical cancer in the United States should include more focused attention on pockets of high risk," the team notes.

Introduction in 2006 of a vaccine for human papillomaviruses (HPV), which cause most cases of cervical cancer, gives doctors "an additional tool" to reduce illness and death from cervical cancer. When administered appropriately, the HPV vaccine can prevent about 70 percent of all cervical cancers in this country and worldwide, they point out.

The surveillance system in place in the U.S., Saraiya's team adds, will provide a consistent means of measuring trends in the incidence of invasive cervical cancer in the post-cervical cancer vaccine era, although the effect of the vaccine may not be seen for two decades.

Contraceptives protect against endometrial cancer

Reuters has an article about the Pill, the IUD, and uterine cancer protection (judging by the title and the leading paragraph, you'd think Reuters is bringing you the latest medical discovery):

NEW YORK (Reuters Health) - Oral contraceptives and intrauterine devices (IUD) appear to provide long-term protection against endometrial cancer, researchers report in the International Journal of Cancer.

This has been reported by several studies, but few have been conducted in Chinese populations, Dr. Xiao Ou Shu of Vanderbilt University, Nashville, Tennessee, and colleagues note.

To investigate further, the team studied 1,204 women from Shanghai with newly diagnosed endometrial cancer and 1,212 healthy women, matched to the cancer patients for various characteristics. The endometrium is the lining of the uterus, or womb.

Overall, 223 of the cancer patients (18.5 percent) and 302 of the controls (24.9 percent) reported using an oral contraceptive.

After accounting for other known risk factors or protective factors for endometrial cancer, the use of oral contraceptives was associated with a 25 percent reduced risk. The risk decreased with long-term use. After 72 months, the cancer risk was reduced by 50 percent.

This protective effect was maintained, even after 25 years or longer after oral contraceptives were discontinued.

IUD use was associated with a 47 percent lower risk of endometrial cancer. The duration of IUD use, and age when it was first and last use did not significantly alter the association.

The researchers suggest that the "the inverse association between oral contraceptives use and endometrial cancer may be due to the progestin component of oral contraceptives," which may help reduce the overgrowth of cell in the endometrium.

The protective effect of IUDs, they add, may be prompted by "inflammatory actions that eliminate abnormal and precancerous endometrial cells; decreased abnormal cell growth -- a known risk factor for endometrial cancer -- and reduce the concentration of estrogen receptors."

N.B. Just in case you missed the fact that this article isn't reporting what Reuters thinks it's reporting: The news isn't that the Pill and the IUD protect against endometrial cancer (that's an established effect), it's that this benefit has now been studied, and observed, in a Chinese population.