Study: Cancers on the rise in pregnant women.

The number of pregnant women diagnosed with cancer has increased over the past couple of decades, a new study from Australia suggests.

In 2007, the most recent year studied, researchers found 192 out of every 100,000 pregnant and postpartum women received a cancer diagnosis - up from 112 per 100,000 women in 1994.

Researchers couldn't determine what was behind that increase in risk, but said it could be due in part to the older average age of expectant moms combined with better cancer detection.

Another explanation could be "the increased interaction with health services during pregnancy," said Christine Roberts, an obstetrics researcher at the University of Sydney who worked on the study.

Roberts said some doctors in her department had seen a few cases of expectant moms with cancer and wanted to know whether this was indicative of any increase in risk.

To try to answer that question, her group collected information from three large databases on births, cancer cases and hospital admissions in New South Wales, Australia. That included data on roughly 780,000 women who gave birth more than 1.3 million times between 1994 and 2008.

During the same period, there were about 1,800 new cancers diagnosed in moms-to-be and those who'd given birth within the last year.

As diagnoses became more common over the years, pregnant women also got older, on average, the researchers noted in the obstetrics and gynecology journal BJOG.

For example, in 1994, 13 percent of pregnant women were over age 35, compared to almost 24 percent in 2007.

The risk of cancer is known to increase with age - and 35-plus women in the study were over three times more likely to get cancer compared to those under 30 in 2007.

But age only accounted for a fraction of the increased cancer risk over time, the researchers found.

Dr. Lloyd Smith, who treats gynecologic cancers at the University of California, Davis, agreed that improved detection likely accounts for some portion of the increase in cases.

He pointed out that melanoma was the most common cancer diagnosed, affecting 45 out of every 100,000 pregnant or postpartum women.

Australia claims the highest rate of melanoma diagnoses in the world.

Given increasing awareness of the problem of melanoma in Australia, "they probably also have ramped up their surveillance of melanoma, so they're going to detect more," Smith, who wasn't involved in the new study, told Reuters Health.

Roberts said that despite the increase in cancer risk, it is still considered a rare event among pregnant or postpartum women.

Women in the study with cancer were more likely to plan an early birth, but "importantly there was no evidence of harm to the babies of women with cancer - they were not at increased risk of reduced growth or death," Roberts wrote in an email to Reuters Health.

She said more research on cancer treatments for pregnant women is needed.

Smith said that in his experience, treating pregnant patients has been extremely difficult.

"When you have a pregnant woman who has cancer, the infant's at risk, the woman's at risk, the family is in extreme distress and they're seeking the best advice, which is often confused because no one knows quite what to do," Smith said.

One recent study found that chemotherapy does not appear to harm the fetus, while planning an early delivery to avoid chemo exposure to the baby is actually more risky (see Reuters report of September 27, 2011).

Daily multivitamin shown to help ward off cancer in men

Swallowing a daily multivitamin can reduce the risk of cancer slightly in middle-aged and older men and appears to have no dangerous side-effects, according to the first large-scale, randomized study on the subject.

The protective effect of the daily pill was described as "modest" by the trial investigators who emphasized that the primary use of vitamins was to prevent nutritional deficiencies. The findings were published in the Journal of the American Medical Association and presented on Wednesday at a meeting of the American Association for Cancer Research in Anaheim, California.

"This is indeed a landmark study," said Cory Abate-Shen, a professor of urological oncology at Columbia University Medical Center who was not involved in the trial. "It suggests that a balanced multivitamin approach is probably more beneficial than increasing to high levels any one vitamin."

About half of U.S. adults take at least one daily dietary supplement - the most popular being a multivitamin, according to the U.S. Centers for Disease Control and Prevention.

The U.S. Physicians Health Study II included more than 14,600 male doctors aged 50 and older and spanned more than 10 years. Participants were randomly assigned to a multivitamin - Pfizer Inc's Centrum Silver - or a placebo. The research was sponsored by the National Institutes of Health.

Several previous studies, many relying on self-reported use of specific vitamins or supplements, have generated mixed results in terms of cancer outcomes.

"There have been some other trials that have tested combinations, often at high doses, of certain vitamins and minerals," said Howard Sesso, one of the study's authors and an associate epidemiologist at Brigham and Women's Hospital in Boston. "Our trial took a very commonly used multivitamin that has basically low levels of all the different essential vitamins and minerals."

The findings suggest that the biggest health benefit may come from a broad combination of dietary supplements, he said.

EFFECT IS GREATER FOR NON-PROSTATE CANCERS

Last year, the questionnaire-based Iowa Women's Health Study found that older women who take multivitamins have slightly increased death rates compared to those who don't.

A study examining whether vitamin E and selenium could reduce the risk of prostate cancer was stopped prematurely in 2008 after men taking 400 international units (IU) of the vitamin showed an increased risk of developing the cancer. Over-the-counter multivitamins typically contain 15 to 25 IU of vitamin E.

The newly-released Physicians Health Study showed an 8 percent reduction in total cancer occurrence for participants taking a multivitamin, but no benefit was seen for rates of prostate cancer, the most common cancer seen among the participants in the study.

But the absolute risk reduction was small. Out of 1,000 men taking daily vitamins, 17 developed cancer each year, the researchers found, compared to 18.3 in the placebo group. That means some 770 men would need to take the supplements daily to stave off one cancer per year.

Excluding prostate cancer, researchers found about a 12 percent reduction in overall cancer occurrence and said the protective effect seemed to be greater in people who had previously battled cancer.

They did not see a statistically reliable reduction in the risk of dying from cancer, however.

Men taking multivitamins were also slightly more likely to get skin rashes and nose bleeds, but less likely to have small amounts of blood in the urine.

Researchers said they planned to continue to follow the study group to monitor the effect of vitamin intake over time, and said additional studies would be needed to see if there were similar benefits for women or younger men.

"It doesn't seem like there is any particular risk associated with taking a vitamin and there might be a small benefit," said Dr. David Weinberg, chief of the department of medicine at Fox Chase Cancer Center in Philadelphia. He was not involved in the study.

 

SOURCE: http://bit.ly/Tuau4b Journal of the American Medical Association