Wednesday, November 5, 2014

HPV Vaccination Programs Shown Effective in Australia

Photo: Flickr/PAHOWHO
by Sarah Cortez

When given before the start of sexual activity, the HPV (human papillomavirus) vaccine prevents most cases of cervical cancer and genital warts. It can also lower the risk of oropharyngeal, penile and anal cancer.

HPV is a sexually transmitted infection, and we target the vaccine to 11-12 olds, as we expect children at this age to not be sexually active. This allows immunity to build up before any exposure to HPV occurs.

Though girls were the initial focus of the vaccine, it is now recommended that boys get vaccinated, too. Boys do not have cervices and, therefore, can’t get cervical cancer, but they certainly can get genital warts and the other rarer cancers linked to HPV. Importantly, males can also spread the cancer-causing virus to females.

As we have covered in previous posts, the use of the HPV vaccine has been slow to build in the US. But this is not the case in other countries.

A new study published in the open access journal PLOS ONE, details the effect of the Australian government’s national HPV vaccination program, using the Gardasil vaccine. Starting in 2007, the Australian government offered the HPV vaccine for free at school to all 11-12 year old girls on the standard schedule:

1. 1st dose at start
2. 2nd dose 1-2 months after 1st dose
3. 3rd dose 6 months after 1st dose

The Australian government also offered older schoolgirls (13-18 years old) and young adult women (18-26 year old) the vaccine for free through their general practitioners and community health clinics. This was referred to as the catch-up program due to the increased likelihood that patients were more likely to already be sexually active.

Preliminary results showed that by 2012, over 70% of all Australian girls had received the full 3 dose vaccine by age 15 and over 85% were vaccinated by the last year of high school. As a comparison, in 2012, the rates of 3-dose vaccination among adolescent girls in the US were only 35% by age 15 and 45% by age 17. 

So what resulted from this Australian vaccination program? Following its onset, the diagnosis of genital warts decreased by 93% among young women seen in the sexual health clinics. Additionally, the diagnoses of genital warts decreased by 82% among young heterosexual men. Remember, the vaccine was only free for girls, so the decrease in genital wart diagnoses for men who have sex with women was possibly due to something called “herd immunity,” where vaccination of a large percentage of a population (the “herd”) benefits even those who were not vaccinated.

The decrease in genital warts seen in the sexual health clinic is great, but the sexual health clinics see many fewer patients than general practitioners. So was the decrease in genital wart diagnoses also found in the general population?

To find out, the new study used data collected from over 11,000 Australian general practitioners who saw at least some Medicaid patients. Once a year since 1998, each general practitioner recorded 100 patient encounters. This method logged over 1 million patient encounters between 2000 and 2012.

What was the result? Did the general practitioners find the same decrease in genital warts after the start of the HPV vaccination program?

The answer is yes. Genital warts were found most often in 15-27 year old males and females. Following the vaccination program, genital wart management decreased by 61% among 15-27 year old females. As a comparison, they tracked the rate of other STDs like genital herpes. As expected, the diagnoses of other STDs did not decrease following the vaccination program.

There was no change in males or the 27+ age group, which did not receive the vaccination.

All in all, this is great news. The HPV vaccine works. It decreases genital warts among those who are vaccinated, and hopefully, in the future, we can replicate here in the United States the success Australia has seen. As for us at CNiC, we will continue to report the findings and outcomes of this important preventative health tool. 

References

Harrison C, Britt H, Garland S, Conway L, Stein A, Pirotta M, Fairly C. Decreased management of genital warts in young women in Australian general practice post introduction of national HPV vaccination program: Results from a nationally representative cross-sectional general practice study. PlosOne 2014; 9(9): e105967.

"Genital HPV Infection - Fact Sheet." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 20 Mar. 2014. Web. 12 Oct. 2014.

"National and State Vaccination Coverage Among Adolescents Aged 13–17 Years — United States, 2012." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 30 Aug. 2013. Web. 13 Oct. 2014.

Friday, October 31, 2014

Friday, October 10, 2014

Breast Cancer Prevention Now

By Graham A. Colditz, MD, DrPH


It is time to bring our focus back to lowering the risk or reducing the onset of new cases of breast cancer at all ages. Worldwide incidence of the disease is rising as societies across the globe modernize, which brings with it higher rates of breast cancer risk factors, such as overweight, lack of physical activity, and key reproductive factors like beginning families later in life and have fewer children.

While modernization has many important benefits, it is also directly driving up the risk of breast cancer. Globally, one in every four new cancers diagnosed in women is breast cancer, and over 1.7 million new cases are diagnosed each year.

We need a global breast cancer prevention strategy - now.

We currently understand how the longer interval from first menstrual period (menarche) to first baby increases lifetime risk for beast cancer. This interval has expanded over centuries in Western Europe following the Industrial Revolution, and - in dramatic fashion - over just a few decades in Asian countries. Data from China and Korea show a rapid decline in age at first menstrual period since World War II, as well as a decline in number of children, which has accelerated. The age women have their first babies is now above the Organization for Economic Cooperation and Development (OECD) average of 28 years old. This means that a typical woman has 16 or more years between her first period and her first baby (first birth at 28 minus first period at 12 years of age). In 1950 in China, this interval was just three years (first birth at 19 minus first period at 16).

Given these social movements, are there approaches early in life that can help mitigate the impact of these changes in reproductive factors? It appears so.

We, and others, have studied diet and physical activity as two key aspects of lifestyle, and then alcohol intake in later adolescence and early adult life.
  • Eating a diet high in fiber and vegetable protein is related to significantly lower risk of both premalignant breast lesions and breast cancer.
  • Being more physicaly active from ages 12 to 22 is powerfully protective against breast cancer.
  • Avoiding alcohol before first pregnancy is strongly protective against both benign breast lesions and invasive breast cancer.
Together, we need to work to improve diet in children, adolescents, and young adults – fostering access to, and consumption of, fruits, vegetables, and whole grains – as well as reducing alcohol intake among women under age. Especially for high school- and college-aged women, we must create an environment that encourages less alcohol intake. Also important is sustaining physically active lifestyles through the adolescent and early adult years, which has both immediate and long-term benefits.

Multifaceted approaches are needed to achieve such behaviors across a broad set of the population, but doing so will have lasting benefits, not only for breast cancer but also colon cancer, heart disease, stroke, as well as mental health. Momentum in this direction can take time to gather, but is achievable and important, and can have a positive impact for generations to come.

Related posts

Tuesday, September 23, 2014

PALB2 Mutation: A "New" Gene That Greatly Increases Breast Cancer Risk

Photo: Flickr/Micahb37
by Sarah Cortez

There’s been a recent surge in women asking for genetic testing for breast cancer, due in large part to Angelina Jolie’s public decision last year to get a prophylactic mastectomy after discovering she had a mutation in the BRCA1 gene. These days, another breast cancer gene has been making headlines, a gene called PALB2.

Mutations in BRCA1, and its related gene, BRCA2, are the two most important known genetic links to breast cancer risk. Well, new findings on PALB2 have some describing it as the “third gene” to be linked with breast cancer.

Previous studies have found that mutations in PALB2 combined with mutations in the BRCA genes increased the risk of breast cancer. PALB2 is even short for Partner and Localizer of BRCA2. What we didn’t know was how much the risk of breast cancer increased with a PALB2 mutation alone – that is without a related BRCA mutation.

In August, the New England Journal of Medicine published a study that characterized patients with only a PALB2 mutation. To do this, researchers identified patients who did not have a BRCA1/2 mutation but who had a history of breast cancer in at least one family member. These patients were then tested for the PALB2 mutation.

So, what did they find?

The results showed that a PALB2 mutation by itself increased the risk of breast cancer 9.5 times compared to the general population. They also showed that, for those with a mutation in PALB2, the risk of developing breast cancer by age 70 was about 33%, as compared to a 12% lifetime risk in the general population. Furthermore, for those with a PALB2 mutation who also had two first-degree relatives (like your mom and your sister) with breast cancer, the risk of developing breast cancer by age 70 increased to more than 50%. For comparison, a BRCA1 mutation increases your risk of developing breast cancer, by age 70, to 55-65%. So BRCA mutations are still considered more risky.

So what does all this new information mean to you?

Just like with the BRCA genes, it would only be recommended that you get screened for PALB2 mutation if you have a strong history of breast or ovarian cancer in your family, such as:
  • Breast cancer in more than one family member
  • Breast cancer diagnosed before the age of 50
  • Breast cancer diagnosed in both breasts (bilateral breast cancer)
  • Male breast cancer
  • Breast cancer plus ovarian or pancreatic cancer
  • Ashkenazi Jewish ethnicity
Many women at low risk for gene mutations are needlessly tested every year, which can cause a great deal of unnecessary anxiety.

If a woman tests positive for a BRCA mutation, we offer increased cancer screening, risk-reducing medications, prophylactic mastectomy, or some combination of these. While it’s likely such approaches will also help protect women with a PALB2 mutation, there is currently no evidence that they have benefit. More research is needed.

Genetic mutations like BRCA1/2 and PALB2 are frightening because they increase the risk of breast cancer by such a great degree. But it’s important to also keep in mind that they are rare. Around one in 400 women in the United States have a BRCA mutation, which translates to 0.25 percent of American women. And even women who have such mutations are not guaranteed to develop the disease.

For the large majority of women, the most important things they can do to improve their health and lower the risk of breast cancer is to focus on living an overall healthy lifestyle that includes: being physically active for at least 30 minutes a day, keeping weight in check, and drinking alcohol only moderately, if at all.


References
Antonis C. Antoniou, Ph.D., Silvia Casadei, Ph.D., Tuomas Heikkinen, Ph.D., Daniel Barrowdale, B.Sc., Katri Pylkäs, Ph.D., et al. Breast-Cancer Risk in Families with Mutations in PALB2. N Engl J Med 2014; 371:497-506.

Chen S, Parmigiani G. Meta-analysis of BRCA1 and BRCA2 penetrance. Journal of Clinical Oncology 2007; 25(11):1329–1333.

Tuesday, September 2, 2014

Hormonal IUDs and Breast Cancer: Is There a Link?


by Sarah Cortez

It certainly goes without saying that birth control has been a major news story the past couple of months. Much of this coverage, of course, has revolved around the recent Supreme Court ruling and reactions to it. Outside of that media storm, there have been some other health-related birth control stories as well, a number of which have focused on the potential of a specific type of IUD - the levonorgestrel IUD - to increase breast cancer risk. 

Photo: Flickr/Theilr
So what do the data actually say about this link? Let’s take a look.

In case you are unfamiliar with the levonorgestrel IUD (brand name Mirena or Skyla), it is a small, plastic, T-shaped device that is inserted into your uterus by a healthcare provider, usually your gynecologist. It prevents pregnancy by releasing a hormone called levonorgestrel and can be left in your uterus for up to five years.

Much of this recent interest in levonorgestrel-releasing IUDs was sparked by a study published in Obstetrics & Gynecology that looked at the records of all 30-49 year old women in Finland who used a levonorgestrel IUD to treat menorrhagia (heavy periods).

The study reports finding that the Finnish women who used the levonorgestrel IUD for 5 years had a 19% increased rate of breast cancer compared to the general Finnish population. That’s bad, right? Well, hold on.

The study also reports that, for these women, ovarian cancer was decreased by 40% and endometrial (uterine) cancer was decreased by 54%. Seeing if the IUD could decrease the risk for, or prevent, endometrial (uterine) cancer was the actual goal of the study.

Remember, these women were receiving a levonogrestrel IUD to treat very heavy periods. Periods, which if caused by endometrial hyperplasia (overgrowth of the uterine lining), put them at increased risk for endometrial cancer. So the study showed that it helped prevent endometrial (uterine) cancer in women who used it to treat very heavy periods.

But, what about the increase in breast cancer?

The authors of the study advised not being too quick to assume that this increase in breast cancer is real. Prior studies have never found an association between levonogrestrel IUD use and breast cancer. So, the finding could just be an outlier or something else could be going on. We don’t know, for example, whether a group of women with very heavy periods has the same breast cancer risk as the general population.

Exactly how this finding translates from Finnish women to American women is also unclear, since the IUDs available in Finland are not exactly the same as those available in the United States

So before you decide to get rid of your IUD because of concerns about breast cancer risk, have an in-depth talk to your doctor. Discuss your family-planning goals, your family history, and your personal risk for breast, endometrial, and ovarian cancer. If your overall risk for breast cancer is low, the levonogrestrel IUD isn’t likely to put you in the high-risk category.

The three most important things women of child-bearing age can do to prevent breast cancer are: be physically active, stay at a healthy weight, and drink only moderate amounts of alcohol – if at all.


Reference

Soini T, Hurskainen R, Grenman S, Maenpaa J, Paavonen J, Pukkala E. Cancer Risk in Women Using the Levonorgestrel-Releasing Intrauterine System in Finland. Obstet Gynecol 2014;124:292-299.

Friday, August 15, 2014

New Study Confirms Weight is a Major Cancer Risk Factor

Photo: Flickr/Kizette
The subjects of weight gain, the obesity epidemic, and their major impact on health are brought up so much these days that they're easy to tune out.  So, if a few articles and news reports here and there pass you by - on accident or on purpose - we understand.  But we won't let that keep us from continuing to write regularly about the topic because it's something we're passionate about here at CNiC.

Why?

That's simple.  Overweight really is one of the most important health issues of our time, and much like tobacco in the middle part of the last century - unless we make some big strides against today's weight problem, generations will experience a greatly decreased quality of life and greatly increased rates of conditions like heart disease, diabetes, stroke, and cancer.  By keeping the issue upfront in articles, journals, and on social media, we can help push for policy changes and shifts in public attitude that will help address the obesity epidemic - much like we did with tobacco.  We've seen some very small positive steps recently on the obesity front, but we need to keep up - and expand on - these efforts.  

A study out today further confirms why.  Building on results from previous studies, researchers with the London School of Hygiene and Tropical Medicine published an analysis in The Lancet showing that increases in weight raise the risk of 11 different cancer, including esophageal, colon, liver, gallbladder, pancreatic, breast (post-menopause), cervical, uterine, ovarian, and kidney cancers, as well as leukemia.  Even for those in the healthy weight range (BMI of 18.5 - 24.9; or someone 5' 9" weighing 125 - 168 pounds), an increase of just one BMI point, say from 23 up to 24, was linked to an increased risk of cancer.

The researchers also calculated the percent of specific cancers likely caused by being obese or overweight (figure).  Five percent of all breast cancers diagnosed after menopause were linked to weight, as well as 11 percent of all colon cancers.  Each of these cancers is quite common.  Less common - but still very important - cancers had much greater percentages linked to weight.

In an accompanying editorial, titled Obesity: a certain and avoidable cause of cancer, Peter Campbell of the American Cancer Society concludes:
"We have sufficient evidence that obesity is an important cause of unnecessary suffering and death from many forms of cancer, in addition to the well recognised increased risks of mortality and morbidity from many other causes. More research is not needed to justify, or even demand, policy changes aimed at curbing overweight and obesity."
We certainly agree.  It's time to act more forcefully for prevention.  Yet, even though disease prevention is increasingly listed as a public health priority, funding and political backing for prevention programs still often lag behind fields like treatment and diagnosis. If we are to truly make headway in the fight against obesity and other key risk factors, prevention needs funding and political will commensurate with its large potential to reduce future disease burden.

Tuesday, August 12, 2014

Evolution of the Science on Aspirin Use and Colon Cancer Prevention

Yesterday, we posted about a new analysis suggesting that long term aspirin use is likely to have an overall health benefit in the general population even when its side effects are taken into account.  At risk of being wonky, we wanted to follow up on that with a figure that shows the general evolution of the science on aspirin use and colon cancer prevention.  

Though it's the cardiovascular benefits that come to most people's minds when they think of reasons to take a daily aspirin, the Cuzick et al analysis shows that most of the benefits from regular aspirin use don't come from the prevention of heart attack and ischemic stroke, they actually come from the prevention of cancer - including colorectal, esophageal, and stomach cancer, and possibly breast, prostate, and lung cancer.  Of these, colorectal cancer is the most important, making up about a third of the total cancer and cardiovascular disease benefits of aspirin use.  

The figure below (full size PDF) shows the evolution of the evidence on aspirin and colon cancer prevention.  Though the science has taken a while to develop, the findings of a number of early positive studies have been confirmed in later studies, and it seems we're finally reaching a point where broad recommendations for daily aspirin use to prevent cardiovascular disease as well as cancer may become a reality.