Vim & Vigor - Summer 2018 - University of Virginia - 50

f you are one of the
millions of women using
hormonal contraceptives,
recent headlines may have
caused you to rethink your
birth control. But ... before
you abandon the Pill or trade
in your IUD, be sure to do a
little bit of legwork and get
the whole story. To jumpstart your research, we spoke
to University of Virginia
Cancer Center oncologist
Patrick Dillon, MD, about the
most recent study findings
that put this topic back in
the spotlight.

Is it true that doctors have known for
some time that hormonal contraceptives
increase a woman's risk of
developing breast cancer?

Yes, there were three historical studies prior to the most recent one, which
appeared in the New England Journal of
Medicine last December. The important
thing to note with all of these studies,
including the one that recently came out
of Denmark, is that they were observational studies, not prospective randomized studies, so they do not show cause
and effect.

How is this study
different from those
done in previous years?

Namely, the formulations of
hormonal therapies have changed compared with contraceptives used in the

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past. There are new progestins used and
lower doses of estrogen, so the hope
was that the breast cancer risk would be
lower with newer hormonal contraceptives, but the exact same breast cancer
risks were observed in this newer study.
So this study really is not expected to be
practice-changing.

What were the results
of the study?

How is this significant?

The study revealed that women
who were using or had used
hormonal contraceptives had a 20 percent higher relative risk of developing
breast cancer compared to those who
never used them. This included women
using birth control pills or intrauterine
devices (IUDs) that release hormones.

This is a relative risk increase,
which means a comparison. It
does not mean that a woman
taking hormonal contraceptives has a
20 percent risk of breast cancer. In
fact, in this study there were only 13
additional breast cancers per 100,000
patients. That's a pretty low risk. In
women under the age of 35, there were
just two additional cases per 100,000
women. Overall, this results in one extra
breast cancer diagnosed for every 7,690
women using hormonal contraception
for one year. And some of these women
had other risk factors for breast cancer
that weren't accounted for. They may

have been obese or had a family history of breast cancer-we are unable to
account for these cofactors in this study.

What is the takeaway
from these findings?

This study is a good reminder
that it's important to be
aware of the risks of all medications.
Hormonal contraceptives do raise your
risk for breast cancer slightly. They
also increase the risk of blood clots for
women who smoke. But keep in mind
that there are benefits to these drugs
as well, so you have to weigh the pros
and cons.
Contraceptives have been shown to
lower a woman's risk for endometrial,
ovarian and colon cancers. They also
have advantages for women with menorrhagia or painful, heavy periods, and
mood issues. Indeed, the rates of hysterectomy done for reasons of uncontrollable bleeding have substantially
dropped since the inception of hormonal contraception and innumerable
lives have been saved because of this. In
many cases, the benefits far outweigh
the risks. Women should talk to their
doctor about their personal risk factors and health concerns before deciding on a contraceptive. Those women
who are already at an increased risk for
breast cancer may want to choose an
alternative birth control method. It's a
personal decision and women should be
sure they have done their research. ■
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