Cancer

"The greatest single risk factor for breast cancer, after gender and advancing age, is the presence of two or more affected first order relatives. There are a number of commonly experienced risk factors including being 20 per cent overweight, delaying childbirth until 30 or older, consuming two glasses of alcohol daily, and lack of regular exercise. Long-term use of HT is of comparable magnitude to this group of risk factors."

SOGC 2006 Menopause Consensus Report

What are my risk factors for cancer with the onset of menopause?

While overall cancer risk specifically associated with the onset of menopause is minimal, Canadian doctors agree that the following factors need to be considered when assessing a women’s risk of cancer:

  • Body weight (if 20 per cent overweight)
  • Age at puberty
  • Age at childbirth, especially if pregnancies were delayed
  • Breastfeeding history
  • Current age
  • Alcohol consumption
  • Smoking
  • Physical fitness
  • Family history (presence of one or more affected first order relatives)
  • Hormone therapy use

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Are some kinds of cancer more common in menopausal women?

Health providers treating menopausal women have been particularly focused on the risks of endometrial and breast cancer and so have been cautious about hormone therapy.  But recent studies provide new evidence that the risk of cancer for hormone therapy (HT) users is of no greater magnitude than for other factors, such as age at puberty, or age at childbirth, or family history.

Cumulative absolute risk and additional risk of breast cancer with duration of use of hormone therapy

Cumulative absolute risk and additional risk of breast cancer with duration of use of hormone therapy
Age at calculation (years) Age range (years) Risk with no hormone replacement therapy Additional risk (%) with combination therapy* (%) with oestrogen only therapy* (years of use)
Ratio % 3 years 5 years 10 years 15 years 3 years 5 years 10 years 15 years
40 40-79 1 in 14 7.21 0.18 0.38 1.18 2.22 0.05 0.12 0.34 0.64
45 45-79 1 in 15 6.76 0.26 0.52 1.45 2.54 0.07 0.15 0.41 0.73
50 50-79 1 in 16 6.10 0.31 0.60 1.59 2.82 0.09 0.18 0.45 0.81
55 55-79 1 in 19 5.30 0.33 0.64 1.76 3.17 0.09 0.19 0.50 0.91
60 60-79 1 in 23 4.44 0.37 0.73 2.01 3.51 0.10 0.21 0.57 1.00
65 65-79 1 in 29 3.48 0.42 0.84 2.19 3.27 0.12 0.25 0.62 0.91
70 70-79 1 in 42 2.37 0.47 0.88 1.64 - 0.13 0.25 0.50 -
75 75-79 1 in 88 1.14 0.43 0.58 - - 0.12 0.14 - -

*The additional risk for a specific formulation and duration of use can be added to the baseline risk with no hormone therapy to provide an estimate of a woman’s specific cumulative absolute risk of breast cancer from a specific age to age 79 years.

†The ratio is calculated as the reciprocal of the cumulative absolute breast cancer risk (%) of non-users.

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What is the risk of breast cancer during menopause?

There is an increased risk of breast cancer for women who have used combined hormone therapy for more than five years.  This increase is of a similar magnitude to other common risk factors for breast cancer, such as your age of puberty, being older than age 30 when you had your first child, or being overweight.  The good news is that the absolute risk for any one person is small, and the risk returns to normal soon after stopping hormone therapy (HT).

Risk Factors for Breast Cancer

Risk Factors for Breast Cancer
Factor Baseline breast cancers* per 1,000 women Additional cancers per 1,000 women Total cancers per 1,000 women
No HT use (baseline) 45 0 45
5 years of HT use 45 2 47
10 years of HT use 45 6 51
15 years of HT use 45 12 57
Alcohol consumption
(2 drinks per day)
45 27 72
Lack of regular exercise
(<4 hours/week)
45 27 72
Late menopause
(10-year delay)
45 13 58
Body mass index
(10 kg/m2 increase)
45 14 59
Weight gain after menopause
(>=20 kg)
45 45 90

*Baseline or basic risk applies to all women and is due to factors that cannot be controlled (e.g., aging, gender)

And since all women face an increased risk of breast cancer as they age, you should participate in regular breast cancer screening programs to enhance your chances for early detection.

And finally, quit smoking!  Women who smoke increase their risk of all types of cancer, including breast cancer.

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Should I consider hormone therapy for my menopause symptoms if I have any of these risk factors?

Since every woman is different, your risk factors need to balanced against your particular menopause symptoms and concerns. Sitting down with your doctor to review your medical history and assess your treatment options is the first step to deciding if hormone therapy (HT) is going to be right for you.

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If I develop cancer while on hormone therapy should I stop that therapy immediately?

With the exception of brain tumours, breast cancer, and endometrial cancer, there is no biological evidence that hormone therapy (HT) may increase the risk of recurrence.  Some cancers are known to increase the risk of blood clots in the veins and your doctor should advise you about this concern.

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Are my overall risks of cancer higher if I am on hormone therapy?

A number of recent studies that followed women through their menopause years have shed new light on the topic of cancer risk and hormone therapy (HT).  These studies provide new evidence that the risk of cancer for HT users is of no greater magnitude than for other predictors such as age at puberty or age at childbirth, or family history.

There is an incraeased risk of breast cancer for women who have used combined HT for more than five years.  This increase is of a similar magnitude to other common risk factors for breast cancer, such as your age of puberty, being older than age 30 when you have your first child, or being overweight.  The good news is that the absolute risk for any one person is small, and the risk returns to normal soon after stopping HT.

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Is my age a factor in breast cancer?

All women face an increased risk of breast cancer as they age, and as a result you should participate in regular breast cancer screening programs.  If a woman lives to age 85, she will have a one in nine chance of developing breast cancer. Most breast cancers occur after age 60.

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Where do I get screened for breast cancer?

Screening programs for breast cancer are different in each province and territory in Canada.  A mammogram is an important screening tool for the early detection of breast cancer.  Some women on hormone therapy (HT) have an increase in breast density that makes it harder to detect a small breast lump.  For these women, breast ultrasound may be useful to help get a better “look” at the health of your breasts.

Be proactive: Ask your doctor about what is available in your area and how you can participate.  Pap smears screen for cervical cancer and mammograms for breast cancer; they are the first line of defense in the detection of cancer.  Colorectal exams screen for cancers of the colon and rectum and are recommended for everyone over the age of 50.

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What is the Society of Obstetricians and Gynaecologists' position on hormone therapy?

After carefully reviewing scientific research on hormone therapy from Canada and around the world, Canadian obstetricians and gynaecologists recommend hormone therapy (HT) as a safe option for most women who are experiencing a reduction in their quality of life due to the symptoms of menopause.

The Society of Obstetricians and Gynaecologists of Canada (SOCG) published a report in 2006, The Menopause Consensus Report and the Menopause and Osteoporosis Update 2009, which says that hormone therapy may safely be prescribed in the dose and for the duration necessary to achieve treatment objectives, unless a woman has a specific risk factor for a specific disease or health condition.  The Society recommends that health care providers regularly review the risks and benefits of hormone therapy with their patients.  Emerging advice is suggesting that for women under age 60 HT is a safe and reasonable choice.

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SOGC