Women’s Health Update

by Tori Hudson, ND

Higher Vitamin D Levels Associated with Lower Cancer Risk

In the last 3.5 decades, research has proposed a link between several cancers and lower serum levels of vitamin D. Multiple epidemiologic studies have found inverse associations between serum levels of 25-hydroxyvitamin D (25[OH]D) concentration and the risk of many cancers, including breast, colorectal, and prostate. In one randomized controlled trial, women who were given vitamin D and calcium had a 60% reduced incidence in all non-skin cancers compared with those women in the placebo group.¹

The purpose of the current study was to be more precise in determining any association between 25(OH)D concentration and the risk of non-skin cancer in women 55 years and older. Two different cohorts were used. The first (n = 1169) was one from a randomized, controlled clinical trial in Nebraska with a median level of serum vitamin D of 30 ng/mL. The second was from a prospective cohort study of individuals living in 52 countries, although 90% were in either the US or Canada (n = 1135), with an average serum D level of 48 ng/ml. By using this approach, the analysis was able to be done across a broad range of 25(OH)D serum levels.

The incidence of all invasive cancers excluding skin cancer was evaluated over several years with a median of 3.9 years was compared in relationship to 25 (OH)D concentrations. The incidence of cancer was lower at higher concentrations of 25(OH)D levels and women with concentrations of 40 ng/ml or more had a 67% lower risk of cancer than women with levels <20 ng/ml.

Comment

: The results of this analysis support the importance of serum levels and cancer risk and thus direct us more precisely to a target serum level of vitamin D to optimize cancer prevention. The significant risk reduction comes at levels that are considerably higher than the >20 ng/ml considered adequate for bone health, the minimum recommended by the Institute of Medicine. I urge patients and practitioners to pay close attention to the units used by their labs. For example, 12–20 ng/ml = 30–50 nmol/L.

McDonnell SL, Baggerly C, French CB, et al. Serum 25-hydroxyvitamin D concentrations ≥40 ng/ml are associated with >65% lower cancer risk: pooled analysis of randomized trial and prospective cohort study. PLoS ONE. 2016;11(4):e0152441;doi:10.1371/journal.pone.0152441.

Menopausal Hormone Therapy and Risk of Ovarian Cancer

This meta-analysis was performed to examine the risk of ovarian cancer according to different types and regimens (either continuous or sequential) of menopausal hormone therapy. While ovarian cancer is not a common women’s cancer, and has been decreasing in the US in the last 30 years, it accounts for 5% of cancer deaths and is responsible for more cancer deaths than any other gynecological cancer. Several studies have shown that unopposed estrogen in postmenopausal women has been associated with up to a 50% increased risk of ovarian cancer. Data on the combination of estrogen plus progestins are inconsistent, although in general, studies have shown no association with estrogen plus progestins in regard to ovarian cancer, or at least an association that is much weaker than with estrogen alone. In 2009, a meta-analysis reported a relative risk of ovarian cancer with estrogen plus a progestin of 1.10 per 5 years of used as compared with a relative risk of 1.22 for estrogen alone. However, prospective studies have shown no difference in ovarian cancer risk with estrogen alone vs. estrogen plus a progestin. In the Women’s Health Initiative (WHI), the hazard ratio was 1.58 for estrogen plus progestin compared with placebo. Other meta-analyses have suggested an association with menopausal hormone therapy and ovarian cancer risk, but the regimen of cyclic estrogen-progestin or continuous estrogen-progestin or the different types of ovarian cancer was not assessed.

In the current meta-analysis, 180 studies were identified and 12 met the inclusion criteria. Of these 12 studies, 9 were cohort studies of over 2.3 million women and 7549 cases of ovarian cancer. The other 3 were case-control studies including 1347 cases and 2052 controls. Both continuous and sequential regimens were associated with an increased risk of ovarian serous ovarian cancer, but not clear-cell, endometrioid, or mucinous ovarian cancer. Also in the current meta-analysis, the hazard ratio and relative risk was lower in the estrogen-progestin group than the estrogen alone group, which is consistent with the opposing effects of progestogens. This seeming protective effect of progestogens requires further studies, as well as making a distinction between different types of estrogens and different types of progestogens – different synthetics and bioidentical progesterone.

Comment

: All meta-analyses are fraught with problems. Not every study included in this meta-analysis is the same with different ethnic groups, different durations of hormone use, different years since menopause, hysterectomy or no hysterectomy, different estrogens and different doses and deliveries, and different progestational agents and dosages. That all said, menopausal hormone therapies – estrogen alone and estrogen-progestins, whether cyclic or sequential – are associated with a slight increase in risk of ovarian cancer. This will be especially important in women with a first-degree relative with ovarian cancer and in obese women.

Shi L, Wu Y, Li C. Hormone therapy and risk of ovarian cancer in postmenopausal women: a systematic review and meta-analysis. Menopause 2016; 23(4):417–424.

Mammogram Screening: A Summary Guide of Different Recommendations and Patient Handout

Screening Mammograms:

One Procedure, Many Opinions

Keep in mind that these guidelines apply to average-risk women. You are considered average risk if all of the following are true:

• no personal history of breast cancer.

• no known genetic mutation increasing risk for breast cancer (i.e., BRCA).

• no history of chest radiation

The major purpose of mammograms is to detect cancerous lumps before they can be felt and start treatment sooner, with the hope that earlier detection and treatment will save lives. Unfortunately, it appears that women die at a similar rate whether breast cancer was detected early by mammogram or later by breast exam.^2,3 In addition, screening mammograms lead to healthy women receiving unnecessary breast biopsies and even cancer treatment; a Cochrane Review estimates that for every life saved by mammography, 10 women receive unnecessary breast cancer treatment.⁴

So why bother with mammograms at all? Consider the following:

• Early detection of breast cancer with mammograms may spare women from more aggressive treatment regimens, improving quality of life for women diagnosed with breast cancer.

• We know that women who get breast cancer before age 50 tend to have more aggressive cancers. Delaying screening mammograms to age 50 or later may result in a more aggressive cancer in a younger woman being missed.

Increasingly, the medical community is giving weight to the individual risk factors and informed choice of women in the decision of when and how often to screen for breast cancer using mammography. In fact, population studies in Switzerland found that opportunistic screening (mammograms only when requested by doctor or patient) worked as well as uniform screening (mammograms at specified intervals) in identifying breast cancer.⁵

Source: Jennifer Johnson, ND, LAc, and Tori Hudson, ND; A Woman’s Time Clinic; Portland, Oregon

Notes

1. Lappe J, Travers-Gustafson D, Davies K, et al. Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial. Am J Clin Nutr. 2007;85(6):1586–1591.

2. Miller A et al. Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ. 2014;348:g366.

3. Autier P, Koechlin A, Smans M, Vatten L, Boniol M. Mammography screening and breast cancer mortality in Sweden. J Natl Cancer Inst. 2012;104(14):1080–1093.

4. Gøtzsche P, Jørgensen K. Screening for breast cancer with mammography. Cochrane Database Syst Rev. 2013;6. Art. No.:CD001877. doi:10.1002/14651858.CD001877.pub5.

5. De Gelder R et al. Cost-effectiveness of opportunistic versus organised mammography screening in Switzerland. Eur J Cancer 2009; 45(1):127–138.

Dr. Tori Hudson graduated from the National College of Naturopathic Medicine (NCNM) in 1984 and has served the college in many capacities over the last 28 years. She is currently a clinical professor at NCNM and Bastyr University; has been in practice for over 30 years; and is the medical director of the clinic A Woman’s Time in Portland, Oregon, and director of research and development for Vitanica, a supplement company for women. She is also a nationally recognized author, speaker, educator, researcher, and clinician.