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Scrutinizing the evidence for breast
cancer procedures and treatments
Supplement Strategies - Melatonin

Melatonin is a
hormone produced
in the pineal gland
located in the brain.
It is best known for
its role in the
regulation of the
sleep/wake cycles.









Read An Overview of
Melatonin and Breast
Cancer by Tina
Kaczor, ND

*
Dosage: Melatonin
can be safely taken
for an indefinite
dose of melatonin
for breast bedtime.  
Some people initially
experience vivid
dreams or morning
drowsiness. To
avoid slowly
increased over a
period of several
weeks. Consult your
doctor before
starting this or any
supplement --
Life Extension
Foundation
.



    Several studies indicate that melatonin levels may be linked with
    breast cancer risk. Laboratory experiments have found that low
    levels of melatonin stimulate the growth of certain types of breast
    cancer cells.  Researchers found adding melatonin to these cells
    inhibits their growth. Melatonin is widely recommended because it
    has several beneficial methods of action.

  • High number of women with estrogen receptor positive tumors have
    low levels of melatonin in their blood.

  • Melatonin appears to work as an anti-estrogen on tumor cells. although
    differently than Tamoxifen. When the two are combined, the result is better
    than Tamoxifen alone. (Lissoni et`al., 1995.)

  • A 2006 study showed Melatonin may work as a kind of aromatase
    inhibitor. (Cos et al.)

  • Low levels of melatonin have been associated with breast cancer
    occurrence and development. Women who work predominantly at night
    and are exposed to light, which inhibits melatonin production and alters
    the circadian rhythm, have an increased risk of breast cancer
    development (Schernhammer et al. 2003).

  • The circadian rhythm alone is a  significant predictor of survival time for
    breast cancer patients (Sephton et al. 2000).

  • Melatonin demonstrates growth inhibitory effects by inducing
    differentiation (“normalizing” cancer cells)(Cos et al. 1996) as well directly
    inhibits breast cancer cell proliferation (Ram et al. 2000) and  boosting the
    production of immune components, including natural killer cells (NK cells)
    that have an ability to kill metastasized cancer cells.

 Melatonin can be safely taken for an indefinite period of time. The
suggested dose of melatonin for breast cancer patients is 3-50 mg at
bedtime.  Some people initially experience vivid dreams or morning
drowsiness. To avoid these minor side effects melatonin may be taken in
low doses nightly and the dose slowly increased over a period of several
weeks. Consult your doctor before starting this or any supplement.
--------------------------------------

    Interesting research on Melatonin

    Epidemiology. 2006 Jan;17(1):108-11.

    Night work and risk of breast cancer.

    Schernhammer ES, Kroenke CH, Laden F, Hankinson SE.

    Channing Laboratory, Department of Medicine, Brigham and Women's
    Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
    eva.schernhammer@channing.harvard.edu

    BACKGROUND: Melatonin shows potential oncostatic activity and is acutely
    suppressed by light exposure. Some evidence suggests an association
    between night work and breast cancer risk, possibly through the melatonin
    pathway. METHODS: In a cohort of premenopausal nurses, we
    prospectively studied the relation between rotating night shift work and
    breast cancer risk. Total number of months during which the nurses
    worked rotating night shifts was first assessed at baseline in 1989 and
    periodically updated thereafter. We used Cox proportional hazards models
    to calculate relative risks (RRs) and 95% confidence intervals (CIs).
    RESULTS: Among 115,022 women without cancer at baseline, 1,352
    developed invasive breast cancer during 12 years of follow up. Women
    who reported more than 20 years of rotating night shift work experienced
    an elevated relative risk of breast cancer compared with women who did
    not report any rotating night shift work (multivariate RR = 1.79; 95% CI =
    1.06-3.01). There was no increase in risk associated with fewer years of
    rotating night work. CONCLUSION: Our results suggest a modestly
    elevated risk of breast cancer after longer periods of rotating night work.
    Additional studies are warranted to rule out small sample size or
    uncontrolled sources for confounding as alternative explanations..

    Melatonin increases the survival time of animals with untreated mammary
    tumours: neuroendocrine stabilization.

    Saez MC, Barriga C, Garcia JJ, Rodriguez AB, Masot J, Duran E, Ortega E.

    Department of Physiology, Faculty of Science, University of Extremadura,
    Badajoz, Spain.

    The aim of this study was to evaluate the therapeutic effect of melatonin,
    the main hormone of the pineal gland, on rats with advanced and
    untreated mammary tumours. Mammary tumours were chemically induced
    in Sprague-Dawley rats with the carcinogen 9,10-dimethyl-1,2-
    bezanthracene (DMBA). After the appearance of tumours the effect of
    melatonin (5 mg/ml per rat per day) was then evaluated on the survival
    time, tumour multiplicity, and tumour volume until the death of the animals.
    In addition, the variations in prolactin, noradrenaline and adrenaline
    concentrations, and in the percentage of NK cells were evaluated after
    one month of the treatment with melatonin. Daily administration of
    melatonin increased significantly the survival time of tumour-bearing
    animals (p<0.05 with respect to the control non-melatonin-receiving rats).
    The increased survival time did not correlate, however, with changes in
    either tumour multiplicity or tumour growth rate. Animals with mammary
    tumours exhibited an increase (p<0.05 with respect to healthy animals) in
    prolactin and catecholamine concentrations. The administration of
    melatonin stabilized the hormone levels, returning them to those in the
    basal-healthy animals. Rats with mammary tumours also presented lower
    percentages of NK cells, which were not increased by the administration of
    melatonin. The results strongly suggest that melatonin per se is beneficial
    during advanced breast cancer. It increases survival time, maybe by
    improving the homeostatic and neuroendocrine equilibrium which is
    imbalanced during advanced breast cancer.
    -----------------------

    Int J Cancer. 2006 Jan 15;118(2):274-8.

    Melatonin inhibits the growth of DMBA-induced mammary tumors by
    decreasing the local biosynthesis of estrogens through the modulation of
    aromatase activity.

    Cos S, Gonzalez A, Guezmes A, Mediavilla MD, Martinez-Campa C, Alonso-
    Gonzalez C, Sanchez-Barcelo EJ.

    Department of Physiology and Pharmacology, School of Medicine,
    University of Cantabria, Santander, Spain.

    Melatonin inhibits the growth of breast cancer cells by interacting with
    estrogen-responsive pathways, thus behaving as an antiestrogenic
    hormone. Recently, we described that melatonin reduces aromatase
    expression and activity in MCF-7 human breast cancer cells, thus
    modulating the local estrogen biosynthesis. To investigate the in vivo
    aromatase-inhibitory properties of melatonin in our current study, this
    indoleamine was administered to rats bearing DMBA-induced mammary
    tumors, ovariectomized (ovx) and treated with testosterone. In these
    castrated animals, the growth of the estrogen-sensitive mammary tumors
    depends on the local aromatization of testosterone to estrogens.
    Ovariectomy significantly reduced the size of the tumors while the
    administration of testosterone to ovx animals stimulated tumor growth, an
    effect that was suppressed by administration of melatonin or the
    aromatase inhibitor aminoglutethimide. Uterine weight of ovx rats, which
    depends on the local synthesis of estrogens, was increased by
    testosterone, except in those animals that were also treated with
    melatonin or aminoglutethimide. The growth-stimulatory effects of
    testosterone on the uterus and tumors depend exclusively on locally
    formed estrogens, since no changes in serum estradiol were appreciated
    in testosterone-treated rats. Tumors from animals treated with melatonin
    had lower microsomal aromatase activity than tumors of animals from other
    groups, and incubation with melatonin decreased the aromatase activity of
    microsomal fractions of tumors. Animals treated with melatonin had the
    same survival probability as the castrated animals and significantly higher
    survival probability than the uncastrated. We conclude that melatonin
    could exert its antitumoral effects on hormone-dependent mammary
    tumors by inhibiting the aromatase activity of the tumoral tissue.



    These statements have not been evaluated by the U.S. Food & Drug Administration.  The supplements
    discussed are not intended to diagnose, treat, cure, or prevent any disease.

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    Web page updated July 13,  2010.