Life Extension Magazine®

Issue: Jun 1999

In The News June 1999

Prolactin and breast cancer, aminoguanidine, WebWatch.

Scientifically reviewed by: Dr. Gary Gonzalez, MD, on January 2021.

Elevated Prolactin Linked
To Breast Cancer

In last month's issue of Life Extension magazine, we repeated our recommendation that prostate cancer patients should have there prolactin blood levels checked, as excess amounts of this hormone can promote prostate cancer cell proliferation and prevent successful treatment.

A new study indicates that high levels of prolactin predispose healthy women to an increased risk of breast cancer. Prolactin is produced by the pituitary gland and, along with other hormones, stimulates the growth of the mammary glands and the production of milk after childbirth.

Postmenopausal women who had blood prolactin levels in the upper 25% of the reference range had about twice the risk of breast cancer compared with those in the lower 25% of the distribution, according to a report in the April 7th issue of the Journal of the National Cancer Institute.

The size of this association is similar to that observed between breast cancer and estrogen levels, report Dr. Susan E. Hankinson of Harvard Medical School in Boston, Massachusetts, and colleagues. The study included 306 women who were healthy at the time blood samples were obtained, but went on to develop cancer. Those women were compared with 448 healthy women who did not develop cancer. This new analysis is part of the ongoing Nurses' Health Study, the largest ongoing study of women's health in human history.

There are similarities to breast and prostate cancer cells, and prolactin seems to be a common growth factor in these two cancers. Based on the new report showing that women with high levels of prolactin have twice the risk of breast cancer, it would appear prudent for healthy women to lower their prolactin levels. Here are the standard laboratory reference ranges for blood prolactin levels:

- Non-pregnant 2.8 to 29.2 ng/ml
- Pregnant 9.7 to 208.5 ng/ml
- Postmenopausal 1.8 to 20.3 ng/ml

- 2.1 to 17.7 ng/ml

Evidently, prolactin levels have a very wide range that conventional doctors would consider "normal." The problem is that few doctors are aware of the dangers of elevated prolactin, and if their healthy patients are in the high "normal" range, they would do nothing to treat this condition. A "normal" range often means a person has a "normal" risk for contracting a disease. Since members of The Life Extension Foundation don't want to have "normal" risk factors, here are some guidelines for those to follow who care about optimal health:

Healthy Female
- Non-pregnant - Prolactin level no higher than 7.3 ng/ml
- Postmenopausal - Prolactin level no higher than 5.0 ng/ml

Female - Breast Cancer Patient
- Prolactin level no higher than 1.8

Male - Prostate Cancer Patient
- Prolactin level no higher than 2.0

There are three FDA-approved drugs that suppress prolactin secretion. If a blood test reveals prolactin levels are elevated, ask your doctor to prescribe one of the following drugs:

- Bromocriptine (2.5 mg one or more times a day)
- Pergolide (.25 mg to .50 mg twice a day)
- Dostinex (.5 mg twice a week)

Check prolactin levels again in 30 days to make sure the drug you choose is suppressing prolactin release from the pituitary gland into the blood.

Dostinex is the newest and cleanest drug to use. Dostinex has fewer side effects than the older drugs, is more effective in suppressing prolactin than the older drugs, and requires only twice a week dosing. It should be noted that Durk Pearson and Sandy Shaw recommended bromocriptine as a prolactin suppressing agent back in 1982, and the FDA spent millions of taxpayer dollars keeping Americans from accessing this drug for the purpose of disease prevention. Since 1982, about 700,000 American women have died of breast cancer.


Journal of the National Cancer Institute (1999;9 1:629-634)

European Journal of cancer (1995; Vol 31A, No.6)

Life Extension (1982; Warner Books; pp-190,202,236,343,471 477,339,766)

LabCorp (1999 Communication)