Sen. Cayetano wrong on hormonal contraceptives

I would just like to make some clarifications regarding the supposed arguments made by Sen. Pia Cayetano at the Supreme Court in defense of the Reproductive Health Law as reported by Christine Avendaño (“Pia, Edcel defend RH Law,” News, 8/14/13).

The news article said that “Associate Justice Roberto Abad also peppered Cayetano with questions on her position when it was the turn of the senator to present her case. Abad argued that hormonal contraceptives have the highest possibility of causing cancer and that they can cause ‘Class I’ cancer. Cayetano countered that the Class I rank was actually the ‘lowest class’ as it was similar to the risk of women getting sick from microwaves and television.”

It is obvious to us doctors and public health workers that Associate Justice Abad did his research well and is well-read and -informed. It is equally evident to us in the medical profession that Senator Cayetano did not do her homework well and is ill-advised regarding the mechanism of action and side effects of hormonal contraceptives.

Substances and exposures that can lead to cancer are called carcinogens. One important way to identify carcinogens is through epidemiologic studies, which look at human populations to determine which factors might be linked to cancer. The lists of known and probable human carcinogens have been developed by two highly respected agencies—the International Agency for Research on Cancer (IARC) and the US National Toxicology Program. The IARC is part of the World Health Organization. Its major goal is to identify causes of cancer. The most widely used system for classifying carcinogens comes from the IARC. In the past 30 years, the IARC has evaluated the cancer-causing potential of more than 900 likely candidates, placing them into groups. When the evidence is conclusive that the substance or exposure is carcinogenic to humans, it is labeled “Group or Class 1” and it is the “highest class” of carcinogens; only a little over 100 substances and exposures are classified as such. On the other hand, the IARC classifies radiofrequency electromagnetic fields from microwaves, TV and wireless telephones as possibly carcinogenic to humans (Group or Class 2B). Obviously, Senator Cayetano got her data wrong on this matter. Other medical journals have shown evidence as to the carcinogenicity of hormonal contraceptives such as that of the meta analysis made by Dr. Chris Kahlenborn and coworkers published in Mayo Clinic Proceedings in 2006, which came up with the conclusion that the use of oral contraceptives is associated with an increased risk of premenopausal breast cancer.

As a doctor who takes care of terminally ill cancer patients, I would caution Senator Cayetano about downplaying the risk of cancers brought about by hormonal contraceptives. Cancer kills. It would be lacking in prudence to expose oneself to known carcinogens when the risks are much more than the benefits (if any, such as in the case of hormonal contraceptives).

—DR. MARIA F. C. MANALO, M. Sc., Epidemiology, Department of Community  and Family Medicine, FEU-NRMF Medical Center, Fairview, Quezon City