Recent developments in cancer therapy, including hormone replacement and use of anti-depressants
It has long been understood that hormone therapy to mediate the symptoms of menopause probably has a deleterious impact on cancer treatment. Nearly twenty years ago, we prevailed in a malpractice claim against a General Surgeon who continued estrogen therapy throughout a woman's treatment for breast cancer. Our claim was supported by an oncologist from the National Cancer Institute, and even the Defendant's expert was forced to concede the connection. Even at that time, the medical research showed a likely negative impact, and continuing estrogen therapy was not recommended. A new study out of the UCLA Medical Center adds weight to the argument and also suggests a tie between hormone replacement therapy, smoking and an enhanced cancer risk.
The data is pulled from a 2002 study involving Prempro that was discontinued when researchers found a strong connection between hormone replacement therapy and breast cancer. The new data confirms that in addition to the identified breast cancer risks, there is also an increased likelihood of lung cancer and that the patient's risks are further aggravated by smoking.
A second new study presented at the meeting of the American Society of Clinical Oncology suggested that taking Avastin may prevent the recurrence of colon cancer, but only while it is being taken. Avastin reduces blood flow and had previously been approved only for treatment of late stage cancers. It has not been used on a long-term basis in the past because it costs about $50,000.00 per year and physicians are concerned about the complications of long-term chemotherapy.
A third study reported at the Oncology meeting and in this case described by Bloomberg.com, suggests that Tamoxifen loses its effectiveness in fighting cancer when taken with certain antidepressants. The study by Medco Health Solutions, Inc., appears to show that "tumors were more than twice as likely to return after two years" in women taking certain depression medications. Treatment of "hot flashes" with antidepressants was never an approved use of the medication, however, doctors are free to use an approved drug for any "off-label" purpose, and some had initiated this treatment use seven years ago when estrogen therapy was unequivocally eliminated.
In recent years, researchers have argued that a specific warning should be added to the label to protect consumers and assure that this class of anti-depressants not be prescribed to cancer survivors taking Tamoxifen. Some researchers suggest that antidepressants such as Effexor may be safer since they apparently do not interfere with the operation of Tamoxifen. The latter drug mixes in the body with a liver enzyme called CYP2D6 to become endoxifen, a proven effective anti-tumor agent.
Anti-depressants such as Paxil, Prozac, Zoloft, Celexa and Lexapro (called SSRIs) are believed to combine with the same enzyme, thereby reducing its availability to combine with Tamoxifen to fight cancer. A study of nearly a thousand women showed that two years after treatment for breast cancer, they experienced a 7.5 percent recurrence rate on Tamoxifen, but a 14 percent recurrence rate if Tamoxifen was taken with an SSRI. If the SSRI was Paxil, Zoloft or Prozac, the recurrence risk increased to 16 percent.