When medical researcher Elwood Jensen died in December, thousands of breast-cancer survivors probably had no idea of the effect his findings had made on their lives.
Through his collaboration with Nobel Prize winners at the University of Chicago in the 1950s, Jensen discovered that steroid hormones — specifically estrogen — affect cells by binding to a specific receptor protein inside them. He then developed a test to detect the presence of estrogen receptors in breast-cancer cells.
Now, breast cancers that have receptors for estrogen can be treated with medications such as tamoxifen, which parks in the receptor and blocks estrogen's effect on the cancer. Other medicines block a key enzyme, aromatase, needed to make estrogen. Aromatase inhibitors reduce the amount of estrogen, which decreases the hormone's cancer- promoting effects. Cancers that appear to be located only in the breast can be removed completely by surgery. After surgery, drugs that block or reduce estrogen reduce the likelihood of cancer coming back.
Jensen's death was even more poignant because it occurred the same month that results were released on trials of Adjuvant Tamoxifen: Longer Against Shorter, or ATLAS. In prior trials, it had been proven that tamoxifen used for five years after breast cancer surgery was better than just two years of use. The ATLAS study set out to determine whether 10 years of treatment might be even better.
Nearly 7,000 women with early-stage, estrogen-receptor positive breast cancer were enrolled in ATLAS from 1996 to 2005. Results showed that 10-year tamoxifen use led to a greater reduction in breast cancer recurrences and deaths than taking the drug for only five years after surgery. Among women who took tamoxifen for 10 years, the risk of breast cancer returning from 10 to 14 years after starting tamoxifen was 25 percent lower than it was among women who took it for just five years, and the risk of dying from breast cancer was nearly 30 percent lower.
Such valuable knowledge would not be possible without researchers such as Jensen and tens of thousands of patients who participate in cancer-research trials. Research helps us understand cancer's causes, determine how best to prevent it and discover new ways to save or extend the lives of those who have it.
Cancer research is being done locally. Participants not only take advantage of the most advanced technology and therapies, but they improve our knowledge in ways that will help people with cancer live longer and enjoy a better quality of life.
Dr. Lee G. Hicks is a medical oncologist with Baptist Lexington Oncology Associates and serves as principal investigator for several cancer research studies at Baptist Health Lexington.