Dr. Jillian H. Davis is an Assistant Professor of Pharmaceutical Sciences in the School of Pharmacy at Hampton University, where she conducts cancer research. Her research focuses on increasing the effectiveness of breast cancer chemotherapy while reducing the negative side effects of therapy. Dr. Davis' long term goal is to perform cutting edge research at Hampton University centered on developing optimal chemotherapeutic treatments and reducing health disparities among women and minorities.

Dr. Davis has published her research in several peer-reviewed journals. She currently serves on the editorial board for the Journal of Best Practices in Health Professions Diversity: Research, Education and Policy. She is also a member of the Research Advisory Council for the Association of Minority Health Professions Schools (AMPHS). Dr. Davis earned her Ph.D. in Pharmacology from Howard University, and a Bachelor of Science degree in Chemistry from North Carolina A&T State University . In February 2007, Dr. Davis was named by Ebony magazine as one of their “30 Leaders Of The Future”.

Questions and Answers

I have heard a lot recently about proton beam therapy. What is the difference between radiation therapy and proton beam therapy? If it is so much more effective, why isn't it made more readily available?

A: As you probably already know, conventional radiation therapy treats cancers with beams of high energy particles, namely x-ray particles. Radiation therapy is currently employed in the treatment of many cancers, most often in conjunction with surgery and/or chemotherapy. Radiation therapy is a localized method of treatment and is utilized to decrease recurrence and to shrink tumor size prior to surgery. Although conventional radiation therapy has been around for more than one hundred years, there are many drawbacks. One of the major drawbacks is the toxicity caused to surrounding healthy tissue by conventional radiotherapy. In the case of breast cancer therapy, this toxicity may affect the heart and lungs leading to cardiovascular disease and secondary malignancies. Proton beam therapy is a very precise type of radiation therapy that delivers a more accurate dose of radiation to the specific target site. Proton beam therapy differs from conventional radiation therapy in many ways. First, conventional radiation therapy uses x-ray beams whereas proton beam therapy utilizes protons, which are positively charged particles found in the nucleus of an atom. Proton therapy, like all forms of radiotherapy, works by aiming energetic ionizing particles, in this case protons, to the target tumor. These particles damage the DNA of cells and ultimately results in cell death. Because of their high rate of division and their reduced ability to repair damaged DNA, cancerous cells are particularly susceptible to this attack on their DNA. Proton therapy’s ability to deliver a low dose of radiation to the surface of tissue with an increased dose at the tumor site makes it superior to conventional radiation. The second major difference between conventional radiotherapy and proton beam therapy is that proton therapy is a much more accurate method of delivering radiation. The radiation pattern emitted by the proton beam can be conformed or shaped to the exact size of the tumor. In addition, a highly concentrated dose of radiation is delivered to the tumor site with decreased effects to the surface layer of skin and decreased toxicity to the surrounding tissues. The proton beam enters the body at a low concentration and reaches its maximum concentration at the target site. This in turn reduces the toxic effects to healthy nearby tissues. This target specific effect can reduce the risk of acute and chronic toxicity, including side effects of the heart and lungs that may accompany conventional radiation therapy in the treatment of breast cancer.

Currently, there are five operating proton facilities in the United States which offer proton beam therapy. This therapy is not more widespread because the building of these state-of-the-art proton beam treatment facilities is extremely expensive. There are however several facilities in the development phase including a facility at the University of Pennsylvania Medical Center and one at my home institution, Hampton University in the Tidewater, Virginia area. Proton beam therapy is covered by most insurance plans as well as Medicare. To learn more about proton beam therapy and the facilities that offer such therapy you can visit the website of The National Association for Proton Therapy (www.proton-therapy.org).

Research to evaluate the efficacy of treating breast cancer with proton beam therapy is ongoing. Physicians at Loma Linda University Treatment Center, in southern California, are currently developing a protocol that may soon be used for the treatment of breast cancer. To stay abreast of current advances in the treatment of breast cancer with proton beam therapy and whether you would be a good candidate for such therapy you should consult your oncologist or health care provider.

Questions & Answers

I am 28 years old and I have recently been diagnosed with breast cancer. I don’t have any children but have always dreamed of being a mother. Will chemotherapy make me infertile? Are there options for preserving my fertility so that I may have children in the future?

A: Your first reaction to a diagnosis of breast cancer may understandably be anger, sadness and depression. For many young women diagnosed with breast cancer, these feelings may be coupled with uncertainties about fertility. According to the American Cancer Society, 25% of new breast cancer cases are in women of childbearing age. However, with the strides that have been made in cancer research women diagnosed with breast cancer are living longer, more productive lives. Breast cancer is no longer a death sentence. Treatment options have expanded to focus not only on survival but quality of life as well. Future fertility is a major concern for a lot of women diagnosed with breast cancer. There are many avenues young women with breast cancer can explore to preserve fertility.

The current therapies for the treatment of breast cancer include surgery, radiation and chemotherapy. Surgery does not affect fertility and radiation has little to no affect. However, chemotherapy can greatly reduce a breast cancer patient’s fertility. The extent of the detrimental effects that chemotherapy will have on a woman’s fertility depends on the age of the patient, the specific chemotherapeutic agent used, and the total dose of that agent. Chemotherapeutic agents cause infertility due to their harmful affects on the ovaries. As you may know, the ovaries are the organs that produce and house a female’s eggs until they are released during ovulation. While chemotherapeutic drugs produce their desired effects by killing cancer cells, they also kill normal cells in the process. Some of the normal cells that are affected are the woman’s reproductive eggs. It is important to note that chemotherapy can cause a more rapid loss of eggs than the decrease that normally occurs over time. You see, women are born with a certain number of eggs and as we age this number decreases. Coupled with the natural decline in reproductive eggs, the effects of chemotherapy on the ovaries in older women are more pronounced leading to an increased chance of infertility. However, in the case of younger women, there is a better chance of maintaining fertility after chemotherapy due to a larger supply of eggs that still remains. Because of these reasons, the risk of infertility is largely dependent on the age of the patient.

Research has shown that certain chemotherapeutic drugs are more likely to result in infertility than others. The most common chemotherapy used for the treatment of breast cancer is CMF which consists of cyclophosphamide, methotrexate, and 5-fluorouracil. Alkylating agents, which are a common class of drugs used in the treatment of cancer, are the most toxic agents to the ovaries and a woman’s fertility. Cyclophosphamide is one example of an alkylating agent. Methotrexate and fluorouracil, on the other hand are thought to have minimal effects on the ovaries and ultimately the patient’s fertility. Not only is the specific drug that is used a factor in infertility, the total dose of that drug is also a factor. The higher the dose and the longer the length of administration the greater the damage that is done to the ovaries.

There are options for women who have been diagnosed with breast cancer and would like to have children in the future. These options include embryo freezing, also known as embryo cryopreservation, freezing eggs (oocyte cryopreservation), and ovarian cryopreservation. Embryo cryopreservation involves extracting the eggs from the female patient, fertilizing them outside the body and freezing the fertilized eggs or embryos until the woman is ready to become pregnant. Oftentimes, prior to extracting the eggs, the woman is given fertility drugs to increase the number of eggs that can be produced. However, it may not be a good idea to give women diagnosed with breast cancer fertility treatments. The reasoning is because these treatments increase estrogen production which may stimulate the growth and metastasis of the existing cancer. However, in the absence of the fertility treatments only 1-2 eggs may be extracted and preserved per cycle. If fertility treatments are necessary, a short course of high dose tamoxifen may be most beneficial for breast cancer patients. Tamoxifen will increase the production of eggs while minimizing the risk of breast cancer growth and metastasis. Once the woman has completed chemotherapy, she should speak with her oncologist about when it is safe to utilize the embryos for pregnancy.

An additional therapy that can be used is the freezing of the patient’s eggs. In this procedure the eggs are harvested in the same manner as embryo freezing. Oocyte cryopreservation may be a viable option for women who do not have a significant other nor wish to use a sperm donor. These eggs are frozen without being fertilized. They are stored until the woman is ready to become pregnant. To date, the number of live births utilizing this method have been few, however major advances have been made in perfecting this technique.

An experimental method that is also used to preserve fertility is the freezing of ovarian tissue, a procedure known as ovarian cryopreservation. In this procedure, a woman’s entire ovary or a slice of ovarian tissue containing eggs is removed prior to chemotherapy. This ovarian tissue is frozen until the woman is ready to become pregnant. Once that time has arrived, the tissue is implanted in the pelvis or arm of the woman. Over time, blood vessels nourish the tissue and eggs begin to develop and mature. The mature eggs are then removed and fertilized. After fertilization, the embryo is implanted in the woman’s uterus and she is able to carry the baby to term.

It is understandable that the thought of breast cancer is marked by mixed emotions. However, for the woman with a maternal instinct, the focus does not have to be on grim fertility outcomes. There are multiple interventions that have been researched to decrease the chance of infertility and increase the possibility of pregnancy. If having children is a concern, you should speak with your oncologist and a fertility specialist prior to undergoing breast cancer treatment. They will be able to advise you about the best options to protect your fertility.