Texas Health Presbyterian Hospital Dallas
Vol. 2, No. 3 — March 2012
In this Issue
Cancer and Weight
By James Davidson, M.D.
When one thinks of obesity, the medical problems associated with diabetes, high blood pressure and joint problems come to mind. In addition the medical profession first realized in the 1970s that obesity increases the risk for cancer. Unfortunately, less than 10 percent of Americans are aware of the relationship between cancer and obesity. Even fewer know that being heavier at the time of their diagnosis decreases the likelihood of cancer survival.
Some cancers affected by obesity are:
- Uterine – endometrial
- Breast – post-menopausal
- Colon, kidney, stomach, gallbladder, prostate, pancreatic and esophageal
Researchers have known for 100 years that mammals, fish and insects that are slightly underweight have greater longevity. The telomeres at the end of their chromosomes seem to last longer, giving the cells of the tissues a longer life span. Benjamin Franklin said it first, “To lengthen thy life, lessen thy meals.”
Americans are becoming heavier, resulting in a higher body mass index (BMI). BMI is determined by dividing weight (in kilograms) by height (in meters) squared.
- A healthy BMI is between 19 and 24.9.
- An overweight individual has a BMI of between 25 and 29.9.
- Individuals with a BMI of 30.0 or higher are characterized as obese.
Approximately 33 percent of Americans have a BMI above 30. A BMI of only 28 is the level at which cancer rates start to climb. Cancer Preventions Study number 2 found that obesity accounted for 14 percent of all cancer deaths in men and 20 percent in women, suggesting that 90,000 cancer deaths per year could be prevented if Americans maintained a healthy weight.
Extra fat cells are deleterious to one’s health because they are very metabolically active. They release and make more than 400 substances (adipocytokines and hormones) that control and modify the body’s physiology. Hormones such as estrogen and testosterone have effects on the breast, uterus and prostate gland, possibly increasing the cancer risk. Inflammation is controlled by the release and manufacture of pro-inflammatory cytokines, affecting the immune system and causing a chronic inflammatory state. A chronic inflammatory state is thought to result in many diseases, including cancer. Cell division of normal organ cells and cancer cells is increased by fat, releasing the insulin-like growth factor-1. Diabetics have more cancer than nondiabetics, possibly because of this cytokine. Other cytokines can affect cell death (apoptosis); damaged precancerous cells do not die but can differentiate into cancer cells.
Fat cells like to be as fat as possible. They regulate hunger through the cytokines (an example is leptin) and hormones that tell the brain to feed them so they can grow. One theory is that the fat cells outgrow their blood supply. A fat cell with inadequate blood flow becomes damaged and releases more cytokines that stimulate the immune system, resulting in a chronic inflammatory state. The result is that normal tissue and organs are damaged, causing diseases like arteriosclerosis and cancer.
The bottom line is that too many fat cells have detrimental effects on health. Bariatric or weight-loss surgery is the only known way to have the greatest likelihood of permanent weight loss. One study found that without surgery, only 1 percent of people can lose 30 pounds and keep it off for five years. Bariatric surgery, especially gastric bypass and sleeve gastrectomy, has been found to have a 50 percent-plus excess weight loss at five years. A Canadian study found that the incidence of cancer after a gastric bypass decreased as quickly as six months after surgery and had an 80 percent reduction in the expected cancer incidence at five years. Weight loss and weight-loss surgery need to be used more often in our war against cancer.
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Advances in Robotic Surgery
By Jonathan Oh, M.D.
Robotic surgery. The term conjures images of futuristic machines more at home at NASA than in an operating room. However, robotics are a reality of modern surgery whose application continues to advance. First introduced in 1985, the PUMA® 560 surgical arm was initially utilized for neurosurgical procedures and was later approved for use in general laparoscopic and urologic surgery. In 1990, the AESOP® surgical system became the first to be approved by the Food and Drug Administration for use in endoscopic procedures. However, it wasn’t until 2000, with the approval of the da Vinci® surgical system, that a complete suite of surgical instruments and cameras was developed.
Since its advent, the da Vinci® robotic system has garnered widespread popularity, but it continues to remain a mystery to much of the medical field and the general patient population. To demystify the concept of robotic surgery, it may be more helpful to think of it as standard laparoscopic surgery using highly sophisticated instrumentation. While seated at a console, the surgeon visualizes the operative field through a high-definition 3D monitor and controls a series of surgical arms by utilizing finger controls. The console is directly attached to a surgical tower that has multiple surgical arms docked to laparoscopic ports. Movements made on the finger controls are electronically translated into very precise movements on the various arms. The da Vinci® system offers several distinct advantages over standard laparoscopic surgery: a high-definition 3D monitor, “wristed” instruments that articulate like a surgeon’s own hands, a wide variety of endoscopic instruments, and the ability to control multiple surgical arms simultaneously.
In my practice of gynecologic oncology, these advances have created a paradigm shift in the treatment of both cervical and endometrial cancer. What previously required a large laparotomy incision and a long hospital stay can now be accomplished through a series of 8mm and 12mm ports and less than a day in the hospital.
This procedure may translate into an enhanced surgical experience for the patient, with less post-operative pain and a shorter recovery time. All of this is accomplished without affecting the quality of the surgical procedure.
With the recognition of the potential advantages, both patients and referring physicians now seek out da Vinci®-certified surgeons. This increased use in turn, helps to further the advancement of minimally invasive surgery in a number of other specialties as well. Certainly, any technology has its limitations, but the future of robotic surgery remains promising as advances continue and techniques continue to be refined.
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Oncology Nurses at Texas Health Dallas
By Joyce Lee, M.S.N., R.N., O.C.N.
Texas Health Presbyterian Hospital Dallas offers leading-edge oncology services. In 2009, the hospital became one of only eight hospitals in Texas to receive the Outstanding Achievement Award from the American College of Surgeons. This award is one of the highest honors for oncology services. In 2012, Texas Health Dallas achieved Magnet redesignation from the American Nursing Credentialing Center, placing emphasis on the organization’s excellent nursing services.
Oncology services available on campus include staging and diagnostic procedures; various cancer-related surgeries, such as the Whipple procedure for pancreatic tumors and mastectomies and breast reconstruction for breast cancers; chemotherapy and biotherapy infusions; radiation therapy; blood transfusions; management of symptoms related to cancer or treatment for cancer; and comfort care for terminally ill patients. The outpatient clinic consists of four beds and seven treatment chairs, and the inpatient unit consists of 24 hospital beds.
The care of oncology patients requires highly specialized and competent nursing staff for optimal patient outcomes. Oncology nurses are responsible for maintaining up-to-date knowledge of cancers and their treatment regimens. They are required to attend an intense two-day chemotherapy and biotherapy course prior to becoming certified to administer biotherapy and chemotherapy. Several members of the nursing staff have taken the extra initiative to obtain the national oncology certification for nurses. Oncology nurses recognize that it is nearly impossible to learn everything about cancer on the job and therefore seek outside opportunities for continued education in order to deliver evidence-based care. Nurses from Texas Health Dallas represent a large presence in the local Dallas chapter of the Oncology Nursing Society, and some staff hold or have held positions as board members of the organization.
Competency in oncology care is only one of two qualities of the outstanding oncology nursing staff at Texas Health Dallas. Nursing staff must have the heart to care for the oncology patient population. Compassion includes empathizing with patients and realizing when it is appropriate to sit at their bedsides and hold their hands when they receive poor prognoses. Compassion includes learning what is important to the patients and helping them cope with their illnesses. Compassion may also include engaging with patients in prayer or song.
It takes special individuals to be a part of the oncology nursing staff at Texas Health Dallas. The general public often has difficulty understanding why anyone would pursue a career in oncology nursing. Oncology nursing is viewed as grim, depressing and hopeless. On the contrary, oncology nursing is an extremely rewarding specialty. Nurses have the opportunity to develop close bonds with patients and their family members, allowing them to provide specific and individualized care. Oncology nursing requires skills in both science and in art, competency as the science and compassion as the art.
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Vitamin D and Cancer Prevention
By Katherine Wang, M.D.
Vitamin D is an oil-soluble vitamin with several important functions. It promotes the absorption of calcium from the small intestine and helps maintain adequate blood levels of the calcium and phosphate needed for bone formation, mineralization (incorporating minerals to increase strength and density), growth and repair. It also helps reduce inflammation and improve muscle strength and the immune function.
Most people get vitamin D through exposure to sunlight. It can also be obtained through diet, but very few foods naturally contain vitamin D. These foods include fatty fish, fish liver oil and eggs. Smaller amounts are found in meat and cheese. Most dietary vitamin D comes from dietary supplements and fortified foods such as milk, juices, yogurt, bread and breakfast cereals.
A person’s vitamin D status is usually checked by measuring the level of 25-hydroxyvitamin D (25-(OH)D) in serum. A serum level of 25-(OH)D of less than 20 ng/mL is considered a vitamin D deficiency.
Vitamin D deficiency can lead to low blood calcium (hypocalcemia), low blood phosphate (hypophosphatemia) and osteomalacia (softening of the bones in adults). However, these complications have become less common because many foods and drinks have supplementary vitamin D. "Subclinical" vitamin D deficiency, called vitamin D insufficiency, which is more common, is defined as a lower-than- normal vitamin D level that has no visible signs or symptoms. Vitamin D insufficiency is associated with reduced bone density (osteopenia or osteoporosis), a mild decrease in the blood calcium level, and increased risk of falls, and possibly fractures, all of which can seriously affect a person's quality of life.
A large amount of recent evidence suggests that vitamin D may play a role in cancer prevention and treatment. Many epidemiological studies now support the hypothesis that individuals with lower levels of vitamin D may have increased risk of a number of cancers, whereas higher levels of vitamin D in the blood are associated with reduced risk of cancers, including breast cancer, colorectal cancer and rare malignancies. For example, one large epidemiological study reported that more than 40,000 individuals with higher vitamin D levels were associated with a reduction in the risk of head/neck, esophageal and pancreatic cancers, and acute leukemia, by 15 to 50 percent.
Even though laboratory studies have showed that exposure of cancer cells to high concentrations of vitamin D compound have stopped tumor cell growth and even lead to tumor cell death (apoptosis), no large-scale randomized clinical trials have yet examined the role of vitamin D replacement in the incidence of cancers and/or treatment for established cancers. Many studies are under way, so stay tuned and ask your doctors whether you should be tested for vitamin D level.
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