Ruwaida Dhala, BSc, MSc

Vaccination has one of the greatest impacts on disease prevention. Most vaccines generate protective immune responses against a pathogen, preventing disease initiation. Often the immunity generated by vaccines to specific pathogens is lifelong. Preventative vaccines are not effective in cancer prevention, however, mostly because cancer antigens elicit poor immune responses. For this reason many cancers evade the immune system. Cancer vaccine strategy focuses on eliciting anti-tumour responses in patients that are already afflicted with cancer. These vaccines will presumably prevent cancer progression and reoccurrence rather than prevent cancer initiation.

In order for the body to mount an immune response, the invading pathogen, or components of it, must be exposed to the immune system. There are two major components of the immune system, humoral and cellular. Humoral immunity is involved in the generation of antibody responses. These antibodies are usually directed against extracellular pathogens such as bacteria. Most preventative vaccines rely on this arm of the immune system.

Cancer and Nutrition: Be Cautious When Making Dietary Recommendations

Eleanor Brownridge,
Registered Dietitian

While a number of major dietary components--including fat, total energy, salt, red meat and alcohol--have been implicated as contributing to specific cancers, current case-control and cohort studies do not support some of the predominant hypotheses that are influencing Canadian eating habits. A major reason for the current level of certainty is the challenges inherent in nutrition epidemiology.

Diets are extremely complex. Nutrients are found in a multitude of foods, and their absorption and activity is influenced by other dietary components eaten at the same time. People change their eating habits over time and we have no idea as to the relevant latency period for various diet-related effects.

If the thought of packing into a crowded banquet hall this summer to get those CME credits does not excite you, then you may want to consider "studying" at The Arthritis University. Produced by McNeil Consumer Healthcare, in consultation with Canadian Rheumatologists, GPs and The Arthritis Society, the newly launched CD-ROM is designed to support doctors in refining their diagnosis and treatment of musculoskeletal conditions. MAINPRO-M2 accreditation is available.

"With the prevalence of arthritis growing at such a rapid pace, and newer treatments for the disease being developed all the time, we saw a need to provide some context on the critical issues of diagnosis and management," said Dr. J Carter Thorne, Rheumatologist, Medical Coordinator of The Arthritis Program (TAP) at York County Hospital, and chairman of the Teaching Faculty of The Arthritis University. "And when we considered the time constraints that physicians face, we decided to take advantage of the available technology."

The virtual campus has three larger buildings: a lecture hall, where expert faculty provide key insights into arthritis and discuss epidemiology, diagnosis, treatment and patient issues; a library which is filled with practice management tools such as treatment matrices and algorithms, as well as web links and an arthritis prevalence calculator; and a clinic/laboratory where users can access six patient case studies with accompanying video and commentary.

The CD-ROM also in-cludes a campus building for The Arthritis Society outlining its programs and services as well as downloadable patient information, and the McNeil building , which offers physicians an osteoarthritis CME toolkit complete with downloadable slides. "Clearly, one of the benefits of learning via CD-ROM is that it allows physicians to learn at their own pace, and to revisit areas of particular interest," said Dr. Thorne.

According to Dr. Thorne, one of the primary focuses of the CD-ROM is diagnosis, which emphasizes the need for a thorough case history. "Correctly diagnosing patients leads to more appropriate treatment plans. The pain experienced in mild to moderate osteoarthritis, for example, is primarily related to the mechanical nature of the disease as opposed to the presence of inflammation. In these situations, it may be more appropriate to prescribe a simple analgesic."

According to Denis Morrice, President of the Arthritis Society, The Arthritis University is a valuable tool for sorting through the huge volume of information on the disease. "Ongoing research has enabled us to gain a vast amount of knowledge about arthritis. The key now is to ensure that all of this information filters down to the people who need it most…"

To obtain a free copy of The Arthritis University, please call McNeil Consumer Healthcare at 1 800 265-7323.

Michelle Durkin, BSc

The most common form of cancer today is skin cancer. Approximately half of all new cancers diagnosed are one of three defined types: basal cell carcinoma (BCC) , squamous cell carcinoma (SCC), or malignant melanoma (MM). Although the age of diagnosis is decreasing, most skin cancers do not appear until after the age of fifty, making this disease a serious threat to the elderly population. Fortunately it is also a disease which is successfully treated if detected early.

Epidemiology
The incidence of nonmelanoma (BCC and SCC) and MM skin cancers has increased so significantly over the past few decades it may have reached epidemic proportions, particularly in the United States and Canada. It has been projected by the National Cancer Institute along with the Center for Disease Control that in 1999 alone, skin cancer (all types combined) will claim the lives of nearly 9,200 people in the United States. Besides increasing annual incidence, more women are getting skin cancer and people are getting skin cancer at younger ages.

Individual types of skin cancer follow different morbidity and mortality distributions. About 80% of skin cancers are BCC, 16% SCC, and 4% MM. The mortality rate for nonmelanoma skin cancer is decreasing and that of melanoma is increasing.

Lilia Malkin, BSc

Breast cancer has the dubious distinction of being the most frequently diagnosed neoplasm and the second leading cause of cancer deaths in Canadian women today. Since the incidence of breast cancer increases with age, its appropriate diagnosis, management, and prevention are highly important in the geriatric population.

Epidemiology
A widely quoted statistic is that one in nine Canadian women will develop breast cancer in her lifetime, while one in twenty-five will die from it. The National Cancer Institute of Canada (NCIC) estimates that 18,700 Canadian women will be diagnosed with breast cancer and that 5,400 will succumb to it in 1999. In Ontario alone, more than 7,000 new cases are reported and approximately 2,000 women die each year. Although breast cancer affects men as well as women, male patients make up less than one percent of all cases. In 1994, when nearly 16,000 Canadians were diagnosed with breast cancer, only 97 of them were male.

Breast cancer remains a significant contributor to morbidity and mortality in the female geriatric population. More than 50% of breast cancer patients are older than 65 at diagnosis. According to NCIC's 1999 estimates, 6,000 of the new breast cancer cases will occur in Canadian women aged 70 and over.

Shechar Dworski, BSc

Lung cancer is the most common cause of cancer-related deaths in both men and women, accounting for 34% of cancer-related deaths in men, and 22% in women. Lung cancer survival rates are dismal: the five-year survival rate is 14% for all cases of lung cancer, and the median survival is less than half a year for untreated patients. The lung cancer mortality rate in the United States is approximately 50 in 100,000, 68% of which occur in people over 65 years of age. Lung cancer mortality in the elderly is rising, which may be due to the aging of the population. Between 1968 and 1983, there was an 8.2% annual growth in mortality in white women 54 to 74 years old. The mortality rates in males seemed to reach a plateau in the 1980's, or may even be declining, possibly due to a decrease in the cigarette smoking by men from 67% in the 1950's, to 28% presently in the United States.

Over one half of all cases of lung cancer are reported in people aged 65 and over. Men aged 65 years and over have an incidence of lung cancer three times higher than men age 45 to 64. This trend is thought to be related to increased lifetime exposure to tobacco smoke and other carcinogens. The rate of lung cancer has risen dramatically in the last 70 years, accounting for 18% of all cancer cases in men, and 12% in women.

Sheldon Singh, BSc

Colorectal cancer is the second leading cause of cancer death in North America and Western Europe. This disease tends to occur mainly in older individuals. Early-stage disease is curable in more than 80% of patients. Unfortunately, more than 55% of patients present late with evidence of lymphatic or distant metastases. There is now compelling evidence that screening of average risk individuals over 50 can identify disease at a more curable stage thereby allowing for more effective management and subsequent reduction in mortality.

Epidemiology
Cancer of the colon and rectum kills more Canadians than any other cancer with the exception of lung cancer. During their lifetime, women have a 1 in 18 chance of developing colorectal cancer while men a 1 in 16 chance. This year, the disease is expected to affect 16,600 Canadians (with roughly 93% occurring in people over age 50) and claim 6,300 lives (with roughly 95% occurring after age 50). Rates of colorectal cancer in Canada have been declining, particularly among women. This may be due to changes in diet as well as the casual use of screening techniques.

Risk Factors
Age is a major risk factor for developing colorectal cancer. Approximately 75% of colorectal cancers are sporadic and without any identifiable risk factors other than age. Colorectal cancers are rare before 50 and over 90% are diagnosed after 60.

Rhonda Witte, BSc

Cancer. The word alone is enough to send fear into the hearts of people. It is safe to assume that everyone knows of someone who has been touched by cancer; they know of someone who is living with or has died of the disease. There are also people who have triumphed over the disease--they have fought cancer and won, they are survivors. Over the years, there have been numerous advances in cancer research. A hot topic in cancer research, in recent years, has focused around a process called angiogenesis. Specifically, researchers are trying to understand angiogenesis and use this knowledge to prevent the growth and spread of cancer.

Angiogenesis, also called neovascularization, is the growth of new blood vessels. Normally, the endothelial cells comprising the capillary walls do not divide. However, during pregnancy, menstruation, and wound repair, endothelial cells are stimulated to grow and divide, increasing the number of blood vessels.^1-3 During angiogenesis, endothelial cells must break through the basal lamina around the capillary wall. They do this by releasing proteases, thereby degrading the extracellular matrix. Endothelial cells then migrate toward the stimulatory signal, proliferating and aligning to form new capillaries.⁴ When properly regulated, angiogenesis stops after a short period of time.

Michel Silberfeld, MD, MSc, CRCP(C)

Coordinator, Competency Clinic, Department of Psychiatry
Baycrest Centre for Geriatric Care. North York, Ontario

In Ontario, as in some other provinces, there was a push to modernize guardianship and consent legislation, which culminated in new statutes in 1992. The motivations for new legislation came from several directions. The Ontario Mental Incompetency Act was felt to be outdated because it only permitted plenary guardianship. Plenary guardianship gives a person authority over all decision-making, much like a parent has over a small child. Furthermore, incapacity was poorly defined, based primarily on evidence as to the severity of an illness, and a person deemed incapable had to be incapable in all respects. There were no provisions for Powers of Attorney for personal care.

Several policy initiatives came from patient rights advocates. There was a desire to promote patient autonomy. This was accomplished by clarifying the definitions of capacity in statutes. The new definitions permitted the recognition of partial competence whereby a person could be incapable in one respect and yet retain the right of discretion in all others.