ABSTRACT: Surgery is still the most important treatment for solid tumors, regardless of the age of the patient. In this article, we discuss the physiology of aging as it relates to risk assessment in the elderly surgical oncology patient. A brief review of the role of surgery in the treatment of breast, colorectal, pancreatic, and gastric cancer is provided, because these solid tumors primarily affect elderly patients. Options for palliation are discussed. We conclude that older patients should not be deprived of curative surgery based on chronologic age alone. [ONCOLOGY 16:183-199, 2002]
The population of the United States is growing and aging. Because the incidence of cancer, particularly solid tumors, increases with age, the number of elderly patients with cancer who require surgical intervention is expected to rise markedly in the next decade. Surgery remains the most important treatment for solid tumors, regardless of the patient’s age. In hematologic malignancies such as lymphoma and leukemia, surgery is often required for diagnosis and consolidation of treatment. The most common tumors in elderly patients—colorectal, breast, gastric, and pancreatic cancer—require surgery for cure.
Because clinicians often underestimate the life expectancy of elderly patients, cancer in these patients is frequently undertreated. Inadequate initial therapy for an older cancer patient can result in recurrence, metastasis, or death. Not only are these outcomes potentially preventable with appropriate intervention, they can also have a severe impact on the quality of life of the elderly patient, in whom preservation of quality of life is paramount.
The elderly tend to be underrepresented in most clinical trials, and as a result, optimal therapy for elderly cancer patients is not always clearly delineated. This is particularly true of trials with a surgical component. Scientific data from randomized studies are not available for the older population, and most available information comes from retrospective studies.
According to the Metropolitan Life Insurance tables, life expectancy in the United States continues to rise. Thus, it is likely that the grass roots efforts of groups interested in the health and welfare of the elderly will demand and receive appropriate inclusion in federally funded clinical studies. Until that time, the limited information available on outcomes in elderly cancer patients will have to be used along with the judgment of clinicians who treat and operate on elderly patients to determine the appropriate therapy for an individual.
Many factors influence the selection of therapy for elderly patients. There is growing interest in trying to establish physiologic age as opposed to relying solely on chronologic age as a means of determining whether a patient may be a candidate for surgery. Comorbid diseases, decreased functional status, limited economic resources, and cognitive status clearly affect outcome in elderly cancer patients. However, clinician biases such as perceived limited life expectancy due to chronologic age and assumed fragility and inability to tolerate treatment may be preventing elderly cancer patients from receiving the appropriate definitive therapy for a specific malignancy.
Quality of life is often the most important factor when deciding on whether to pursue curative or palliative options for a cancer diagnosis in elderly patients. Because surgery, by its nature, diminishes the quality of life of all patients regardless of age in the short term (with the expectation of improving or extending quality of life in the long term), it is often shunned by both patients and referring physicians. For the elderly patient considering surgical management, the risk of diminishing quality of life in the long term may be considered prohibitive.
However, current literature does not support this perception. Although cancer procedures are often complex and carry with them significant morbidity and mortality, appropriate and accurate counseling of patients and their supporters can minimize fear and produce realistic expectations. This article reviews the current knowledge regarding risk assessment and surgical management of some of the most common solid tumors found in the elderly.
Risk assessment in the elderly involves the interaction of the underlying physiologic status—including the normal physiologic changes of aging and those attributed to comorbid disease—the disease process, the surgical procedure, and the type of anesthesia required for the operation. Chronologic age alone should not be the sole criterion for assessing surgical risk in the elderly cancer patient. Attempts have recently been made to calculate physiologic age as a predictor of outcome.
In one study of more than 250 patients aged 70 years or older who underwent elective abdominal surgery under general anesthesia, 24 preoperative variables were compared between patients who left the hospital in satisfactory condition and those who died in the hospital despite the operative procedure performed. Although no significant differences were found in the group aged 70 to 79 years, there was a significant difference in performance status and total lymphocyte count in the group over age 80 years. When combined with age, a computer-generated discriminant function analysis yielded an equation that calculated survival with 97% accuracy and mortality with 83% accuracy. This crude method of determining outcome was an attempt to combine chronologic age with variables that reflect the normal physiologic changes that occur with aging.
Every major organ system undergoes changes in its physiology with age, and this can affect response to surgery. Cardiovascular complications are commonly associated with major surgery in the elderly. Atherosclerotic disease, dysrhythmias, and conduction disturbances are more common with age. Volume depletion is not well tolerated in the elderly, because the aged body relies more on preload to increase cardiac output, due to a generalized decrease in the distensibility of the cardiac wall. Complex cancer operations often involve significant fluid shifts that may cause more morbidity in elderly patients.
The Goldman criteria were developed by multivariate analysis to predict cardiac complications independently in patients undergoing noncardiac surgery (Table 1). By ranking these factors, a patient can be assigned to one of four risk categories that correlate well with the risk for cardiac death. Chronologic age is one factor, but the type and nature of the surgery as well as the clinical evaluation of the patient’s cardiac status contribute more significantly to the patient’s ranking.
Hepatic and Psychological Changes
Liver function also changes with age because of decreased liver mass, blood flow, and perfusion. Histologic and metabolic changes that decrease the ability of the liver to metabolize drugs occur with age and result in an increase in the half-life of many drugs. Furthermore, the need for multiple medications, common in the elderly, is known to increase the risk of adverse drug reactions caused by hepatic dysfunction.
Dementia and depression commonly develop in the postoperative period among the elderly. Reductions in the number of neurons, cerebral blood flow, metabolic oxygen consumption, and number of receptor sites for neurotransmitters contribute to an increased sensitivity to drugs in the elderly and can lead to postoperative delirium. Anesthetic agents and postoperative analgesics must be used with caution to avoid postoperative changes in mental status, delirium, hypoventilation, and anoxia.
Surgical Risk Assessment
Surgical risk can be assessed in several ways. One of the most widely used tools for estimating risk from anesthesia alone is the American Society of Anesthesiologists (ASA) General Classification of Physical Status. The mortality rate, as related to anesthesia, is classified in one of five categories depending on the physical status of the patient (Table 2).
Increases in morbidity and mortality are generally associated with emergency surgery and advanced disease states.[7-9] Because many elderly patients present with advanced disease (often because of a delay in diagnosis), they tend to require more emergency interventions that ultimately increase their surgical risk. Appropriate screening, earlier diagnosis, and earlier surgery can diminish the risk of surgery in elderly cancer patients.