by Ilene Browner, M.D.
- Demographics of Cancer and Aging
- Biology of Cancer and Aging
- Barriers to Treatment
- Comprehensive Assessment of the Older Patient
- Common Tumors in the Older Adult
- Summary
Demographics of Cancer and Aging The Aging Population
Incidence of Cancer in the Aging Population
Thus, the elderly are disproportionately affected by cancer and its associated sequelae (top of page)
| ||||||||||||||||||||||
The association between cancer and aging may be attributed to age-related changes in molecular, cellular and physiologic processes.
This age-altered molecular environment favors carcinogenesis.
Age-related alterations in growth factor (cytokines and chemokines) production and activity, metalloproteinase expression, hormonal status, inflammation, and immune cell number and function may contribute to changes in tumor biology and expression of cancers in the elderly. Tumorogenesis: A Simplified Model Step 1 -Initiation: Accumulated irreversible changes occur at the level of stem cell DNA in oncogenes, antiproliferative and apoptotic genes, and cell lines leading to cellular immortality and initiation of the multistep process.
(reference: Repetto. Supportive Oncology. 1(S2), 2003) Age-related changes in physiology and organ function may lead to changes in the pharmacokinetics and pharmacodynamics of cancer chemotherapeutic agents, increasing the risk for drug-related morbidity in the elderly.
Pharmacokinetics is the effect of bodily processes on the drug. PK is impacted by body composition, bioavailability and organ function.
(reference: Lichtman et al. Crit Rev Onc Hem. 46:101-114, 2003) Pharmacodynamics is the effect of the drug in the body over time. Age-related changes in PD may alter the activity of and increase the toxicity from chemotherapeutic agents in older cancer patients
(top of section) | ||||||||||||||||||||||
Barriers to Receiving Cancer Care The Institute of Medicine (IOM) states that in “many cases, older patients are less likely to get effective cancer treatment than are younger patients despite evidence that the elderly can tolerate and benefit from it.” Barriers to Screening
When discussing therapeutic options, all parties (patient, patient’s family, physicians, etc) must be included in the discussion. Each party’s perspective must be reviewed within the context of disease- and age-related factors. One must be conscientious of the fact that older patients may defer to family members or a physician thus, masking their own wishes. Patient, physician and family biases may contribute to inappropriate staging and treatment decisions.
Surgery
However,
Chemotherapy
Supportive Care/End of Life Care (EOLC)
(top of section) | ||||||||||||||||||||||||
Comprehensive Assessment of the Older Patient Patient Assessment Age is often based on one’s “Chronological age”, a discrete ‘age in years’ cut-off. This definition was established during the depression era and from the constraints of Medicare. Better definitions of age should include measures of biologic and functional status. From a mere snapshot in time, assumptions regarding a patient’s functional and biologic status can be made, but only a direct assessment will reveal the actual nature of this status. Oncologists often use the ECOG performance status (PS) scale or the Karnofsky scale to assess a patient’s functional level and ability to tolerate therapy. Geriatricians use a more age-specific and global assessment of function and general health to assess patient status and potential disease and treatment outcomes. Geriatric oncologists use a combination of performance scales and a global direct assessment, an example of which is the Comprehensive Geriatric Assessment (CGA), to evaluate older patients with cancer. Eight domains should be included in this direct assessment: Function, comorbidities, cognition, emotion, geriatric syndromes, nutrition, pharmacy, and socioeconomic status. The CGA “currently provides the best estimate of individual functional {capacity and} reserve and life expectancy” (Balducci and Extermann. The Oncologist. 5:224, 2000). The CGA can be used to estimate life expectancy, detect unsuspected, treatable conditions, increase diagnostic and prognostic accuracy, identify psychosocial needs, limit costs and hospitalization, improve quality of life, and maintain or improve function.
*In the functional assessment, Activities of Daily Living (ADL) are assessed. ADLs are required for maintenance of basic, independent living and include bathing, toileting, dressing and feeding. Deficits in ADLs are predictive of post-hospitalization and 2-year overall mortality. Instrumental Activities of Daily Living (IADL) include shopping and cooking, house and money management, transportation and ability to take medication. IADLs reflect one’s ability to function within society. Deficits in IADL are predictive of poor therapeutic tolerance, and often are harbingers of ADL deficits. **Comorbidities include information about the number, types and severity of medical conditions. Older patients are likely to have at least one comorbid illness. Three or more comorbidities may be predictive of increased disability, and decreased function and survival. ***Polypharmacy is common among community-dwelling elders. The average patient takes > 4 prescribed medications (not including OTC or CAM) which increase the risk for side effects and drug interactions (competition, binding, pH modification). (Lichtman et al. Crit Rev Onc Hem. 46:101-114, 2003). Frailty
Cancer is a VERY acute stressor which tests the limits of a system that may be in full homeostasis (fit) or in compensated (vulnerable or frail) homeostasis. Cancer may alter the natural course of concurrent co-morbid conditions or these conditions may impact the efficacy and tolerability of cancer-related therapies The brief schematic below is one approach to the decision tree in elderly patients with a new (or recurrent) diagnosis of cancer. (Balducci. The Oncologist, 2000) Fit patients are relatively well-defined. Frail patients may or may not “appear” frail. Definitions of vulnerability and frailty in elderly cancer patients are still in the process of being defined and validated. Treatment Outcomes Assessment Outcomes must be maximized while stressors are minimized.
Pain control in older patients is a somewhat controversial topic. There is concern for overmedication leading to delirium and sedation. Many older patients present atypically: confusion, fatigue, depression, social withdrawal. They do not report pain because pain is seen as a sign of weakness, may indicate disease progression and may distract the physician from caring for the disease itself. Elderly fear addiction to narcotics, and its associated stigma. Many older patients do not wish to complain or believe complaints will not be addressed. However, pain must be adequately treated to avoid complications – “Start Low and go slow” using WHO pain pyramid. Caregiver stress should be addressed. (Haley. Supportive Oncology. 1(S2), 2003)
Stress should be minimized by involving a case Stress should be minimized by involving a case manager and clearly stating the treatment plan, increasing access to home services, facilitating transport, increasing communication among care team, patient and family, and decreasing clinic visits. (top of section)
|
Common Tumors in the Older Adult
Older women skew the lifetime risk ratio with 50% new breast cancer cases being diagnosed in women > 65 yrs. Age confers the second highest relative risk (RR= 6.5) for breast cancer; family history confers the highest relative risk. 35% of invasive breast cancers are diagnosed in women > 70 yrs. The presence of hormone receptor positivity is higher among women > 65 yr: 83% < 65 yo, 87% > 65 yo and 91% > 85 yo. There is also a reduction in proliferation markers and Her2/neu expression, thus, confirming a more favorable tumor biology. Although early stage is common, 48% women with metastatic disease will be > 65 yo and very old women (> 85 yr) tend to present with unknown stage or metastatic disease (9%).
Older age may correlate with worse disease-specific survival in both treated and non-treated patients. (A. Krongrad. J Urol. 156:1084, 1996)
Age > 65 years imparts a 15-fold increased incidence of lung cancer & 16.5-fold increased lung cancer-mortality when compared to < 65 years. (LAG Ries. SEER data. http://seer.cancer.gov/csr/1975_2000) Unfortunately, age is the primary determinant for withholding therapy. According to A. Hurria and M. Kris, CA Cancer J Clin, 53:325-41, 2003, patients > 65 years receive less treatment than younger patients (12% vs. 29%). Surgery: There is a 65% decrease in likelihood of undergoing surgery for loco-regional control with each decade of life after 65. Yet, surgery for SI or SII can be curative and studies have shown that older patients can tolerate lobectomy with similar complication and survival rates as younger patients. Surgical risk must be assessed with regard to age-related changes in cardio-pulmonary function and for comorbidities. In patients > 65 years, older age, anemia & disease stage are prognostic for survival peri- & post-surgical resection. Consider VATS if peripheral lesion; this procedure preserves intercostal muscles, reduces pain and decreases LOS in hospital. Radiation: May be curative for early stage disease in non-surgical candidates but survival rates are lower than rates for surgery alone. Radiation is relatively well tolerated, with age being a risk factor for greater weight loss (which in the elderly is predictive of poor outcome). Excellent modality for palliation. Concurrent chemoradiation is relatively well tolerated, but increased risk of acute toxicity vs. sequential therapy. Chemotherapy: Patients > 65 years are less likely to receive chemotherapy for metastatic disease (5%) vs. younger patients (19%). Single agent therapy improves QoL and survival.
(top of section) |
|




