Acute Leukemia in the Elderly

Pharmacology of Chemotherapy in the Older Cancer Patient

Background

The incidence of cancer among the elderly population is increasing. The aging process can deplete functional reserve of many organ systems and thus affects the treatment goals for this age-group.

Methods

The pharmacologic consequences of the aging process on elderly cancer patients are reviewed, and guidelines are suggested for assessing and treating this patient population with antitumor drugs.

Results

Individualized management of the older cancer patient reflects the results of a comprehensive geriatric assessment. Factors that affect treatment decisions include estimates of the extent of treatment toxicity, the impact of treatment on quality of life, estimates of life expectancy, and the influence of age on pharmacokinetic parameters.

Conclusions

Management of older patients with cancer includes individual assessments that consider the effects of aging on the pharmacodynamics, therapies, and complications of treatment for this population. Treatment can be made safer and more effective by adjusting chemotherapy dosage, maintaining hemoglobin levels, and using hemopoietic growth factors when appropriate.

[Myelopoiesis and bone marrow function in elderly tumor patients]

According to a model described by Balducci, the human myelopoietic stem cell reserve shows a shift from the reproductive to the proliferative pool corresponding to higher immunological demands resulting from the breakdown of infection defences. Every "hematopoietic stress," i.e., sepsis and/or cytoreductive chemotherapy, leads to a reduction of myelopoietic stem cells in the elderly in contrast to an increase in younger individuals. These changes are relevant starting at the age of 70 years and show a reduced compensation capacity in the aged organism. In addition, the function of the effector cells, i.e., the granulocytes and especially their phagocytic capacity, as well as the balance between stimulating and inhibiting cytokines are compromised. A significant influence on leukopenia and febrile septicemia has been shown for several comorbidities, especially chronic inflammation. The prophylactic use of myelopoietic growth factors is, therefore, recommended for the elderly when there is an expected risk for hematotoxicity grade III or IV. However, prognostic tests to predict the individual risk of hematotoxicity and septicemia are lacking.

A systematic literature review of the clinical and epidemiological burden of acute lymphoblastic leukaemia (ALL)

Our goal was to identify and summarize the published literature pertaining to the incidence, prevalence, mortality, aetiology, clinical diagnosis, and management of acute lymphoblastic leukaemia (ALL). Acute lymphoblastic leukaemia represents 12% of all leukaemia cases, with a worldwide incidence projected to be 1-4.75 per 100,000 people. Italy, the United States (US), Switzerland, and Costa Rica are the countries with the highest incidence of ALL. Hereditary link, genetic defects, and possibly radiation or chemical exposures are listed amongst the most significant risk factors. Acute lymphoblastic leukaemia is predominantly a disease of childhood, but it affects adults as well. It accounts for 80% of all leukaemia cases in children. The incidence is slightly higher in men than in women and greater in white people than in black people. In 2003 in the US, there were an estimated 5800 deaths from ALL. Presenting signs and symptoms of ALL are fairly non-specific and include fever, anaemia, petechiae, and bone and joint pain. Staging of the disease and patient risk profile are routinely performed to define ALL subtypes and guide management. Chemotherapy, cranial radiation in patients with high-risk disease, and stem cell transplantation for selected patients are the prevalent therapies. Complete remission rates are high, especially amongst children (even 100%); however, long-term survival at 10 years (event-free survival) is in the range of 63% for children and 25-35% for adults. This implies that there is still a strong need for new therapies to maintain remission and prolong survival. Future treatment strategies may be driven by the patient's minimal residual disease status, a measure that more precisely defines remission, prognosis, responsiveness to therapy, and expected long-term survival.

Aging and the hemopoietic system

While increasing numbers of elderly patients are expected to require chemotherapy and/or radiotherapy in the future, the application of standard-dose chemotherapy in unselected cohorts of older patients usually results in a higher rate of life-threatening myelosuppression and treatment-related deaths compared to young individuals treated with the same chemotherapy regimens. The biologic mechanisms underlying reduced tolerance to chemotherapy of the hemopoietic system in older individuals are still poorly understood. Unveiling such mechanisms therefore represents a fundamental issue to ameliorate chemotherapy strategies for older cancer patients. Current evidence suggests that aging-related bone marrow changes are rather subtle and most probably irrelevant for the hemopoietic function of normal older individuals. These changes, however, may become clinically evident under conditions of severe hemopoietic stress such as the administration of repeated courses of chemo-radiotherapy. The mechanisms underlying age-dependent decline in the hematopoietic reserve are not fully clarified and probably involve age-associated changes in the stem and progenitor cells compartments which may ultimately lead to a reduced ability of recovery from hematologic stress. Age-related changes in endogenous anti-tumor immune responses also need to be accounted for in the aim of managing residual disease in elderly cancer patients treated with effective chemo-radiotherapy. Since dendritic cells (DCs) generated from older individuals appear fully functional, dendritic cell-based immunotherapy may represent an important tool to treat residual disease in aged cancer patients. While it is clearly established that primary prophylaxis with hemopoietic growth factors currently enables a large fraction of older cancer patients to receive appropriate chemotherapy, innovative strategies in the use of such growth factors may allow time-intensification of standard-dose chemotherapy for treating chemosensitive tumors, i.e. non-Hodgkin's lymphomas (NHLs), occurring in older individuals.

A pooled analysis of adjuvant chemotherapy for resected colon cancer in elderly patients

BACKGROUND

Adjuvant chemotherapy is standard treatment for patients with resected colon cancer who are at high risk for recurrence, but the efficacy and toxicity of such treatment in patients more than 70 years of age are controversial.

METHODS

We performed a pooled analysis, based on the intention to treat, of individual patient data from seven phase 3 randomized trials (involving 3351 patients) in which the effects of postoperative fluorouracil plus leucovorin (five trials) or fluorouracil plus levamisole (two trials) were compared with the effects of surgery alone in patients with stage II or III colon cancer. The patients were grouped into four age categories of equal size, and analyses were repeated with 10-year age ranges (< or =50, 51 to 60, 61 to 70, and >70 years), with the same conclusions. The toxic effects measured in all trials were nausea or vomiting, diarrhea, stomatitis, and leukopenia. Patients in the fluorouracil-plus-leucovorin and fluorouracil-plus-levamisole groups were combined for the efficacy analysis but kept separate for toxicity analyses.

RESULTS

Adjuvant treatment had a significant positive effect on both overall survival and time to tumor recurrence (P<0.001 for each, with hazard ratios of death and recurrence of 0.76 [95 percent confidence interval, 0.68 to 0.85] and 0.68 [95 percent confidence interval, 0.60 to 0.76], respectively). The five-year overall survival was 71 percent for those who received adjuvant therapy, as compared with 64 percent for those untreated. No significant interaction was observed between age and the efficacy of treatment. The incidence of toxic effects was not increased among the elderly (age >70 years), except for leukopenia in one study.

CONCLUSIONS

Selected elderly patients with colon cancer can receive the same benefit from fluorouracil-based adjuvant therapy as their younger counterparts, without a significant increase in toxic effects.

Antineoplastic chemotherapy of the older cancer patient

Cancer chemotherapy may be effective and safe in older patients if some proper provisions are made. Doses of chemotherapy should be adjusted to the patient's glomerular filtration rate, and his or her hemoglobin should be maintained for the duration of the therapy. For patients who are 70 years of age or older and who are receiving moderately toxic chemotherapy, growth factors should be used. The risk of mucositis increases with the age of the patient, so it is important to treat it aggressively at the first signs of the complication.

Cancer and aging. An evolving panorama

This article illustrates how the nosology of cancer evolves with the patient's age. If the current trends are maintained, 70% of all neoplasms will occur in persons aged 65 years and over by the year 2020, leading to increased cancer-related morbidity among older persons. Cancer control in the older person involves chemoprevention, early diagnosis, and timely and effective treatment that entails both antineoplastic therapy and symptom management. These interventions must be individualized based on a multidimensional assessment that can predict life expectancy and treatment complications and that may evaluate the quality of life of the older person. This article suggests a number of interventions that may improve cancer control in the aged. Public education is needed to illustrate the benefits of health maintenance and early detection of cancer even among older individuals, to create realistic expectations, and to heighten awareness of early symptoms and signs of cancer. Professional education is needed to train students and practitioners in the evaluation and management of the older person. Of special interest is the current initiative of the Hartford Foundation offering combined fellowships in oncology and geriatrics and incorporating principles of geriatric medicine in medical specialty training. Prudent pharmacologic principles must be followed in managing older persons with cytotoxic chemotherapy. These principles include adjusting the dose according to the patient's renal function, using epoietin to maintain hemoglobin levels of 12 g/dL or more, and using hemopoietic growth factors in persons aged 70 years and older receiving cytotoxic chemotherapy of moderate toxicity (e.g., CHOP). To assure uniformity of data, a cooperative oncology group should formulate a geriatric package outlining a common plan for evaluating function and comorbidity. This article also suggests several important areas of research items: Molecular interactions of age and cancer Host-tumor interactions in the older tumor host Chemoprevention of cancer and aging Laboratory evaluation of aging Development of shorter forms of geriatric assessment Management of the frail cancer patients Clinical trials of tumor-specific issues.