Acute leukemia in elderly patients is a severe, high-risk hematological disease whose incidence is increasing with the age of the population[17]. Survey data in the United States in 2006 (Surveillance, Epidemiology and End Results, SEER) showed that the incidence rate of acute myeloid leukemia (AML) was 16.9/10 million in the population 65 years and over[18]. Survival rates have not improved for older patients with acute leukemia, in part because they may not be offered aggressive therapies and clinical trials, or they may choose to forego chemotherapy or choose to stop therapy before completion[6, 9]. This study shows that older patients (≥ 60) present with more co-morbidities than younger patients, have a poorer remission status and more complications of chemotherapy, and are more likely to stop chemotherapy before completing prescribed cycles due to severity of disease and economic factors. As the age of acute leukemia patients increases, adherence to chemotherapy regiment decreases[13]. Our findings suggest that a careful history and physical examination at presentation, treatment selection based on multiple factors rather than age, aggressive management of complications of therapy and co-morbidities, and sufficient support resources to remain in therapy are needed to improve outcomes in older leukemia patients.
The performance status of a patient may determine the type of induction therapy offered. If a patient is perceived as too frail because of co-morbid conditions or age, supportive care without chance for remission may be the only option, but investigating less toxic regimens or clinical trials may offer acceptable alternatives[4]. The initial symptoms of the two groups included fatigue, pallor, fever, skin and mucous membrane bleeding, lower extremity edema, and dizziness. There were no significant differences between the two groups with the exception of lower extremity edema. In elderly patients, the co-morbidities of hypertension, coronary heart disease, COPD, diabetes, and liver disease may have similar presenting symptoms to that of acute leukemia. A diagnosis of acute leukemia may be missed in clinical practice based on the similarity of presentations without extensive laboratory and other testing. While a literature search revealed no specific studies related to co-morbidities masking the onset of leukemia, one case report described a patient with persistent cervical lymphadenopathy with an initial diagnosis of toxoplasmosis that masked non-Hodgkin's lymphoma[19]. Disease onset is often less evident in elderly patients who describe multiple non-specific symptoms, and patients and families may not pay attention to described symptoms leading to a delay in diagnosis. A delay in seeking treatment may lead to fewer options for the patient.
Complete blood count monitoring in elderly patients is important in clinical practice for early diagnosis and treatment of a variety of diseases, including leukemia. Pancytopenia in peripheral blood was common in elderly patients with newly diagnosed acute leukemia. Varying degrees of anemia occurred in 93.44% of elderly patients and 16.94% of elderly patients experienced severe anemia, which were not significantly different than that of younger patients. In elderly patients, the platelet count was lower than normal, with 21.31% of patients with platelets lower than 10 × 109 /L. The percentage of younger patients whose platelet count was less than 10 × 109 /L was 32.2%, which was significantly different from that of elderly patients. The degree of bone marrow cellularity in elderly patients was significantly reduced compared with that of younger patients (33.3% vs. 49.2%) (Table 2).
This study found that AML accounted for 89.62% of the leukemias in the elderly patient group, with M5 (acute monocytic leukemia) as the most common, accounting for 48.63% of cases. ALL (acute lymphoblastic leukemia) represented the remaining 10.38% in the elderly patient group. In the younger group, the incidence of ALL was higher (36.61%); with AML accounting for 63.4% of cases, of which M5 accounted for 23.50%. Our findings are similar to literature findings that more than half of diagnosed AML patients are over 60 years of age[17].
The complete remission rate was 49.45% for all participants in the elderly patient group after one to two courses of regular chemotherapy which was significantly lower than that of the younger patient group (66.67%)(Table 3). This was consistent with most reports in the literature[9]. Reasons may include that elderly patients have less immunity, may have drug resistance due to physiologic changes associated with aging, often exhibit more underlying diseases and cardio-pulmonary complications, their hematopoietic function recovers slowly, and combination chemotherapy has significant side effects. Some elderly patients only agreed to simple examinations at the hospital, and refused bone marrow biopsy, resulting in delayed treatment. When symptoms progressed to high fever, bleeding, severe anemia, weight loss, and failure to thrive, the optimal timing for treatment was missed. Carefully explaining the reason for diagnostic testing and examinations may mitigate some treatment refusals when the elderly patient presents with symptoms. Physiological age should be considered as well as chronological age in treatment choices[11]. Future studies of newer agents with less severe side effects and studies of clinicopharmacologic implications of drug therapy in older patients are indicated.
The results of this study also showed that the percentage of elderly patients with acute leukemia who discontinued chemotherapy was 50.27%, which was significantly higher than that of the younger group (37.3%). Family members often worry that patients may not tolerate chemotherapy. Traditional Chinese beliefs in families lead to the hope that elderly patients can die at home, leading to a request for discharge from the hospital rather than aggressive treatment in some cases. In a study by Alam et al.[13], it was reported that Canadian patients discontinued chemotherapy prematurely in greater numbers than American patients. Considering our results and that of other studies, the question of whether cultural and national differences influence therapy discontinuation should be investigated.
Financial difficulties were the second most common reason (36.96%) that elderly patients discontinued chemotherapy prematurely, while 66.7% of younger patients discontinued chemotherapy for financial constraints. Treatment of acute leukemia often leads to high medical cost. Currently many families cannot afford high medical expenses as the National Health Care system and the Social Welfare system have not been fully established in China. In one study, patients from lower socio-economic classes had poorer survival perhaps due to class bias, greater co-morbidities, or ability to pay[20]. Psychological distress in cancer patients may impact treatment decisions and additional studies are warranted[21]. Patients and their families may choose to give up treatment if costs cannot be managed. Identifying social support measures may mitigate financial difficulties as a reason for stopping chemotherapy.
Studies in the literature state that proactive identification of patients at high risk of side effects is important and aggressive management is crucial[2]. A discussion of the multiple options for treatment of acute leukemia with the patient and family is also important to select a regimen that delivers the best possible outcome with the least toxic side effects[9]. Of the 50.27% of older newly diagnosed AL patients who discontinued therapy in this study, 11.96% of elderly patients discontinued chemotherapy during the first or second course because they could not tolerate the side effects of chemotherapy. In addition to decreased normal physiological functions, prognosis of acute leukemia in elderly patients is affected by multiple poor prognostic factors. One third of older patients experience combined vital organ diseases including heart, brain, and kidney diseases, and a lower tolerance and slower clearance of cytotoxic drugs; so toxic side effects may be increased accordingly[2]. Patients exhibit different tolerances to chemotherapy based on individual factors, and patients who are sensitive to chemotherapy may still refuse treatment because of the seriousness of side effects induced by chemotherapy.
Univariate analysis in this study also showed that adherence to chemotherapy was poorer in older patients. The percentage of elderly patients who discontinued chemotherapy (50.27%) was significantly higher than in younger patients (37.3%) (Table 3). In some cases, family members could not deal with patients' suffering, and requested discharge from the hospital as soon as the disease condition was improved slightly. Patients either remained at home after discharge or were admitted to their local hospital. Older patients sometimes felt their lives were less valuable. They requested discharge and discontinuation oftreatment because there was no improvement in their illness even when they spent much of their savings.
Limitations of the study include the retrospective nature of medical record reviews, limited demographic information, lack of stratification by treatment regimen in group comparisons, the fact that the two groups were not matched other than by general diagnosis, and there were no defined criteria to measure and compare toxicity. Efforts should be made to determine if cultural factors play a more significant role than evident in our study. Data was not captured that indicated whether the patient or family made the decision to discontinue chemotherapy. Future studies should incorporate a prospective design, define additional data points for study, and consider incorporating additional information requests about non-clinical reasons for treatment decisions.
