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Anemia in Stage II and III Breast Cancer Patients Treated With Adjuvant Doxorubicin and Cyclophosphamide Chemotherapya Hematology-Oncology Associates of Central New York, East Syracuse, New York, USA; b Clinical Operations and Medical Affairs, Abt Associates Clinical Trials, Cambridge, Massachusetts, USA; c AMF Consulting, Inc., Los Angeles, California, USA; d Medical Affairs, Pharmacoeconomics, Amgen, Inc. Thousand Oaks, California, USA Correspondence: Jeffrey Kirshner, M.D., Hematology-Oncology Associates of Central New York, P.C., 5008 Brittonfield Parkway, East Syracuse, New York 13057, USA. Telephone: 315-472-7504; Fax: 315-479-9639; e-mail: Jkirshner{at}Hoacny.com
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Purpose. The incidence and severity of prechemotherapy anemia and chemotherapy-induced anemia experienced by women treated with adjuvant doxorubicin and cyclophosphamide (AC) therapy for stage II and III breast cancer are described.
Patients and Methods. Medical charts of 310 breast cancer patients who received chemotherapy at eight oncology practices during 1997 through 2001 were reviewed in this historical case series study. Prechemotherapy anemia was defined as a baseline hemoglobin value <12 g/dl. An anemic event during chemotherapy (used to define chemotherapy-induced anemia) was defined as either a drop in hemoglobin level below the threshold (
Results. Overall, 40.0% of patients experienced moderate to severe anemia (i.e., their hemoglobin levels dropped to <10 g/dl) and 31.3% (97/310) were anemic prechemotherapy. Of the patients with mild anemia prechemotherapy, 61.9% developed moderate to severe anemia during chemotherapy. Only 47.4% (46/97) of those patients received epoetin alfa therapy during chemotherapy. Of the patients with normal prechemotherapy hemoglobin levels ( Conclusions. We conclude that a significant proportion (31.3%) of stage II and III breast cancer patients are anemic prechemotherapy and that the incidence of anemia increases substantially from prechemotherapy through the postchemotherapy period. This evidence appears to warrant earlier evaluation of anemia and an intervention in the prechemotherapy stage. Key Words. Anemia • Breast cancer • Chemotherapy • Erythropoietin
Approximately 50% of cancer patients develop anemia, generally defined as a hemoglobin level <12 g/dl [1]. The severity of anemia depends on many factors including the nutritional status of the patient, the type of cancer, the stage and extent of tumor burden (especially bone marrow involvement), the intensity of myelosuppressive treatment, and bleeding. Cancer-related anemia can be associated with debilitating symptoms and can have a profound effect on health-related quality of life (HRQOL) [25]. Recently published American Society of Clinical Oncology/American Society of Hematology guidelines on the use of epoetin alfa (recombinant human erythropoietin [rHuEpo]) in patients with chemotherapy-associated anemia [6] recommend treatment at a hemoglobin (Hb) level <10 g/dl. For patients with less severe anemia (Hb <12 g/dl but not <10 g/dl), treatment should be determined by an evaluation of the clinical manifestations of anemia. Other proposed evidence-based guidelines (per the United States Cancer Pain Relief Committee 2001) recommend that rHuEpo therapy be initiated in patients for whom symptoms of anemia may impair functional capacity or HRQOL. Additionally, rHuEpo therapy is recommended both for anemia determined to be severe enough to require a blood transfusion and/or if a blood transfusion is not an acceptable option [7]. The incidence and severity of anemia appear to vary with the type of cancer, the extent of the disease, and the myelosuppressive characteristics of the chemotherapy regimen. For example, the incidence of anemia associated with various treatment regimens for metastatic breast cancer ranges from 6% to as high as 98% for grades 1 and 2 anemia and from <1% to 80% for grades 3 and 4 anemia [8]. Little information is available about anemia rates associated with many commonly used adjuvant chemotherapy regimens in early-stage breast cancer (ESBC). A recent retrospective chart analysis evaluated ESBC patients treated with doxorubicin/cyclophosphamide (AC) chemotherapy in community practice and found that 17% of the patients developed anemia [9]. The purpose of this study was to evaluate the incidence and severity of anemia experienced by women with ESBC treated with adjuvant chemotherapy and describe the anemia treatment delivered in eight oncology practices across the U.S. Further, we explored the clinical characteristics of women who are likely to develop anemia and who may require treatment during the course of chemotherapy, as identified in a previous study [9, 10].
Data Collection Data on stage II and III breast cancer patients who received adjuvant chemotherapy were collected from patient medical records. This study focused on data from 310 patients who received adjuvant AC (doxorubicin 60 mg/m2 and cyclophosphamide 600 mg/m2 every 3 weeks) chemotherapy (currently, the most prescribed regimen for ESBC) and who had prechemotherapy measures of Hb or hematocrit. At all eight participating community-based oncology practices, data collection started from 2001 and proceeded backward in time (to 1997). Patients were eligible for inclusion in the study if they received adjuvant chemotherapy for stage II or III breast cancer and were at least 18 years of age. Patients who were on a clinical research protocol (within the previous 30 days) were excluded to limit the applicability of the results to community practice patients on standard treatment. Likewise, patients who had other primary invasive cancers, had received a previous course of chemotherapy, or were HIV positive were excluded. Data from the patients medical charts were abstracted under the supervision of the principal investigator at each site using a standardized electronic clinical report form. The following information was collected: A) patient characteristics, including age, ethnicity, comorbidities, height, weight for each cycle, body surface area (BSA), tumor stage (defined according to the tumor/node/metastasis staging criteria), and number of positive nodes; B) the planned and delivered chemotherapy regimen, including the drugs, doses, route of administration, and number and length of cycles; C) all CBCs; D) epoetin alfa and growth factor use during the course of therapy; E) prior and concurrent radiotherapy, and F) medical record notation regarding chemotherapy dose modifications, mucositis, febrile neutropenia, and early termination of chemotherapy.
Variable Definitions Patient Characteristics
Anemia Measures
Iron Parameters and Iron Therapy
Statistical Methods
Patient Characteristics The characteristics of the 310 patients included in this analysis are summarized in Table 1
Patients who were anemic prechemotherapy tended to be younger and, consequently, were more likely to be premenopausal and have fewer comorbid conditions. The event and no event groups differed significantly (i.e., p < 0.05) only in their mean prechemotherapy Hb levels, and differences between these groups approached significance with respect to age and the administration of radiotherapy. The mean prechemotherapy Hb level (not shown in table) for the no event patients was 13.4 g/dl (95% confidence interval [CI], 13.113.5), compared with 12.9 g/dl (95% CI, 12.813.1) for the event patients (p = 0.0002). Twenty-seven percent of the event group were 65 years or older, compared with 17.7% of the no event group (p = 0.051). A total of 36% of patients in the event group had a course of radiotherapy either prior to or during chemotherapy, compared with 25.7% of the no event group (p = 0.08).
Prechemotherapy Anemia and Chemotherapy-Induced Anemia
For the combination of low Hb, transfusions, or rHuEpo therapy, 41.8% (89/213) experienced an anemic event. These mutually inclusive events consisted of 5.6% (5/89) of patients given blood transfusions, 55.1% (49/89) of patients given rHuEpo therapy, and 66.3% (59/89) of patients whose Hb levels dropped to <10 g/dl.
Anemia Treatment Patterns
Of the prechemotherapy nonanemic patients, 23.0% (49/213) were treated with rHuEpo during chemotherapy. Interestingly, 45.8% (27/59) (Table 2 Blood transfusions were required for 6.2% (6/97) of the prechemotherapy anemic patients, with a median hemoglobin concentration of 7.8 g/dl (range, 6.311.0 g/dl) at the time of first transfusion. In comparison, 4.1% (5/213) of prechemotherapy nonanemic patients required blood transfusions, with a median hemoglobin concentration of 8.6 g/dl (range, 6.710.3 g/dl) at the time of first transfusion. Supplemental iron therapy during chemotherapy, suggesting iron deficiency, was given to 12.4% (12/97) of prechemotherapy anemic patients, compared with 4.7% (10/213) of the patients who were not anemic prechemotherapy (p = 0.001). The majority (15/22) of patients who received iron therapy also received rHuEpo. All but one patient received oral iron supplements (data not shown). Overall, only 54.8% (68/124) of patients whose HB levels dropped to <10 g/dl at their lowest anemia grade during chemotherapy were treated with either rHuEpo therapy or blood transfusions and, similarly, only 20.5% (33/161) of those whose levels dropped to 1011.9 g/dl received such treatment (data not shown).
Anemia During Four AC Cycles and Follow-up
As expected due to the myelotoxicity of the chemotherapy, Hb values dropped for all groups as cycles progressed and recovered after chemotherapy completion. The slope of the Hb decrease over time is steeper for the normal than for the anemic prechemotherapy patients. The mean rate of Hb decrease across the four chemotherapy cycles for the prechemotherapy normal patients was 0.58 g/dl per cycle, compared with 0.22 g/dl per cycle for the prechemotherapy anemic patients, with the sharpest decreases observed in the first cycle. Patients who were anemic prechemotherapy recovered to mean Hb levels higher than their prechemotherapy levels by about 1 g/dl, while the nonanemic patients recovered to mean values lower than their prechemotherapy levels.
Multiple Logistic Regression Model
A significant proportion (31%) of stage II and III breast cancer patients may be anemic at the time chemotherapy is initiated, as demonstrated by the prevalence of prechemotherapy anemia in this study sample. Possible reasons include blood loss from surgery, iron deficiency, and possibly anemia of chronic disease as a result of their cancer. It was somewhat surprising that only 10% of anemic patients had iron studies recorded. Oncologists may need to be reminded to check for this very treatable cause of anemia and to prescribe iron supplementation to those women who are found to be deficient, even before commencing chemotherapy. Of the prechemotherapy anemic patients, about 50% did not receive treatment for their anemia during chemotherapy. Of the patients with Hb levels 12 g/dl at the start of chemotherapy, about 28% experienced chemotherapy-induced anemia (Hb < 10 g/dl); of these, 42% did not receive rHuEpo or blood transfusion treatment during chemotherapy. Irrespective of anemia grade prechemotherapy, and considering the lowest anemia grade experienced during chemotherapy, the results show higher proportions of rHuEpo therapy and blood transfusions for patients whose Hb level dropped to <10 g/dl than for those whose Hb levels dropped to 1011.9 g/dl, as expected. Again, our results show that a large proportion of anemic patients (45% and 79%, respectively) did not receive anemia treatment. Supplemental iron therapy, suggesting iron deficiency, was given to 12% of prechemotherapy anemic patients and 5% of the patients who were not anemic prechemotherapy, mostly to patients receiving rHuEpo.
The incidence of anemia may also increase substantially from prechemotherapy to postchemotherapy. Despite treatment with blood transfusions and/or rHuEpo therapy, anemia was frequent during chemotherapy. Of the 213 patients with normal prechemotherapy Hb levels (
In our retrospective study, two risk factors (age Our results indicate that patients with prechemotherapy anemia recovered during the follow-up time to Hb levels even higher than their prechemotherapy levels. This is in contrast to the patients who started with normal Hb levels, for whom the recovery was not complete. It is possible that, for those patients, the recovery is slower. It is also possible that, once patients with prechemotherapy anemia were treated with surgery and chemotherapy, the removal of the tumor helped to expedite the recovery of the Hb to normal levels during the follow-up period. Anemia is a debilitating condition that has a significant impact on patients and their caregivers. It seems to be prevalent in cancer patients even prior to initiating chemotherapy, and preexisting anemia is exacerbated by chemotherapy treatment [10].
We conclude that a significant proportion (31.3%) of stage II and III breast cancer patients are anemic prechemotherapy and that the incidence of anemia increases substantially from prechemotherapy through the postchemotherapy period. This evidence appears to warrant earlier evaluation of anemia and an intervention in the prechemotherapy stage. It also warrants increased vigilance and more frequent monitoring in treating elderly and patients with prechemotherapy Hb levels at the lower end of normal (i.e., close to the 12-g/dl threshold).
The authors wish to thank Greg Rossi, Ph.D., for his insightful suggestions to the development of this manuscript. This study was supported in part by research funding from Amgen Inc., Thousand Oaks, California. Data in this study were published, in part, as an abstract (#5580) at the American Society of Hematology 44th Annual Meeting and Exposition, San Francisco, CA, December 2002.
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