Obesity is not associated with increased myelosuppression in patients receiving chemotherapy for breast cancer

Adjuvant Dose Dense Chemotherapy in patients with obesity: short-term toxicities and breast cancer outcome

BACKGROUND

Dose dense adjuvant chemotherapy is associated with improved outcomes in breast cancer compared to standard dosing. Despite current guidelines recommending that chemotherapy is dosed according to actual body weight, reviews have shown patients with obesity often receive a capped chemotherapy dose. The latter is commonly undertaken as clinicians have concerns that adverse events are more frequent if full doses are administered. This study assessed surgical, radiotherapy and chemotherapy related adverse events between patients with and without obesity receiving dose dense adjuvant chemotherapy for breast cancer.

MATERIALS AND METHODS

A retrospective review of prospective collected data for patients receiving adjuvant chemotherapy from 30 April 2018 from a single institution was analyzed. Data collected included demographic data, height, weight, pathological information, comorbidities, surgical, radiotherapy chemotherapy treatment, and toxicity. Primary outcomes were surgical complications at 30 days, radiotherapy skin toxicity at 30 days and chemotherapy side-effects. Secondary outcomes were rates of recurrence and time to recurrence.

RESULTS

A total of 280 patients were included in the analysis: 55 obese and 225 nonobese. Obese status was associated with higher rates of grade >2 skin toxicity and this difference was significant after adjusting for age, comorbidity and radiotherapy field (P = .017). Obese status was not associated with higher rates of surgical or chemotherapy related adverse events. All patients regardless of obese status received adequate dose intensity with similar rates of recurrence and time to recurrence.

CONCLUSION

Patients with obesity who receive dose dense adjuvant chemotherapy do not experience higher rates of surgical or chemotherapy related adverse events although they do experience higher rates of grade >2 radiotherapy related skin toxicity. This supports the use of dose dense chemotherapy being based on actual body weight in patients with obesity.

The ambiguous role of obesity in oncology by promoting cancer but boosting antitumor immunotherapy

Obesity is nowadays considered a pandemic which prevalence's has been steadily increasingly in western countries. It is a dynamic, complex, and multifactorial disease which propitiates the development of several metabolic and cardiovascular diseases, as well as cancer. Excessive adipose tissue has been causally related to cancer progression and is a preventable risk factor for overall and cancer-specific survival, associated with poor prognosis in cancer patients. The onset of obesity features a state of chronic low-grade inflammation and secretion of a diversity of adipocyte-derived molecules (adipokines, cytokines, hormones), responsible for altering the metabolic, inflammatory, and immune landscape. The crosstalk between adipocytes and tumor cells fuels the tumor microenvironment with pro-inflammatory factors, promoting tissue injury, mutagenesis, invasion, and metastasis. Although classically established as a risk factor for cancer and treatment toxicity, recent evidence suggests mild obesity is related to better outcomes, with obese cancer patients showing better responses to treatment when compared to lean cancer patients. This phenomenon is termed obesity paradox and has been reported in different types and stages of cancer. The mechanisms underlying this paradoxical relationship between obesity and cancer are still not fully described but point to systemic alterations in metabolic fitness and modulation of the tumor microenvironment by obesity-associated molecules. Obesity impacts the response to cancer treatments, such as chemotherapy and immunotherapy, and has been reported as having a positive association with immune checkpoint therapy. In this review, we discuss obesity's association to inflammation and cancer, also highlighting potential physiological and biological mechanisms underlying this association, hoping to clarify the existence and impact of obesity paradox in cancer development and treatment.

Antineoplastic dosing in overweight and obese cancer patients: an Associazione Italiana Oncologia Medica (AIOM)/Associazione Medici Diabetologi (AMD)/Società Italiana Endocrinologia (SIE)/Società Italiana Farmacologia (SIF) multidisciplinary consensus position paper

Most anticancer molecules are administered in body-size-based dosing schedules, bringing up unsolved issues regarding pharmacokinetic data in heavy patients. The worldwide spread of obesity has not been matched by improved methods and strategies for tailored drug dosage in this population. The weight or body surface area (BSA)-based approaches may fail to fully reflect the complexity of the anthropometric features besides obesity in cancer patients suffering from sarcopenia. Likewise, there is a lack of pharmacokinetic data on obese patients for the majority of chemotherapeutic agents as well as for new target drugs and immunotherapy. Therefore, although the available findings point to the role of dose intensity in cancer treatment, and support full weight-based dosing, empirical dose capping often occurs in clinical practice in order to avoid toxicity. Thus a panel of experts of the Associazione Italiana Oncologia Medica (AIOM), Associazione Medici Diabetologi (AMD), Società Italiana Endocrinologia (SIE), and Società Italiana Farmacologia (SIF), provides here a consensus statement for appropriate cytotoxic chemotherapy and new biological cancer drug dosing in obese patients.

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The worldwide spread of obesity is an emerging challenge also in cancer patients

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Weight or BSA-based approaches do not adequately address the critical issue of optimal dosing for cancer drugs under obesity

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Empirical dose capping is often employed in clinical practice to avoid toxicities among overweight and obese patients

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There is a lack of clinical and pharmacokinetic studies in this population

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Clinical practice recommendations should guide suitable dosing of cytotoxic and biological cancer drugs in obese patients

Obesity and Cancer Treatment Outcomes: Interpreting the Complex Evidence

A wealth of epidemiological evidence, combined with plausible biological mechanisms, present a convincing argument for a causal relationship between excess adiposity, commonly approximated as body mass index (BMI, kg/m²), and incident cancer risk. Beyond this relationship, there are a number of challenges posed in the context of interpreting whether being overweight (BMI 25.0-29.9 kg/m²) or obese (BMI ≥ 30.0 kg/m²) adversely influences disease progression, cancer mortality and survival. Elevated BMI (≥ 25.0 kg/m²) may influence treatment selection of, for example, the approach to surgery; the choice of chemotherapy dosing; the inclusion of patients into randomised clinical trials. Furthermore, the technical challenges posed by an elevated BMI may adversely affect surgical outcomes, for example, morbidity (increasing the risk of surgical site infections), reduced lymph node harvest (and subsequent risk of under-staging and under-treatment) and increased risk of margin positivity. Suboptimal chemotherapy dosing, associated with capping chemotherapy in obese patients as an attempt to avoid excess toxicity, might be a driver of poor prognostic outcomes. By contrast, the efficacy of immune checkpoint inhibition may be enhanced in patients who are obese, although in turn, this observation might be due to reverse causality. So, a central research question is whether being overweight or obese adversely affects outcomes either directly through effects of cancer biology or whether adverse outcomes are mediated through indirect pathways. A further dimension to this complex relationship is the obesity paradox, a phenomenon where being overweight or obese is associated with improved survival where the reverse is expected. In this overview, we describe a framework for evaluating methodological problems such as selection bias, confounding and reverse causality, which may contribute to spurious interpretations. Future studies will need to focus on prospective studies with well-considered methodology in order to improve the interpretation of causality.

Obesity and chemotherapy administration: between empiric and mathematic method review

Introduction: Obesity is a major risk factor for chronic disease and cancer development. Therapeutic management of obese patients with cancer is a real challenge for physician because of the alteration of antineoplastic pharmacokinetics parameters in this population. In routine clinical practices, chemotherapy doses in obese patients are arbitrarily capped or adjusted to an ideal weight to minimize excessive toxicities. Material and methods: The main goal of this review is to describe the current state of knowledge concerning the correlation between the adjustment of BSA (capping or ideal weight) and the rates of global toxicities and survival outcomes in obese patients under chemotherapy in different types of cancer. We searched in the Medline database (via PubMed) in order to identify all publications of literature reviews whose subject chemotherapy dosing in obese population. Results: Only a single study was pointing toward increased of global toxicities of full weight dosing. Furthermore, some studies suggests that the practice of limiting doses in overweight and obese patients may negatively influence the quality of care and outcomes in a constantly increasing population. Conclusion: This review highlights the lack of prospective studies focusing on chemotherapy methods of administration in obese patients. At this time, there is no prospective study comparing capping and full weight dose chemotherapy administration in obese patient population.

The association between BMI and BSA-temozolomide-induced myelosuppression toxicities: a correlative analysis of NRG oncology RTOG 0525

Background

Fearing increased myelotoxicity, many practitioners adjust the body surface area (BSA)-calculated doses in obese patients. Regarding temozolomide (TMZ), a prior study suggested men with a BSA >2 m² may experience increased toxicity; however, surprisingly, the inverse observation was noted in women, ie, BSA <2 m² was associated with higher toxicity. To further clarify this issue, data derived from a large clinical trial were analyzed.

Methods

The incidence of grade 3 and 4 myelotoxicity in a newly diagnosed glioblastoma phase 3 trial (RTOG 0525) was statistically correlated with BMI and separately with BSA. All patients received radiation and TMZ followed by adjuvant standard dose TMZ vs dose-dense TMZ; dosing regimen-associated myelotoxicity and BMI/BSA were analyzed separately. Obesity was defined as a BMI ≥30.

Results

There was no statistically significant correlation between gender and BSA and the occurrence of myotoxicities. For the standard arm, surprisingly the incidence of grade 3/4 myotoxicities in patients with a BMI <30 was significantly higher than in patients with a BMI ≥30 (12% vs 1%, odds ratio [OR] 12.5, P < .001). There was no significant difference between obese and nonobese patients (BMI "cut-point" of 30) in the dose-dense arm (OR = 0.9, 95% confidence interval: 0.4-1.6). The grade hematological 3/4 toxicity rate was significantly higher in women vs men (14% vs 8%) P = .009 in spite of the lack of association between gender and BSA or BMI.

Conclusion

TMZ dosing based on actual BSA is recommended with the caveat that woman are likely at higher toxicity risk.

The impact of actual body weight-based chemotherapy dosing and body size on adverse events and outcome in older patients with breast cancer: Results from Cancer and Leukemia Group B (CALGB) trial 49907 (Alliance A151436)

OBJECTIVE

Actual weight-based (AWB) chemotherapy dosing is recommended for obese patients in the 2012 ASCO Clinical Practice Guideline. CALGB 49907, which utilized ABW-based adjuvant chemotherapy dosing, was a phase 3 trial in women age≥65years with early stage breast cancer, providing the opportunity to examine impact of such dosing on toxicities and outcome in older patients with breast cancer.

MATERIALS AND METHODS

Adverse event data were available for 615 of 633 enrolled patients. Objectives were to assess grade≥3 hematologic/non-hematologic toxicities by treatment arm, age, study entry BSA/BMI, and relapse-free (RFS) and overall survival (OS) by BSA/BMI.

RESULTS

The 615 patients were sub-grouped by BSA (quartiles) and standard BMI categories, with BMI underweight/normal weight categories combined. Overall, grade≥3 non-hematologic and hematologic toxicities occurred in 39.8% and 28.3% of patients, respectively. There were no significant differences in grade≥3 toxicities among BSA quartiles. However, more grade≥3 hematologic toxicities occurred in the underweight/normal weight BMI subgroup compared to overweight/obese subgroups (p=0.048). Type of chemotherapy and age had no impact on toxicity occurrence by BSA/BMI categories. RFS was superior in the 25th-50th BSA percentile patients in univariate analysis (p=0.042), as was OS in both univariate and multivariate analyses (p=0.007, p=0.009, respectively). No differences in RFS or OS were found by BMI categories.

CONCLUSION

Obesity was not correlated with adverse relapse or survival outcome, and grade≥3 toxicities were not greater with ABW-based dosing. This supports safety and efficacy of ABW-based dosing as per the 2012 ASCO clinical practice guideline. ClinicalTrials.gov Identifier: NCT00024102 (49907).

Chemotherapy dosing in overweight and obese patients with cancer

Retrospective and prospective preclinical and clinical data have demonstrated an association between chemotherapy dose intensity and both clinical efficacy and toxicity. The optimum tolerable and effective dose and schedule of chemotherapeutic agents is based on data from dose-finding studies and early clinical trials. There is considerable evidence that reductions in the recommended dose intensity often occurs in actual clinical practice, particularly among overweight and obese patients with cancer. With increasing rates of obesity, and variation and uncertainty about appropriate dosing of chemotherapy in obese patients, ASCO has generated clinical practice guidelines for appropriate chemotherapy dosing for obese adult patients with cancer. Without evidence of any increase in treatment-related toxicity among obese patients receiving chemotherapy, the guidelines recommend that, after considering any accompanying comorbidities, chemotherapy dosing should be calculated based on body surface area using actual weight, rather than an estimate or idealization of weight. While further research is needed, pharmacokinetic studies support the use of actual body weight to calculate chemotherapy doses for most chemotherapy drugs in obese patients. We highlight the issue of chemotherapy dosing in this population, how a more personalized approach can be achieved, as well as discussing areas for further research.

Effect of obesity on toxicity in women treated with adjuvant chemotherapy for early-stage breast cancer: a systematic review

The purpose of this study is to provide more definite evidence regarding the role of dose modification of chemotherapy in obese women with breast cancer by systematically reviewing current literature regarding chemotherapy-induced toxicity rates in obese and non-obese women with early-stage breast cancer. A systematic search of Pubmed and EMBASE was conducted to identify original studies investigating chemotherapy-induced toxicity in obese women receiving adjuvant chemotherapy treatment for breast cancer. Ten studies were identified. We noted low rates of adjustment for confounders such as prophylactic hematopoietic growth factor use and empirical dose reductions. Seven studies found reduced toxicity in obese compared to non-obese women. Of four studies, where dose capping was precluded or statistically adjusted for, three found reduced toxicity in obese women. These outcomes include less febrile neutropenia (body mass index (BMI) >23.6; odds ratio (OR) 4.4; 95 % confidence interval (CI) 1.65-12.01), fewer hospital admissions (BMI >35; OR 0.61, 95 % CI 0.38-0.97), and fewer neutropenic events (BMI >25; OR 0.49; 95 % CI 0.37-0.66). Only a single study reported higher rates of toxicity in obese women, but this study had significant methodological issues. As a conclusion, we observed that obese patients tolerate chemotherapy better than lean patients. However, this may be confounded by poorly specified dose capping practices and the use of hematopoietic growth factors. Further research should focus on improved documentation of body size, of dose, and of use of growth factors, and analysis of how these affect recurrence rates, toxicity, and survival.

Appropriate chemotherapy dosing for obese adult patients with cancer: American Society of Clinical Oncology clinical practice guideline

PURPOSE

To provide recommendations for appropriate cytotoxic chemotherapy dosing for obese adult patients with cancer.

METHODS

The American Society of Clinical Oncology convened a Panel of experts in medical and gynecologic oncology, clinical pharmacology, pharmacokinetics and pharmacogenetics, and biostatistics and a patient representative. MEDLINE searches identified studies published in English between 1996 and 2010, and a systematic review of the literature was conducted. A majority of studies involved breast, ovarian, colon, and lung cancers. This guideline does not address dosing for novel targeted agents.

RESULTS

Practice pattern studies demonstrate that up to 40% of obese patients receive limited chemotherapy doses that are not based on actual body weight. Concerns about toxicity or overdosing in obese patients with cancer, based on the use of actual body weight, are unfounded.

RECOMMENDATIONS

The Panel recommends that full weight-based cytotoxic chemotherapy doses be used to treat obese patients with cancer, particularly when the goal of treatment is cure. There is no evidence that short- or long-term toxicity is increased among obese patients receiving full weight-based doses. Most data indicate that myelosuppression is the same or less pronounced among the obese than the non-obese who are administered full weight-based doses. Clinicians should respond to all treatment-related toxicities in obese patients in the same ways they do for non-obese patients. The use of fixed-dose chemotherapy is rarely justified, but the Panel does recommend fixed dosing for a few select agents. The Panel recommends further research into the role of pharmacokinetics and pharmacogenetics to guide appropriate dosing of obese patients with cancer.

The two major epidemics of the twenty-first century: obesity and cancer

It is a well-known fact that severe obesity is associated with the metabolic syndrome, type 2 diabetes, cardiovascular disease, hypertension, and other diseases. Epidemiological studies have suggested that obesity is also associated with increased risk of several cancer types. The number of people who are suffering from severe obesity is growing, and clinical data suggest that severely obese patients belong to a unique population with regards to risk, efficacy of screening, and cancer treatment. This review will point out the potential mechanism linking obesity and cancer and will discuss several challenges in various treatment modalities of cancer in obese patients.

Description of current practices of empiric chemotherapy dose adjustment in obese adult patients

PURPOSE

The literature is not clear on the best method to empirically dose chemotherapy in obese adult patients. The purpose of our study was to determine whether a standard of practice existed, characterize current practices of empiric dose adjustment (EDA) in obese adult patients, and identify factors affecting this decision.

METHODS

An electronic survey was distributed to oncologists and board-certified oncology pharmacists via the Association of Community Cancer Centers and Board of Pharmaceutical Specialties e-mail distribution lists. The survey contained patient scenarios assessing the impact of various factors on EDA of chemotherapy, demographic information, and details of institutional policies.

RESULTS

Responses were collected from 174 professionals. Pharmacists comprised 95% of respondents. Of these, 50% practiced in academic medical centers, and 19% practiced in institutions with a standard of practice regarding EDA for obesity. The most common methods of EDA were use of an adjusted body weight in the body-surface area (BSA) equation and capping BSA. Factors with the most impact on EDA were curative intent, degree of obesity, type of chemotherapy, and performance status.

CONCLUSION

There is no standard of practice regarding EDA of chemotherapy in obese adult patients. Although many factors affect this decision, intent of treatment, degree of obesity, performance status, age, and type of medication seem to carry the most weight.

Obesity is an independent predictor of poor survival in metastatic breast cancer: retrospective analysis of a patient cohort whose treatment included high-dose chemotherapy and autologous stem cell support

The purpose of the study was to identify predictors of long-term survival in metastatic breast cancer (MBC). A cohort of 96 patients, who received high-dose chemotherapy with autologous stem cell support (HD-ASCT) as part of their treatment, was analyzed. Percent long-term survival at 10 years was 24.5% (CI 17.2-34.9%) when metastasis was diagnosed and 14.4% (CI 8.7-23.9%) when MBC was diagnosed. Survival was impacted significantly by body mass index (BMI). Median overall survival from initial diagnosis or from time of metastasis for patients with BMIs ≤30 and >30 (obese) was 7.1 (CI 4.4-8.7) and 3.2 years (2.41-6.75), respectively, or 3.2 or 2.3 years (all P = 0.02). Also, obesity was the only independent patient-related predictor of time to metastasis and of survival. While obesity is linked with poor outcomes in earlier stages of breast cancer, this has not been previously reported for MBC.

Risk analysis of severe myelotoxicity with temozolomide: the effects of clinical and genetic factors

A benefit of temozolomide (TMZ) is that myelotoxicity is uncommon. Recently, several small series have reported significant myelotoxicity resulting in treatment delays or death. The ability to predict risk of myelotoxicity may influence patient care. We retrospectively reviewed 680 malignant glioma patients and developed a clinical risk formula for myelotoxicity for each gender by logistic regression. The variables that remained were assigned a score of 1 and added together for a final risk score. Women experienced more myelotoxicity than did men (p = 0.015). For males, risk factors included body surface area (BSA) > or = 2 m(2) (odds ratio [OR] = 2.712, p = 0.04), not on steroids (OR = 2.214, p = 0.06), and on bowel medication (OR = 3.955, p = 0.008). For females, final factors included no prior chemotherapy (OR = 3.727, p = 0.001), creatinine > or = 1 mg/dl (OR = 6.08, p = 0.002), platelets < 270,000/mm(3) (OR = 2.438, p = 0.03), BSA < 2 m(2) (OR = 4.178, p = 0.04), not on medication for gastroesophageal reflux disease (OR = 2.942, p = 0.01), and on analgesics (OR = 2.169, p = 0.05). Age was included because of observable trends. Risk of developing myelotoxicity ranged from 0% to 33% (male) and from 0% to 100% (females). Polymorphisms in NQO1 (NAD(P)H dehydrogenase, quinone 1), MGMT (O(6)-methylguanine-DNA methyltransferase), and GSTP1 (glutathione S-transferase pi 1) were related to risk of developing myelotoxicity in a subset of patients. Myelotoxicity with TMZ is a significant clinical issue for those at risk. Use of a clinical model to predict risk and evaluation of identified genetic polymorphisms related to myelotoxicity may allow for individualized dosing, optimizing patient management.

Dose-rounding of adjuvant chemotherapy for breast cancer: an audit of toxicity

Purpose. Dose-rounding of chemotherapy is increasingly being used in oncology departments to improve the efficiency of outpatient clinics. There is, however, no published data on the effect of this strategy on drug toxicity.

Methods. We have analysed acute chemotherapy side effects in a cohort of 662 consecutive patients receiving adjuvant FEC (5-fluorouracil, epirubicin, cyclophosphamide) for breast cancer. A dose-rounding algorithm was used to deliver drug doses that were within 5% of the standard dose based on body surface area.

Results. Patients receiving a rounded dose of chemotherapy that was higher than that calculated from their body surface area were not at increased risk of acute haematological or non-haematological toxicity.

Conclusions. Dose-rounding of adjuvant FEC within the range ±5% is not associated with any difference in acute chemotherapy side effects. Longer term follow-up is required to determine whether patients receiving rounded doses below that calculated from their body surface area are at increased risk of relapse.

Dose calculation of anticancer drugs

BACKGROUND

Anticancer drugs are characterized by a narrow therapeutic window and significant inter-patient variability in therapeutic and toxic effects. Current body surface area (BSA)-based dosing fails to standardize systemic anticancer drug exposure and other alternative dosing strategies also have their limitations. Just as important as the initial dose selection is the subsequent dose revision to ensure the dose is correct.

OBJECTIVE

To provide an insight into the different dose individualization and dose adjustment methods, their feasibility and applicability in daily oncology practice and to suggest a practical framework for dose calculation and a basis for future research.

METHODS

Review of relevant literature related to dose calculation of anticancer drugs.

RESULTS

Strategies using clinical parameters, genotype and phenotype markers, and therapeutic drug monitoring all have potential and each has a role for specific drugs. However, no one method is a practical dose calculation strategy for many or all drugs.

CONCLUSION

Given that BSA-dosing leads to significant underdosing it is not reasonable to use this as the sole method of dose calculation. Because of wide disparity in individual patient characteristics and elimination mechanisms, we are unlikely to find the 'Holy Grail' of a single individualized dosing strategy for every patient and anticancer drug in the near future. We propose a pragmatic, although invalidated system for initial dose calculation using dose clusters and structured subsequent dose revision based on treatment-related toxicities and therapeutic drug monitoring. These models need to be tested in clinical trials.

Breast cancer adjuvant chemotherapy dosing in obese patients: dissemination of information from clinical trials to clinical practice

BACKGROUND

Substantial variation in adjuvant breast cancer chemotherapy dosing in obese women suggests that there is uncertainty about optimal practices. The purpose of this study was to investigate variations in dose determinations in clinical trial protocols and publications over the last 3 decades as potential sources of this uncertainty.

METHODS

The National Cancer Institute database was used to identify protocols of breast cancer adjuvant chemotherapy conducted by cooperative groups between 1970-2000, and these protocols were then obtained directly from the cooperative groups. Dose determinations were categorized in each protocol and in published reports from each clinical trial. Fisher exact tests were used to compare the proportions of protocols that used full weight-based doses over time.

RESULTS

Protocol-specified chemotherapy dosing was obtained for all of 44 eligible trials. A significant increase was identified in the use of full weight-based doses in the later time period compared with the earlier (P = .004; 2-sided Fisher exact test). A notable exception was 1 cooperative group that continues to require dose limitations for doxorubicin and cyclophosphamide in patients with a body surface area of more than 2.0 m(2). Regardless of publication date, published reports of clinical trials rarely provide information on use of full or limited weight-based doses.

CONCLUSIONS

Variations in dose determinations among clinical trial protocols and lack of information on use of full weight-based doses in most publications are 2 likely sources of variation in chemotherapy dosing in obese women. Developing consensus and disseminating information on optimal chemotherapy dosing will likely reduce such variation and may improve survival among obese patients with breast cancer.

Evaluation of Alternate Size Descriptors for Dose Calculation of Anticancer Drugs in the Obese

Purpose

Despite the rising prevalence of obesity, there is paucity of information describing how doses of anticancer drugs should be adjusted in clinical practice. Here, we assessed the pharmacokinetics of eight anticancer drugs in adults and evaluated the potential utility of alternative weight descriptors in dose calculation for the obese.

Patients and Methods

A total of 1,206 adult cancer patients were studied, of whom 162 (13.4%) were obese (body mass index ≥ 30). Pharmacokinetic parameters were calculated using noncompartmental analysis, and compared between lean (body mass index ≤ 25) and obese patients.

Results

The absolute clearance of cisplatin, paclitaxel, and troxacitabine was significantly increased in the obese (P < .023), but this was not observed for carboplatin, docetaxel, irinotecan, or topotecan (P < .17). For doxorubicin, the systemic clearance was statistically significantly reduced in obese women (P = .013), but not in obese men (P = .52). Evaluation of alternate weight descriptors for dose calculation in the obese, including predicted normal weight, lean body mass, (adjusted) ideal body weight, and the mean of ideal and actual body weight, indicated that, for most of the evaluated drugs, weight scalars used to calculate body-surface area should consider actual body weight regardless of size.

Conclusion

The results suggest that a number of widely used empiric strategies for dose adjustments in obese patients, including a priori dose reduction or dose capping, should be discouraged.