Katherine Tkaczuk

Improved Outcomes From Adding Sequential Paclitaxel but Not From Escalating Doxorubicin Dose in an Adjuvant Chemotherapy Regimen for Patients With Node-Positive Primary Breast Cancer

PURPOSE This study was designed to determine whether increasing the dose of doxorubicin in or adding paclitaxel to a standard adjuvant chemotherapy regimen for breast cancer patients would prolong time to recurrence and survival. PATIENTS AND METHODS After surgical treatment, 3,121 women with operable breast cancer and involved lymph nodes were randomly assigned to receive a combination of cyclophosphamide (C), 600 mg/m(2), with one of three doses of doxorubicin (A), 60, 75, or 90 mg/m(2), for four cycles followed by either no further therapy or four cycles of paclitaxel at 175 mg/m(2). Tamoxifen was given to 94% of patients with hormone receptor-positive tumors. RESULTS There was no evidence of a doxorubicin dose effect. At 5 years, disease-free survival was 69%, 66%, and 67% for patients randomly assigned to 60, 75, and 90 mg/m(2), respectively. The hazard reductions from adding paclitaxel to CA were 17% for recurrence (adjusted Wald chi(2) P =.0023; unadjusted Wilcoxon P =.0011) and 18% for death (adjusted P =.0064; unadjusted P =.0098). At 5 years, the disease-free survival (+/- SE) was 65% (+/- 1) and 70% (+/- 1), and overall survival was 77% (+/- 1) and 80% (+/- 1) after CA alone or CA plus paclitaxel, respectively. The effects of adding paclitaxel were not significantly different in subsets defined by the protocol, but in an unplanned subset analysis, the hazard ratio of CA plus paclitaxel versus CA alone was 0.72 (95% confidence interval, 0.59 to 0.86) for those with estrogen receptor-negative tumors and only 0.91 (95% confidence interval, 0.78 to 1.07) for patients with estrogen receptor-positive tumors, almost all of whom received adjuvant tamoxifen. The additional toxicity from adding four cycles of paclitaxel was generally modest. CONCLUSION The addition of four cycles of paclitaxel after the completion of a standard course of CA improves the disease-free and overall survival of patients with early breast cancer.

Reduced Cardiotoxicity and Preserved Antitumor Efficacy of Liposome-Encapsulated Doxorubicin and Cyclophosphamide Compared With Conventional Doxorubicin and Cyclophosphamide in a Randomized, Multicenter Trial of Metastatic Breast Cancer

PURPOSE To determine whether Myocet (liposome-encapsulated doxorubicin; The Liposome Company, Elan Corporation, Princeton, NJ) in combination with cyclophosphamide significantly reduces doxorubicin cardiotoxicity while providing comparable antitumor efficacy in first-line treatment of metastatic breast cancer (MBC). PATIENTS AND METHODS Two hundred ninety-seven patients with MBC and no prior chemotherapy for metastatic disease were randomized to receive either 60 mg/m(2) of Myocet (M) or conventional doxorubicin (A), in combination with 600 mg/m(2) of cyclophosphamide (C), every 3 weeks until disease progression or unacceptable toxicity. Cardiotoxicity was defined by reductions in left-ventricular ejection fraction, assessed by serial multigated radionuclide angiography scans, or congestive heart failure (CHF). Antitumor efficacy was assessed by objective tumor response rates (World Health Organization criteria), time to progression, and survival. RESULTS Six percent of MC patients versus 21% (including five cases of CHF) of AC patients developed cardiotoxicity (P =.0002). Median cumulative doxorubicin dose at onset was more than 2,220 mg/m(2) for MC versus 480 mg/m(2) for AC (P =.0001, hazard ratio, 5.04). MC patients also experienced less grade 4 neutropenia. Antitumor efficacy of MC versus AC was comparable: objective response rates, 43% versus 43%; median time to progression, 5.1% versus 5.5 months; median time to treatment failure, 4.6 versus 4.4 months; and median survival, 19 versus 16 months. CONCLUSION Myocet improves the therapeutic index of doxorubicin by significantly reducing cardiotoxicity and grade 4 neutropenia and provides comparable antitumor efficacy, when used in combination with cyclophosphamide as first-line therapy for MBC.

Body mass and stage of breast cancer at diagnosis

Obesity is a well‐known risk factor for postmenopausal breast cancer. In contrast, the relationship between obesity and stage of breast cancer at diagnosis is less clear. We hypothesized that increased breast size in obese women may delay discovery of breast tumors. Thus, the purpose of our study was to examine whether there is an association between body mass and stage of breast cancer at diagnosis using hospital medical records. Newly diagnosed breast cancer cases (n = 966) in the Baltimore metropolitan area from 1991 to 1997 were included in our study. Patient information including age, ethnicity, weight, height and pathology data were obtained from hospital medical records. High body mass was significantly associated with late stage of breast cancer at diagnosis. Women who were obese (body mass index [BMI] ≥ 27.3) were more likely to be at an advanced stage at diagnosis compared with women with a BMI of < 27.3 (multivariate‐adjusted odds ratio [OR] 1.57, 95% confidence interval [CI] 1.15–2.14). The association between body mass and stage at diagnosis was stronger among women younger than 50 years (OR 2.34, 95% CI 1.34–4.08) compared with women 50 years or older (OR 1.30, 95% CI 0.89–1.91). Our study suggests that higher body mass is associated with advanced stage of breast cancer at diagnosis. This finding may be of considerable concern, given the increasing prevalence of obesity in women in the United States and the poor prognosis associated with late‐stage tumors.

Suramin, an Active Drug for Prostate Cancer: Interim Observations in a Phase I Trial

BACKGROUND Previous studies indicate that suramin may be an active agent for treatment of solid tumors. The clinical use of suramin is complicated by a broad spectrum of toxic effects and complex pharmacology. Studies have suggested that the dose-limiting neurotoxicity of this agent is closely related to sustained plasma drug concentrations of 350 micrograms/mL or more. PURPOSE This phase I clinical trial in patients with solid tumors was designed to determine whether plasma concentrations resulting in both antitumor activity and manageable toxicity could be achieved with short, intermittent infusions of suramin. METHODS Thirty-seven patients, including 33 with metastatic, hormone-refractory prostate cancer, collectively received 43 courses of suramin designed to maintain a plasma concentration range of 200-300, 175-275, or 150-250 micrograms/mL. Patients received a test dose of 200 mg and an initial loading dose of 1000 mg/m2 on day 1 of therapy. Subsequent suramin doses and schedules were individually determined using a strategy of adaptive control with feedback, which used a maximum a posteriori Bayesian algorithm to estimate individual pharmacokinetic parameters. Patients were treated until dose-limiting toxicity or progressive disease developed. RESULTS Thirty-five of the 37 study patients and 31 of the 33 with prostate cancer were assessable for toxicity and response. Treatment was discontinued in 28 patients because of dose-limiting toxicity consisting of a syndrome of malaise, fatigue, and lethargy; recurrent reduction in creatinine clearance of 50% or more; or axonal neuropathy. Evidence of major antitumor activity was observed in patients with prostate cancer treated at all three plasma drug concentrations. Measurable responses (one complete response and five partial responses) were noted in six of 12 patients with measurable disease. Twenty-four (77%) of 31 patients had a reduction in prostate-specific antigen of 50% or more, and 17 (55%) of 31 had a reduction of 75% or more. Twenty (83%) of 24 patients reported reduction in pain. CONCLUSIONS Suramin can be safely administered as an intermittent bolus injection by use of adaptive control with feedback to control plasma drug concentrations; toxicity is significant but manageable and reversible. Suramin is active against hormone-refractory prostate cancer. IMPLICATIONS Future trials should address the role and necessary extent of therapeutic drug monitoring; the optimal plasma drug concentration range and duration of therapy; and the activity of suramin in combination with other agents, in earlier stages of prostate cancer, and in other tumor types.

Review of the contemporary cytotoxic and biologic combinations available for the treatment of metastatic breast cancer

BACKGROUND Treatment of metastatic breast cancer (MBC) with > or =2 chemotherapeutic agents concurrently has been shown to increase response rates, often at the cost of a substantial increase in toxicity, and with minimal impact on the overall survival. However, some combinations of the newer cytotoxic agents, as well as combinations of chemotherapeutic agents and targeted biologic anticancer agents, can produce synergistic efficacy with a manageable toxicity profile. OBJECTIVES The aims of this work were to provide an overview of the currently approved combination regimens available for the treatment of MBC and to consider the clinical data supporting other drug combinations that may supplement the current therapeutic choices in the near future. METHODS Literature searches were performed using MEDLINE/PubMed, with a focus on combination therapies for the treatment of MBC that are approved by the US Food and Drug Administration (FDA) or in Phase III clinical trials. The National Institutes of Healths Clinical Trial Registry was searched for relevant ongoing clinical trials in specific areas. Bibliographies were also searched for additional relevant material. Preference was given to recently published, larger, well-designed clinical trials that influence current prescribing practices. Phase I and II studies, and/or studies older than 10 years (ie, published earlier than 1999), were afforded less emphasis or were disregarded. RESULTS Combinations of taxanes with capecitabine or gemcitabine, and ixabepilone plus capecitabine, are approved by the FDA as combination regimens for the treatment of MBC. The use of targeted therapies such as trastuzumab, bevacizumab, or lapatinib in combination with taxanes (for the former two) or capecitabine (for lapatinib) is also approved. Several investigational drug combinations are also currently undergoing evaluation in clinical trials, including combinations of bevacizumab and gemcitabine with capecitabine or alternative taxanes. Although results from Phase I and II studies are largely encouraging so far, the data from ongoing Phase III studies will ultimately dictate changes in clinical practice. It seems unlikely that any single agent or combination regimen will emerge as superior in all patients with MBC, given the heterogeneous nature of the disease and patient population. CONCLUSION New combination regimens for MBC may broaden the range of treatment options currently available to delay disease progression for as long as possible.

Can Obesity Explain the Racial Difference in Stage of Breast Cancer at Diagnosis between Black and White Women

OBJECTIVE Black women are more likely to be diagnosed at a more advanced stage of breast cancer than are white women. Traditionally, this has been attributed in part to social or cultural factors. Given that black women are more likely to be obese than white women and that being obese is associated with a more advanced stage at diagnosis, this study aims to assess to what extent the racial difference in stage at diagnosis can be explained by racial differences in obesity. METHODS Incident cases of breast cancer between 1991 and 1997 (white, n = 585; black, n = 381) were identified from hospitals in the Baltimore metropolitan area. Information, including age, race, weight, height, and pathology reports, was obtained from hospital medical records. RESULTS Black women were more likely than white women to be diagnosed with breast cancer at tumor-node-metastasis (TNM) stage II or greater (age-adjusted odds ratio [OR] = 1.51, 95% confidence interval [CI] 1.15-1.99). Further, black women were more likely than white women to be overweight or obese. A high body mass index (BMI) was significantly associated with an advanced stage of breast cancer at diagnosis. Adjustment for the higher prevalence of obesity in black women attenuated the risk estimate of more advanced stage of breast cancer at diagnosis in black women compared with white women by approximately 30%. CONCLUSIONS Our results suggest that the higher prevalence of obesity among black women plays an important role in explaining their relative disadvantage in stage at diagnosis of breast cancer. Nonetheless, a racial difference in stage of breast cancer at diagnosis persists after adjustment for obesity.

Similar survival with breast conservation therapy or mastectomy in the management of young women with early-stage breast cancer

PURPOSE To evaluate survival outcomes of young women with early-stage breast cancer treated with breast conservation therapy (BCT) or mastectomy, using a large, population-based database. METHODS AND MATERIALS Using the Surveillance, Epidemiology, and End Results (SEER) database, information was obtained for all female patients, ages 20 to 39 years old, diagnosed with T1-2 N0-1 M0 breast cancer between 1990 and 2007, who underwent either BCT (lumpectomy and radiation treatment) or mastectomy. Multivariable and matched pair analyses were performed to compare overall survival (OS) and cause-specific survival (CSS) of patients undergoing BCT and mastectomy. RESULTS A total of 14,764 women were identified, of whom 45% received BCT and 55% received mastectomy. Median follow-up was 5.7 years (range, 0.5-17.9 years). After we accounted for all patient and tumor characteristics, multivariable analysis found that BCT resulted in OS (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.83-1.04; p = 0.16) and CSS (HR, 0.93; CI, 0.83-1.05; p = 0.26) similar to that of mastectomy. Matched pair analysis, including 4,644 BCT and mastectomy patients, confirmed no difference in OS or CSS: the 5-, 10-, and 15-year OS rates for BCT and mastectomy were 92.5%, 83.5%, and 77.0% and 91.9%, 83.6%, and 79.1%, respectively (p = 0.99), and the 5-, 10-, and 15-year CSS rates for BCT and mastectomy were 93.3%, 85.5%, and 79.9% and 92.5%, 85.5%, and 81.9%, respectively (p = 0.88). CONCLUSIONS Our analysis of this population-based database suggests that young women with early-stage breast cancer have similar survival rates whether treated with BCT or mastectomy. These patients should be counseled appropriately regarding their treatment options and should not choose a mastectomy based on the assumption of improved survival.

Association of tamoxifen (TAM) and TAM metabolite concentrations with self-reported side effects of TAM in women with breast cancer.

The positive effects of tamoxifen (TAM) on breast cancer recurrence and survival as well as on overall mortality have led to its use as the predominant adjuvant therapy among women with breast cancer. However, the association of TAM intake with undesirable side effects has been reported in numerous studies. This analysis was carried out to assess whether the concentrations of TAM or TAM metabolites, N-desmethyltamoxifen (N-DMT) and 4-hydroxytamoxifen (4-OHT), were associated with self-reported side effects of TAM. Participants were 99 breast cancer patients who had been taking TAM for at least 30 days. Each participant completed a questionnaire that was used to ascertain whether she experienced certain specific symptoms while taking TAM. In addition, each woman provided a blood sample that was used to measure plasma concentrations of TAM, N-DMT, and 4-OHT by high performance liquid chromatography. Results of the analysis showed that women who experienced at least one TAM-related side effect had significantly higher levels of TAM than women not experiencing any TAM-related side effects. Furthermore, women who reported experiencing visual problems had significantly higher levels of both TAM and N-DMT compared to those women who reported experiencing no visual problems. The levels of 4-OHT were negatively associated with the occurrence of vaginal discharge. The results of this study suggest that the self-reported occurrence of certain symptoms during TAM treatment is related to TAM metabolism. Future studies should assess subgroups of women with specific TAM and TAM metabolite profiles to determine whether alternate, equally effective therapies would decrease their risk of experiencing certain undesirable side effects.

Chemotherapy dose reduction due to chemotherapy induced peripheral neuropathy in breast cancer patients receiving chemotherapy in the neoadjuvant or adjuvant settings: a single-center experience

PurposeTaxanes are a cornerstone treatment in early and advanced stage breast cancer and in other common solid tumor malignancies; however, the development of chemotherapy induced peripheral neuropathy (CIPN) often necessitates dose-reduction, which may hamper the effectiveness of the drug and compromise survival outcomes especially when used in the adjuvant setting. Limited literature is available on the prevalence and severity of dose reduction due to CIPN. We sought to determine the frequency and severity of CIPN-induced dose reduction in early stage breast cancer patients who received taxane-based chemotherapy in the neoadjuvant or adjuvant settings.MethodsWe conducted a retrospective single-institution breast cancer clinic chart review of 123 newly diagnosed breast cancer patients and treated with taxane-based neoadjuvant/adjuvant chemotherapy at the University of Maryland Greenebaum Cancer Center between January 2008 and December 2011.ResultsForty-nine of 123 (40%; 95% CI: 31-49%) patients required dose reduction. Twenty-one (17%; 95% CI: 11-25%) of these patients were dose-reduced specifically due to CIPN that developed during treatment. The median relative dose intensity (received dose/planned dose) for the 21 CIPN-induced dose reduction patients was 73.4% (range, 68.0-94.0%). Patients with diabetes appeared to have a higher risk of taxane-induced dose reduction (p-value=0.01). African-American patients and those treated with paclitaxel (rather than docetaxel) experienced a higher-risk of CIPN-induced dose reduction (p-values are <0.001 and 0.001, respectively).ConclusionsThe incidence of CIPN-associated dose reduction in our patient population was 17%. African-American patients, diabetics and subjects treated with paclitaxel had a higher risk for CIPN-associated dose reduction in our study.

Biosimilars in oncology: from development to clinical practice.

Biologics play an integral role in the treatment of cancer not only for their therapeutic effects and ability to improve outcomes, but also as supportive care agents. Biologics are more complex to manufacture and take longer to bring to market. Because biologics are considerably more costly than small-molecule drugs, their use has placed an increasing economic demand on healthcare systems worldwide. Biosimilars are designed to be highly similar to existing branded biologics, but because biologics cannot be exactly copied, biosimilars should not be referred to as generic, exact versions of the innovator biologic. Biosimilars have the potential to increase access and provide lower cost options for cancer care as patent protection for some of the most widely used biologics begins to expire. Regulatory requirements for biosimilars are evolving, as are global harmonization and/or standardization strategies that can facilitate their robust clinical development. This review highlights critical factors involved with the integration of biosimilars into oncology treatment paradigms and practices. Clinicians will likely seek out practice guidelines and position statements from established scientific societies to help evaluate key information regarding biosimilars, such as efficacy, safety, comparability, and interchangeability with the reference biologic. Automatic substitution, nomenclature, extrapolation of clinical data from one indication to another, as well as parameters for ongoing pharmacovigilance are evolving considerations. Education of physicians and other healthcare providers, payers, and patients about biosimilars may facilitate informed decision making, promote acceptance of biosimilars into clinical practice, increase accessibility, and expedite associated health and economic benefits.