Circadian variation in plasma 5-fluorouracil concentrations during a 24 hour constant-rate infusion.

BACKGROUND: Varying the rate of continuous intravenous infusions of 5-fluorouracil (5FU) chemotherapy over a 24-hour period has been reported to improve patient outcomes. It has been hypothesized that circadian variation in drug disposition is a contributing factor. We analyzed 5-FU concentrations during a 24-hour continuous 5-FU infusion. METHODS: Sixty-four subjects with advanced malignancies including pancreatic, hepatocellular, colorectal as well as other epithelial malignancies and either abnormal hepatic or renal function were treated on a phase I and pharmacokinetic study of weekly 24-hour intravenous infusions of 5-FU and leucovorin. No other concomitant anticancer therapy was administered. Blood samples were collected every three hours from 61 subjects for measurement of plasma 5-FU during the first two weekly infusions. RESULTS: After adjusting for differences in dose, elapsed time from start of infusion and infusion number (2 versus 1), mean 5-FU concentration was highest at 6 am and lowest at 3 pm, with an overall change in the mean from 3 pm to 6 am of +20 percent (95% CI = 12-28%). However, this variation in mean concentration associated with time of day was comparable in magnitude to the between-patient differences, within-patient differences between infusions, and the residual variation within infusion (coefficient of variation = 21%). CONCLUSIONS: Our data show systematic variation by time of day in plasma concentrations of 5-FU administered at a constant rate over 24 hours, but it is small compared to the total variation in plasma concentration contributed by other sources. Circadian variation in men was more pronounced than in women.

Feasibility of 4 cycles of docetaxel and cyclophosphamide every 14 days as an adjuvant regimen for breast cancer: a Wisconsin Oncology Network study.

INTRODUCTION: Dose-dense therapies have had a major effect on reducing toxicity and improving outcomes in breast cancer. A combination of TC every 3 weeks has emerged as a common chemotherapy regimen used for treatment of node-negative or lower-risk node-positive breast cancer. We tested whether it is feasible to deliver TC on a dose-dense schedule, with therapy completed within 10 weeks. PATIENTS AND METHODS: We enrolled women with early stage breast cancer on a single-arm phase II study of adjuvant dose-dense TC through a regional oncology network. All women completed primary surgery before accrual, and subsequent therapy with TC was deemed appropriate by the treating physician. Planned treatment was docetaxel 75 mg/m(2) plus cyclophosphamide 600 mg/m(2) every 2 weeks for 4 cycles with subcutaneous pegfilgrastim 6 mg administered 24 to 48 hours after the administration of each chemotherapy cycle. RESULTS: Of 42 women enrolled, 41 were evaluable using prespecified criteria. Of these, 37 (90.2%) completed therapy within 10 weeks and 34 (83%) completed therapy at 8 weeks without dose modification. Rates of neuropathy were similar to that reported previously. The rate of neutropenic fever was low (2.5%). Rash and plantar-palmar erythrodythesia were common and reached grade 3 in 4 subjects (9.8%). CONCLUSION: Dose-dense TC is feasible with tolerability profiles similar to standard TC and a low likelihood of neutropenic fever. This study supports further clinical development of this 8-week adjuvant chemotherapy regimen.

Neo-adjuvant capecitabine chemotherapy in women with newly diagnosed locally advanced breast cancer in a resource-poor setting (Nigeria): efficacy and safety in a phase II feasibility study.

The majority of clinical trials of neo-adjuvant therapy for breast cancer have been conducted in resource-rich countries. We chose Nigeria, a resource-poor country, as the major site for a phase II feasibility open-label multicenter clinical trial designed to evaluate the efficacy, safety, and tolerability of neo-adjuvant capecitabine in locally advanced breast cancer (LABC). Planned treatment consisted of 24 weeks of capecitabine at a dose of 1,000 mg/m(2) twice daily (2,000 mg/m(2) total per day). The primary endpoints were overall, partial, complete clinical response rate (OCR, PCR, CCR) and complete pathologic response (cPR). A total of 16 patients were recruited from August 2007 to April 2010. The study was terminated early as a result of slow accrual. After the first three cycles of therapy, PCR were seen in five of 16 patients (31%; 95% CI 11-59%). Of the remaining 11 patients, eight had no response (NR) or stable disease (SD), and three had progressive disease (PD). Seven patients proceeded with further therapy of which had SD. OCR at the end of eight cycles was 44% (95% CI 20-70%). Clinical response and radiologic response by ultrasonomammography were highly concordant (spearman correlation 0.70). The most common adverse effect was Grade 1 hand-foot syndrome, which was seen in 75% of patients. Despite several limitations, we successfully carried out this phase II feasibility study of neo-adjuvant capecitabine for LABC in Nigeria. Capecitabine monotherapy showed good overall response rates with minimal toxicity and further studies are warranted.

Integration of cell line and clinical trial genome-wide analyses supports a polygenic architecture of Paclitaxel-induced sensory peripheral neuropathy.

PURPOSE: We sought to show the relevance of a lymphoblastoid cell line (LCL) model in the discovery of clinically relevant genetic variants affecting chemotherapeutic response by comparing LCL genome-wide association study (GWAS) results to clinical GWAS results. EXPERIMENTAL DESIGN: A GWAS of paclitaxel-induced cytotoxicity was conducted in 247 LCLs from the HapMap Project and compared with a GWAS of sensory peripheral neuropathy in patients with breast cancer (n = 855) treated with paclitaxel in the Cancer and Leukemia Group B (CALGB) 40101 trial. Significant enrichment was assessed by permutation resampling analysis. RESULTS: We observed an enrichment of LCL cytotoxicity-associated single-nucleotide polymorphisms (SNP) in the sensory peripheral neuropathy-associated SNPs from the clinical trial with concordant allelic directions of effect (empirical P = 0.007). Of the 24 SNPs that overlap between the clinical trial (P < 0.05) and the preclinical cytotoxicity study (P < 0.001), 19 of them are expression quantitative trait loci (eQTL), which is a significant enrichment of this functional class (empirical P = 0.0447). One of these eQTLs is located in RFX2, which encodes a member of the DNA-binding regulatory factor X family. Decreased expression of this gene by siRNA resulted in increased sensitivity of Neuroscreen-1(NS-1; rat pheochromocytoma) cells to paclitaxel as measured by reduced neurite outgrowth and increased cytotoxicity, functionally validating the involvement of RFX2 in nerve cell response to paclitaxel. CONCLUSIONS: The enrichment results and functional example imply that cellular models of chemotherapeutic toxicity may capture components of the underlying polygenic architecture of related traits in patients.

Genetic determinants of breast cancer risk: a review of current literature and issues pertaining to clinical application.

Despite major advances in breast cancer therapy, annual mortality remains significant with a sizeable proportion of patients eventually succumbing to metastatic disease. Clearly, optimizing approaches for identification and management of women at heightened risk for breast cancer will reduce overall morbidity and mortality from the disease. Over the past few decades, advances in molecular genetics and linkage analyses have allowed for the identification of specific germline mutations underlying a significant fraction of hereditary breast cancer. Genome-wide association studies have been developed as a powerful tool in identifying lower penetrance mutations, and it is believed that such genome-level variations may act in concert to give rise to the majority of inherited breast cancer risk. Controversies and uncertainties remain in clinical application of newly identified genomic loci that confer genetic susceptibility. This article reviews the well-characterized breast cancer susceptibility genes, highlights recent publications pertaining to the less well known and lower penetrance genetic polymorphisms, summarizes challenges in translating research findings to the clinical scenario, and offers some recommendations for clinical practice.

Whole-genome studies identify solute carrier transporters in cellular susceptibility to paclitaxel.

OBJECTIVE: The clinical use of paclitaxel is limited by variable responses and the potential for significant toxicity. To date, studies of associations between variants in candidate genes and paclitaxel effects have yielded conflicting results. We aimed to evaluate the relationships between global gene expression and paclitaxel sensitivity. METHODS: We utilized well-genotyped lymphoblastoid cell lines derived from the International HapMap Project to evaluate the relationships between cellular susceptibility to paclitaxel and global gene expression. Cells were exposed to varying concentrations of paclitaxel to evaluate paclitaxel-induced cytotoxicity and apoptosis. Among the top genes, we identified solute carrier (SLC) genes associated with paclitaxel sensitivity and narrowed down the list to those that had single nucleotide polymorphisms associated with both the expression level of the SLC gene and also with paclitaxel sensitivity. We performed an independent validation in an independent set of cell lines and also conducted functional studies using RNA interference. RESULTS: Of all genes associated with paclitaxel-induced cytotoxicity at P less than 0.05 (1713 genes), there was a significant enrichment in SLC genes (31 genes). A subset of SLC genes, namely SLC31A2, SLC43A1, SLC35A5, and SLC41A2, was associated with paclitaxel sensitivity and had regulating single nucleotide polymorphisms that were also associated with paclitaxel-induced cytotoxicity. Multivariate modeling demonstrated that those four SLC genes together explained 20% of the observed variability in paclitaxel susceptibility. Using RNA interference, we demonstrated increased paclitaxel susceptibility with knockdown of three SLC genes, SLC31A2, SLC35A5, and SLC41A2. CONCLUSION: Our findings are novel and lend further support to the role of transporters, specifically solute carriers, in mediating cellular susceptibility to paclitaxel.

Treatment of therapy-related myeloid neoplasms with high-dose cytarabine/mitoxantrone followed by hematopoietic stem cell transplant.

Few clinical protocols have focused on patients with therapy-related myeloid neoplasms (t-MN). Therefore, we enrolled 32 patients with previously untreated t-MN on a clinical trial testing the effectiveness of a unified induction regimen of high-dose cytarabine and mitoxantrone. The complete remission (CR) rate was 66% (95% CI 47-81%) and the partial remission (PR) rate was 16% (95% CI 5-33%), for an overall response rate of 82%. Day 30 treatment mortality was 9% (3/32), and the most serious induction toxicity was cardiac dysfunction. Among the patients with CR, 13 (62%) received consolidation therapy using an allogeneic hematopoietic cell transplant (HCT), four (21%) received an autologous HCT, and three (16%) received further chemotherapy. We observed long-term disease-free survival in patients who received all three types of consolidation therapy. The remission induction of high-dose cytarabine and mitoxantrone for t-MN is a well-tolerated efficacious combination, which allows aggressive consolidation and long-term disease-free survival.

Metastatic prostatic adenocarcinoma mimicking inflammatory breast carcinoma: a case report.

Prostate adenocarcinoma can manifest as a fairly indolent tumor or as a very aggressive cancer with significant invasive and metastatic potential. Common metastatic sites include bone, liver, lymph nodes, and adrenal glands. Dermatologic manifestations are rare. We present a case of a man who presented with breast skin changes that mimicked inflammatory breast carcinoma with specialized testing ultimately giving a diagnosis of metastatic prostatic adenocarcinoma. A 78-year-old man presented with left breast redness and swelling. Examination revealed an erythematous rash with subcutaneous edema over the left hemithoracic area. A breast ultrasound showed no focal mass, and a breast core biopsy had no evidence of tumor. A skin biopsy showed metastatic carcinoma in dermal lymphatics, and the tumor was found to have no estrogen or progesterone receptors or HER2 expression. Computed tomography scans, positron emission tomography, and a nuclear bone scan revealed widespread skeletal metastases. The patient received a 3-month course of capecitabine and cyclophosphamide with no improvement in his skin lesions. Subsequent immunohistochemical staining on the tumor specimen was positive for prostate-specific antigen (PSA) and alpha-methyl-CoA-racemase, confirming a diagnosis of metastatic prostatic adenocarcinoma. He received leuprolide and bicalutamide and demonstrated significant improvement with near-complete resolution of his skin lesions and a decrease in his PSA level. Prostatic adenocarcinoma presenting initially as a breast malignancy is a rarely recognizable clinical event. Undoubtedly, increased awareness and recognition of the rare entity described herein will allow for the prompt initiation of specific therapies, which might be of benefit to many patients.