Measurement of 5-fluorouracil in scalp hair: a possible index of patient compliance with oral adjuvant chemotherapy

Adherence to oral anticancer chemotherapy: What influences patients' over or non-adherence? Analysis of the OCTO study through quantitative-qualitative methods

Background

Numerous oral anticancer chemotherapies are available. Non-adherence or over-adherence to these chemotherapies can lead to lowered efficacy and increased risk of adverse events. The objective of this study was to identify patients’ adherence profiles using a qualitative–quantitative method.

Methods

A capecitabine treatment was initiated for 38 patients with advanced breast or colorectal cancer. At inclusion, information on patients’ beliefs was reported using a questionnaire. Later, Information on patients’ relation to treatment was obtained from a sub-group during an interview with a sociologist. Questionnaires were analyzed using Multiple Classification Analysis to cluster patients. Treatment adherence was evaluated by an electronic medication event monitoring systems (MEMS caps) and then correlated with patient clusters. Interviews were analyzed to complete and explain results.

Results

38 patients were enrolled between 2008 and 2011 and completed the questionnaire. Twenty had adherence measured with MEMS caps all along treatment. Between 4 and 6 months after inclusion, 16 patients were interviewed. Patient profile B (retired, with a regular life, surrounded by a relative’s attention to drug adherence, with a low educational level) was statistically associated with adequate adherence (p = 0.049). A tendency for lower adherence was observed among more highly educated patients with an irregular, active life (NS). All patients taking capecitabine demonstrated a risk of over-adherence, potentiating side effects.

Conclusions

These encouraging primary results suggest that further studies should be undertaken and that educational programs tailored to patient profiles should be evaluated to enhance adherence for those who need it and to empower all patients to manage treatment side effects.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1231-8) contains supplementary material, which is available to authorized users.

Oral cancer chemotherapy adherence and adherence assessment tools: a report from North Central Cancer Group Trial N0747 and a systematic review of the literature

Oncologists are now prescribing more oral chemotherapy than ever before, thus placing the onus for taking the right dose at the right time under the right circumstances directly on the patient. This study was undertaken to understand emerging adherence issues and to explore available adherence assessment tools. This two-part study (1) examined N0747, a randomized phase II trial that tested the oral agents, sunitinib and capecitabine, in patients with metastatic esophageal cancer from an adherence standpoint, and (2) conducted a systematic review to compile and assess adherence tools that can be used in future clinical trials. First, in N0747, patients were assigned to sunitinib and capecitabine versus capecitabine; 53 chemotherapy cycles were prescribed to this 12-patient cohort. Nearly all patients denoted that they "always or almost always" took their pills as prescribed, and two patients who reported lack of full adherence suffered from grade 3+ adverse events. Surprisingly, however, over 14 cycles, 9 patients reported grade 3+ toxicity but checked "always or almost always" to describe their adherence. No relationships were observed between adherence and cancer outcomes. Secondly, 21 articles identified the following adherence tools: (1) healthcare providers' interviews, (2) patient-reported adherence with diaries/calendars, (3) patient-completed adherence scales, (4) medication event monitoring, (5) automated voice response, (6) drug/metabolite assays, and (7) prescription databases. Of note, only the automated voice response seems capable of real-time detection of over-adherence, as observed in N0747. Oral chemotherapy adherence should be further studied, particularly from the standpoint of over-adherence.

A review of analytical methods for the determination of 5-fluorouracil in biological matrices

5-Fluorouracil (5-FU) is a cytostatic agent that has been widely used in the treatment of various solid tumours for more than 20 years, and is still considered to be among the most active antineoplastic agents in advanced colorectal cancer and malignancies of the head and neck. A large number of non-chromatographic and chromatographic methods for the quantitation of 5-FU, related prodrugs and their metabolites in biological matrices have been developed in the last 30 years to support preclinical and clinical studies. However, 5-FU monitoring has not been widely used, at least not in the USA, and certainly not outside the clinical research setting, given the absence of simple, fast and inexpensive testing methods for 5-FU monitoring. Recent developments with testing based on liquid chromatography-tandem mass spectrometry and a nanoparticle antibody-based immunoassay may facilitate routine monitoring of 5-FU in daily clinical practice. In this review the advantages and disadvantages of the bioanalytical methods developed and used for 5-FU, its metabolites and related prodrugs are discussed.

Determination of Opioid Analgesics in Hair Samples Using Liquid Chromatography/Tandem Mass Spectrometry and Application to Patients Under Palliative Care

Hair testing procedures allow a cumulative reflection of long-term drug abuse and are useful as a test for compliance in clinical toxicology. In the present study, liquid chromatography coupled with tandem mass spectrometry was used to determine analgesic opioid drugs in hair samples. The procedure used a simple methanolic extraction, and the evaporated extract was analyzed directly. A selective and sensitive procedure for the simultaneous determination of bisnortilidine, nortilidine, tilidine, buprenorphine, codeine, oxycodone, fentanyl, norfentanyl, hydromorphone, morphine, normorphine, oxymorphone, methadone, piritramide, and tramadol was developed and fully validated. The method fulfilled validation criteria and was shown to be sensitive, with limits of detection ranging from 0.008 to 0.017 ng/mg hair matrix, and precision ranging between 3.1% and 14.9 %. The applicability of the method was shown by analysis of authentic hair samples from patients receiving opioids for the treatment of cancer pain (eg, fentanyl was detected in concentrations up to 0.292 ng/mg, tramadol in concentrations up to 0.612 ng/mg of hair of 1 patient). Hair analysis was shown to be a complementary and useful tool in monitoring the drug-taking behavior of patients consuming opioid analgesics for the treatment of pain. In self-reports and medical records especially, the ingestion of tramadol and methadone was found to be dramatically underreported. In summary, hair analyses gave important additional information for the medical treatment of patients, the results often coming as a surprise to even the attending physicians.

Analytical pitfalls in hair testing

This review focuses on possible pitfalls in hair testing procedures. Knowledge of such pitfalls is useful when developing and validating methods, since it can be used to avoid wrong results as well as wrong interpretations of correct results. In recent years, remarkable advances in sensitive and specific analytical techniques have enabled the analysis of drugs in alternative biological specimens such as hair. Modern analytical procedures for the determination of drugs in hair specimens - mainly by gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) - are reviewed and critically discussed. Many tables containing information related to this topic are provided.

Do people with cancer comply with oral chemotherapy treatments?

Many people with cancer have oral medication as part or all of their regime. This medication is primarily self administered in the community. This mini-review aimed to determine the level of compliance of adult cancer patients with oral chemotherapy and to assess the quality of the available evidence. Searches were undertaken using three electronic databases (Medline, Embase, CINAHL) for studies which evaluated the compliance of adult cancer patients with oral anti-neoplastic agents through self-report, pill counts, drug/metabolite levels or microelectronic monitoring system (MEMS). Articles were selected if the follow-up was higher than 80% of patients. Six papers were identified for the review. The methodological quality of the studies was poor. The sample size of the majority of them was small and the method used to measure adherence was not entirely reliable. The results of these papers were varied and contradictory. A firm conclusion cannot be drawn because the studies present significant methodological flaws. The comparison of results between studies is difficult due to the lack of a gold-standard measure of adherence and a standardised definition of non-compliance. Further research in this area is needed. However it does appear that compliance is a problem in this patient group.

State of the art in hair analysis for detection of drug and alcohol abuse

Hair differs from other materials used for toxicological analysis because of its unique ability to serve as a long-term storage of foreign substances with respect to the temporal appearance in blood. Over the last 20 years, hair testing has gained increasing attention and recognition for the retrospective investigation of chronic drug abuse as well as intentional or unintentional poisoning. In this paper, we review the physiological basics of hair growth, mechanisms of substance incorporation, analytical methods, result interpretation and practical applications of hair analysis for drugs and other organic substances. Improved chromatographic-mass spectrometric techniques with increased selectivity and sensitivity and new methods of sample preparation have improved detection limits from the ng/mg range to below pg/mg. These technical advances have substantially enhanced the ability to detect numerous drugs and other poisons in hair. For example, it was possible to detect previous administration of a single very low dose in drug-facilitated crimes. In addition to its potential application in large scale workplace drug testing and driving ability examination, hair analysis is also used for detection of gestational drug exposure, cases of criminal liability of drug addicts, diagnosis of chronic intoxication and in postmortem toxicology. Hair has only limited relevance in therapy compliance control. Fatty acid ethyl esters and ethyl glucuronide in hair have proven to be suitable markers for alcohol abuse. Hair analysis for drugs is, however, not a simple routine procedure and needs substantial guidelines throughout the testing process, i.e., from sample collection to results interpretation.

Do injections of 5-fluorouracil after trabeculectomy have toxic effects on the anterior segment?

OBJECTIVE

To discourage fibrosis of the filtering bleb, 5 fluorouracil (5-FU) may be injected after trabeculectomy. 5-FU is an antimetabolite that also can damage extraocular tissues at concentrations as low as 0.5%. This study ascertained whether repeated injection of 5-FU has toxic effects on intraocular structures.

METHODS

After unilateral trabeculectomy in anesthetized New Zealand rabbits, 5-FU (5.0 mg/0.1 mL) was injected at the trabeculectomy site every 5 days for 15 days. Evaluation included slit-lamp examination, confocal microscopy, and intraocular pressure (IOP). After sacrifice, aqueous humor (AH) was drawn and eyes excised for scanning electron microscopy (SEM) and light microscopy.

RESULTS

The 5-FU injection not decrease IOP beyond trabeculectomy alone. Bleb height remained constant, thickness increased, and vascularity decreased. No changes in cornea or anterior segment were observed. No inflammation was observed in the bleb or surrounding tissues by slit-lamp or histologic examination. Protein in AH increased from 0.6 +/- 0.5 microg/mL at baseline to 19.8 +/- 4.4 microg/mL after trabeculectomy but only to 0.9 +/- 0.6 microg/mL after trabeculectomy plus 5-FU. Both in vivo confocal microscopy and SEM revealed deleterious effects on corneal epithelial and endothelial cells with a minor shift toward smaller cells.

CONCLUSIONS

In this study 5-FU did not provoke an intraocular inflammatory response and had minimal effect on extraocular structures. Changes in corneal epithelium and endothelium detectable by confocal microscopy suggest a small toxic effect. These in vivo measurements by confocal microscopy were confirmed by SEM. Repeated administration did not cause additional cumulative toxic effects in the anterior segment. Therefore, multiple injections of 5- FU into the filtering bleb pose minimal risk to intraocular structures.

Assessing the health implications for healthcare workers of regulatory changes eliminating locally developed occupational exposure limits in favor of TLVs: an evidence-based bipartite approach

In response to the intention of the Workers' Compensation Board of British Columbia (WCB of BC) to eliminate made-in-BC occupational exposure limits (OELs) and adopt threshold limit values (TLVs), this study assessed the potential health impacts on healthcare workers (HCWs) of the proposed change, by (1) reviewing the processes used to establish the OELs and TLVs, (2) selecting of substances of health concern for HCWs, (3) identifying chemicals with discordances between existing OELs and the 2002 TLVs, and 4) reviewing the discordances and assessing the potential health implications. Differences in philosophies, policies and processes that influenced the setting of OELs and TLVs were substantial. The TLV process involves U.S. and international priorities; in BC, a tripartite committee determined OELs taking into consideration how OELs should be interpreted in the local context. 47 chemicals of concern to BC HCWs were discordant, with significant discordances totalling 57; 15 compounds had BC 8-hour OELs lower than their respective TLVs and three TLVs were lower than the 8-hour BC OELs. Review of six chemicals with discordances suggested a potential for increased risks of adverse health effects. Eliminating the local capacity and authority to set OELs is unlikely to cause major health problems in the short run, but as chemicals in use locally may not have up-to-date TLVs, eliminating the capacity for local considerations should be undertaken with great caution. While the WCB of BC did implement the change, the present report resulted in procedural changes that will provide better protection for the workforce.

Simultaneous determination of flucytosine and fluorouracil in human plasma by high-performance liquid chromatography

A validated, sensitive and precise reversed-phase high-performance liquid chromatographic method for the simultaneous determination of 5-flucytosine (5-FC) and 5-fluorouracil (5-FU) in human plasma is described. Two compounds, 5-methylcytosine (5-MC) and 5-chlorouracil (5-CU), were used as internal standards for the determination of 5-FC and 5-FU, respectively. Plasma samples were deproteinized with trichloroacetic acid and chromatographed on an octylsilica column, maintained at 30 degrees C during elution, using a 0.04 M phosphate buffer, pH 7.0, as eleunt. Spectrophotometric diode array detection was used at 266 nm. 5-FC, 5-FU, 5-MC and 5-CU were found to have retention times of 4.8, 5.8, 7.7 and 11.0 min respectively. Recoveries of 91-120% with reproducibility and repeatability coefficients of variation of 0.8-6% were obtained. Mean correlation coefficients of 0.99989 and 0.9995 were found for the linear calibration curves (n = 2) of 5-FC (4.816-192.6 mg/l) and 5-FU (0.05368-5.368 mg/l), respectively. The limits of quantitation were 0.3 mg/l for 5-FC and 0.05 mg/l for 5-FU.

Testing hair for pharmaceuticals

More than hundred pharmaceuticals, drugs of abuse or doping agents have been reported to be detectable in human hair. This article reviews the analysis of 90 drugs and drug metabolites by chromatographic procedures, including the pretreatment steps, the extraction methods, the reported limits of detection and the measured concentrations in real human hair samples. Some progress is observed in the detection of low dose drugs, like fentanyl or flunitrazepam. The general tendency in the last years, to highly sophisticated techniques (GC-MS-NCI, HPLC-MS, GC-MS-MS) illustrates well this constant fight for sensitivity. Some new findings, based on the recent experience of the authors, are also added.

Therapeutic drug monitoring of antimetabolic cytotoxic drugs

Therapeutic drug monitoring is not routinely used for cytotoxic agents. There are several reasons, but one major drawback is the lack of established therapeutic concentration ranges. Combination chemotherapy makes the establishment of therapeutic ranges for individual drugs difficult, the concentration-effect relationship for a single drug may not be the same as that when the drug is used in a drug combination. Pharmacokinetic optimization protocols for many classes of cytotoxic compounds exist in specialized centres, and some of these protocols are now part of large multicentre trials. Nonetheless, methotrexate is the only agent which is routinely monitored in most treatment centres. An additional factor, especially in antimetabolite therapy, is the existence of pharmacogenetic enzymes which play a major role in drug metabolism. Monitoring of therapy could include assay of phenotypic enzyme activities or genotype in addition to, or instead of, the more traditional measurement of parent drug or drug metabolites. The cytotoxic activities of mercaptopurine and fluorouracil are regulated by thiopurine methyltransferase (TPMT) and dihydropyrimidine dehydrogenase (DPD), respectively. Lack of TPMT functional activity produces life-threatening mercaptopurine myelotoxicity. Very low DPD activity reduces fluorouracil breakdown producing severe cytotoxicity. These pharmacogenetic enzymes can influence the bioavailability, pharmacokinetics, toxicity and efficacy of their substrate drugs.