ABSTRACT
BACKGROUND: Despite histological and molecular differences between invasive lobular carcinoma (ILC) and invasive carcinoma of no special type, according to national treatment guidelines no distinction is made regarding the use of (neo)adjuvant chemotherapy. Studies on the long-term outcome of chemotherapy in patients with ILC are scarce and show inconclusive results. METHODS: All patients with estrogen receptor (ER)-positive, human epidermal growth factor receptor 2 (HER2)-negative ILC with an indication for chemotherapy treated with adjuvant endocrine therapy were selected from the Erasmus Medical Center Breast Cancer database. Cox proportional hazards models were used to estimate the effect of chemotherapy on recurrence-free survival (RFS), breast cancer-specific survival (BCSS), and overall survival (OS). RESULTS: A total of 520 patients were selected, of whom 379 were treated with chemotherapy and 141 were not. Patients in the chemotherapy group were younger (51 vs. 61 years old; p < .001), had a higher T status (T3+, 33% vs. 14%; p < .001), and more often had lymph node involvement (80% vs. 49%; p < .001) in comparison to the no-chemotherapy group. After adjusting for confounders, chemotherapy treatment was not associated with better RFS (hazard ratio [HR], 1.20; 95% confidence interval [CI], 0.63-2.31), BCSS (HR, 1.24; 95% CI, 0.60-2.58), or OS (HR, 0.97; 95% CI, 0.56-1.66). This was also reflected by adjusted Cox survival curves in the chemotherapy versus no-chemotherapy group for RFS (75% vs. 79%), BCSS (80% vs. 84%), and OS (72% vs. 71%). CONCLUSIONS: Chemotherapy is not associated with improved RFS, BCSS, or OS for patients with ER+/HER2- ILC treated with adjuvant endocrine therapy and with an indication for chemotherapy.
Subject(s)
Breast Neoplasms , Carcinoma, Lobular , Humans , Middle Aged , Female , Breast Neoplasms/pathology , Carcinoma, Lobular/drug therapy , Carcinoma, Lobular/pathology , Retrospective Studies , Breast/pathology , Chemotherapy, Adjuvant , Receptor, ErbB-2/metabolism , Adjuvants, Immunologic , Immunologic Factors/therapeutic useABSTRACT
We investigated the effect of trastuzumab on cardiac function in a real-world historic cohort of patients with HER2-positive metastatic breast cancer (MBC) with reduced baseline left ventricular ejection fraction (LVEF). Thirty-seven patients with HER2-positive MBC and baseline LVEF of 40% to 49% were included. Median LVEF was 46% (interquartile range [IQR] 44%-48%) and median follow-up was 18 months (IQR 9-34 months). During this period, the LVEF did not worsen in 24/37 (65%) patients, while 13/37 (35%) patients developed severe cardiotoxicity defined as LVEF <40% with median time to severe cardiotoxicity of 7 months (IQR 4-10 months) after beginning trastuzumab. Severe cardiotoxicity was reversible (defined as LVEF increase to a value <5%-points below baseline value) in 7/13 (54%) patients, partly reversible (defined as absolute LVEF increase ≥10%-points from nadir to a value >5%-points below baseline) in 3/13 (23%) patients and irreversible (defined as absolute LVEF increase <10%-points from nadir and to a value >5%-points below baseline) in 3/13 (23%) patients. Likelihood of reversibility was numerically higher in patients who received cardio-protective medications (CPM), including ACE-inhibitors, beta-blockers and angiotensine-2 inhibitors, compared to those who did not receive any CPM (71% vs 13%, P = .091). Sixty-five percent of patients who received trastuzumab for HER2-positive MBC did not develop severe cardiotoxicity during a median follow-up of 18 months, despite having a compromised baseline LVEF. If severe cardiotoxicity occurred, it was at least partly reversible in more than two-thirds of the cases. Risks and benefits of trastuzumab use should be balanced carefully in this vulnerable population.
Subject(s)
Breast Neoplasms , Neoplasms, Second Primary , Breast Neoplasms/pathology , Cardiotoxicity/drug therapy , Cardiotoxicity/epidemiology , Cardiotoxicity/etiology , Female , Humans , Neoplasms, Second Primary/chemically induced , Receptor, ErbB-2 , Stroke Volume , Trastuzumab/adverse effects , Ventricular Function, LeftABSTRACT
BACKGROUND: Maintaining functional status is among the most important patient-centered outcomes for older adults with cancer. This study investigated the association between comprehensive geriatric assessment (CGA) and progressive disease or decline of IADL-independence 1 year after chemotherapy, overall survival (OS), and premature termination of chemotherapy. CGA-based functional status and quality of life (QOL) 1 year after chemotherapy are also described. METHODS: This prospective cohort study involved patients agedâ ≥65 years treated with chemotherapy for any cancer type. CGA and the G8-screening tool were performed before and after the completion of chemotherapy. Analyses were adjusted for tumor type and treatment intent: (a) indolent hematological malignancies, (b) aggressive hematological malignancies, c) solid malignancies treated with curative intent, and (d) solid malignancies treated with palliative intent. RESULTS: All 291 included patients lived in The Netherlands; 193 (67.4%) lived fully independent prior to chemotherapy. The median age was 72 years; 164 (56.4%) were male. IADL independence, CGA-based functional status, and QOL were maintained in half of the patients 1 year after chemotherapy. An abnormal G8-score before chemotherapy was a higher risk for progressive disease or a decline of IADL-independence (OR 3.60, 95% CI, 1.98-6.54, Pâ <â .0001), prematurely terminated chemotherapy (OR 2.12, 95% CI, 1.24-3.65, Pâ =â .006), and shorter median OS (HR 1.71, 95% CI, 1.16-2.52, Pâ =â .007). The impact of an abnormal G8-score differed across tumor type (oncological or hematological) and treatment indication (adjuvant or palliative). CONCLUSION: An abnormal G8 score before chemotherapy is associated with progressive disease and functional decline after chemotherapy and shorter median OS, especially in patients with solid malignancies.
Subject(s)
Hematologic Neoplasms , Neoplasms , Aged , Humans , Male , Female , Geriatric Assessment , Quality of Life , Prospective Studies , Functional StatusABSTRACT
BACKGROUND: We aimed to study the predictive value of early two-dimensional echocardiography (2DE) speckle tracking (ST) for left ventricular ejection fraction (LVEF) changes during trastuzumab treatment for HER2-positive breast cancer. METHODS: HER2-positive breast cancer patients receiving trastuzumab, with or without anthracycline, underwent 2DE-ST at baseline and after 3 and 6 months (m) trastuzumab. Cardiac magnetic resonance (CMR) imaging (with ST) was performed at baseline and 6 m. We studied the correlation between 2DE-ST- and CMR-derived global longitudinal strain (GLS) and global radial strain (GRS) measured at the same time. Additionally, we associated baseline and 3 m 2DE-ST measurements with later CMR-LVEF, and with cardiotoxicity, defined as CMR-LVEF < 45% and/or absolute decline > 10% during trastuzumab. RESULTS: Forty-seven patients were included. Median baseline LVEF was 60.4%. GLS measurements based on 2DE-ST and CMR showed weak correlation (Pearson's r = 0.33; p = 0.041); GRS measurements were uncorrelated (r = 0.09; p = 0.979). 2DE-LVEF at baseline and 3 m, and 2DE-ST-GLS at 3 m were predictive of CMR-LVEF at 6 m. In contrast, the change in 2DE-ST-GLS at 3 m was predictive of the change in CMR-LVEF at 6 m, whereas the change in 2DE-LVEF was not. Importantly, the 11 patients who developed cardiotoxicity (28%) had larger 2DE-ST-GLS change at 3 m than those who did not (median 5.2%-points versus 1.7%-points; odds ratio for 1% difference change 1.81, 95% confidence interval 1.11-2.93; p = 0.016; explained variance 0.34). CONCLUSIONS: Correlations between 2DE-ST and CMR-derived measurements are weak. Nevertheless, ST-measurements appeared useful to improve the performance of 2DE in predicting LVEF changes after 6 m of trastuzumab treatment.
Subject(s)
Breast Neoplasms , Trastuzumab , Ventricular Dysfunction, Left , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/drug therapy , Echocardiography , Female , Humans , Magnetic Resonance Imaging , Prospective Studies , Stroke Volume , Trastuzumab/adverse effects , Ventricular Function, LeftABSTRACT
Trastuzumab prolongs progression-free and overall survival in patients with human epidermal growth factor receptor 2 (HER2) positive breast cancer. However, trastuzumab treatment is hampered by cardiotoxicity, defined as a left ventricular ejection fraction (LVEF) decline with a reported incidence ranging from 3 to 27% depending on variable factors. Early identification of patients at increased risk of trastuzumab-induced myocardial damage is of great importance to prevent deterioration to irreversible cardiotoxicity. Although current cardiac monitoring with multi gated acquisition (MUGA) scanning and/or conventional 2D-echocardiography (2DE) have a high availability, their reproducibility are modest, and more sensitive and reliable techniques are needed such as 3D-echocardiography (3DE) and speckle tracking echocardiography (STE). But which other diagnostic imaging modalities are available for patients before and during trastuzumab treatment? In addition, what is the optimal frequency and duration of cardiac monitoring? At last, which biomarker monitoring strategies are currently available for the identification of cardiotoxicity in patients treated with trastuzumab?
Subject(s)
Antineoplastic Agents, Immunological/therapeutic use , Breast Neoplasms/drug therapy , Cardiotoxicity/diagnostic imaging , Echocardiography/methods , Trastuzumab/therapeutic use , Ventricular Dysfunction, Left/chemically induced , Biomarkers/blood , C-Reactive Protein , Echocardiography, Three-Dimensional/methods , Female , Humans , Immunoglobulin E , Incidence , Interleukin-1 Receptor-Like 1 Protein , Natriuretic Peptide, Brain , Peptide Fragments , Peroxidase , Receptor, ErbB-2/metabolism , TroponinABSTRACT
BACKGROUND: Early identification of cardiac dysfunction by non-invasive imaging in HER2-positive breast cancer patients treated with trastuzumab is challenging. In particular multigated acquisition (MUGA) scan, which is most widely used, is unable to detect subclinical cardiac changes. The use of N-terminal pro-brain natriuretic peptide (NT-proBNP), a serum biomarker of myocardial stress, might improve timely diagnosis. METHODS: This prospective, single-center, cohort study included patients with HER2-positive breast cancer who started trastuzumab therapy. Echocardiography was scheduled at regular intervals every 3 months during one year follow-up for cardiac function monitoring. For research purposes, NT-proBNP was determined at the same time points. Trastuzumab-induced cardiotoxicity (TIC) was the primary study endpoint, defined as a left ventricular ejection fraction (LVEF) < 45%, and/or an absolute decline in LVEF > 10% since inclusion, and/or the incidence of a clinical cardiac event. RESULTS: A total of 135 patients were enrolled between April 2008 and June 2016, with a median age of 54 years (IQR: 47-61). By three-dimensional echocardiography (3DE), the median LVEF at baseline was 62% (IQR: 58-65). At a median of 6 months (IQR: 5-11), 45 patients (33%) reached the study endpoint of TIC. Patients with TIC had a mean change of - 9.5% in LVEF (95% CI -7.2 to - 11.7; p = 0.001) during 1 year of trastuzumab treatment. Both NT-proBNP at baseline (HR 1.04, 95% CI 1.02-1.07; p = 0.003) and LVEF decline during anthracycline treatment prior to the start of trastuzumab (HR 1.16, 95% CI 1.07-1.25; p < 0.001) were independently associated with development of TIC. The level of NT-proBNP during follow-up was associated too with development of TIC (HR 1.06 per 10 pmol/l difference, 95% CI 1.02-1.10; p = 0.008). No steadily or sudden increase in NT-proBNP prior to TIC was observed. CONCLUSIONS: NT-proBNP cannot be used as a surrogate monitoring tool for trastuzumab-induced cardiotoxicity in HER2-positive breast cancer patients during the first year of treatment. Patients showing an LVEF decline during anthracycline pre-treatment appeared vulnerable for trastuzumab-induced cardiotoxicity.
ABSTRACT
Background: Aromatase inhibitors (AIs) are given as adjuvant therapy for hormone receptor-positive breast cancer in postmenopausal women, also to those with chemotherapy-induced ovarian function failure. The current analysis reports on endocrine data of patients with chemotherapy-induced ovarian function failure who were included in the phase III DATA study assessing different durations of adjuvant anastrozole after tamoxifen. Methods: We identified all patients with chemotherapy-induced ovarian function failure. Women who underwent a bilateral ovariectomy or used luteinizing hormone-releasing hormone agonists before random assignment were excluded. Plasma estradiol and follicle-stimulating hormone levels were monitored until 30 months after random assignment at local laboratories. We aimed to determine the ovarian function recovery (OFR) rate during AI use by the cumulative incidence competing risk method and analyzed the trend of estradiol levels during AI use by a nested case-control approach in which a subset of control subjects were compared with the OFR patients excluding the value at OFR diagnosis. Results: The 329 eligible patients had a median age of 50.0 years (range = 45-57 years) at random assignment. Thirty-nine patients developed OFR, corresponding with a 30-month recovery rate of 12.4%. Of these, 11 (28.2%) were age 50 years or older at AI initiation. The estradiol level decreased statistically significantly by 37.8% (95% CI = 27.4% to 46.7%) over the initial 30 months of AI treatment in both groups. However, the estradiol levels in the women who experienced OFR remained statistically significantly higher (difference = 20.6%, 95% CI = 2.0% to 42.7%) prior to OFR diagnosis compared with those who did not experience OFR. Conclusions: The risk of OFR during AI treatment in breast cancer patients with chemotherapy-induced ovarian function failure is relevant, even beyond 45 years. Furthermore, women experiencing OFR had statistically significant higher estradiol levels during AI treatment (before OFR) than those without, with potential consequences regarding efficacy.
Subject(s)
Anastrozole/therapeutic use , Breast Neoplasms/drug therapy , Estradiol/metabolism , Ovarian Diseases/drug therapy , Ovary/drug effects , Recovery of Function , Tamoxifen/adverse effects , Adult , Antineoplastic Agents, Hormonal/adverse effects , Aromatase Inhibitors/therapeutic use , Breast Neoplasms/pathology , Case-Control Studies , Chemotherapy, Adjuvant , Clinical Trials, Phase III as Topic , Female , Humans , Middle Aged , Ovarian Diseases/chemically induced , Prognosis , Randomized Controlled Trials as TopicABSTRACT
BACKGROUND: Irinotecan is metabolized by various enzymes, including carboxylesterases, cytochrome P450 3A isozymes (CYP3A) and uridine-diphosphate glucuronosyltransferase 1A isoforms (UGT1A). Here we report on the disposition of irinotecan and its metabolites in plasma, urine, bile and feces of a single cancer patient with an external bile drain. METHODOLOGY: Irinotecan (450 mg) was administered during a 90-minutes continuous infusion to a cancer patient with an external bile drain. Blood samples were collected up to 55 hours after infusion, while bile, feces and urine were collected during six consecutive days after administration. Samples were analyzed using high-performance liquid chromatography (HPLC)-assays with fluorescence detection. RESULTS: Plasma pharmacokinetics were characterized by a relatively slow clearance of irinotecan and a relatively high exposure to 7-ethyl-10-[4-N-(5-aminopentanoic acid)-1-piperidino] carbonyloxycamptothecin (APC). Exposures to the other metabolites was within the normal range. Overall, 83.4% of the administered dose was recovered in the excreta, with the majority excreted during the first 24 hours. CONCLUSIONS: Enterohepatic recirculation is of minor importance for the plasma disposition of irinotecan and its metabolites. The high percentage of the dose recovered in urine, the relatively slow clearance of irinotecan and the preferential urinary over biliary excretion of APC in this particular patient are likely related to reduced functioning of ABC-transporters. Circumstantial evidence was found that APC is subject to further intestinal biotransformation indicating a role in the etiology of irinotecan-induced diarrhea. Since intra-luminal exposure to SN-38 in patients with an external bile drain is limited, neutropenia will be the dose-limiting toxicity. Based on presented data, although collected from only one patient, irinotecan therapy in patients with an external bile drain is feasible. No a priori dose adjustments are recommended, although in the absence of severe side-effects in previous courses, a higher dose may be considered.
Subject(s)
Adenocarcinoma/metabolism , Bile Ducts/surgery , Biliary Tract/metabolism , Camptothecin/analogs & derivatives , Liver/metabolism , Pancreatic Neoplasms/metabolism , Prodrugs/pharmacokinetics , Adenocarcinoma/blood , Adenocarcinoma/drug therapy , Aged , Antineoplastic Agents, Phytogenic/administration & dosage , Antineoplastic Agents, Phytogenic/blood , Antineoplastic Agents, Phytogenic/pharmacokinetics , Antineoplastic Agents, Phytogenic/urine , Camptothecin/administration & dosage , Camptothecin/blood , Camptothecin/pharmacokinetics , Camptothecin/urine , Drainage , Feces/chemistry , Humans , Irinotecan , Liver Neoplasms/drug therapy , Liver Neoplasms/metabolism , Liver Neoplasms/secondary , Male , Pancreatic Neoplasms/blood , Pancreatic Neoplasms/drug therapy , Prodrugs/administration & dosageABSTRACT
OBJECTIVE: One key aspect of cancer survivorship is return-to-work. Unfortunately, many cancer survivors face problems upon their return-to-work. For that reason, we developed a hospital-based work support intervention aimed at enhancing return-to-work. We studied effectiveness of the intervention compared to usual care for female cancer patients in a multi-centre randomised controlled trial. METHODS: Breast and gynaecological cancer patients who were treated with curative intent and had paid work were randomised to the intervention group (nâ=â65) or control group (nâ=â68). The intervention involved patient education and support at the hospital and improvement of communication between treating and occupational physicians. In addition, we asked patient's occupational physician to organise a meeting with the patient and the supervisor to make a concrete gradual return-to-work plan. Outcomes at 12 months of follow-up included rate and time until return-to-work (full or partial), quality of life, work ability, work functioning, and lost productivity costs. Time until return-to-work was analyzed with Kaplan-Meier survival analysis. RESULTS: Return-to-work rates were 86% and 83% (pâ=â0.6) for the intervention group and control group when excluding 8 patients who died or with a life expectancy of months at follow-up. Median time from initial sick leave to partial return-to-work was 194 days (range 14-435) versus 192 days (range 82-465) (pâ=â0.90) with a hazard ratio of 1.03 (95% CI 0.64-1.6). Quality of life and work ability improved statistically over time but did not differ statistically between groups. Work functioning and costs did not differ statistically between groups. CONCLUSION: The intervention was easily implemented into usual psycho-oncological care and showed high return-to-work rates. We failed to show any differences between groups on return-to-work outcomes and quality of life scores. Further research is needed to study which aspects of the intervention are useful and which elements need improvement. TRIAL REGISTRATION: Nederlands Trial Register (NTR) 1658.
Subject(s)
Cost-Benefit Analysis/economics , Neoplasms/economics , Neoplasms/rehabilitation , Return to Work/economics , Work/economics , Female , Hospitals , Humans , Male , Middle Aged , Physician-Patient Relations , Quality of Life , Sick Leave/economicsABSTRACT
OBJECTIVE: To date, data regarding the potential of cannabinoids to modulate cytochrome P450 isozyme 3A (CYP3A) activity are contradictory. Recently, a standardized medicinal cannabis product was introduced in The Netherlands. We anticipated an increased use of medicinal cannabis concurrent with anticancer drugs, and undertook a drug-interaction study to evaluate the effect of concomitant medicinal cannabis on the pharmacokinetics of irinotecan and docetaxel, both subject to CYP3A-mediated biotransformation. PATIENTS AND METHODS: Twenty-four cancer patients were treated with i.v. irinotecan (600 mg, n = 12) or docetaxel (180 mg, n = 12), followed 3 weeks later by the same drugs concomitant with medicinal cannabis (200 ml herbal tea, 1 g/l) for 15 consecutive days, starting 12 days before the second treatment. Blood samples were obtained up to 55 hours after dosing and analyzed for irinotecan and its metabolites (SN-38, SN-38G), respectively, or docetaxel. Pharmacokinetic analyses were performed during both treatments. Results are reported as the mean ratio (95% confidence interval [CI]) of the observed pharmacokinetic parameters with and without concomitant medicinal cannabis. RESULTS: Medicinal cannabis administration did not significantly influence exposure to and clearance of irinotecan (1.04; CI, 0.96-1.11 and 0.97; CI, 0.90-1.05, respectively) or docetaxel (1.11; CI, 0.94-1.28 and 0.95; CI, 0.82-1.08, respectively). CONCLUSION: Coadministration of medicinal cannabis, as herbal tea, in cancer patients treated with irinotecan or docetaxel does not significantly influence the plasma pharmacokinetics of these drugs. The evaluated variety of medicinal cannabis can be administered concomitantly with both anticancer agents without dose adjustments.
Subject(s)
Antineoplastic Agents, Phytogenic/pharmacokinetics , Camptothecin/analogs & derivatives , Cannabinoids/pharmacology , Neoplasms/drug therapy , Taxoids/pharmacokinetics , Adult , Aged , Area Under Curve , Camptothecin/pharmacokinetics , Cannabinoids/administration & dosage , Cytochrome P-450 CYP3A/metabolism , Docetaxel , Drug Interactions , Female , Humans , Irinotecan , Male , Middle Aged , Statistics, NonparametricABSTRACT
PURPOSE: Because of its supposed inhibiting capacities of uridine-diphosphate glucuronosyltransferase 1A (UGT1A)-mediated glucuronidation in rats, the antiepileptic drug valproic acid has been investigated as modulator of irinotecan-induced delayed-type diarrhea in rats. Here, we report on the pharmacokinetic and pharmacodynamic effects of this combination in a cancer patient. EXPERIMENTAL DESIGN: A patient who used valproic acid was administered irinotecan (600 mg). To investigate dose-limiting hepatotoxicity encountered during the first course, which was clinically attributed to a supposed higher exposure to the active irinotecan metabolite SN-38, valproic acid was tapered off. Blood samples for pharmacokinetic purposes were drawn during a course with and a course without concomitant valproic acid. Plasma-levels of irinotecan, SN-38, and SN-38G were determined using HPLC-assays. RESULTS: When irinotecan was combined with valproic acid, the exposure to SN-38 was 41% lower. Additionally, reversible elevations of the liver enzyme tests were noted. In particular, seven days after irinotecan administration gammaGT and transaminase levels raised up to 5.3-11.3 times the ULN (CTCAE grade 3). CONCLUSIONS: Valproic acid-induced plasma protein binding displacement and/or metabolic modulation of enzymes and drug transporters involved in irinotecan disposition may explain the reduced exposure to SN-38 in the presence of valproic acid. Given the herewith-coupled potential undertreatment, patients should firstly switch to another antiepileptic drug not known to interfere with irinotecan treatment. Additionally, this particular combination should not be implemented in clinical studies without simultaneously adjusting the irinotecan dose, and the risk of (severe) hepatotoxicity should be considered when designing protocols studying valproic acid (as histone deacetylase-inhibitor) in combination with other (anticancer) drugs.
Subject(s)
Antineoplastic Agents/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Camptothecin/analogs & derivatives , Liver/drug effects , Valproic Acid/administration & dosage , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Antineoplastic Combined Chemotherapy Protocols/pharmacokinetics , Camptothecin/administration & dosage , Camptothecin/pharmacokinetics , Chromatography, High Pressure Liquid , Female , Glucuronates/pharmacokinetics , Glucuronosyltransferase/metabolism , Humans , Irinotecan , Middle Aged , Models, Biological , Transaminases/metabolism , Treatment Outcome , Valproic Acid/pharmacokineticsABSTRACT
Conventional pharmacokinetic trials in oncology measure the total amount of drug and its metabolites in the plasma of patients. These total drug concentrations are then correlated with clinical parameters such as toxicity and/or drug efficacy. However, total drug concentrations in plasma are often not directly related to tumor or tissue concentrations and the kinetics in (tumor) tissue may be very different from the kinetics of the drug in plasma. As only the unbound fraction of drugs can passively diffuse or can be actively transported across the cell membrane of endothelial cells and penetrate the tissues and tumor cells, binding of drugs to plasma components may, in part, be responsible for the variability in clinical outcomes. Also, variation in binding to cellular components may be important. As an overall consequence, in in vivo models high inter-individual variabilities of drug concentrations in the tumor have been observed, which affected drug activity. Many current cancer drug-therapies aim for a clinical benefit at the edge of acceptable toxicity, without paying attention to (variability in) plasma and tumor or tissue pharmacokinetics. This review discusses the potential applicability of microdialysis, a minimally invasive method used to determine the unbound fraction of drugs in blood or in the interstitial fluid of tissues, in clinical oncology. Although faced with some methodological challenges, the technique offers many advantages over others, and enables direct tumor assessment for pharmacokinetics and even pharmacodynamics.