E.G.E. de Vries

Cardiovascular Morbidity in Long-Term Survivors of Metastatic Testicular Cancer

PURPOSE To determine whether long-term survivors of metastatic testicular cancer have an increased risk of cardiovascular morbidity more than 10 years after chemotherapy. PATIENTS AND METHODS Eighty-seven patients treated with cisplatin-containing chemotherapy before 1987 who were in remission for at least 10 years and whose ages were </= 50 years at the time of analysis were evaluated for the occurrence of cardiovascular events. Sixty-two of 87 patients were additionally evaluated for cardiac damage and cardiovascular risk factors. Their cardiovascular risk profile was compared with that of 40 patients with comparable age and follow-up duration treated with orchidectomy only for stage I disease. RESULTS Major cardiac events were found in five (6%) of the 87 patients (age at time of event, 30 to 42 years; time after chemotherapy, 9 to 16 years): two with myocardial infarction and three with angina pectoris with proven myocardial ischemia. An increased observed-to-expected ratio of 7.1 (95% confidence interval, 1.9 to 18.3) for coronary artery disease, as compared with the general male Dutch population, was found. In addition, one patient experienced a cerebrovascular accident. Exercise ECG did not reveal cases of subclinical coronary artery disease. Echocardiography showed normal systolic left ventricular function in most patients, but diastolic left ventricular function was disturbed in 33% of the patients. Of 62 chemotherapy patients, 79% had hypercholesterolemia, 39% had hypertension, 25% still experienced Raynauds phenomenon, and 22% had microalbuminuria. Compared with patients with stage I disease, the chemotherapy patients had higher blood pressure and higher total cholesterol and triglyceride levels and were more insulin-resistant. CONCLUSION In long-term survivors of metastatic testicular cancer, we observed a significantly increased risk for occurrence of cardiac events accompanied by a persisting unfavorable cardiovascular risk profile. Accurate follow-up, focused on cardiovascular complications and aimed at intervention in these young cancer survivors, seems to be important.

Genes other than BRCA1 and BRCA2 involved in breast cancer susceptibility

This review focuses on genes other than the high penetrance genes BRCA1 and BRCA2 that are involved in breast cancer susceptibility. The goal of this review is the discovery of polymorphisms that are either associated with breast cancer or that are in strong linkage disequilibrium with breast cancer causing variants. An association with breast cancer at a 5% significance level was found for 13 polymorphisms in 10 genes described in more than one breast cancer study. Our data will help focus on the further analysis of genetic polymorphisms in populations of appropriate size, and especially on the combinations of such polymorphisms. This will facilitate determination of population attributable risks, understanding of gene-gene interactions, and improving estimates of genetic cancer risks.

Efficacy and safety of prolonged-release lanreotide in patients with gastrointestinal neuroendocrine tumors and hormone-related symptoms

PURPOSE To evaluate the prolonged release (PR) of the long-acting somatostatin analog lanreotide in patients with gastrointestinal neuroendocrine tumors and its effect on hormone-related symptomatology, tumor markers, tumor size, tolerability, and quality of life (QOL). PATIENTS AND METHODS Eligible patients had the following substantial daily symptoms: for patients with carcinoid tumors, three or more stools and/or 1.5 or more flushing episodes; for patients with gastrinoma, greater than 50% elevated basic acid output; and for patients with vasoactive intestinal peptide-secreting tumors (VIPomas), four or more stools and/or a stool volume of >/= 800 mL, a measurable tumor, and an elevated biochemical tumor marker (>/= two times the upper limit of the normal reference range). Lanreotide PR was administered intramuscularly every 14 days at 30 mg for 6 months. We measured efficacy by studying symptoms, tumor markers, tumor size, and QOL. Side effects were scored according to the National Cancer Institutes toxicity grading system and ultrasound examination of the gallbladder. RESULTS Fifty-five patients were included in the study (48 patients with carcinoid tumors, six patients with gastrinoma, and one patient with VIPoma). Symptomatic improvement (> 50% reduction) occurred in 38% of the assessable patients with carcinoid tumors, in 67% of the gastrinoma patients, and in the VIPoma patient. Tumor markers normalized in two of 45 assessable patients, 19 patients exhibited a reduction (> 50%), 19 patients exhibited no change, and tumor markers rose by more than 50% in five patients. Tumor size was reduced in two of 31 assessable patients and remained stable in 25 patients; four patients experienced progression. QOL assessments after 1 month showed improvements in emotional and cognitive function, and diminished fatigue, sleeping disorders, and diarrhea. Eight of 30 assessable patients developed gallstones. CONCLUSION Lanreotide PR is a well-tolerated somatostatin analog with significant clinical, biochemical, and antitumor effects that bring about a significant improvement in QOL for patients with neuroendocrine tumors.

Prospective Evaluation of Early Cardiac Damage Induced by Epirubicin-Containing Adjuvant Chemotherapy and Locoregional Radiotherapy in Breast Cancer Patients

PURPOSE To evaluate prospectively the cardiotoxic effects of epirubicin-containing adjuvant chemotherapy in breast cancer patients. PATIENTS AND METHODS Patients (median age, 46 years; range, 28 to 55 years) were treated with five cycles of fluorouracil, epirubicin (90 mg/m2), and cyclophosphamide (FEC) (group I, n = 21) or with four cycles of FEC followed by high-dose chemotherapy consisting of cyclophosphamide, thiotepa, and carboplatin (group II, n = 19). Locoregional radiotherapy was applied subsequently. Cardiac evaluation was performed before chemotherapy (T0), 1 month after chemotherapy, 1 month after radiotherapy (T2), and 1 year after start of chemotherapy (T3). Left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography and diastolic function by echocardiography. Autonomic function was assessed by 24-hour ECG registration for heart rate variability (HRV) analysis. Time-corrected QT (QTc) was assessed and N-terminal atrial natriuretic peptide (NT-ANP) and brain natriuretic peptide (BNP) were measured as biochemical markers of cardiac dysfunction. RESULTS No patient developed overt congestive heart failure (CHF) and the mean LVEF declined from 0.61 at T0 to 0.54 at T3 (P =.001), resulting in an LVEF below 0.50 (range, 0.42 to 0.49) in 17% of the patients, whereas 28% had a decline of more than 0.10. Plasma NT-ANP levels increased gradually from 237 pmol/L at T0 to 347 pmol/L at T3 (P <.01), whereas plasma BNP levels increased from 2.9 pmol/L to 5.1 pmol/L (P =.04). Mean QTc increased from 406 msec at T0 to 423 msec at T3 (P <.01). No persistent alterations were found in diastolic function and HRV. CONCLUSION Relatively low doses of epirubicin in adjuvant chemotherapy for breast cancer results in mild subclinical myocardial damage demonstrated by a decline in LVEF, an increase in natriuretic peptide levels, and an increase in QTc, which may indicate a long-term risk of CHF.

Complete in vivo reversal of P-glycoprotein pump function in the blood-brain barrier visualized with positron emission tomography

1 Homozygously mdr1a gene disrupted mice (mdr1a(−/−) mice) and wild type mice (mdr1a(+/+) mice) were used to develop a method for P‐glycoprotein (P‐gp) function imaging non‐invasively and to study the effect of a P‐gp reversal agent on its function in vivo. 2 [11C]verapamil (0.1 mg/kg) was administered and the changes in tissue concentrations were determined ex vivo by organ extirpation and in vivo with PET. To block P‐gp function, cyclosporin A was administered. 3 Biodistribution studies revealed 9.5‐fold (P<0.001) and 3.4‐fold (P<0.001) higher [11C]verapamil in the brain and testes of mdr1a(−/−) mice than in mdr1a(+/+) mice. Cyclosporin A (25 mg/kg) increased [11C]verapamil levels in the brain and testes of mdr1a(+/+) mice in both cases 3.3‐fold (P<0.01 (brain); P<0.001 (testes)). Fifty mg/kg cyclosporin A increased [11C]verapamil in the brain 10.6‐fold (P<0.01) and in the testes 4.1‐fold (P<0.001). No increases were found in the mdr1a(−/−) mice. This indicates complete inhibition of P‐gp mediated [11C]verapamil efflux. 4 Positron camera data showed lower [11C]verapamil levels in the brain of mdr1a(+/+) mice compared to those in mdr1a(−/−) mice. [11C]verapamil accumulation in the brain of mdr1a(+/+) mice was increased by cyclosporin A to levels comparable with those in mdr1a(−/−) mice, indicating that reversal of P‐gp mediated efflux can be monitored by PET. 5 We conclude that cyclosporin A can fully block the P‐gp function in the blood brain barrier and the testes and that PET enables the in vivo measurement of P‐gp function and reversal of its function non‐invasively.

Visualization of multidrug resistance in vivo

Abstract. Various mechanisms are involved in multidrug resistance (MDR) for chemotherapeutic drugs, such as the drug efflux pumps, P-glycoprotein (Pgp) and multidrug resistance-associated protein (MRP). In this review the mechanisms involved in MDR are described and results are reviewed with particular attention to the in vivo imaging of Pgp and MRP. Various detection assays provide information about the presence of drug efflux pumps at the mRNA and protein levels. However, these methods do not yield information about the dynamic function of Pgp and MRP in vivo. For the study of Pgp- and MRP-mediated transport, single-photon emission tomography (SPET) and positron emission tomography (PET) are available. Technetium-99m sestamibi is a substrate for Pgp and MRP, and has been used in clinical studies for tumour imaging, and to visualize blockade of Pgp-mediated transport after modulation of the Pgp pump. Other 99mTc radiopharmaceuticals, such as 99mTc-tetrofosmin and several 99Tc-Q complexes, are also substrates for Pgp, but to date only results from in vitro and animal studies are available for these compounds. Several agents, including [11C]colchicine, [11C]verapamil and [11C]daunorubicin, have been evaluated for the quantification of Pgp-mediated transport with PET in vivo. The results suggest that radiolabelled colchicine, verapamil and daunorubicin are feasible substrates with which to image Pgp function in tumours. Uptake of [11C]colchicine and [11C]verapamil is relatively high in the chest area, reducing the value of both tracers for monitoring Pgp-mediated drug transport in tumours located in this region. In addition, it has to be borne in mind that only comparison of Pgp-mediated transport of radioalabelled substrates in the absence and in the presence of Pgp blockade gives quantitative information on Pgp-mediated pharmacokinetics. Leukotrienes are specific substrates for MRP. Therefore, N-[11C]acetyl-leukotriene E4 provides an opportunity to study MRP function non-invasively. Results obtained in MRP2 mutated GY/TR rats have demonstrated visualization of MRP-mediated transport. This tracer permits the study of MRP transport function abnormalities in vivo, e.g. in Dubin-Johnson patients, who are MRP2 gene deficient. Results obtained show the feasibility of using SPET and PET to study the functionality of MDR transporters in vivo.

Preventive Intervention Possibilities in Radiotherapy- and Chemotherapy-induced Oral Mucositis: Results of Meta-analyses

The aim of these meta-analyses was to evaluate the effectiveness of interventions for the prevention of oral mucositis in cancer patients treated with head and neck radiotherapy and/or chemotherapy, with a focus on randomized clinical trials. A literature search was performed for reports of randomized controlled clinical studies, published between 1966 and 2004, the aim of which was the prevention of mucositis in cancer patients undergoing head and neck radiation, chemotherapy, or chemoradiation. The control group consisted of a placebo, no intervention, or another intervention group. Mucositis was scored by either the WHO, the National Cancer Institute-Common Toxicity Criteria (NCI-CTC) score, or the absence or presence of ulcerations, or the presence or absence of grades 3 and 4 mucositis. The meta-analyses included 45 studies fulfilling the inclusion criteria, in which 8 different interventions were evaluated: i.e., local application of chlorhexidine; iseganan; PTA (polymyxin E, tobramycine, and amphotericin B); granulocyte macrophage-colony-stimulating factor/granulocyte colony-stimulating factor (GM-CSF/G-CSF); oral cooling; sucralfate and glutamine; and systemic administration of amifostine and GM-CSF/G-CSF. Four interventions showed a significant preventive effect on the development or severity of oral mucositis: PTA with an odds ratio (OR) = 0.61 (95% confidence interval [CI], 0.39–0.96); GM-CSF, OR = 0.53 (CI: 0.33–0.87); oral cooling, OR = 0.3 (CI: 0.16–0.56); and amifostine, OR = 0.37 (CI: 0.15–0.89). To date, no single intervention completely prevents oral mucositis, so combined preventive therapy strategies seem to be required to ensure more successful outcomes.

EFFECTS OF SUPPLEMENTAL DIETARY CALCIUM ON QUANTITATIVE AND QUALITATIVE FECAL FAT EXCRETION IN MAN

Oral calcium supplementation is thought to be a useful interventional agent to decrease colon cancer risk. This is supposedly due, at least in part, to the binding of bile acids and fatty acids by calcium in the colon, thus prohibiting the damaging effects of these substances to the epithelium. To determine the effects of calcium supplementation on fecal fat excretion, 24 subjects kept a fat and calcium constant diet for one week and were supplemented with either 0, 2 or 4 g elemental calcium as calcium carbonate in a double-blind fashion. At the end of the week 72-hour feces was collected, and total fat, neutral fat, fatty acids and the ratio of polyunsaturated and saturated fatty acids (P/S ratio) were measured. Calcium dose-dependently increased the percentual excretion of total fat as related to fat intake: 6.8 +/- 0.9% during 0 g, 7.4 +/- 1.0% during 2 g and 10.2 +/- 1.4% during 4 g, r = 0.44, p = 0.03. This was due to increased fatty acid excretion, excretion of neutral fat was not affected, nor was the P/S ratio. It is concluded that calcium supplementation modestly increases fecal fatty acid excretion. No adverse metabolic effects are to be expected from this in case of long-term calcium supplementation in subjects at increased risk for colon cancer.

The sulfhydryl containing compounds WR-2721 and glutathione as radio- and chemoprotective agents: A review, indications for use and prospects

SummaryRadio- and chemotherapy for the treatment of malignancies are often associated with significant toxicity. One approach to reduce the toxicity is the concomitant treatment with chemoprotective agents. This article reviews two sulfhydryl compounds, namely the agent WR-2721 (amifostine), a compound recently registered for use in human in many countries, and the natural occurring compound glutathione (GSH). GSH is not registered as a chemoprotective agent. WR-2721 is an aminothiol prodrug and has to be converted to the active compound WR-1065 by membrane-bound alkaline phosphatase. WR-1065 and GSH both act as naturally occurring thiols. No protective effect on the tumour has been found when these compounds are administered intravenously. There is even in vitro evidence for an increased anti-tumour effect with mafosfamide after pretreatment with WR-2721, and in vivo after treatment with carboplatin and paclitaxel. Randomized clinical studies have shown that WR-2721 and GSH decrease cisplatin-induced nephrotoxicity and that WR-2721 reduces radiation radiotherapy-induced toxicity. Side-effects associated with WR-2721 are nausea, vomiting and hypotension, GSH has no side-effects. An exact role of WR-2721 and GSH as chemoprotectors is not yet completely clear. Future studies should examine the protective effect of these drugs on mucositis, cardiac toxicity, neuro- and ototoxicity, the development of secondary neoplasms and their effect on quality of life.

Review article: anthranoid laxatives and their potential carcinogenic effects

Anthranoid laxatives are widely used laxatives of natural origin. Because of their chemical structure they are carried unabsorbed to the large bowel, where metabolism to the active aglycones takes place. These aglycones exert their laxative effect by damaging epithelial cells, which leads directly and indirectly to changes in absorption, secretion and motility. Damaged epithelial cells can be found as apoptotic bodies in the pigmented colonic mucosa, characteristic for pseudomelanosis coli. Pseudomelanosis coli is a condition caused by chronic (ab)use of anthranoid laxatives and has recently been associated with an increased risk of colorectal carcinoma. In vitro and animal studies have shown a potential role of anthranoid laxatives in both the initiation and promotion of tumorigenesis. Studies in humans have also suggested tumour promoting activities for these laxatives. Although the short‐term use of these substances is generally safe, long‐term use cannot be recommended.