G. Milano

Expression of epidermal growth factor receptor and survival in upper aerodigestive tract cancer.

PURPOSEnTo determine the expression of epidermal growth factor receptor (EGFR) in head and neck squamous cell carcinoma and to evaluate its prognostic value.nnnMATERIALS AND METHODSnEGFR was determined in tumor biopsies obtained from 109 consecutive patients with head and neck cancer (100 men, nine women). Control biopsies were obtained from 94 patients in a symetric nontumoral area of the same anatomic site. EGFR was measured by a binding assay using human recombinant iodine 125-EGF.nnnRESULTSnThe presence of detectable EGFR levels was found in all explored tumors with highly marked differences between patients (median, 71 fmol/mg protein; range, 2 to 2,302). In 93 of 94 cases, EGFR levels were higher in tumor samples as compared with healthy control zones. There was no significant difference in EGFR expression according to the various anatomic sites explored or tumoral differentiation status. There was a significant difference of distribution for EGFR levels between stages I and II tumors and stages III and IV tumors. The tumor EGFR levels were not linked to the response to first-line chemotherapy by cisplatin (CDDP) and fluorouracil (5FU). Survival was assessable for 103 patients for overall survival and for 81 patients for recurrence. EGFR overexpression was associated with shorter relapse-free (P = .0125) and overall survival (P = .028) rates. By multivariate analysis, the only significant variable was EGFR for relapse-free survival and tumor staging for overall survival. The association of EGFR to tumor staging markedly improves the significance for overall survival predictability (P = .002).nnnCONCLUSIONnEGFR determination deserves particular attention in head and neck cancer, since it independently carries a strong prognostic value.

Population study of dihydropyrimidine dehydrogenase in cancer patients.

Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme of 5-fluorouracil (5-FU) catabolism. The clinical importance of DPD has recently been demonstrated with the identification of severe and/or lethal 5-FU-related toxicity in patients with suspected or proven DPD deficiency revealed in lymphocytes. We conducted a prospective study on 185 cancer patients in order to evaluate the incidence of complete or partial DPD deficiency. The population comprised 152 men (mean age 62.1) and 33 women (mean age 59.2). Sixty eight were head and neck patients treated by a 5-day continuous infusion of 5-FU (starting dose 1 g/m2/day, with dose adaptation at mid-cycle) for which DPD activity was measured 2-3 days before 5-FU administration (94 cycles analyzed). DPD activity was measured by a radioenzymatic assay using 14C-5-FU. DPD activity showed a unimodal distribution, which globally fits a Gaussian distribution. Mean and median DPD activity were 0.222 and 0.211 nmol/min/mg prot respectively (range 0.065-0.559). No total DPD deficiency was found. Neither liver function nor age influenced DPD activity, but DPD activity was on average 15% lower in women than in men (0.194 and 0.228 nmol/min/mg prot respectively, p = 0.03). In patients treated with 5-FU, the risk of developing side effects was not linked to pretreatment DPD activity. 5-FU-related toxicity was linked to FU systemic exposure. The correlation between DPD activity and FU clearance was weak (n = 90, r = 0.31, p = 0.002). As a corollary, DPD activity in patients requiring a dose reduction was not significantly different from DPD activity in patients who did not require dose modification. From the present study it appears that total DPD deficiency is a very rare event. Although pre-treatment DPD activity cannot be a useful indicator for improving 5-FU dose adaptation strategy, the identification of partial DPD deficiency (< 0.100 nmol/min/mg prot, 3% of the population) could lead to starting the treatment with a markedly reduce 5-FU dose.

A role for dihydropyrimidine dehydrogenase and thymidylate synthase in tumour sensitivity to fluorouracil

Despite being one of the oldest anti-cancer drugs, fluorouracil (FU) is still being increasingly used in cancer chemotherapy. The source of variability for FU sensitivity in patients may be complex, although an overproduction of thymidylate synthase (TS) was the only mechanism of resistance identified in tumours from FU-resistant patients. Dihydropyrimidine dehydrogenase (DPD) is the first and rate-limiting enzyme of FU catabolism. Thus, DPD activity may be a potential factor for controlling FU responsiveness. A panel of 19 human tumour cell lines, including digestive tract, breast and head and neck cancer cells, were investigated. Both TS and DPD activities were measured in parallel to FU responsiveness. None of the cell lines had been previously exposed to FU, and thus expressed a spontaneous sensitivity to FU. Sensitivity between cell lines showed marked differences, with IC50 values ranging from 45 ng/ml (colon cell line) to 5063 ng/ml (head and neck cell line). TS activity was measurable in all cell lines and varied within a 46-fold range. DPD activity was detected in all but four cell lines, showing a 100-fold range of variation. Cell lines most sensitive to FU exhibited the lowest DPD and TS activities and vice versa. Simple linear regression analysis showed that both TS (r2 = 0.22, P = 0.042) and DPD (r2 = 0.27, P = 0.022) activities were significantly correlated to FU effectiveness (log 10 IC50): the greater the enzyme activities, the higher the FU IC50. TS and DPD were demonstrated to be independent variables. A multiple regression analysis showed that the combination of TS and DPD activities explained 36% of the variability in FU IC50 (r2 = 0.36, P = 0.01). Two groups of cell lines could be identified, one group with both low TS and low DPD activities (G1), and the other with either high TS and/or high DPD activities (G2). Mean FU IC50 values were 193 and 930 ng/ml in G1 and G2, respectively, and this difference in FU sensitivity was highly significant (P = 0.009). The present study shows, for the first time, that DPD activity in tumour cells is an independent factor significantly related to FU sensitivity. These results should encourage DPD and TS coupled measurements in tumours of patients before FU treatment in order to establish their prognostic relevance. DPD and TS measurements could also be used during the treatment course to determine the implication of these enzymes in the development of tumour resistance to FU.

Influence of sex and age on fluorouracil clearance.

PURPOSEnCurrently, fluorouracil (5-FU) is one of the major drugs used in cancer chemotherapy. Several investigators, including ourselves, have demonstrated a link between abnormalities in 5-FU clearance (Cl) and the risk of developing more or less 5-FU-related toxicities. Age and sex are among the host factors that have been implicated in the pharmacokinetic variability of drugs. Presently, no data are available on the possible influence of sex and age on 5-FU Cl.nnnPATIENTS AND METHODSnThree hundred eighty patients (mean age, 61.7 years; range, 25 to 91; 301 men and 79 women) with squamous cell carcinoma (sre) of the head and neck were treated in our institution between 1987 and 1991. 5-FU Cl was determined for a total of 1,092 chemotherapy cycles. Each cycle consisted of cisplatin and 5-day continuous intravenous infusion 5-FU (daily doses ranging between 365 and 1,224 mg/m2).nnnRESULTSn5-FU Cl values (L/h/m2) showed a wide dispersion for both men (median, 179; range, 29 to 739) and women (median, 155; range, 56 to 466). 5-FU Cl values were lower significantly for women compared with men (P = .0005). When adjusted for age and dose, the influence of sex on log Cl remained significant (P = .013). There was no evidence that age modified 5-FU Cl when adjusted for sex and dose. Interestingly, for both men and women, the oldest patients (greater than 70 years) maintained their ability to clear 5-FU with daily doses that ranged from 500 to 1,000 mg/m2.nnnCONCLUSIONSnThese data indicate that the capacities to clear 5-FU are lower in women compared with men and are not influenced by age. It would be of interest to know whether this sex-related difference in 5-FU Cl may be clinically relevant by considering both toxicity and tumor response to 5-FU treatment.

Prognostic Value of Tumoral Thymidylate Synthase and p53 in Metastatic Colorectal Cancer Patients Receiving Fluorouracil-Based Chemotherapy: Phenotypic and Genotypic Analyses

PURPOSEnThe aim of this multicenter prospective study was to evaluate the role of intratumoral parameters related to fluorouracil (FU) sensitivity in 103 metastatic colorectal cancer patients receiving FU-folinic acid.nnnPATIENTS AND METHODSnLiver metastatic biopsy specimens were obtained for all patients and primary tumor biopsy specimens for 54 patients. Thymidylate synthase (TS), folylpolyglutamate synthetase, and dihydropyrimidine dehydrogenase were measured by radioenzymatic assays; TS promoter polymorphism (2R/2R v 2R/3R v 3R/3R) was determined by polymerase chain reaction; and p53 protein and mutations were analyzed by immunoluminometric assay and denaturing gradient gel electrophoresis, respectively.nnnRESULTSnp53 mutations were observed in 56.7% of metastases. TS activity was significantly higher in 2R/3R tumors as compared with 2R/2R or 3R/3R. TS activity in metastasis was the only parameter linked to clinical responsiveness (responders exhibited the lower TS, P =.047). Univariate Cox analyses demonstrated that TS activity in primary tumor (the greater the TS, the poorer the survival; P =.040), TS promoter polymorphism in primary tumor (risk of death of 2R/3R v 2R/2R, 2.68; P =.035), and p53 stop mutation in metastasis (risk of death of stop mutations v wild type, 3.14; P =.018) were the only significant biologic predictors of specific survival. Stepwise analysis did not discriminate between TS activity and TS polymorphism.nnnCONCLUSIONnPresent results confirm the value of tumoral TS activity for predicting FU responsiveness, point out the importance of detailed p53 mutation analysis for predicting survival, and suggest that TS genotype in primary tumor carries a prognostic value similar to that of TS activity.

Potential Regional Differences for the Tolerability Profiles of Fluoropyrimidines

PURPOSEnWe conducted a retrospective analysis of safety data from randomized, single-agent fluoropyrimidine clinical trials (bolus fluorouracil/leucovorin [FU/LV] and capecitabine) to test the hypothesis that there are regional differences in fluoropyrimidine tolerability.nnnMETHODSnTreatment-related safety data from three phase III clinical studies were analyzed by multivariate analysis: two comparing capecitabine with bolus FU/LV in metastatic colorectal cancer (MCRC) and one comparing capecitabine plus oxaliplatin (XELOX) with bolus FU/LV as adjuvant treatment for colon cancer. The United States (US) was compared with non-US countries (all three studies) and with the rest of the world and East Asia (adjuvant study).nnnRESULTSnIn the MCRC studies (n = 1,189), more grade 3/4 adverse events (AEs; relative risk [RR], 1.77), dose reductions (RR, 1.72), and discontinuations (RR, 1.83) were reported in US versus non-US patients. Likewise, in the adjuvant colon cancer study (n = 1,864), more grade 3/4 AEs (RR, 1.47) and discontinuations (RR, 2.09) were reported in US versus non-US patients. After further dividing non-US patients into those in East Asia and the rest of the world, differential RRs for related grade 3/4 AEs, grade 4 AEs, and serious AEs were again observed, with East Asian patients having the lowest and US patients the highest RR.nnnCONCLUSIONnRegional differences exist in the tolerability profiles of fluoropyrimidines. More treatment-related toxicity was reported in the US compared with the rest of the world for bolus FU/LV and capecitabine in first-line MCRC and adjuvant colon cancer. In the adjuvant setting, a range of fluoropyrimidine tolerability was observed, with East Asian patients having the lowest, and US patients the highest, RR.

Relationship between fluorouracil systemic exposure and tumor response and patient survival.

PURPOSEnThe aim of this study was to analyze the link between fluorouracil (FU) systemic exposure and tumor response and overall survival.nnnPATIENTS AND METHODSnOne hundred eighty-six patients (162 men, 24 women) with head and neck cancer were studied. All received cisplatin plus FU for three cycles as first-line chemotherapy. The treatment consisted of cisplatin (100 mg/m2 intravenously [IV]) followed by a 5-day continuous venous infusion of FU (1 g/m2/d). The median follow-up duration for the 104 patients alive was 24 months. For each cycle, we calculated the area under the curve over the duration of pharmacokinetic follow-up (AUC0-105 h) for plasma FU. For each patient, we analyzed the averaged AUC0-105 h and the averaged total dose for the three cycles.nnnRESULTSnThe response rate was 30% complete responses (CRs), 22% partial responses (PRs) more than 75%, 25% PRs less than 75%, and 23% no response (NR). Medians for averaged AUC and dose per cycle were 27,906 ng/mL h (first through third quartile, 25,398 to 31,060) and 7,000 mg (first through third quartile, 6,200 to 7,833), respectively. The tumor response was significantly linked to tumor stage (P < .001) and to averaged AUC (P = .05), but not to averaged dose. Analysis of parameters (continuous variable) expressing FU treatment intensity showed that dose did not influence survival contrary to the AUC (P = .001). The AUC remains significant (P = .025) in a multivariate analysis including tumor stage, demonstrating that the greater the FU systemic exposure, the longer the survival.nnnCONCLUSIONnThese results strengthen the interest of individual FU dose adaptation based on pharmacokinetics.

Genetic Markers of Toxicity From Capecitabine and Other Fluorouracil-Based Regimens: Investigation in the QUASAR2 Study, Systematic Review, and Meta-Analysis

PURPOSEnFluourouracil (FU) is a mainstay of chemotherapy, although toxicities are common. Genetic biomarkers have been used to predict these adverse events, but their utility is uncertain.nnnPATIENTS AND METHODSnWe tested candidate polymorphisms identified from a systematic literature search for associations with capecitabine toxicity in 927 patients with colorectal cancer in the Quick and Simple and Reliable trial (QUASAR2). We then performed meta-analysis of QUASAR2 and 16 published studies (n = 4,855 patients) to examine the polymorphisms in various FU monotherapy and combination therapy regimens.nnnRESULTSnGlobal capecitabine toxicity (grades 0/1/2 v grades 3/4/5) was associated with the rare, functional DPYD alleles 2846T>A and *2A (combined odds ratio, 5.51; P = .0013) and with the common TYMS polymorphisms 5VNTR2R/3R and 3UTR 6bp ins-del (combined odds ratio, 1.31; P = 9.4 × 10(-6)). There was weaker evidence that these polymorphisms predict toxicity from bolus and infusional FU monotherapy. No good evidence of association with toxicity was found for the remaining polymorphisms, including several currently included in predictive kits. No polymorphisms were associated with toxicity in combination regimens.nnnCONCLUSIONnA panel of genetic biomarkers for capecitabine monotherapy toxicity would currently comprise only the four DPYD and TYMS variants above. We estimate this test could provide 26% sensitivity, 86% specificity, and 49% positive predictive value-better than most available commercial kits, but suboptimal for clinical use. The test panel might be extended to include additional, rare DPYD variants functionally equivalent to *2A and 2846A, though insufficient evidence supports its use in bolus, infusional, or combination FU. There remains a need to identify further markers of FU toxicity for all regimens.

Clinical pharmacokinetic study of 5-FU in continuous 5-day infusions for head and neck cancer.

SummaryTwenty-nine previously untreated patients with head and neck carcinoma received a total of 63 cycles of an initial chemotherapy protocol combining cis-platinum (100 mg/m2 on day 1) and continuous 5-day infusion of 5-FU (1000 mg/m2/24 h) from day 2 to day 6. This protocol was repeated on day 16 and day 31. Two daily blood samples obtained from all patients every day during 5-FU administration were analyzed by HPLC to determine the 5-FU concentrations. In the majority of cases a constant elevation was observed in total 5-FU cycle exposure (CxT) from cycle to cycle. A close relationship was demonstrated between elevated 5-FU CxT values (over 30 000 ng h ml-1) and the frequency of cycles in which signs of toxicity (myelosuppression, mucositis, diarrhea) were observed. By contrast, no obvious association was noted between response to treatment and systemic 5-FU exposure.

Intragenic deletions and a deep intronic mutation affecting pre-mRNA splicing in the dihydropyrimidine dehydrogenase gene as novel mechanisms causing 5-fluorouracil toxicity

Dihydropyrimidine dehydrogenase (DPD) is the initial enzyme acting in the catabolism of the widely used antineoplastic agent 5-fluorouracil (5FU). DPD deficiency is known to cause a potentially lethal toxicity following administration of 5FU. Here, we report novel genetic mechanisms underlying DPD deficiency in patients presenting with grade III/IV 5FU-associated toxicity. In one patient a genomic DPYD deletion of exons 21–23 was observed. In five patients a deep intronic mutation c.1129–5923C>G was identified creating a cryptic splice donor site. As a consequence, a 44xa0bp fragment corresponding to nucleotides c.1129–5967 to c.1129–5924 of intron 10 was inserted in the mature DPD mRNA. The deleterious c.1129–5923C>G mutation proved to be in cis with three intronic polymorphisms (c.483xa0+xa018G>A, c.959–51T>G, c.680xa0+xa0139G>A) and the synonymous mutation c.1236G>A of a previously identified haplotype. Retrospective analysis of 203 cancer patients showed that the c.1129–5923C>G mutation was significantly enriched in patients with severe 5FU-associated toxicity (9.1%) compared to patients without toxicity (2.2%). In addition, a high prevalence was observed for the c.1129–5923C>G mutation in the normal Dutch (2.6%) and German (3.3%) population. Our study demonstrates that a genomic deletion affecting DPYD and a deep intronic mutation affecting pre-mRNA splicing can cause severe 5FU-associated toxicity. We conclude that screening for DPD deficiency should include a search for genomic rearrangements and aberrant splicing.