Quantification of plasma Epstein-Barr virus DNA in patients with advanced nasopharyngeal carcinoma.

BACKGROUND: We investigated the clinical significance of plasma concentrations of Epstein-Barr virus (EBV) DNA in patients with advanced nasopharyngeal carcinoma. METHODS: Ninety-nine patients with biopsy-proven stage III or IV nasopharyngeal carcinoma and no evidence of metastasis (M0) received 10 weekly chemotherapy treatments followed by radiotherapy. Plasma samples from the patients were subjected to a real-time quantitative polymerase-chain-reaction assay. EBV genotypes of paired samples from plasma and primary tumor were compared. RESULTS: Plasma EBV DNA was detectable before treatment in 94 of the 99 patients, but not in 40 healthy controls or 20 cured patients. The median concentrations of plasma EBV DNA were 681 copies per milliliter among 25 patients with stage III disease, 1703 copies per milliliter among 74 patients with stage IV disease, and 291,940 copies per milliliter among 19 control patients with distant metastasis (P<0.001). Patients with relapse had a significantly higher plasma EBV DNA concentration before treatment than those who did not have a relapse (median, 3035 vs. 1202 copies per milliliter; P=0.02). The consistent genotyping of EBV DNA between paired samples of plasma and primary tumor suggested that the circulating cell-free EBV DNA may originate from the primary tumor. Unlike the rebound of plasma EBV DNA concentrations in the patients who had a relapse, the plasma EBV DNA concentration was persistently low or undetectable in patients with a complete clinical remission. Overall survival (P<0.001) and relapse-free survival (P=0.02) were significantly lower among patients with pretreatment plasma EBV DNA concentrations of at least 1500 copies per milliliter than among those with concentrations of less than 1500 copies per milliliter. Patients with persistently detectable plasma EBV DNA had significantly worse overall survival (P<0.001) and relapse-free survival (P<0.001) than patients with undetectable EBV DNA one week after the completion of radiotherapy. CONCLUSIONS: Quantification of plasma EBV DNA is useful for monitoring patients with nasopharyngeal carcinoma and predicting the outcome of treatment.

Outpatient weekly 24-hour infusional adjuvant chemotherapy of cisplatin, 5-fluorouracil, and leucovorin for high-risk nasopharyngeal carcinoma.

BACKGROUND: Distant metastasis rather than locoregional recurrence is the major site of failure after adequate radiotherapy in nasopharyngeal carcinoma (NPC). The aim of this study is to evaluate the toxicity and survival of outpatient weekly 24-hour infusion adjuvant chemotherapy for NPC patients with high-risk of distant failure. METHODS: Our definition of high-risk NPC included patients with (1) 1992 AJCC staging system of N3, T4N2, or N2 with one of nodal size > 4 cm; (2) supraclavicular node metastasis; and (3) residual disease after radiotherapy or neck relapse. From August 1994 to August 1997, 41 NPC patients matching the preceding criteria agreed to receive weekly PFL (cisplatin 25 mg/m(2), 5-fluorouracil 1250 mg/m(2), and leucovorin 120 mg/m(2)) adjuvant chemotherapy for a total of 18 weeks. Clinical data of another 88 patients with similar disease status who did not receive adjuvant chemotherapy during the same period were collected and analyzed for comparison. Survival analysis was investigated by the Kaplan-Meier method and the Cox proportional hazards model. RESULTS: A total of 700 weekly chemotherapy doses was delivered to 41 patients. The ratio of actual/planned dose delivery was 94.9%. Grade 3-4 toxicity of adjuvant chemotherapy included leucopenia (7.3%), anemia (2.4%), thrombocytopenia (2.4%), and nausea/vomiting (2.4%). After a median follow-up of 70 months, 26.8% (11 of 41) and 47.7% (42 of 88) of patients in PFL and no adjuvant chemotherapy groups had distant metastasis (p =.0247). The 5-year metastasis-free survival rates were 71.9% for the PFL group compared with 48.4% for no adjuvant chemotherapy patients (p =.0187). The 5-year overall survival rates were 53.7% (PFL group) and 38.3% (no adjuvant chemotherapy group), respectively (p =.0666). Multivariate Cox analysis showed PFL adjuvant chemotherapy was the independent factor that predicted metastasis-free survival after adjustment for other variables. CONCLUSIONS: Outpatient weekly 24-hour continuous infusion PFL adjuvant chemotherapy is a well-tolerated regimen with promising results in high-risk NPC patients and merits investigation in phase III studies.

PCR detection of circulating tumor cells in nasopharyngeal carcinoma patients with distant metastasis: effect of enzyme and sampling.

BACKGROUND: Nasopharyngeal carcinoma (NPC) has a high potential to develop distant metastasis after radiotherapy. Cytokeratin 19 (CK-19) mRNA has been frequently used as a marker in the detection of circulating tumor cells of epithelial origin, but has rarely been investigated in NPC. This study was performed to evaluate the effect of blood sampling and different Taq DNA polymerase on the results of nested reverse transcriptase-polymerase chain reaction (RT-PCR) assay. METHODS: Peripheral blood samples from a total of 37 NPC patients with well-documented distant metastasis (M1) were collected before treatment. Eighteen patients had more than one blood sampling. Five different Taq DNA polymerases were used to test the blood from 17 patients. Peripheral blood of 37 nonmetastatic (M0) NPC patients was tested by the same nested RT-PCR system using multiple Taq DNA polymerases to evaluate the impact of multienzyme assay in the prediction of subsequent distant metastasis. RESULTS: Among M1 NPC patients, the accumulative positive rates of CK-19 mRNA were 22.2%, 44.4%, 70.6%, 75.0%, and 80.0% when one, two, three, four, or five blood sampling were taken, respectively. The accumulative positive rates increased as the numbers of different enzymes increased-from 35.5% by one enzyme to 82.4% by five enzymes. Six of 37 M0 patients had distant metastasis develop after a median follow-up time of 20 months. The detection sensitivity for four-enzyme test (5 of 6 = 83.3%) is better than that of one-enzyme test (2 of 6 = 33.3%). CONCLUSIONS: Our data demonstrate that multiple blood sampling or using multiple enzymes for nested RT-PCR assay significantly enhances the sensitivity in the molecular diagnosis of NPC metastasis.

Definition of three minimal deleted regions by comprehensive allelotyping and mutational screening of FHIT,p16(INK4A), and p19(ARF) genes in nasopharyngeal carcinoma.

BACKGROUND: Recurrent deletion on a chromosomal location in tumor cells can be detected by frequent allelic loss and generally is considered to be an indication of the existence of a tumor suppressor gene (TSG) in the region. In the current study, using fluorescent-labeled, high-density microsatellite markers for allelotyping, the authors pinpointed three minimal deleted regions (MDRs) and screened mutations of putative TSGs on chromosomes 3, 9, and 11 in nasopharyngeal carcinoma (NPC) cases occurring in Taiwan. METHODS: A total of 133 informative microsatellite markers were used on chromosomes 3, 9, and 11 with an average marker density of 4 centimorgans (cM) for the allelotyping of genomic DNAs isolated from NPC tissues and their corresponding lymphocytes in 48 patients. The correlation between allelic loss and the clinicopathologic parameters of NPC tissues was examined. In addition, putative TSGs including FHIT, p16(INK4a), and p19(ARF) were selected for mutation screening to investigate their potential participation in NPC tumorigenesis. RESULTS: Of 3787 informative allelotyping data, 25 frequent allelic losses (or loss of heterozygosity [LOH]) in 13 cytogenetic loci were identified based on a deletion frequency that was greater than the average of allelic loss on that particular chromosome. Several significant associations were determined after statistical analysis of the correlation between allelic loss and clinicopathologic parameters. The allelic losses by D9S318 and D11S1304 were associated with N2/N3 (P = 0.035 and P = 0.005, respectively), and those by D9S905 and D11S1304 were associated with grouped American Joint Committee on Cancer (AJCC) Stage III/IV samples (P = 0.022 and P = 0.017, respectively) of NPC tissues. In addition, three MDRs were revealed on 3p25.3-24.1 (< 19 cM), 3p23-21.31 (< 9 cM), and 11q22.1-23.2 (< 8 cM). To examine somatic mutations in previously reported TSGs located near these frequent LOH loci, three candidate genes, p16(INK4a), p19(ARF), and FHIT, were analyzed. Point mutations in the coding region of FHIT and in the intron 1 splicing acceptor site of both p16(INK4a) and p19(ARF) were detected in NPC cell lines. Sequence analysis of both p16(INK4a) and p19(ARF) transcripts revealed that the point mutation resulted in skipping of exon 2 and the generation of shorter transcripts. CONCLUSIONS: High-density allelotyping permitted the discovery of 3 MDRs on 3p25.3-24.1 (< 19 cM), 3p23-21.31 (< 9 cM), and 11q22.1-23.2 (< 8 cM) and a correlation was determined between allelic loss and clinicopathologic parameters of NPC tissues. More important, one somatic mutation in NPC cell lines on the intron 1/exon 2 splicing acceptor site of the INK4a/ARF locus was found to result in exon 2 skipping both p16(INK4a) and p19(ARF) transcripts, which presumably inactivates the functions of both the p16(INK4a) and p19(ARF) proteins.

A phase III study of adjuvant chemotherapy in advanced nasopharyngeal carcinoma patients.

PURPOSE: To evaluate the role of adjuvant chemotherapy in locally advanced nasopharyngeal carcinoma (NPC) patients, we conducted a randomized Phase III trial comparing radiotherapy (RT) followed by adjuvant chemotherapy to RT alone in patients with advanced NPC. METHODS AND MATERIALS: Between November 1994 and March 1999, 157 patients with Stage IV, M(0) (UICC/AJCC, 1992) advanced NPC disease were randomized to receive standard radiotherapy, as follows: 35-40 fractions, 1.8-2.0 Gy/fraction/day, 5 days/week, to a total dose 70-72 Gy with or without 9 weekly cycles of 24-h infusional chemotherapy (20 mg/m(2) cisplatin, 2,200 mg/m(2) 5-fluorouracil, and 120 mg/m(2) leucovorin) after RT. Of 157 patients enrolled, 154 (77 radiotherapy, 77 combined therapy) were evaluable for survival and toxicity analysis. RESULTS: With a median follow-up of 49.5 months, the 5-year overall survival and relapse-free survival rates were 60.5% vs. 54.5% (p = 0.5) and 49.5% vs. 54.4% (p = 0.38) for the radiotherapy-alone group and the combined radiotherapy and adjuvant chemotherapy group, respectively. The Cox regression showed that the hazard rates ratio of combined treatment to RT alone was 0.673 (p value = 0.232); the 95% confidence interval was 0.352 and 1.288, respectively. Patients who received combined treatment had a lower systemic relapse rate than radiotherapy-alone patients, according to relapse pattern analysis. The incidence of leukopenia (>or= Grade 3) occurred in 17 out of 819 (2.1%) cycles of weekly chemotherapy. No patient developed moderate to severe mucositis (>or= Grade 3). CONCLUSIONS: We conclude that adjuvant chemotherapy after RT for patients with advanced NPC has no benefit for overall survival or relapse-free survival.

Evaluation of cytokeratin-19 mRNA as a tumor marker in the peripheral blood of nasopharyngeal carcinoma patients receiving concurrent chemoradiotherapy.

The reverse transcriptase-polymerase chain reaction (RT-PCR) technique is a tool capable of detecting minute quantities of circulating tumor cell-derived transcripts. Nasopharyngeal carcinoma (NPC) is a rapidly growing tumor of epithelial origin and high metastatic potential. The aim of our study is to investigate the clinical value of circulating cytokeratin-19 (CK-19) mRNA detection in NPC patients. Between June 1997 and March 1999, 57 previously untreated, advanced NPC patients without distant metastasis were uniformly treated by concurrent chemoradiotherapy. Peripheral blood samples were collected prospectively before treatment and subjected to a nested RT-PCR assay. Measures were taken to prevent contamination and pseudogene interference. PCR products of positive results were verified by restriction enzyme Hae II and direct sequencing. Under our nested RT-PCR experimental conditions, 33.3% (19/57) clinically nonmetastatic NPC patients had CK-19 mRNA in their blood. The positive detection rates of CK-19 mRNA in the peripheral blood for different stages were 20.0% for stage II, 31.6% stage III and 43.5% stage IV (p = 0.1335). After a median follow-up time of 35 months, 2 patients had recurrences of their primary tumors and 14 developed distant metastases without locoregional recurrence. Nine of 19 (47.4%) CK-19 mRNA-positive patients and 5 of 38 (13.2%) CK-19 mRNA-negative patients developed distant metastasis (p = 0.00826). The 3-year metastasis-free survival rates were 49.9% for patients with detectable CK-19 and 85.9% for those with undetectable CK-19 (p = 0.0089, log-rank test). Our data suggest that the presence of CK-19 mRNA in the peripheral blood may be a potential marker of micrometastasis for NPC.