Nasopharyngeal swab and PCR for the screening of nasopharyngeal carcinoma in the endemic area: a good supplement to the serologic screening.
BACKGROUND
Nasopharyngeal carcinoma (NPC) is a common head and neck cancer in Taiwan. Early detection is the best way to improve survival for this disease. A prospective study was designed to assess the feasibility of a new screening method for NPC by use of polymerase chain reaction (PCR) based on the close association of NPC and Epstein-Barr virus (EBV).


METHODS
One hundred thirty-three different tissues from nasopharynx, nose, and sinus were investigated by use of PCR to check for the presence of EBV genome. Subsequently, from April 1996 to March 1997, 55 patients were enrolled in a prospective screening study. All patients underwent nasopharyngeal swabs before biopsy. Polymerase chain reaction detection of EBV genome was conducted on swab samples. Anti-EBV viral capsid antigen (VCA) in IgA and IgG class were checked at the same visit.


RESULTS
The EBV genome was present in 91.4% (85/93) of NPC tissues and in 25.0% (10/40) of non-NPC tissues (p < .001, chi2 test). Of the 55 swabs, 49 (89.1%) specimens obtained enough cells for PCR examination. Thirty of these 49 patients were pathologically proved NPC. The presence of EBV were 86.7% (26/30) in NPC group and 42.1% (8/19) in non-NPC group. The sensitivity and specificity were 86.7% and 57.9%, respectively, which were similar to those of serologic method (87.5% and 43.5%) when the cut-off point was set at anti-VCA IgG > or = 160 and IgA > or = 10. Combining both methods elevates the specificity to 84.2%.


CONCLUSIONS
The sensitivity of this PCR screening method is similar to that of the serologic method. Combining both methods can greatly increase the specificity, indicating this new method is a good supplement to the serologic screening of this endemic disease.
Sheen
T S
TS
Department of Otolaryngology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Republic of China.
Ko
J Y
JY
Chang
Y L
YL
Chang
Y S
YS
Huang
Y T
YT
Chang
Y
Y
Tsai
C H
CH
Hsu
M M
MM
D000914:Antibodies, Viral / Q000097:blood; D017931:DNA Primers; D004279:DNA, Viral / Q000302:isolation & purification; D005240:Feasibility Studies; D016679:Genome, Viral; D004854:Herpesvirus 4, Human / Q000235:genetics* / Q000276:immunology; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000821:virology*; D016133:Polymerase Chain Reaction; D011446:Prospective Studies; D012680:Sensitivity and Specificity
D000914:Antibodies, Viral; D017931:DNA Primers; D004279:DNA, Viral