The effectiveness of HPV viral load, reflected by Cobas 4800 HPV-Ct values for the triage of HPV-positive women in primary cervical cancer screening: Direct endocervical samples.

OBJECTIVE

To explore the relationship between the viral load reflected by the Ct value of Cobas 4800 HPV test and cervical lesions, and the effectiveness of the viral load for secondary triage of HPV-positive women.

METHODS

The Chinese Multi-Center Screening Trial (CHIMUST) evaluated both self-collected samples and physician-collected samples from women, aged 30 to 59, who were screened for cervical cancer in 6 regions across China. Using physician collected samples, the relationship between the HPV-Ct values of different subtypes and the cervical lesions was analyzed. Then the combined use of the HPV-Ct values with the HPV subtypes was evaluated as a secondary screening algorithm for the women who were HPV positive.

RESULTS

The Ct values of HPV16 and 12 other HPV subtypes(12-type pool), tested with Cobas decreased with the progression of cervical lesion (HPV16: r = -0.429, P<0.001; 12 other HR-HPV subtypes: r = -0.099, P<0.01). The HPV18-Ct value was not correlated with cervical lesion(P>0.05). Compared with HPV16/18 and cytology (HPV16/18 positive and 12-type pool plus cytology ≥ ASC-US), the sequential secondary screening using HPV16/18 and the viral load of 12-type pool (cut-point HPV-Ct≤31) had equal sensitivities for CIN2+ and CIN3+ (83.1%vs.80.3%,100%vs.92.6%,P>0.05), with slightly lower specificities (96.2%vs.94.4%,96.5%vs.93.9%,P<0.001) and higher colposcopy referral rate (4.90%vs.6.59%, P<0.05), but required no cytology.

CONCLUSION

Type-specific HPV viral load is closely related to cervical lesions severity. It is feasible and efficient to use HPV16/18 and the viral load of 12 other HPV subtypes (with cut-point HPV-Ct≤31) as the secondary screening for HPV positive women. This algorithm may be useful in low resource regions.