241P - P16 IHC stain is an useful marker for predicting outcome of oropharyngeal cancer in Taiwan

Background

Human papillomavirus-associated oropharyngeal squamous cell carcinoma (HPV-associated OPSCC) is well known to have a relatively indolent behavior, and it should be staged separately. P16 is a useful surrogate marker for HPV status in OP region. However, the low prevalence of HPV infection in Taiwan (lower than 30%) may cause increased possibility of false positive for p16 staining. This study is aimed to determine the concordance of p16 IHC stain and HPV RNA ISH in Taiwan population.

Methods

There were 141 oropharyngeal cancer patients are retrieved from the archives of VGHTC from 2016 to 2020. HE stain was done and reviewed by 2 pathologist and p16 IHC stain was performed for all cases. Forty-nine (34.8%) of all cases were p16(+) oropharyngeal cancer. HPV-ISH was done for p16(+) oropharyngeal cancer patients.

Results

HPV-ISH found 44 (89.7%) of 49 cases were HPV-ISH (+). On univariate analysis, p16 (+) oropharyngeal cancer patients had better 3-year overall survival (90.4 % vs. 73.4 %, p=0.02) and 3-year disease-free survival (95.4% vs. 65.3%, p=0.0005) than p16(-) oropharyngeal cancer patients. HPV-ISH (+) oropharyngeal cancer patients also had better 3-year overall survival (92.0 % vs. 73.5 %, p=0.02) and 3-year disease-free survival (94.9% vs. 67.4%, p=0.002) than HPV-ISH(-) oropharyngeal cancer patients. We also found p16(+)HPVISH(+) oropharngeal cancer patients had better 3-year disease-free survival than p16(-)HPVISH(-) oropharngeal cancer patients (94.9% vs. 65.3%, p=0.002).

Conclusions

By far, p16 is still a useful surrogate marker for OPSCC in Taiwan.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The author.

Funding

Has not received any funding.

Disclosure

The author has declared no conflicts of interest.