risk of second primary cancer in HPV+ head and neck squamous cell carcinoma (HNSCC)
Purpose/Objective
Human papilloma virus (HPV) was long known to be primarily causing cervical cancers. However, recently, HPV was discovered to be carcinogenic in other regions in the body most predominantly in the head and neck region. We have little information about the nature of HPV caused head and neck SCC and its associations with a second primary cancer in the head and neck region and non-head and neck regions. So, that is the aim of our study.
Material/Methods
Data of 8,547 patients were extracted from the Surveillance, Epidemiology, and End Results (SEER) database diagnosed from 2000-2019. Using MP-SIR seer session, the standardized incident ratio (SIR) was assessed as Observed/Expected (O/E) ratio and Excess Absolute Risk (EAR) is per 10000. Confidence intervals are 95% and P value is significant P<0.05. We assessed the risk of a second primary cancer in both head and neck regions and distant regions.
Results
Out of all patients, 652 got a second primary tumor for which 407 were in the head and neck region and 245 were in distant sites. The primary sites at risk for a second primary tumor in the head and neck region were the tonsils and the tongue. The tonsils had the highest risk of a second primary tumor of an EAR=105.6, and O/E= 730.8 (P<0.05, 95%CI: 608.3-870.8) with the highest risk being at 12-59 months after the diagnosis of HPV+ HNSCC; EAR=109.3, O/E=741.6 (P<0.05, 95%CI: 557.1-967.6). The tongue was found to be at the second highest risk with an overall EAR=97 and O/E=340.19 (P<0.05, 95%CI: 280.9-408.4). The highest risk for second primary tongue cancer was at the first 11 months with EAR=101.3, O/E=362.3 (P<0.05, 95%CI: 282.5-457.8).
For non-head and neck regions, Sites with the highest risk were the esophagus and the lungs. The esophagus had the biggest risk with an EAR=10, O/E=6.4 (P<0.05, 95%CI: 3.5-10.80). The highest risk was at months 12-59 with EAR=12.3, O/E=7.6 (P<0.05, 95%CI: 3.1-15.6). Lungs were the second with EAR=8.5, O/E=1.8 (P<0.05, 95%CI: 1.1-2.7) and the highest risk was at months 12-59 with EAR=23.3, O/E=3.1 (P<0.05, 95%CI: 1.8-5).
Conclusion
These results showed that 7.6% of patient with primary HPV+ HNSCC suffered a second primary cancer. The tonsils showed an overall 730-fold risk to develop a second primary tumor with the highest risk to be between 12-59 months of HPV+ HNSCC diagnosis. The tongue had a 340-fold risk increase for developing second primary cancer with highest risk at the first 11 months.
Regarding distant region, the esophagus had 6-fold increase in the chances of developing a second primary cancer while it was around 2-fold risk for the lungs. Both had the highest risk at months 12-59
We recommend follow up screening of newly diagnosed patients in the first 11 months for tongue cancer and at months 12-59 for tonsillar cancer. For non-head and neck region, we only recommend screening follow up for high risk patients at months 12-59 for both esophageal and lung cancer.
