BACKGROUND

Recent data from all over the world shows the incidence of Oropharyngeal cancer due to HPVinfection, a virus that causes the more than a quarter of all cancer new cases in Tanzania. On the other hand these cancers are very preventable, primarily through vaccination against HPV. A vaccine available in Tanzania but gender specific.
HPV associated oropharyngeal squamous cell carcinoma (OPSCC) has been shown to be a distinct molecular and
clinical entity in terms of its demographics, staging, survival and prognosis. International guidelines recommend that decisions regarding the staging, prognosis, and treatment of patients with OPSCC should be made after determining their p16 expression (a surrogate marker for HPV infection). Unfortunately, our local treatment guidelines in Tanzania still has not in-cooperated p16 IHC testing as a guide for staging and treatment despite having qualified pathologists and laboratories to do P16 IHC test. We assessed the socio-demographic and clinicopathological profile and influence of p16 expression on survival in our OPSCC patients.

METHODS

Retrospective cohort hospital based study conducted at Ocean Road Cancer Institute and at the Muhimbili National Hospital.

RESULTS

The prevalence of P16 positive OPSCC was found to be 43.4% which is higher than most of the few studies conducted in Africa. P16 positive patients were younger, predominantly males, with a better 3 years OS of 36% compared to 16.6% in those with p16 negative tumors. With multivariate analysis on Cox proportional hazard models p16 expression showed no significant association with overall survival. Receiving more than 2 cycles of concurrent chemotherapy and ECOG PS were found to be potential predictors of survival.

CONCLUSION

The high prevalence of p16 positive tumors in Tanzania suggests preventive measures such as gender-neutral HPV
vaccine should be implemented in the Tanzanian population. Our results confirm the use of p16 IHC as a prognostic biomarker for OPSCC.