Correlation of mutant P53 protein expression and Ki67 index with tumor response to concurrent chemoradiation in locally advanced head and neck cancer

Background

Concurrent chemoradiotherapy (CRT) remains mainstay of management in locally advanced head and neck squamous cell cancers. Despite advancements in treatment delivery, there is heterogeneity in treatment outcome and only marginal improvement in survival rates. This study was done to find out the correlation of mutant P53 protein expression and Ki67 index with the treatment response to concurrent chemoradiotherapy.

Methods

55 patients of stage III-IVA non-nasopharyngeal head and neck squamous cell carcinoma were enrolled and the expression of mutant P53 protein and Ki67 index in the tumor were analysed. All patients were treated with concurrent chemoradiotherapy using conventional planning to a dose of 66Gy in 33 fractions and 2 cycles of Inj cisplatin 100mg/m² as concurrent chemotherapy. The degree of mutant P53 protein expression and Ki67 index were correlated with the response to concurrent chemoradiotherapy, examined within three months of treatment completion with RECIST1.1 criteria.

Results

It was observed that 30 patients had complete response and 25 patients had partial response to CRT. It was found that 76% of the study patients had mutant p53 protein expression and 95% had Ki67 positivity. On statistical analysis it was found that the expression of mutant p53 protein and Ki67 index showed strong association with N-stage, TNM stage and tumor response following CTRT. All patients whose tumors were negative for mutant P53 protein expression and negative Ki-67 had complete response to CRT.

Conclusions

Rate of mutant P53 protein expression and Ki67 were significant in predicting tumor response to CRT. With careful evaluation and molecular prognostication of all head and neck cancer, high risk patients can be identified, who tend to show partial response to CRT. This might provide a cohort of patient selection for future trials planning for targeted therapy against these molecular markers.

Clinical trial identification

Legal entity responsible for the study

Priya Baskaran Shanmuga

Funding

VMMC and SJH hospital

Disclosure

All authors have declared no conflicts of interest.