Field Cancerisation in Oral Squamous Cell Carcinoma Patients: A Systematic Review

Field cancerisation refers to molecular level cancerous changes that occurs in clinically normal looking tissue. In oral cavity, widespread exposure to carcinogens like tobacco/alcohol makes the entire mucosa susceptible to malignant changes. This manifests as local recurrence and/second primary after initial treatment of primary tumours. The purpose of this review is to identify the most commonly used marker in oral cavity field cancerisation and also to find out its prognostic significance.

Systematic review was conducted following PRISMA guidelines. Literature search was conducted using PubMed, Web of Science and Google scholar. Study selection was done independently by two reviewers and any discrepancy was resolved by third reviewer. A total of 23 articles were included after full-text reading. JBI checklist was used to assess the risk of bias for each study and RevMan 5.4 software was used to develop graphs.

Ki-67, p53, cyclin-D1, E-Cadherin, vascular markers like α -SMA, mi-RNAs, chromosomal polysomy, and epigenetic modifications like gene methylations were the various biomarkers used in the included studies. Both Ki-67 and p53 were found to be the most commonly employed markers in field cancerisation. However Ki-67 has more confirmed role in identifying field changes and is an established independent prognostic indicator of loco-regional control and disease free- survival rate. Further prospective studies are needed to fully evaluate the role of these markers in predicting second events like loco-regional recurrences and second primaries.