Is there a relationship between periodontal disease and oral cancer? A systematic review of currently available evidence.

Unlabelled: Oral cancer (OC) is known to have a multi-factorial etiology; tobacco, alcohol and betel quid being the major risk factors. Tooth loss and periodontal disease (PD) have been implicated to increase the risk of developing various cancers. The aim of this systematic review was to assess any possible association between PD and OC. Indexed databases were searched using different combinations of the following key words: "oral cancer", "periodontal disease", "tooth loss", "squamous cell carcinoma", "missing teeth" "alveolar bone loss", "clinical attachment loss" and "periodontitis". PRISMA criteria were followed to accrue data and databases were searched from 1984 up to and including June 2015. In total, 12 case-control studies were selected from the published literature.

Results: Nine studies reported a 2-5 fold increase in the risk of OC among patients with PD as compared to those without PD. Three studies reported no association between PD and OC. In one study, an increased risk of tongue cancer was associated with each millimeter of alveolar bone loss and in two studies clinical attachment loss of more than 1.5mm was associated with an increased risk of OC. In studies reporting significant findings these associations persisted after adjusting for major risk factors. PD is associated with a small but significant increase in risk for OC. In several reported studies this association was attenuated following adjustment for tobacco and alcohol use.