Oral and lip cancer in solid organ transplant patients--a cohort study from a Swedish Transplant Centre

Previous large studies have shown that solid organ transplant (SOT) patients have an increased risk of developing malignancies. Few studies have compared the prognosis for SOT patients who develop cancer with that of non-transplanted cancer patients. In this study we have investigated the increased risk of oral and lip cancer in SOT patients and also compared the relative survival between SOT patients and non-SOT patients with oral and lip cancer.

From the patient registers at the Transplant Institute at Sahlgrenska University Hospital, records of 4604 SOT patients from 1965 to 2010 were collected. These patient records were linked to the nationwide Swedish Cancer Register and compared to those of the normal population regarding the risk of developing oral and lip cancer, and also to non-SOT patients with lip and oral cancer. A Poisson regression model was used to compare the relative survival between SOT and non-SOT patients with oral and lip cancer.

We observed 17 oral cancers (expected 2.69) and 34 lip cancers (expected 0.78) in the cohort. The standardized incidence ratio (SIR) for oral cancer was 6.32 (95% CI, 3.7-10.1) and 43.7 (95% CI, 30.3-61.1) for lip cancer. Relative five-year survival for lip cancer was lower for SOT patients compared to non-SOT patients (p<0.001).

This study shows that SOT patients have a higher risk of developing both oral and lip cancer, and in addition, that SOT patients with lip cancer have a worse prognosis.