American and European research shows an alarming increase in the rate of tonsillar cancer related to the human papillomavirus (HPV).
Experts have suggested that a similar trend has emerged in Canada, and now a new study in Current Oncology has confirmed it (Vol. 20:4, pp. 212-219).
Historically, oropharyngeal cancer was linked primarily to smoking and alcohol use, but recent studies have shown that HPV is now a major cause. To assess the impact in Canada, researchers from Lawson Health Research Institute and Western University conducted a retrospective study of throat cancer patients at London Health Sciences Centre (LHSC).
Looking at three different time periods -- 1993-1999, 2000-2005, and 2006-2011 -- the study authors searched the LHSC pathology database for patients with tonsillar cancer diagnosed during those time periods. The team then reviewed each patient's chart for information on diagnosis, treatment, and follow-up, and analyzed their biopsy samples to determine whether HPV was present in the patients' DNA.
In total, they identified 160 patient records with sufficient data for analysis. HPV was detected in 57% of cases, most commonly among young nonsmokers. In addition, the researchers found that the incidence of these cancers rose significantly over each time period.
Over the same period, treatment generally evolved from radiation to a concurrent mix of chemotherapy and radiation, and survival rates also improved significantly, the researchers reported; recurrence-free survival increased from 53% to 82%, and five-year survival rates increased from 37% to 83%.
While these results show positive patient outcomes, they also suggest serious complications for the available health resources in Canada, the study authors emphasized. Unlike traditional throat cancer patients, those with HPV-related tonsillar cancer are younger, healthier, and more likely to survive their disease. New treatments allow them to live longer but also expose them to more concentrated levels of toxicity, and make them more reliant on healthcare resources for a longer period of time.
