Although cervical cancer is declining, human papillomavirus (HPV)-related cancers of the base of the tongue and tonsils (oropharynx) as well as anal canal cancers are increasing, according to a population-based study in Alberta, Canada, in CMAJ Open.
Human papillomavirus, long linked to cervical cancer, is estimated to cause 5.2% of all cancers worldwide; a link to cancers of the oropharynx and anal cancer has been recently confirmed.
The study, which includes cancers diagnosed over the last 35 years (between 1975 and Dec. 31, 2009) from the Alberta Cancer Registry, looked at trends in HPV-related cancers. During the study period, 8120 HPV-associated cancers were diagnosed in the province, of which 56% were cervical cancers and 18% oropharyngeal cancers. Although the highest number of cases was seen in the older age groups (55-64 and 65-74 years), the greatest percentage increase in oropharyngeal cancers over this period was seen in those in the < 45-years-old group among men. Anal cancer in women doubled, from 0.7 to 1.5 per 100 000 people. The highest increase in women was in those under age 45 years.
"The increases in the incidence of oropharyngeal cancer among younger men and of anal cancer among younger women are disturbing, because there are no screening programs for early detection of these cancers," says Dr. Lorraine Shack, Assistant Professor, Department of Oncology, Cumming School of Medicine, University of Calgary, Alberta, with coauthors.
In Alberta, the publicly funded HPV vaccine program was first introduced in 2008, offering vaccine to Grade 5 girls (with a short-term catch-up program offered to Grade 9 girls for 4 years). Alberta has now expanded this program; effective September 2014, the HPV vaccine will also be offered to all Grade 5 boys in Alberta, with a catch-up program for Grade 9 boys for 4 years after this program begins.
"To have a large impact on the prevention of these HPV-associated cancers, vaccination programs should be considered for males as well as females, as has now been done in Alberta. Both oropharyngeal and anal cancers are associated with substantial side effects when treated; therefore, education and prevention programs, including the HPV vaccination program, are urgently required," says Dr. Harold Y. Lau, Clinical Associate Professor, Department of Oncology, University of Calgary.
This project was funded through a grant from Joe's Team, Alberta Cancer Foundation.