181009. Two unidentified guys smoke Hubbly bubbly in Georginia, Florida. Picture: Dumisani Sibeko

The prevalence of oral sex and dagga use among teenagers is contributing to an alarming increase in mouth and throat cancers, the South African Dental Association (Sada) has said.

Briefing the media in Cape Town this week, Maretha Smit, CEO of Sada, said mouth (oral cancer, OC) and throat cancers (oro-pharyngeal, OP) globally affect up to 400 000 new patients per year. Cancers associated with Human Papilloma Virus (HPV), dagga and hubbly bubbly pipe-smoking occurred mostly in young adults.

“While part of the explanation of this can be attributed to the Human Papilloma Virus and the changing sexual behaviours of a younger generation, where multiple partners and oral sex feature strongly, many other lifestyle practices also become significant in view of recent research results that indicate causal links between OC and OPC and cannabis and hubbly bubbly pipe-smoking.”

She said 50 percent of people affected by mouth and throat cancer died within five years of diagnosis, adding that, in recent years, younger people were being diagnosed with these illnesses.

Sada said the number of school-going children using dagga was increasing in South Africa, following trends elsewhere such as in the United States, and the trend also reflected a decline in cigarette smoking within the same group. “Coupled to changing sexual behaviours in the same age groups, and where oral sex features prominently, these trends will most likely lead to increases in HPV-OPCs in the next 10 to 20 years,” Sada said.

On Tuesday, Sada said dagga carried the same risk as any smoked tobacco because it contained carcinogens.

André van Zyl, from the School of Dentistry at the University of Pretoria, said recent research showed that dagga smoking was “strongly” associated with HPV-positive OPC.

“In those who had smoked the substance at a rate of at least one joint per day for five or more years, a more than 11-fold increase in risk for developing HPV-positive cancer was seen,” Van Zyl said.

He said it was likely that the cannabinoids modified the immune system thereby causing HPV to spread more easily during oral sex. “Once it has spread, the cannabinoids will also promote the persistence of the HPV infection, as well as promoting tumour formation by suppressing those parts of the immune system required to protect against cancer.”

Van Zyl continued: “These young people could never imagine that they might develop OC or OPC, and it therefore is imperative that regular dental check-ups are conducted to ensure an early diagnosis of cancer.”

Smit said more than 90 percent of people diagnosed with early-stage OC/OPC survived. - Cape Times