A phase III clinical trial in which the University of Montreal Hospital Center is participating is testing the effectiveness of a shorter, and potentially less painful, treatment for oropharyngeal cancers caused by human papillomaviruses.
The usual treatment for these cancers, although it is very effective, is not “a walk in the park”, recalled radiation oncologist Houda Bahig: seven weeks of radiotherapy and chemotherapy during which the patient’s quality of life will be seriously compromised, in particular due to difficulties in swallowing so intense that some will be fed through a nasogastric tube.
“We know that it is something that works very well, but we know that it is something very strong and we are looking for ways to maintain this treatment effectiveness and reduce the impact on the quality of life of patients,” summarized Dr. Bahig, who discussed her work first with The Canadian Press.
Dr. Bahig and her colleagues from the United States, Ireland, Australia and Italy are therefore trying to see whether it might not be possible to shorten the treatment duration to 4.5 weeks using highly targeted stereotactic radiotherapy.
This type of radiotherapy, she explained, has long been used to fight other types of cancers, but its use in oropharyngeal cancers faced different obstacles.
“It is a type of ultra-targeted treatment which uses imaging to position us well, to remain precise, and which allows us to give large doses at a time because we are able to target the tumor precisely,” indicated Dr. Bahig.
Moreover, it is the progress made in imaging that today makes it possible to use stereotactic radiotherapy to combat this disease, whereas this was not possible before.
“We give large doses at once, and then we electively treat the areas of the lymph nodes that we need to treat, where we do not see (cancer) cells, but which could have cancer cells, but at a lower dose,” said Dr. Bahig.
The dose of radiation administered remains the same as if the treatment lasted seven weeks, Dr. Bahig emphasized, but it is administered in a more targeted manner.
The results obtained during the phase II clinical trial were sufficiently promising to justify the recruitment of patients for phase III. This is the first time that a treatment different from the usual treatment has given interesting results, all other attempts having ended in failure.
“It’s a different approach which, in theory, helps reduce toxicities, the side effects of treatments,” explained Dr. Bahig.
This method could one day become a new international standard. Indeed, it would improve the quality of life of patients, reduce hospital visits and costs for the health system.
HPV-associated throat cancers are now perhaps the most common cancers caused by these viruses, Dr. Bahig noted, even ahead of cervical cancer.
There are also demographic changes in who suffers from it.
“It’s a patient population that has changed a lot,” she said. Twenty years ago, the majority of throat cancers were caused by tobacco and alcohol. There has really been a demographic change, especially in Western countries where smoking has declined dramatically, and where there has been a significant increase in cancers caused by HPV. »
And as is the case with many other cancers, patients affected by it are increasingly younger. It is no longer rare to see people (and especially men, since oropharyngeal cancers affect them more than women) aged 40 or 50 presenting with advanced disease, even if they have never smoked.
Dr. Bahig estimates that 80% of the throat cancer cases she sees are associated with HPV. The impact of vaccination will probably not be felt for ten or fifteen years, she warned.
“It’s definitely a younger population who (are) always very surprised to have this diagnosis,” she concluded. This further highlights the importance of working to reduce side effects and improve quality of life. This is a patient population that is going to live longer, which means they are more likely to develop and live with longer-term side effects. »
