Throat cancers: CHUM tests shorter, less painful treatment

A Phase III clinical trial involving the University of Montreal Hospital Center 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, while highly effective, is no walk in the park, said radiation oncologist Houda Bahig: seven weeks of radiation therapy and chemotherapy during which the patient’s quality of life will be severely compromised, particularly due to swallowing difficulties so severe that some will be fed through a nasogastric tube.

“We know it’s something that works very well, but we know it’s something very powerful, and we’re looking for ways to maintain this treatment effectiveness and reduce the impact on patients’ quality of life,” summarized Dr. Bahig, who discussed her work with The Canadian Press.

Dr. Bahig and her colleagues from the United States, Ireland, Australia, and Italy are therefore trying to see if it might 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 treat other types of cancer, but its use in oropharyngeal cancers has faced several obstacles.

“It’s a type of ultra-targeted treatment that uses imaging to position us properly, to maintain precision, and which allows us to deliver large doses at once because we are able to precisely target the tumor,” Dr. Bahig explained.

Advances in imaging technology now make it possible to use stereotactic radiotherapy to treat this disease, which was previously impossible.

“We administer large doses all at once, and then we selectively treat the areas of the lymph nodes that need to be treated, where we don’t see any (cancer) cells, but which could have cancer cells, but at a lower dose,” said Dr. Bahig.

The radiation dose 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 promising enough to justify recruiting patients for Phase III. This is the first time that a treatment different from the usual treatment has produced significant results, as all other attempts have failed.

“It’s a different approach that, in theory, reduces toxicities and side effects of treatments,” explained Dr. Bahig.

This method could one day become a new international standard. Indeed, it would improve patients’ quality of life, reduce hospital visits, and reduce costs for the healthcare system.

HPV-associated throat cancers are now perhaps the most common cancers caused by these viruses, Dr. Bahig pointed out, even surpassing cervical cancer.

We are also seeing demographic changes in those who suffer from them.

“It’s a patient population that has changed a lot,” she said. “About twenty years ago, the majority of throat cancers were caused by tobacco and alcohol. There has definitely been a demographic shift, especially in Western countries where smoking has declined dramatically, and there has been a significant increase in cancers caused by HPV.”

And as is the case with many other cancers, the patients affected are increasingly younger. It’s no longer uncommon to see people (especially men, since oropharyngeal cancers affect them more than women) in their 40s or 50s presenting with advanced disease, even if they’ve never smoked.

Dr. Bahig estimates that 80 per cent of the throat cancer cases she sees are associated with HPV. The impact of vaccination likely won’t be felt for another ten or fifteen years, she warned.

“It’s definitely a younger population that is always very surprised to receive this diagnosis,” she concluded. “This further underscores the importance of working to reduce side effects and improve quality of life. This is a patient population that will live longer, which means they are more likely to develop and live with side effects in the longer term.”

–This report by La Presse Canadienne was translated by CityNews