Searching saliva for side effects of chemotherapy

Searching saliva for side effects of chemotherapy

June 2013

Southern Health News

by Sarah Garvis

Saliva from cancer patients will go under the microscope in a new study aiming to discover if an individual’s genetic makeup is a factor in how they react to chemotherapy.

The SpIT (Salivary Predictors in Treatment) Study, which is a collaborative between Flinders Medical Centre (FMC) and the University of Adelaide, will investigate the causes of side effects of chemotherapy treatments, 5 fluorouracil (5-FU) and capecitabine.

Both 5-FU and capecitabine are mucotoxic forms of treatment, meaning they cause damage not only to fast growing cancer cells, but also to the fast growing cells of the digestive tract mucosa, including the mouth, oesophagus, stomach and intestines.

Common side effects of this damage are ulceration, difficulty swallowing, abdominal pain and diarrhoea.

FMC Medical Oncologist Associate Professor Chris Karapetis said the aim of the study was to identify which gene changes were involved in determining the risk of side effects caused by chemotherapy.

“In particular, we are interested in how changes to genes that control the immune system are related to chemotherapy-induced gastrointestinal symptoms,” he said.

“These symptoms can interfere with planned treatment doses because patients feel so unwell they are unable to complete their therapy, and it can increase the chance of bleeding and hospitalisation times.

“The unique genetic makeup specific to each person is likely to play an important role in how that person reacts to cancer treatment, and is something that we can now measure easily with a sample of saliva.”

University of Adelaide Lead researcher Professor Richard Logan developed the idea for the study after noticing some cancer patients treated with these agents had severe side effects, while others had none. 

“By combining the expertise of the research team – a medical oncologist, dentist, geneticist and molecular biologist – we will examine the genetic makeup of patients who suffered from chemotherapy side effects so that this information could be used in the future to predetermine patients at highest risk,” he said.

“This could allow patients at high risk who undergo this treatment in the future to be monitored more closely and offered supportive care to avoid severe cases of gastrointestinal side effects.

“By avoiding these adverse effects, patients can receive their full chemotherapy course and hope to achieve the best outcome from their cancer treatment.”

University of Adelaide Pharmacogenetist Dr Janet Coller said researchers would look at the connection between genetic information in saliva samples and individual responses to treatment.

“Mucosal injury is a complicated process involving a whole host of immune system modulators – of particular importance are pro-inflammatory genes and the factors which activate them,” Dr Coller said.

“Being able to predict the response to a drug such as 5-FU would enable better preparation to cope with toxicities and give the best cancer treatment possible.”

Researchers are looking for 100 patients to be involved in the study, including 50 who have experienced minor or no gastrointestinal symptoms during chemotherapy and 50 who have experienced moderate to severe symptoms.

Patients must have received the chemotherapy drugs 5-FU or capecitabine in their cancer therapy and not had radiotherapy during this time. They must be willing to provide a saliva sample and permission to access clinical case notes.

The SpIT Study has been funded by the Australian Dental Research Foundation.

For more information, call Dr Janet Coller on (08) 8313 3906.