MAKING PROGRESS AGAINST RADIOTHERAPY-INDUCED SIDE EFFECTS

Toronto, ON (August 29, 2012) - In the largest international study of its kind, Sunnybrook researchers highlight the need for more study in the area of RINV (radiotherapy-induced nausea and vomiting). Despite estimates that as many as 80% of patients undergoing common radiation treatments may develop RINV, these symptoms are significantly understudied, compared to nausea and vomiting from chemotherapy.

"Our goal is to encourage radiation oncologists to discuss the potential for RINV with each other, and with their patients," says lead author Dr. Kristopher Dennis, a radiation oncology fellow at Sunnybrook's Odette Cancer Centre who conducted the study under the supervision of Dr. Edward Chow, Professor of Radiation Oncology, University of Toronto, and Head of the Rapid Response Radiotherapy Program in the Department of Radiation Oncology at Sunnybrook's Odette Cancer Centre.

RINV worsen patients' quality of life and can lead to treatment delay or refusal.  Depending on the anatomic area being targeted, patients are determined to have a high, moderate, low or minimal risk of developing RINV according to risk estimates and guidelines produced by the American Society of Clinical Oncology and the Multinational Association of Supportive Care in Cancer.

The study, published online in the International Journal of Radiation Oncology, Biology, Physics included responses from 1,022 practicing radiation oncologists from 12 countries, to a web-based patterns of practice survey developed in collaboration with clinician researchers from around the world. It represents the first peer-reviewed published data describing international patterns of practice in the management of RINV.

Study findings show radiation oncologist risk estimates of RINV and their subsequent decisions on how minimal and high-risk patients should be managed were in line with guidelines. However, for low and moderate risk patients who represent the majority of patients undergoing radiotherapy, risk estimates and management decisions varied greatly.

"What is clear is that we need more observational and validation studies on RINV, as current guidelines and physician decision making are unfortunately based on very limited data," says Dr. Dennis. 

There were a number of recommendations in the study to improve the management of patients, especially those at low and moderate risk, including:

(1) establishing baseline incidence rates of RINV in the setting of modern radiotherapy techniques such as intensity-modulated-, image-guided-, stereotactic- and proton radiotherapy,

(2) refining risk estimates of RINV using personalized patient factors,

(3) conducting new therapeutic trials to test prophylactic strategies in higher risk patients to prevent RINV from occurring in the first place, and rescue strategies in lower risk patients to treat RINV if they do indeed develop after radiotherapy has begun.   

Adds Carlo De Angelis, Pharmacy Clinician Scientist - Oncology, at Sunnybrook's Odette Cancer Centre Department of Pharmacy, "Radiotherapy-induced nausea and vomiting are huge issues and yet they are poorly understood. More research will help to personalize risk assessments and treatment strategies for our patients."

For more information, please contact:

Natalie Chung-Sayers, 416.480-4040, natalie.chung-sayers@sunnybrook.ca

Dr. Kristopher Dennis is funded by a Canadian Institutes of Health Research Fellowship Award. The study was supported in part by a research grant from the Investigator-Initiated Program of Merck Canada Incorporated. The opinions expressed in this article are those of the authors and do not necessarily represent those of Merck Canada Inc. or its affiliates and related companies.