Glioblastoma Multiforme (GBM) is a rapidly dividing brain tumor. The current standard of care for newly diagnosed GBM is six weeks of radiotherapy with concurrent temozolomide (RT/TMZ) followed by maintenance monthly temozolomide for six months up to one year. The addition of temozolomide is a major advance in the treatment of GBM.
A phenomena termed Pseudo-Progression (psPD) has become more apparent with the use of this more efficacious treatment approach. Essentially psPD refers to treatment-induced changes in the tumor resulting in an increase in size and/or a brighter appearance than pre-treatment CT or MRI imaging. These changes may mislead the patient and the doctor in thinking the tumor is getting worse due to true progression when in fact these changes are transient. Eventually the tumor stabilizes or even shrinks. It is important to also realize that the increase in tumor size may accompany a worsening in the patient’s symptoms.
Recent data presented at the Canadian Association of Radiation Oncology from the Sunnybrook Odette Cancer Centre reports a psPD rate of 32% in those patients suspected to have progressed within eight weeks of treatment by imaging. Of those patients, 60% also had clinical symptoms and in each case symptoms also resolved with time.
It is important to consider psPD as a potential explanation of early progression as the oncologist may terminate the maintenance schedule of temozolomide chemotherapy prematurely, and potentially limit the therapeutic benefit of the chemotherapy. Furthermore, alternative chemotherapy agents may be initiated unnecessarily.
Brain Tumour Foundation of Canada would like to extend a special thank you to both Dr. Arjun Sahgal, Department of Radiation Oncology at Sunnybrook Odette Cancer Centre and the Princess Margaret Hospital, and Dr. Normand J. Laperriere, Department of Radiation Oncology at Princess Margaret Hospital for taking the time to answer this important question for our readers. Both Dr. Sahgal and Dr. Laperriere volunteer for Brain Tumour Foundation of Canada as members of our Professional Advisory Group.
Our Professional Advisory Group (PAG) consists of a multi-disciplinary group of health are professionals who volunteer their knowledge and expertise to Brain Tumour Foundation of Canada on an as-needed basis. We are in search of more volunteers from across Canada to participate on our PAG. Specifically we are looking for health care professionals from the following areas: Occupational Therapy, Physiotherapy, Social Work, Palliative Care, Dietary, and Pharmacy. Please contact Janic Gorayeb, Health Information Specialist at jgorayeb@braintumour.ca or 1-800-265-5106 x233 to learn more about this opportunity.