Radiation Oncology PhysicsWestern Science

Research Interests

Cancer recurrence: local and distant metastases

My current research is on understanding how cancer recurs after radiotherapy in order to design treatments to prevent (local and distant) recurrences.

Example questions are:

  • How do cancer cells adapt and the microenvironment change during course of treatment (radiotherapy) that significantly enhance subsequent growth and/or metastases?
  • Does treatment (radiotherapy) of the primary tumour affect the growth of dormant metastases?

Better detection methods and improved targeted treatments aimed at specific disease sites have increased survival from the initial diagnosis of cancer. Combating metastasis - where cancer returns in nearby or distant locations in the body, months or years after the original diagnosis - is entirely a different matter.

Medical science knows remarkably little about preventing metastasis or delaying recurrence in a distant sites as metastases.     

As a result, physicians do not have the most effective tools to detect or prevent metastasis.  This means that a patient's cancer may spread undetected.  Even if there is a chance of disease spread, there are few or no appropriate treatment options, as the majority of therapies are for established and growing tumours. This can leave physicians with the only option of "wait and see," monitoring patient until cancer recurs.

My research group is seeking understanding of causes of recurrences and novel treatments to prevent cancer recurrence after initial primary treatments.

Radiation Treatment Optimization

Background

Rresearch in the cancer problem spans prevention, diagnosis, surgery, radiation treatment, chemotherapy, molecularly targeted therapies, treatment monitoring and response. Such research is multi-disciplinary in nature, involving biology, chemistry, physics and medicine. Recent advances in each area impacts on the optimal combinations of therapies. Our research group focuses in on radiation treatment. The spirit of our research is create tools to aid generation of the best treatment, individualized for each patient. This is done by seeking the role of radiotherapy amongst the treatment options and optimizing radiotherapy in the context of multi-modality therapies. This also entails seeking patient-specific information relevant to radiation therapy, such as tumour characteristics, and exploiting the strengths and mitigating the limitations of radiation.

Generating an optimized radiation treatment plan requires estimation of the risk of radiation induced normal tissue complications and balance it with tumour control. The overall optimization question is "what dose to which volume" to both the surrounding normal tissues and the tumour. In order to answer this question for the tumour, we need to generate a tumour profile that is specific to radiotherapy which is often beyond the information generated at initial diagnosis. Various imaging modalities will be integral in this investigation. In order to generate a tumour profile that is relevant to radiotherapy, we need to understand radiation therapy, how it is planned, the various forms of deliveries, and their capabilities.

To this end, our research group has been developing of a form of radiation delivery: intensity modulated arc therapy (IMAT). It is a category of intensity modulated radiation therapy (IMRT) which exploits trading off radiation intensity levels with beam directions. For example, this has been combined with 3D trans-abdominal ultrasound for daily localization for treatment of localized prostate cancer. Other image guidance such as cone beam CT will be under investigation. Along with optical guidance, we have deployed IMAT for treatment of brain lesions. We have also developed IMAT for the treatment of high-risk endometrial cancer, lung cancer, and head and neck cancer. With these experiences, we are finding out the advantages and disadvantages of IMAT, conventional IMRT as well as Tomotherapy, an integrated and specialized form of radiation delivery.

We cannot truly optimize radiotherapy without following patients and reviewing their outcome for disease and toxicity free survival, and provide feedback to whether the theoretical "optimal" radiation treatment plan was indeed so in practice.

Current Research

  • Image-guided small animal targeted irradiation
  • Microfluidic devices for research in cancer metastasis and dormancy
  • Multi-parametric response map for glioblastoma
  • Adaptive radiotherapy with IMAT
  • Data collection and analyses for normal tissue complications and tumour dose-response relationships

 

For more information about applying see the web page for the graduate program in Physics & Astronomy at Western