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Centre intégré universitaire de santé
et de services sociaux de l'Est-de-l'Île-de-Montréal

Centre intégré universitaire de santé et de services sociaux de l'Est-de-l'Île-de-Montréal

Peter Vavassis

Peter Vavassis

Clinical Assistant Professor

Affiliation

Université de Montréal

Research Axes

Clinical research

Contact information

Phone: 514 252-3425

pvavassis.hmr@ssss.gouv.qc.ca

Dr. Vavassis is a radiation oncologist who specializes in prostate, breast and digestive system cancers. He is interested in radiosurgery, hypofractionation and radiosensitizers. An excellent communicator, he has been a guest lecturer at over 30 provincial and national events.

Fully believing in the patient-doctor relationship, Dr. Vavassis is a co-founder of CROIRE, an organization that is committed to improving the quality of cancer care. He has also partnered with PROCURE to support prostate cancer patients.

Most of his studies deal with prostate cancer and metastases. In addition to serving as principal investigator for 12 studies, Dr. Vavassis is Director of the Radiation Oncology Department Research Unit at the CIUSSS de l'Est-de-l'Île-de-Montréal. He leads a team of 15 physicians and 2 nurses to coordinate local studies as well as studies involving provincial, national and international collaborations.

Publications

Voir toutes les publications
  • Coucke P, Vavassis P, Vanderick J. Tumor Margin After Conservative Breast Cancer Surgery For Early Disease: An Issue or not? Belgian Journal of Medical Oncology 2009;3: 93-100.
  • Janvary L, Broens A, Matinive P, Vavassis P, Fleuw J, Laenarts E, Coucke P. 4DCT evaluation of the respiratory-related movement of the breast using surgical clips as fiducials. Poster. ESTRO 29, Barcelona, Spain 2010.
  • Vavassis P, Nguyen DH, Bahary JP, Yassa M. Hypofractionated radiotherapy in prostate cancer. Expert Rev Anticancer Ther.. 2012; 12(7):965-72.
  • Yassa M, Vavassis P, Fortin B, Fortin MA, Lambert C, Nguyen TV, Bahary JP. Late consequential effects of hypofractionated radiotherapy in prostate cancer: impact of acute toxicity on toxicity at 4 years and 8 years. Poster discussion. ASTRO, Boston, USA, Octobre 2012.
  • Lakosi F, Janvary L, Vanderick J, Lombard N, Meyns M, Seidel L, Vavassis P, Untereiner M, Coucke P. Variability of Whole Breast Target Volume Delineation Between Prone and Supine Position: A Multicentric Study. Int J Radiat Oncol Biol Phys 2014 Nov;84(3S):S252. Poster. ASTRO, Boston, USA, Octobre 2012.
  • Lakosi F, Janvary Beelen Z, Vavassis P, Seidel L, Coucke P. Comparison of Respiration-Related Surgical Clip and Chest Wall Movement Between Prone and Supine Position in the Adjuvant Radiotherapy of Breast Cancer. Radiother Oncol 2012 Mar; 102(1S): S45. Poster. ICTR-PHE12 – ESTRO, Geneva, Switzerland, February 2012.
  • Vanderick J, Lakosi, F, Janvary L, Seidel L, Vavassis P, Coucke P. Does the Effect of Clip Displacement on Target Volume Potentially Hamper the Concept of Partial Breast Irradiation in the Prone Position? European Journal of Cancer 2012 Mar; 48(1S): S186. Poster. European Breast Cancer Conference 8, Vienna, Austria 2012.
  • Yassa M, Vavassis P. Hypofractionated radiotherapy in Quebec: decreasing waiting times for treatment, while reducing healthcare costs, without compromising quality of care. Presentation, UICC 2012, Montréal, Canada 2012.
  • Coucke P, Vavassis P, Vanderick J. Het belang van de tumormarge na conservatieve chirurgie bij borstkanker in een vroeg stadium.
    Nederlandsch Tijdschrift voor Verloskunde en Gynaecologie 2013:6;227-235.
  • Hathout L, Hijal T, Théberge V, Fortin B, Vulpe H, Hogue JC, Lambert C, Bahig H, Provencher L, Vavassis P, Yassa M. Hypofractionated radiotherapy for breast ductal carcinoma in situ. Int J Radiat Oncol Biol Phys 2013 Dec 1 ;87(5) :1058-63.
  • Fawaz ZS, Yassa M, Nguyen DH, Vavassis P. Taux de complication de l’implantation des grains d’or pour la radiothérapie dans le cancer de la prostate. Présentation orale. AROQ, Montréal, Canada, 2013.
  • Fawaz ZS, Yassa M, Nguyen DH, Vavassis P. Complication rates in fiducial marker implantation for prostate radiation therapy. Poster. ACRO/CARO, Montréal, Canada, Septembre 2013. Poster. ASTRO, Atlanta, USA, Septembre 2013.
  • Yassa M , Vavassis P, Niazi T. Whole-pelvic radiation therapy in the context of hypofractionation for high-risk prostate cancer patients: a step forward. Int J Radiat Oncol Biol Phys 2013 Nov;87(4):634-635.
  • Fawaz Z, Yassa M, Nguyen D, Vavassis P. Comparison of organ-at-risk DVHs for intermediate risk prostate cancer using one or
    two plan VMAT techniques. Poster. CARO, Montréal, Canada 2013.
  • Ziad S, Yassa M, Nguyen D, Vavassis P. Complication Rates in Fiducial Marker Implantation for Prostate Radiation Therapy.
    Int J Radiat Oncol Biol Phys 2013 Oct;87(2):S364.
  • Fawaz Z, Nguyen DH, Vavassis P, Yassa M. Outcomes based on tumor response after neoadjuvant chemotherapy in breast cancer
    Poster. European Breast Cancer Conference 9, Glasgow, Scotland 2014.
  • Ziad S, Yassa M, Nguyen D, Vavassis P. Fiducial Marker implantation in prostate radiation therapy: Complication rates and technique.
    Cancer Radiother 2014 Dec;18(8):736-9.
  • Yassa M, Fawaz Z, Nguyen D, Fortin B, Sideris L, Vavassis P. Regional Nodal Radiation Therapy in Breast Cancer Patients With Positive Nodes Who Convert to Negative Nodes After Neoadjuvant Chemotherapy. Int J Radiat Oncol Biol Phys 2014 Sep;84(1S):S238. Poster. ASTRO, San Francisco, USA Septembre 2014.
  • Bahig H, Roussin E, Yassa M, Vavassis P, Lemaire C, Archambault L, Nguyen D. Partial kilovoltage cone beam CT (KV CBCT), complete KV CBCT and electronic portal images for breast radiotherapy: a dose comparison study. Pract Radiat Oncol 2015 Mar 27.
  • Lakosi F, Gulyban A, Simoni SB, Nguyen PV, Cucchiaro S, Seidel L, Janvary L, Nicolas S, Vavassis P, Coucke P. Respiratory motion, Anterior heart displacement and heart dosimetry: comparison between prone (Pr) and supine (Su) whole breast irradiation. Pathol Oncol Res: 2015 Apr 4.
  • Lakosi F, Gulyban A, Janvary L, Simoni SB, Jansen N, Seidel L, Kovacs A, Vavassis P, Coucke P. The influence of treatment position (prone vs. supine) on clip displacement, seroma, tumor bed and partial breast target volumes: comparative study. Pathol Oncol Res: 2015 Dec 16.
  • Tiberi D, Vavassis P, Nguyen D, Yassa M. Hypofractionation for prostate cancer: an update. Expert Review Endocrinology Metabolism: 2017 May: 12 (3): 199-205.
  • Pembroke C, Yassa M, Lambert C, Meterissian S, Tremblay F, Anderson D, Keyserlink J, Vavassis P, Panet-Raymond V, Hijal T. A single pre-operative radiation therapy (SPORT) phase 1 trial for low risk breast cancer. Int J Radiat Oncol Biol Phys 2018. Poster. ASTRO, San Antonio, USA Septembre 2018.
  • Pembroke C, Yassa M, Lambert C, Meterissian S, Tremblay F, Anderson D, Keyserlink J, Vavassis P, Panet-Raymond V, Hijal T. A single pre-operative radiation therapy (SPORT) phase 1 trial for low risk breast cancer. Int J Radiat Oncol Biol Phys 2018. Présentation orale. CARO, Montréal, Canada, 2018.
  • Pembroke C, Yassa M, Lambert C, Panet-Raymond V, Meterissian S, Tremblay F, Anderson D, Vavassis P, , Hijal T. A single pre-operative radiation therapy (SPORT) phase 1 trial for low risk breast cancer. Poster. ESTRO, Milan, Italy, Avril 2019.
  • Nabid A, Carrier N, Vigneault E, Nguyen T, Vavassis P, Brassard M, Bahoric B, Archambault R, Vincent F, Bettahar, R, Wilke D, Souhami L. Radiotherapy with or without short term androgen deprivation therapy in intermediate risk prostate cancer: final results of a phase III randomized trial. Présentation orale. 32nd NUF Congress, Reykjavik, Iceland, Juin 2019.
  • Nabid A, Carrier N, Vigneault E, Nguyen T, Vavassis P, Brassard M, Bahoric B, Archambault R, Vincent F, Bettahar, R, Wilke D, Souhami L. Outcomes Based on Risk Factors in Intermediate Risk Prostate Cancer: a Secondary Analysis of a Randomized Phase III Trial. Présentation orale, ASTRO, Chicago, Illinois, U.S.A, Septembre 2019.
  • Nabid A, Carrier N, Vigneault E, Nguyen T, Vavassis P, Brassard M, Bahoric B, Archambault R, Vincent F, Bettahar, R, Wilke D, Souhami L. Comparison of urinary toxicity between patient reported outcomes and physician evaluation in high risk prostate cancer treated with radiotherapy and hormonal therapy: data from a Phase III Trial. Poster, ISOQOL San Diego, Californie, USA, Octobre 2019.
  • Nabid A, Carrier N, Vigneault E, Nguyen T, Vavassis P, Brassard M, Bahoric B, Archambault R, Vincent F, Bettahar, R, Wilke D, Souhami L. Subsequent Androgen Deprivation Therapy After Initial Treatment in Intermediate Risk Prostate Cancer: Prospective Data From a Phase III Trial. CARO 2019. Présentation orale, CARO, Halifax, Nova Scotia, Canada, Octobre 2019.
  • Tiberi D, Vavassis P, Nguyen D, Guilbert MC, Simon-Cloutier A, Dubé P, Gervais MK, Sideris, Hijal T, Dufresne MP, Yassa M. Tumor response 3 months after neoadjuvant single-fraction radiotherapy for low-risk breast cancer. Curr Oncol. 2020 June:27(3)155–158.
  • Le cancer de la prostate en noir et blanc. Éditions Indomptable.