Oncology TEAM

Our specialist veterinary Oncology and Radiotherapy services offer some of the most advanced cancer treatments for small animals in the UK, including in-house radiation therapy (radiotherapy). With one of the largest teams of oncology Diploma-holders in Europe, including two leading specialists double-boarded in oncology and radiation oncology, the expertise of our team is second to none.

Sarah Mason heads up General Oncology. Sarah is an RCVS Specialist in Small Animal Oncology and European Specialist in Veterinary Oncology and Radiation Oncology. Sarah works closely alongside James Elliott, who heads up our Radiation Oncology team. James is a European Specialist and RCVS Specialist in Veterinary Oncology and Radiation Oncology and is also a recognised American Specialist in Veterinary Radiation Oncology.

Our Oncology and Radiotherapy teams work closely together to determine the best and most comprehensive treatment plan for each patient. The team has many years of combined experience working with a multi-disciplinary approach to cancer patient management.

Sarah Mason

Head of Service – Lead in General Oncology

BVSc BSc PhD CertAVP(SAM) PGCEd DipECVIM-CA [Oncol] (add Rad Oncol) FHEA MRCVS

RCVS Specialist in Small Animal Oncology
EBVS® European Veterinary Specialist in Small Animal Oncology and Radiation Oncology
RCVS Advanced Practitioner in Small Animal Medicine

Sarah is a double-boarded specialist in Oncology and Radiation Oncology with many years of experience. She enjoys seeing patients for radiation, chemotherapy and multi-modal care.
She worked at the Universities of Liverpool and Cambridge Vet Schools before joining Southfields in 2018 and before training as a vet, she was a cancer researcher.
In her spare time she enjoys many different sports and music and she has two rescue cats, Nana and Hatchi.

Hall, J and Mason S.L. 2019 Limb sparing achieved by ray amputation for osteosarcoma of the left third metacarpal bone in a Labrador. Vet Rec Case Rep.

Ravicini, S, Baines, S.J. , Amores-Fuster, I, Taylor, A, Mason, S.L. and Treggiari, E (2018) Outcome and prognostic factors in medically treated canine prostatic carcinomas: a multi-institutional study. Veterinary and Comparative Oncology Manuscript accepted for publication.

Benoit, J.B., Mason, S.L. Maddox, T, Blackwood, L., Killick, D., Amores-Fuster, I., Harper, A. Finotello, R: 2018 Evaluation of a multi-agent chemotherapy protocol combining lomustine, procarbazine, prednisolone (LPP) for the treatment of relapsed canine non-Hodgkin high grade lymphoma. doi: 10.1111/vco.12387

Guilliano, A., Dobson, J.M, Mason, S.L. (2017) Complete remission of an anal sac squamous cell carcinoma treated with carboplatin chemotherapy and palliative radiation: Vet Sci. Sep 14;4(3). pii: E45. doi: 10.3390/vetsci4030045

Mason, S.L., Finotello, R., Blackwood, L., (2017) Epirubicin in the treatment of canine histiocytic sarcoma: sequential, alternating and rescue chemotherapy. Vet Comp Oncol. Mar;16(1):E30-E37. doi: 10.1111/vco.12329

Mason, S.L., Fisher, C., Ressel, L., Bommer, N.X., Buckley, L.M., Nuttall, T., (2016) Presentation, clinical pathological and post-mortem findings in three related Scottish terriers with ligneous membranitis. J Small Anim Pract 57, 271–276.

Mason, S.L. (2015) Palliative treatment in Small Animal Oncology. (2016) In Practice 38: 5

Ainsworth, S., Carter, S., Fisher, C., Dawson, J., Makrides, L., Nuttall, T., Mason, S.L., 2015. Ligneous membranitis in Scottish Terriers is associated with a single nucleotide polymorphism in the plasminogen (PLG) gene. Anim. Genet. 46, 707–10.

Mason, S.L, Elliott J., Grant I., Cripps, P. and Blackwood L. (2014) Effects of maropitant on vomiting in dogs receiving vincristine and cyclophosphamide. JSAP 55, Issue (8) 391–398

Mason, S.L., Jepson R., Maltman, M. Batchelor, D. (2014) Trapped Neutrophil Syndrome in three U.K. Border Collies. JSAP  55(1) 57-60

Mason, S.L., Maddox, T., Lillis, S. and Blackwood L. (2013) Late presentation of canine nasal tumours in a UK hospital and treatment outcomes JSAP  54(7) 347-353

Mason, S.L., McElroy, P. and Nuttall, T. (2012) Genetics of ligneous membranitis in Scottish Terriers (letter to editor) JSAP 53(11) 668

German A.J., Holden S.L., Mason S.L., Bryner C., Bouldoires C., Morris P.J., Deboise M., Biourge V.J. (2011) Imprecision when using measuring cups to weigh out extruded dry kibbled food. Anim Physiol Anim Nutr (Berl) Jun; 95(3):368-73

Medina-Torres C.E., Mason S.L., Floyd R.V., Harris P.A., Mobasheri, A. (2011) Hypoxia and a hypoxia mimetic up-regulate matrix metalloproteinase 2 and 9 in equine laminar keratinocytes A.Vet J. Nov;190(2):e54-9. Epub 2011 Apr 1.

Floyd, R.V, Mason S. L. Proudman, C.J, German, A.J, Marples, D. and Mobasheri, A. (2007) Expression and nephron segment specific distribution of major renal aquaporins (AQP1-4) in Equus caballus, the domestic horse. Am J Physiol Regul Integr Comp Physiol. Jul; 293(1):R492-503. Epub 2007 Apr 18

Mobasheri A., Dobson H., Mason S.L., Cullingham F., Shakibaei M., Moley J.F., Moley K.H. (2005) Expression of the GLUT1 and GLUT9 facilitative glucose transporters in embryonic chondroblasts and mature chondrocytes in ovine articular cartilage. Cell Biol Int. Apr; 29(4):249-60.

Mason S.L., Loughran, O. and La Thangue, N.B. (2002) p14(ARF) regulates E2F activity. Oncogene.  21(27): 4220-30.

de la Luna, S., Allen, K. E, Mason S.L. and La Thangue, N.B. (1998) Integration of a growth-suppressing BTB/POZ domain protein with the DP component of the E2F transcription factor. EMBO J.  18:212-228.

James Elliott

Head of Service – Lead in Radiation Oncology

BVM&S CertSAM Dipl. ECVIM-CA-RO (Oncology & Radiation Oncology) DACVR (RO) MRCVS

EBVS® European Veterinary Specialist in Small Animal Oncology and Radiation Oncology
American Specialist in Veterinary Radiation Oncology

James graduated from the University of Edinburgh and initially worked in small animal practice in England before completing a one year internship and residency in small animal oncology at the University of Liverpool. Here he underwent extensive training in the disciplines of medical oncology and radiotherapy. James holds the European College of Veterinary Internal Medicine (ECVIM) Diploma in Small Animal Oncology and is a recognised European Specialist in Small Animal Oncology and a Royal College of Veterinary Surgeons Recognised Specialist in Veterinary Oncology. He also holds the Royal College of Veterinary Surgeons Certificate in Small Animal Medicine.

Subsequent to his training, James became a lecturer in oncology at the University of Liverpool where, in addition to running busy clinics seeing cancer patients, he was also responsible for teaching undergraduate students, postgraduates undergoing oncology training, and members of the nursing team. In 2013, James joined a large referral centre where he helped to develop the oncology service. James is a member of the Veterinary Cancer Society, the European Society of Veterinary Oncology and is a regular speaker to vets on oncology topics and has published on various subjects in veterinary literature, including blood biomarkers in certain cancers, chemotherapy for canine lymphoma and canine oral mast cell tumours.

Having spent the last few years working in America in one of the most established veterinary radiation centres in the world, James is experienced in all aspects of modern veterinary radiation, clinical oncology and achieve high-level skills in treatment planning; particularly intensity-modulated radiation therapy, stereotactic radiosurgery and stereotactic body radiation therapy.

James was awarded the 2019 ACVR resident prize for his research into radiation therapy for plasma cell tumours

In his spare time James enjoys getting out and about in the countryside, music and travelling.

Successful definitive-intent radiation therapy for recurrent and metastatic feline thymoma with unusual extra-thoracic metastasis

Ionescu I & Elliott J

Veterinary Record Case Reports 2023, epub e717

Transmission of canine transmissible venereal tumour between two dogs in the United Kingdom

Hayes A, Schiava L & Elliott J

Journal of Small Animal Practice 2023, 64(9), 590-594

A modified full thickness labial/buccal rotational flap reconstruction technique following bilateral rostral maxillectomy and nasal planectomy for resection of maxillary tumors: Technique and results in two dogs

Kokkinos P, Elliott & J Ruiz J

Veterinary Surgery 2023,

Retrospective Study of T Cell Leukaemia (Large Granular Lymphocyte Variant) in Dogs Associated with Suspected Immune-Mediated Cytopaenia(s) in the Absence of Peripheral Lymphocytosis 

Capasso A, Villiers E & Elliott J

Animals 2023, 13(3), 357

Guide to radiation therapy use in companion animals

Elliott J

In Practice 2022;44;3:124-140

Feasibility study evaluating arrhythmogenesis and cardiac damage after heart-base irradiation in mice: A brief communication.

Elliott J, Linder K, Nolan MW.

Vet Med Sci. 2020 Jun 10. doi: 10.1002/vms3.303

Response and outcome following radiation therapy of macroscopic canine plasma cell tumours.

Elliott J, Looper J, Keyerleber M, Turek M, Blackwood L, Henry J, Gieger T.

Vet Comp Oncol. 2020 Apr 19. doi: 10.1111/vco.12600

Histiocytic sarcoma in miniature schnauzers: 30 cases.

Purzycka K, Peters LM, Elliott J, Lamb CR, Priestnall SL, Hardas A, Johnston CA, Rodriguez-Piza I.

J Small Anim Pract. 2020 Apr 22. doi: 10.1111/jsap.13139

A Retrospective Study of Multi-agent Chemotherapy including either Cyclophosphamide or Lomustine as Initial Therapy for Canine High-grade T-cell Lymphoma (2011-2017).

Elliott J and Baines S

Aust Vet J. 2019 Sep;97(9):308-315. doi: 10.1111/avj.12847. Epub 2019 Jul 22.

Evaluation of a multi-agent chemotherapy protocol combining dexamethasone, melphalan, actinomycin D, and cytarabine for the treatment of resistant canine non-Hodgkin high-grade lymphomas: a single centre’s experience.

Smallwood K, Tanis JB, Grant IA, Blackwood L, Killick DR, Amores-Fuster I, Elliott J, Mas A, Harper A, Marrington M, Finotello R.

Vet Comp Oncol. 2019 Jun;17(2):165-173. doi: 10.1111/vco.12. Epub 2019 Feb 13.

Response and outcome following toceranib phosphate treatment for stage four anal sac apocrine gland adenocarcinoma in dogs: 15 cases (2013-2017)

Elliott JW

J Am Vet Med Assoc. 2019 Apr 15;254(8):960-966. doi: 10.2460/javma.254.8.960.

Lomustine Chemotherapy for the Treatment of Presumptive Haemophagocytic Histiocytic Sarcoma in Flat-coated Retrievers

Elliott JW

Australian Veterinary Journal (2018) Dec;96(12):502-507. doi: 10.1111/avj.12767

Managing cancer pain in dogs and cats

Elliott J and Alderson B

In Practice 2019;41:361-367.

External beam radiotherapy for the treatment of feline salivary gland carcinoma: six new cases and a review of the literature

Blackwood L, Harper A, Gramer I and Elliott J

J Feline Med Surg. 2019 Feb;21(2):186-194. doi: 10.1177/1098612X18771772. Epub 2018

Indolent, T-cell, Large Granular Lymphocytic Leukaemia (LGLL) in a Dog Presenting with Severe Neutropenia and an Absence of Lymphocytosis

Elliott JE and Villiers E

Open Veterinary Journal (2018) 8(2): 118-124

A Dexamethasone, Melphalan, Actinomycin-D and Cytarabine (DMAC) chemotherapy protocol as a rescue treatment for feline lymphoma

Elliott JW and Finotello R

Vet Comp Oncol (2018) Mar;16(1):E144-E151

Temporary Spontaneous Regression of Feline Non-Hodgkin’s lymphoma

Elliott JW

Aust Vet Journal (2018) Mar;96(3):83-85

Unusual Radiographic Appearance of an Osseous Metastasis to the Distal Radius from a Transitional Cell Carcinoma of the Urinary Bladder

Anesi, Simone; Parry, Andrew; Monti, Paola; Elliott, James

Veterinary Record Case Reports 5: e000474. doi: 10.1136/vetreccr-2017-000474

Temozolomide alone or in combination with doxorubicin as a rescue agent in 37 cases of canine multicentric lymphoma

Treggiari E, Elliott JW, Baines SJ, Blackwood L

Vet Comp Oncol. 2017 Aug 2. doi: 10.1111/vco.12335

Intramuscular mast cell tumors in 7 dogs

Robinson W, Elliott J, Baines S, Owen L & Shales C

Canadian Vet Journal (2017) September, Vol 58, No.9, Page 931-932

Malignant pilomatricoma in a dog with local and distant metastases treated with chemotherapy and bisphosphonates

Treggiari E, Elliott JW

Open Vet J. 2017;7(3):208-213

Successful Treatment of a Metastatic, Gastrointestinal Stromal Tumour in a dog with Toceranib Phosphate (Palladia™)

Elliott JW, Swinbourne F, Parry A, Baines L

J Small Anim Pract. 2017 Jul;58(7):416-418

New drug therapies for treating cancer in dogs and cats

Elliott J

In Practice 2017;39:2-9.

Gastric histiocytic sarcoma in a dog.

Elliott J

J Small Anim Pract. 2016 Dec;57(12):719

Treatment of Acute Undifferentiated Leukaemia in a Dog

Elliott, JW

Veterinary Record Case Reports (2016) 4: e000242. doi: 10.1136/vetreccr-2015-000242

Treatment & Outcome of Oral Mucosal Mast Cell Tumours in Dogs

Elliott J, Grant IA and Blackwood L

Vet Comp Oncol. 2016 Mar;14(1):101-11

Hypersensitivity reaction during epirubicin infusion in a cat.

Elliott J

J Small Anim Pract. 2015 May;56(5):356

Gastrointestinal toxicity after vincristine or cyclophosphamide administered with or without maropitant in dogs

Mason S, Grant IA, Elliott JW and Blackwood L

J Small Anim Pract. 2014 Aug;55(8):391-8

Paraneoplastic syndromes in dogs and cats

Elliott J

In Practice 2014;36:443-452.

Clinical evaluation of small animal cancer patients

Elliott J

In Practice 2014;36:218-228

Atypical, non-secretory presentation of multiple myeloma in a dog

Elliott, JW

Veterinary Record Case Reports (2014) 2: e000110. doi: 10.1136/vetreccr-2014-000110

Epirubicin as part of a Multi-Agent Chemotherapy Protocol for Canine Lymphoma

Elliott J, Cripps P, Grant IA and Blackwood L

Vet Comp Oncol. 2013 Sep;11(3):185-98

Cutaneous mast cell tumor with epitheliotropism in 3 dogs

Oliveira FN, Elliott JW, Lewis BC, Mathews GG, Brown RM and Treadway CM

Vet Pathology. 2013 Mar;50(2):234-7

Thymidine Kinase Assay in Canine Lymphoma

Elliott J, Cripps P and Blackwood L

Vet Comp Oncol. 2013 Mar;11(1):1-13

Treatment and Outcome of Four Cats with Apocrine Gland Carcinoma of the Anal Sac & Review of the Literature

Elliott J and Blackwood L

J Feline Med Surg. 2011 Oct;13(10):712-7

Histiocytic Sarcoma in the Bladder of a Dog

Amores-Fuster IA and Elliott J

J Small Anim Pract. 2011 Dec;52(12):665

Zinc toxicity in two dogs associated with the ingestion of identification tags

Adam F, Elliott J, Dandrieux J, German A, Blackwood L

Vet Rec. 2011 Jan 22;168(3):84-5

Successful Treatment of a Retrobulbar Mast Cell Tumour in a Dog

Elliott J, Grant IA and Blackwood L

Journal of Small Animal Practice (2010) October, 51(10): 561

Petros Frezoulis

EBVS® European Veterinary Specialist in Small Animal Oncology

DVM, MSc, DipECVIM-CA (Oncology), MRCVS

Petros graduated from the Aristotle University of Thessaloniki, Greece in 2013. Soon after graduation, he started a two-year combined Master's degree/medicine internship at the same institution. After a rotating clinical internship and two years in general practice, he joined Southfields Veterinary Specialists in 2019. He completed his residency in Oncology at Southfields in April 2022.

Outside of work, Petros enjoys travelling, going to the gym and spending time with his friends and family.

Danielle Gibson

Senior Oncologist


Danielle graduated with honours from the University of Sydney (Australia) in 2010 and spent several years in small animal general practice both in Australia and the UK. She completed a small animal rotating internship at the University of Cambridge in 2017 and developed an interest in oncology during this time which she furthered by undertaking an oncology internship at Southfields Veterinary Specialists. She then undertook a residency in small animal oncology at the University of Liverpool which she completed in 2022.

Danielle enjoys all aspects of small animal oncology and finds it very rewarding to help her patients continue to have happy, healthy lives whilst undergoing cancer treatment.

Outside of work Danielle enjoys swimming, scuba diving, travelling and spending time with friends and family.

Elisavet Kritsotalaki

Oncology Resident


Elisavet graduated from Aristotle University of Thessaloniki in 2012. She worked in small animal clinics and hospitals in Athens and at the same time she continued her studies by enrolling for a Master’s in Molecular and Applied Physiology at the Medical School of Athens. She worked for around one year as a researcher at the National Hellenic Research Foundation, where she completed her master thesis on skin, bowel and breast cancer in humans.

After completion of her Master’s with distinction, she relocated in the UK in 2017, where she worked for 2 years for a small animal clinic and then for one of the largest and busiest charity hospitals in Bradford. Focused on achieving her dream of becoming an oncologist, she completed a rotating internship in Southfields and the University Hospital of Dublin, before returning “home” to Southfields as a specific intern in Oncology.

Elisavet is currently studying for a medicine certificate to improve her holistic care of cancer patients and her main interest is in a multimodal approach to cancer treatment and palliative care.

Outside work, Elisavet enjoys cinema, rotten TV shows, caring for her cat Freddie Kruger and baking for friends.

Susan Keefe

Senior Oncology Registered Veterinary Nurse


Susan joined us many years ago after completing a foundation degree in Veterinary Nursing & Practice Management. Prior to this she had worked in both mixed & small animal first opinion practice. She has also spent time as a volunteer, working on a rehabilitation project for monkeys and baboons.

During her time with us, Susan has completed a certificate in Small Animal Nutrition. Her main interests at work include oncology, nutrition, medical nursing and physiotherapy.

Outside work, Susan has a keen interest in horses and has owned a horse for many years. She also has a cat called Felicity.

Samara Brunning

Oncology Registered Veterinary Nurse


Samara is a mum to a human and five fur children. One crazy Cocker Spaniel and four cats. She adores everything cat and has a keen interest in feline behaviour. In her spare time, Samara enjoys spending time with her family, cooking and reading.

Samara has been qualified since 2018, and worked in first opinion practice for 12 years before taking the leap into referral. She joined the team at Southfields in 2022.

Samuel Huckle

Oncology Technician

Before joining Southfields, Sam worked for the NHS for over 10 years as part of their oncology service, learning about chemotherapy care and cancer treatments.

Sam's interests include oncology and his love for animals brought him to Southfields. Sam loves chihuahuas and also has an interest in amphibians. Sam has a pet axolotl, cat and dog.