University of Cambridge Evaluation of the necessity of clinical staging in Mast Cell Tumors (MCT): A retrostective study on a referral population of 237 dogs (1998- 2008) Isabel Amores – Fuster MRCVS William Newbury MRCVS Dr Jane M Dobson DECVIM MRCVS

Introduction Canine Cutaneous Mast Cell Tumors: Variable behaviour and metastatic potential. Traditionally a full clinical staging is recommended: CBC and biochemistry Thoracic and abdominal radiographs Abdominal ultrasound (Liver and spleen) FNA of the loco-regional lymph nodes Bone marrow biopsy…

Hypotesis Canine Cutaneous Mast Cell Tumors always metastasize to the loco-regional lymph nodes before they spread to other organs. So… full clinical staging will not be necessary if there are no evidences of metastasis to the loco-regional lymph nodes.

Material and Methods 237 dogs with cutaneous MCT referred to QVSH (Cambridge) between 1998 and 2008. Full clinical staging: FNA of palpable loco-regional lymph nodes Thoracic radiographs Abdominal ultrasound CBC and biochemistry Follow up: Telephonic interviews with referring vets and owners.

Population data Breed: Labrador (31%), Golden Retriever (12.8%), Boxer (9.8%), SBT (7.2%). Age: Mean age at presentation 7.4 years Sex: 102 males and 132 females. No significant differences between sexes.

Of 237 cases… 142  Complete clinical staging and follow up. 29  Complete clinical staging but partial follow up. 20  Complete clinical staging no follow up. 39  Incomplete clinical staging or relevant history. Excluded.

Tumor grade Diagnose  Histological or cytological findings. 23 cases grade I. 154 cases grade II. 20 cases grade III. 8 cases  Multiple tumors on presentation. 22 cases  Only by cytology. 7 cases  disagreement between pathologists.

Tumor grade

Metastasis 69 cases  LN involvement (29.2%) 16 cases  LN and distant metastasis (6.2%) 1 case  Distant metastasis but no LN (0.4%) 105 cases  No metastasis (64.2%)

Metastasis (cont) 6 cases  Grade I 42 cases  Grade II 11 cases  Grade III The rest  Cytology or disagreement in the grade.

Discussion Age, breed and sex results consistent with literature. All dogs with distant metastasis also had LN involvement but one. This case had clinical and radiographic findings consistent with a concurrent pulmonary neoplasia.

Conclusion FNA of the loco regional LN should be performed in all cutaneous MCT cases. Further clinical staging in absence of LN involvement ???? Unless there are other clinical signs or a possible treatment that justify it.

Aknowledgements Jane Dobson, Malcolm Brearley & Frances Taylor The owners and referring vets that participate in the study

Any questions?