Squamous cell carcinoma / SCC | Borys

Borys’s story

The cobbler’s children go barefoot… Borys’s case concerned my beloved pet and, sadly, also a patient. Many years ago Borys had a toe amputated because of a tumour in the last phalanx. Histopathology showed squamous cell carcinoma and my worst fears came true.

Squamous cell carcinoma is the most common tumour of the toes in dogs (47%). The greatest breed predisposition is described in large, black-coated breeds such as standard poodles, black Labradors, Rottweilers and Briards.

Borys underwent many operations for local recurrences affecting various phalanges on all limbs. Surgical treatment was supplemented with adjuvant chemotherapy and radiotherapy.

The prognosis after the first operation was guarded – I was prepared for Borys to live two years at most. In the end Borys survived 6 years from the diagnosis of the tumour and passed away at the age of 16 because of old age – biology is hard to cheat.

The breakthrough in Borys’s treatment – the greatest lengthening of the interval between successive recurrences – was the introduction of a monoclonal antibody inhibiting NGF (bedinvetmab) and lenalidomide, a thalidomide derivative. This treatment was inspired by the therapy of squamous cell carcinoma in humans, and I used it off-label, as an individual therapeutic decision.

Squamous cell carcinoma of the toe in dogs – what you should know

Squamous cell carcinoma (SCC) arises from stratified squamous epithelium. In dogs it often develops in the nail bed and is the most common tumour of the toes. Large, black-coated dogs are predisposed – and in some of them the tumour may later appear in further toes, as in Borys.

Symptoms

• swelling of the toe, redness and pain,
• lameness,
• deformity, splitting or loss of the nail,
• ulceration, bleeding or purulent discharge from the nail area.

These signs are easily mistaken for an infection or a nail injury. If the lesion does not resolve with standard treatment, an X-ray of the toe and a biopsy are necessary.

Diagnosis and treatment

On X-ray the tumour often destroys (osteolysis) the last phalanx. The definitive diagnosis is given by histopathology. Before treatment it is worth assessing the regional lymph nodes and taking chest X-rays.

The mainstay of treatment is amputation of the affected toe. In the event of recurrence, or in selected cases, treatment is supplemented with radiotherapy, electrochemotherapy or targeted drugs. In dogs at risk it is worth examining all paws regularly – early detection of another lesion makes treatment easier.