When an obvious tumor or mass is identified, the first step in the diagnostic process is to take a sample by a fine needle aspirate and/or a surgical biopsy. The samples will be evaluated microscopically, and skilled pathologists usually are able to identify cancer cells when they are present. Other techniques include taking impression smears of surgical specimens or open lesions, staining and evaluating those samples and surgical removal and histopathological assessment of whole masses. If cancer is suspected, thoracic radiographs (chest x-rays) probably will be taken to assess whether the disease has metastasized (spread) to the lungs. Ultrasound and fluoroscopy are other diagnostic options. A complete blood count, serum chemistry panel and urinalysis can provide the attending veterinarian with additional important information. Of course, only the veterinarian presented with the particular patient can decide upon the most appropriate diagnostic approach.
Because of the huge diversity in cancer types, a meaningful discussion of how to identify cancer cannot really be had in a general fashion. Cancerous cells may be coursing through a dog’s blood or localized in a superficial skin tumor. They may be hidden in abdominal masses or multiplying in lymph nodes. They may be in bone or in bone marrow, and they may be on the skin or under the skin. Each type of cancer is diagnosed in a particular way. However, the above diagnostic tools represent the pool from which veterinarians will select their particular techniques in a given case. Thankfully, if caught early enough, there are a number of treatment options for dogs diagnosed with cancer.