Early detection of cancer requires persistent checks

Early detection of cancer requires persistent checks

Veterinarians and owners should develop a battle plan for fighting cancer in patients at highest risk
Oct 01, 2005

Cancer is the leading cause of natural death in dogs and cats. Recent advances in diagnostics and treatment allow for prolonged survival times and improved quality of life in pets with cancer; however, many cancers are not detected until they are advanced, limiting treatment options to palliative care only. In human medicine, tests for early detection of cancers including skin, prostate, cervical, colorectal and breast cancer are increasingly being promoted by physicians and other health advocates to improve patient care and survival. Due to ever-increasing awareness about cancer, pet owners are seeking information about prevention, early detection, diagnosis and treatment of cancers.

Early detection of cancer

Exploring The Vet Cancer Registry
Early detection of cancer in pets requires a conscious effort by the owner and the veterinary healthcare team. From the first time a patient is seen by a veterinarian, the importance of preventative care, including regularly scheduled examinations, should be emphasized. Owners should be encouraged to examine their pets for new or changing problems, and to seek veterinary attention when abnormalities are detected. The best method for early detection of cancer and other conditions in veterinary patients is a semi-annual (or more often in some cases) physical examination by a veterinarian. The history and physical examination should be used to determine if further testing (i.e., bloodwork and imaging) is indicated.

Physical examination

During a routine physical exam, the following organ systems should be carefully examined, especially in older pets or in patients suspected or known to have cancer:

  • Eyes: The periocular and intraocular (including funduscopic examination) structures should be routinely examined. Due to their rich blood supply and extension to the central nervous system, the eyes are often a site of primary or metastatic neoplasia. Decreased ocular retropulsion can indicate nasal or orbital tumors; hyphema may be a sign of intraocular neoplasia (most commonly lymphoma or primary intraocular tumors); raised masses on the iris may be iris melanomas.
  • Ears: Examination of the external ear canals should be performed in every patient. Animals with a history of prolonged or recurrent otitis externa may be at increased risk for development of ear canal tumors. The clinician should maintain a degree of suspicion for neoplasia in older pets with a recent onset of otitis externa or purulent or hemorrhagic aural discharge. Debriding of aural secretions with subsequent otoscopic examination under general anesthesia is required to visualize most ear canal tumors. Because tumors in the ear canal are often infected and inflamed, exercise care to ensure that representative samples of the tumor are obtained.
  • Nose: Clinical signs associated with nasal tumors include mucopurulent or hemorrhagic nasal discharge, rubbing or pawing at the face, sneezing, and uncommonly, neurologic abnormalities, such as seizures or behavior changes or ocular abnormalities such as exophthalmos. It is important to assess patients with suspected nasal tumors for facial deformity, masses protruding through the palate, airflow through the nostrils, and an ability to retropulse the eyes.
  • Throat: Careful palpation of lymph nodes (including mandibular and superficial cervical) and the thyroid area are essential. Because most thyroid tumors in dogs do not secrete thyroid hormone, they often grow undetected until they cause compression of surrounding normal tissues, resulting in clinical signs such as dyspnea and dysphagia. Early detection of thyroid tumors would maximize available treatment options and decrease morbidity associated with this tumor.
  • Peripheral lymph nodes: The regions of the mandibular, superficial cervical (prescapular), axillary, inguinal and popliteal lymph nodes should be routinely palpated. In dogs, axillary lymph nodes are not normally palpable. In most cats, superficial cervical, axillary and inguinal lymph nodes are not routinely palpable. Aspirates are indicated to evaluate lymph nodes that are enlarged or irregular.
  • Thoracic cavity: Thoracic auscultation should be performed in every patient. Muffled heart or lung sounds and/or increased respiratory effort may result from primary or metastatic lung tumors, pleural effusion or heart-based tumors.
  • Abdominal cavity: Careful palpation of the spleen, liver, kidneys and gastrointestinal tract may reveal organ enlargement or masses.