What is Radiotherapy?

Radiation therapy is a form of treatment recommended for many different types of cancers. It can be used to directly kill tumor cells, definitive radiotherapy, or may be used for alleviation of symptoms that arise secondary to cancer, palliative radiotherapy. Radiotherapy is a local treatment option, where the target is the area where the tumor or symptoms are arising from. It may be used alone, but more commonly, it is recommended as part of a broader cancer treatment plan for your pet that may also include treatments such as surgery, chemotherapy and/or immunotherapy. Radiation therapy plays a crucial role in the treatment of over 50% of human cancer patients and comparably is a common part of cancer therapy for animals. We are extremely fortunate to be able to provide this high level of care to our patients.

For our purposes, the term radiation simply implies the transmission of photons, which are high energy x-rays, through the air and into the body. These photons cannot be seen or felt, nor are they radioactive. The photons pass through the body causing damage to the genetic material inside the cells being treated. This damage can lead to cell death within hours to weeks after the treatment is administered.

How is Radiotherapy Administered?

Here at VCA Bay Area Veterinary Specialists & Emergency Hospital, we are very happy to announce the installation of our new radiation therapy unit, a state-of-the-art Varian 2100 EX Linear Accelerator, which is equipped with a 120 MLC (multi-leaf collimator). With our new radiation unit, we now have the ability to deliver radiation using the advanced radiation technique termed IMRT (Intensity Modulated Radiation Therapy). IMRT creates a homogenous dose distribution within the tumor, and also rapid dose fall-off from the tumor to the healthy surrounding tissue; therefore improving avoidance of the critical normal tissues. With this advanced radiation therapy technique, we are able to provide treatments with lessened side effects and potentially improved overall tumor control.

Radiation therapy is administered in multiple treatments known as fractions. Each treatment is a fraction of the total dose prescribed for a particular patient. Fractionation reduces the severity of side effects to normal cells, enhances the killing effect on cancer cells, and allows a higher total dose to be given. Higher total dose will typically lead to more cancer killing but, unfortunately, can also increase risks for side effects to normal cells. Depending on the specific cancer type, its location and outcome related goals, your veterinary oncologist will assist you in determining which total dose and fractionation protocol best meets the needs for you and your pet.

Why Does My Pet Need A Veterinary Oncologist?

Just as in humans, a pet with cancer typically needs the help of an oncologist to help diagnose and treat their disease. Above all, a veterinary oncologist will help you understand your pet's condition, what treatment options are available to them and what the expected outcomes may be. They will help you determine the most appropriate course of treatment that meets the needs of you and your pet and facilitate their therapy. Veterinary oncologists also frequently serve as consultants to veterinarians in private practice to ensure that their patients receive the best treatment possible for their cancer. You can be assured that a veterinarian who refers you and your pet to a veterinary oncologist is one that is caring and committed to ensuring that your pet receives the highest standard of care for his or her illness.

While in some cases, your veterinarian may be able to simply consult with the veterinary oncologist about your pet's care, in other cases it is necessary to actually refer you and your pet to the veterinary oncologist for more advanced diagnostics and treatment. Board certified veterinary oncologists also have access to specialized diagnostic or treatment tools such as radiation therapy machines that a general practice veterinarian may not have.

My Pet Has Cancer. Now What?

Cancer does appear to be becoming more common in pets. The most important point to realize about this dreaded disease is that, just as in people, many forms of the disease can be easily treated, managed, and even cured. Early detection and specialized care are leading to increased survival in almost all the types of cancers that afflict pets. From surgery to chemotherapy to radiation therapy, veterinary cancer specialists can offer your pet the very latest diagnostic and treatment options and the best chance of survival. With optimal treatment, cancer in many cases simply becomes another manageable chronic disease.

If your pet is diagnosed with cancer, it is important not to become overwhelmed. Ask your veterinarian to write down the most important points for you to review later. Be efficient with time as early treatment and/or education may minimize stress and any unnecessary side effects in your pet. However, be aware that most cancers are not considered emergencies. Your veterinarian will advise you of which you pet may have. Regardless, do not procrastinate. You will either want to have your general veterinarian work in consultation with a veterinary oncologist, or refer you to a veterinary oncology specialist as soon as possible.

Common Cancers seen in pets include:

Central Nervous System Tumors

• Brain Tumors
• Spinal Cord Tumors

Skin Tumors

• Mast Cell Tumor (MCT)
• Squamous Cell Carcinoma (SCC)

Soft Tissue Sarcomas (STS)

• Nerve Sheath Tumor (NST)
• Fibrosarcoma (FSA)
• Hemangiopericytoma (HPC)

Oral Tumors

• Oral Malignant Melanoma (OMM)
• Squamous Cell Carcinoma (SCC)
• Fibrosarcoma (FSA)

Urogentital Tumors

• Prostate Carcinoma
• Bladder Transitional Cell Carcinoma (TCC)

Other Tumors

• Nasal Tumor
• Thyroid carcinoma
• Hemangiosarcoma (HSA)
• Osteosarcoma (OSA)

If you have any questions or concerns about your pet, please feel free to contact us. We're here to help you and your pet!