Dog Parvo Symptoms

Despite advanced technologies and extensive research, many cancers are still left without a definite cure. When cancer has a vast systemic dissemination, palliation becomes the main goal of therapy. Palliative radiotherapy treats local discomfort caused by either the primary tumor site or by enlarged metastatic lymph nodes. Approximately 50% of human cancer patients with terminal disease undergo a palliative radiation treatment. In veterinary medicine, the most common example of palliative radiotherapy is for treatment of painful bone cancer (either a primary bone cancer like osteosarcoma, or metastatic bone cancer). Since palliation is the main goal of the treatment, the protocol should be designed so acute effects are minimal to non-existent (so we actually palliate instead of inducing additional discomfort). This is achieved by applying coarser fractionation – which also increases the probable occurrence of late complications if the patient survives longer than expected. Thus, the standard curative fractionation protocol should be altered within reason since some patients will survive past 6 months, particularly when adjuvant chemotherapy is used or
when the cancer metastasizes more slowly than anticipated.

Various protocols have been applied for palliation in both veterinary and human medicine. The fraction size administered will depend on the site being irradiated and the individual case. The sensitivity of the tissues included in the field must still be taken into consideration, just as they are with curative protocols. For example, a treatment involving brain tissue would be approached slightly differently than one involving a distal extremity. The degree of coarse fractionation and the optimal total dose for palliative protocols is still an area of debate in both human and veterinary therapy. Generally, however, three fractions of 8 to 10 Gy is administered. Approximately 70% of osteosarcoma patients show a positive response to palliative radiotherapy and most show clinical pain relief within 2 to 3 weeks of the start of treatment. Response can occur anywhere between a few hours after the initial dose to 6 weeks after the first course of treatment. When a second course is required for pain recurrence, 80 % of patients who responded well the first time will again
have a positive response.

Palliative therapy of soft tissue tumors may be beneficial when a mass is impairing function or causing discomfort due to tissue compression. This would include masses causing urethral, tracheal or laryngeal/pharyngeal, esophageal colorectal, lymphatic, vascular (ex: Vena Cava), or other types of obstructions or masses inducing painful tissue compression such as pressure on the spinal cord, nerve root, brain tissue or orbital tissue.