Dog Parvo Symptoms

Oral malignant melanomas:

Oral malignant melanomas really belong in a separate category. This type of tumor tends to respond in a similar way to radiation therapy as do late responding tissues. In such cases, when typical standard curative protocols are used to spare the late responding tissues, the tumor cells are also spared. For this reason, a better success rate in tumor control has been achieved with the use of larger and fewer fractions. In human medicine research, an effort has been made to try to differentiate melanoma tumors that respond better to large fractions from those that would respond better to smaller fractions. To date, this remains unresolved and, for the most part, a coarse fractionation protocol is chosen. In veterinary medicine, most protocols consist of fractions between 6 to 10 Gy. Malignant melanomas are usually locally invasive and fairly quick to metastasize. Approximately 75% of cases will die of metastatic disease despite good local control. For this reason, chemotherapy for systemic disease should be considered. Unfortunately, an effective agent for this cancer has yet to be identified.

Benign lesions:

It should be realized that although radiotherapy is mostly used for the control of malignant cancer, certain benign lesions (for example: infiltrative lipomas, Granulomatous meningoencephalomyelitis (GME), and chronic lick granulomas non-responsive to medical treatment?) have been successfully treated as well. Like always, the risks and benefits must all be taken into consideration for each individual case.

T. Control-1 and CompL-1 show the probability of Tumor control and Normal Late Tissue Complications for a protocol of lower fractionation while T.Control-2 and CompL-2 show the probability of Tumor control and Normal Late Tissue Complications for a highly fractionated protocol.

As a general rule, a prescribed treatment protocol should have no more than a 10% probability of inducing serious late complications for most tissues, and no more than a 5% probability of late complications for nervous tissue. Due to improved time-dose fractionation, computer treatment planning, and the use of megavoltage therapy, a serious complication rate of less than 5% exists in most veterinary radiation therapy today.