Radiation therapy of osteochondrodysplasia in Scottish fold cats

Abstract

Osteochondrodysplasia in the Scottish Fold cats is the genetic disease, inherited according to the autosomal-dominant type; it is manifested by the deformation of bones and cartilages of the skeleton in the form of unhealthy bone growths in the region of the wrist, metacarpal, fetlock, mesopodial and phalanx joints of breast and pelvic extremities, and also tailed vertebrae. Purpose of research. To assess the effectiveness of radiation therapy in the treatment of Scottish fold cats with osteochondrodysplasia. Materials and methods. 10 Scottish Fold cats (3 males, 7 females; age ― from 5 months to 10 years) with osteochondrodysplasia were treated from 2013 to 2017. All patients had clinical signs of disease in the form of skeletal growths in the wrist, metacarpus, finger bones, lumbar, sacral or tail spine. Most of them (9 of 10) were lame. All patients were examined clinically and radiologically before the treatment. Radiation therapy was carried out on gamma therapy unit «AGAT-R» with inclusion of the affected limbs to the middle of the shoulder or thigh. Immobilization was achieved either by general anesthesia or by means of physical restraint. Fraction doses used were 1.5 Gy up to total doses of 15.0 Gy, 2 to 3 fractions per week. Results. In 9 of 10 cases (90 %) there is a subjective improvement in mobility and regression of lameness after 6 months and furthermore after treatment. Two patients in the group died within 8 and 12 months from extraneous causes, others are alive and well for the time being with no need for pain relief. In three cases a radiological control of skeletal growths was performed, with no signs of progression 6.15 and 71 months after treatment. The maximum observation period is 2196 days, the observation median is 705 days. We used a questionnaire to improve the objectiveness of cat’s mobility and pain assessment before and after treatment. Based on animal owners’ answers the score for each symptom was assigned from 0 (severe dysfunction) to 2 (function not impaired). Scores from individual cases were summed, and the averaged total results were compared. Generally, after radiation therapy, animals’ mobility improved significantly (the averaged mobility score in the group imcreased from 3.0 to 6.5). Conclusion. The radiation therapy is an effective pathogenetic and symptomatic method of treatment of Scottish fold cats with osteochondrodysplasia: in most cases it leads to pain relief and increased mobility of the animal. According to clinical and radiological (in three cases) criteria, it can also be assumed that radiation therapy leads to suppression of the skeletal growths enlargement. The effect of treatment develops within 6 months after its completion and is persistent (lasts for many months and years). The technique involves the use of small total doses, so it does not cause complications and is practically safe for the patient.