Comparison of perioperative versus postoperative intratumoral administration of cisplatin for treatment of cutaneous sarcoids and squamous cell carcinomas in horses.
OBJECTIVE
To determine the benefits of reducing the interval between surgical cytoreduction and intratumoral administration of cisplatin.


METHODS
Randomized clinical study.


METHODS
70 horses with 89 incompletely resected T2- and T3-stage sarcoids (n = 64) and squamous cell carcinomas (25).


METHODS
Horses were given 4 intratumoral treatments of cisplatin at 2-week intervals. The first treatment was given at the time of, or immediately after, surgical resection for horses treated in accordance with the perioperative protocol (group 1). Horses in group 2 were treated with cisplatin after the skin healed following surgical resection in accordance with the postoperative protocol.


RESULTS
A difference was not found in duration of overall local tumor control between the 2 groups. Patterns of treatment failures and interval to failure differed between the 2 groups. Length of the surgical scar was the only factor that affected prognosis; an increase in length was associated with a poorer prognosis. A detrimental effect of postoperative treatment was only found in tumors with a high tumor proliferative fraction. Local reactions were similar for the 2 treatment groups, and chronic reactions were not observed.


CONCLUSIONS
Intratumoral administration of cisplatin is beneficial for treatment of cutaneous tumors in horses. Tumor repopulation during the interval between surgery and intratumoral administration of cisplatin decreases treatment efficacy. These results provide evidence of rapid tumor repopulation following surgical resection without a lag period for tumors with a high proliferation index. When tumor proliferation index is not known, it may be prudent to use the perioperative protocol.
Théon
A P
AP
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616-8745, USA.
Pascoe
J R
JR
Galuppo
L D
LD
Fisher
P E
PE
Griffey
S M
SM
Madigan
J E
JE
D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy / Q000601:surgery / Q000662:veterinary*; D017024:Chemotherapy, Adjuvant / Q000379:methods / Q000662:veterinary; D002945:Cisplatin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006734:Horse Diseases / Q000188:drug therapy* / Q000601:surgery; D006736:Horses; D015552:Injections, Intralesional / Q000662:veterinary; D007430:Intraoperative Care / Q000379:methods / Q000662:veterinary; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control; D018365:Neoplasm, Residual / Q000662:veterinary; D011182:Postoperative Care / Q000662:veterinary; D011897:Random Allocation; D012878:Skin Neoplasms / Q000188:drug therapy / Q000601:surgery / Q000662:veterinary*; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D002945:Cisplatin