Comparison of perioperative versus postoperative intratumoral administration of cisplatin for treatment of cutaneous sarcoids and squamous cell carcinomas in horses.

This research study investigates the efficiency of two different timings of cisplatin treatment on horses with cutaneous tumors. No significant difference was found regarding the overall local tumor control between the treatments administered just after surgery and those administered post-healing; however, the study noted differential failure patterns and found that tumor repopulation could decrease treatment efficacy.

Study Design and Methodology

• The study is a randomized clinical trial, meaning that the participants were randomly assigned to different treatment groups. This reduces bias and increases the reliability of the results.
• The report involved the treatment of 70 horses diagnosed with 89 different T2- and T3-stage sarcoids (64 cases) and squamous cell carcinomas (25 cases). These are types of skin-related tumors in horses, T2- and T3- denoting the size or extent of the tumor.
• The treatment involved using cisplatin, a chemotherapy drug, through intratumoral administration i.e., injected directly inside the tumor.

Treatment Protocols

• Horses were divided into two groups. Group 1, the perioperative protocol, received the first cisplatin treatment at the time of or immediately after surgical tumor removal. Group 2, the postoperative protocol, received cisplatin treatment after the skin had healed from surgery.
• Both groups received a total of four cisplatin treatments at two-week intervals.

Study Findings

• No significant difference was found between the two groups in terms of the duration of overall local tumor control.
• However, the patterns of treatment failures and the interval to failure differed between the two groups. This may mean that timing of cisplatin administration has some bearing on treatment effectiveness.
• The surgical scar’s length was the only factor affecting the prognosis, with longer scars associated with poorer prognosis. This finding suggests that the size of the original tumor could impact treatment outcomes.

Conclusion and Recommendations

• Intratumoral administration of cisplatin is beneficial for treating cutaneous tumors in horses.
• The study provides evidence that rapid tumor repopulation can occur after surgical resection without a lag period for tumors with a high proliferation index. Thus, delaying cisplatin treatment might decrease its efficacy.
• Given these findings, the researchers advocate for the use of the perioperative protocol where the tumor proliferation index is unknown.