Background: Intralesional methotrexate (il-MTX) has been used as neoadjuvant therapy for cutaneous squamous cell carcinoma (cSCC) but studies on its effects on tumor thickness are lacking.
Objective: The objective of this study was to evaluate il-MTX response with ultrasound examination.
Methods: The authors conducted a prospective study in 40 patients with histologically confirmed cSCC. Neodjuvant il-MTX therapy was administered before surgery. Ultrasound evaluation was performed before the first infiltration and before surgical treatment.
Results: Response to neoadjuvant treatment was observed in 92.5% of patients, both clinically and sonographically. There was a good correlation between both types of measurements, with r = 0.892 for the minor diameter and r = 0.944 for the major diameter (p < .001). The authors found an ultrasound overestimation compared to the clinical measurements in 92.5% of patients (mean overestimation: 1.08 mm). There was a good correlation between ultrasound and histological measurements in tumor thickness with r = 0.932 (p < .01), with an ultrasound overestimation in 97.5% of cases (mean overestimation: 0.90 mm).
Conclusion: Neoadjuvant il-MTX can reduce not only surface tumor dimensions but also tumor thickness. Ultrasound improves treatment response control with greater accuracy than clinical assessment alone.