Purpose: The aim of our study was to define the role of grey-scale transrectal ultrasound in the evaluation, staging and follow-up of patients with histologically diagnosed anal canal cancer.
Materials and methods: Seventy-six patients underwent digital rectal examination, anoscopy, abdomino-pelvic CT, inguinal and transrectal ultrasound; Fifty-five received combined chemoradiotherapy, whereas 21 received only radiotherapy due to clinical contraindications to chemotherapy. Before and after treatment TNM and UT staging were compared. After treatment we evaluated the sensitivity of transrectal ultrasound in the differentiation of post-radiation fibrosis from residual tumor/local relapse (gold standard: histological analysis). Ultrasound examination was carried out to assess inguinal and perirectal lymph node involvement, and Computed Tomography to detect abdominal lymph nodes.
Results: In all stages, except stage 4, there were differences between TNM and UT staging, as TNM is often understaged. After treatment ultrasound showed a sensitivity of 71 percent in the differentiation of fibrosis from residual tumor (the results were confirmed by histopathologic analysis), of 93 percent in the identification of perirectal lymph nodes and of 95 percent in the identification of inguinal lymph nodes.
Conclusions: Transrectal ultrasound is very useful in the staging and follow-up of anal canal carcinoma, in the evaluation of initial tumor volume and reduction after therapy. Ultrasound is useful in the distinction of fibrosis from residual tumor after therapy and as biopsy guidance.