Volume Determination of Oral Cavity Tumors by 3-Dimensional Ultrasonography

Purpose: With the help of 3-dimensional (3D) ultrasound, the ultrasonographic determination of tumor volumes offers a new view of tumors in the oral cavity. These are classified according to their maximal diameter in TNM classification whereby the possibility exists in the high T category of overestimating small tumors that have spread into surrounding structures, and in the low T of underestimating large volume tumors that do not extend into surrounding structures. Materials and Methods: We analyzed a group of 49 patients with tumors of the oral cavity, all of whom underwent surgery. Tumor volumes were determined before surgery with 3D ultrasound aided by 3D View program software. After excision, the tumors were classified in pT categories based on pathologic findings. N stage was determined after neck dissection and correlation to tumor volume were performed. Results: The average volume of T1 tumors was 1.74 cm(3); T2 was 5.21 cm(3); T3 was 23.36 cm(3), and T4 was 13.53 cm(3). There were significant differences in tumor volumes between all T categories except T3 and T4. Tumor volumes in our patients did not correlate with N stage. Conclusion: Volume determination of tumors with the help of 3D View software may categorize small tumors better and perhaps become a new refinement in TNM tumor classification. Results show that although T category in oral cavity tumors is determined by diameter in T1 to T3, the volumes match with T category. By using this method, a successful follow-up can be performed and the effects of radiotherapy or chemotherapy can be evaluated. (C) 2008 American Association of Oral and Maxillofacial Surgeons