Validation of the American Joint Committee on Cancer 8th Edition T-staging for Head and Neck Soft Tissue Sarcoma and Proposal of New Stage Groupings

Presentation: C137
Topic: Survivorship
Type: Poster
Date: Thursday, April 19, 2018
Session: 9:00 AM - 7:00 PM
Authors: Katherine E Hicks, MD, MS1, John D Cramer, MD2, Urjeet Patel, MD1, Sandeep Samant, MD1
Institution(s): 1Northwestern Memorial Hospital, 2University of Pittsburgh Medical Center

Importance: The 8th edition AJCC staging system introduces a new T-classification for head and neck soft tissue sarcoma (HN-STS), recognizing its unique characteristics compared with sarcomas located elsewhere in the body. However, validation of the updated T-staging system has not been performed, and new stage groupings have not yet been defined.

Objectives: Our goals herein are (1) to evaluate the performance of the updated T-staging system and (2) to propose new stage groupings for HN-STS.

Design, Setting, and Participants: Retrospective cohort study of adult patients with HN-STS using the National Cancer Database.

Main Outcomes and Measures: Patients were restaged using 8th edition guidelines, and overall survival was calculated based on the new TNM classification. With the goal of optimizing predictive ability, concordance indices were calculated and used to compare potential stage groupings.  

Results: We identified 2,297 patients with HN-STS with median follow-up of 2.36 years (range: 0.01-11.53 years). The updated T-staging showed improved survival discrimination and balance among the groups. In the 7th edition stage groups, the 3-year overall survival rates were 70.8%, 54.0%, 62.6%, 56.5%, 47.5%, and 12.3% for stage IA, IB, IIA, IIB, III, and IV, respectively. We propose a stage grouping system for the 8th edition classification that demonstrates improved survival discrimination with 3-year survival rates of 82.3%, 70.4%, 66.2%, 53.7%, 47.3%, and 12.6% for stage IA, IB, IIA, IIB, III, and IV, respectively.

Conclusions and Relevance: The new T-staging system for HN-STS shows improved balance and modestly improved survival prediction. We propose an adaptation of the stage grouping for the 8th edition AJCC staging system for HN-STS as follows: stage IA (T1N0M0G1/G2/GX or T2N0M0G1), stage IB (T2N0M0G2 or T3-4N0M0G1), stage IIA (T1N0M0G3 or T3-4N0M0G2), stage IIB (T2N0M0G2/GX), stage III (T3-4N0M0G3/GX or Any N1), and stage IV (Any M1).