The necessity of IIb dissection in T1-T2N0M0 oral squamous cell carcinoma: protocol for a randomized controlled trial.

Background: There is a growing debate on the relationship between health-related quality of life (HRQoL) and patient survival which has been going on for the last few decades. The greatest wish of clinicians is to extend the latter while improving the former. Following neck dissection of early-stage oral carcinoma, "shoulder syndrome" appears due to traction of the accessory nerve during removal of level IIb, which greatly affects patient quality of life. Since occult metastasis in level IIb of early-stage oral carcinoma is extremely low, some surgeons suggest that level IIb can be exempt from dissection to improve the HRQoL. However, other surgeons take the opposite view, and thus there is no consensus on the necessity of IIb dissection in T1-2N0M0 oral squamous cell carcinoma (OSCC).
Methods: We designed a parallel-group, randomized, non-inferiority trial that is supported by Shanghai Ninth People's Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai, China. We will enroll 522 patients with early oral carcinoma who match the inclusion criteria, and compare differences in 3-year overall survival, progression-free survival (PFS) and HRQoL under different interventions (retention or dissection of level IIb). The primary endpoints will be tested by means of two-sided log-rank tests. Analysis of overall and progression-free survival will be performed in subgroups that were defined according to stratification factors with the use of univariate Cox analysis. In addition, we will use post-hoc subgroup analyses on the basis of histological factors that were known to have effects on survival, such as death of invasion of the primary tumor. To evaluate HRQoL, we will choose the Constant-Murley scale to measure shoulder function.
Discussion: Currently, there are no randomized controlled trials with large sample sizes on the necessity of IIB dissection in T1-T2N0M0 OSCC. We designed this noninferiority RCT that combines survival rate and HRQoL to assess the feasibility of IIb neck dissection. The result of this trial may guide clinical practice and change the criteria of how early-stage oral cancer is managed. The balance between survival and HRQoL in this trial is based on early-stage breast cancer treatment and may provide new ideas for other malignancies.
Trial Registration: Chinese Clinical Trial Registry, ChiCTR1800019128 . Registered on 26 October 2018.