Impact of preceding treatment for head and neck squamous cell carcinoma on synchronous superficial esophageal squamous cell carcinoma.

Background: Patients with esophageal squamous cell carcinoma (ESCC) frequently develop synchronous head and neck squamous cell carcinoma (HNSCC). With advances in endoscopic technology and widespread screening of synchronous cancers, the detection of synchronous HNSCC and superficial ESCC (SESCC) is increasing. We aimed to evaluate the impact of preceding HNSCC treatment on synchronous SESCC.

Methods: This single-center retrospective study enrolled patients with synchronous HNSCC and SESCC who were treated between January 2010 and December 2023. Tumor size and depth of SESCC before and after HNSCC treatment were evaluated. The factors associated with SESCC progression were investigated.

Results: Of the 299 patients with synchronous HNSCC and SESCC, 134 who underwent preceding HNSCC treatment with follow-up esophagogastroduodenoscopy (EGD) for SESCC were evaluated. Chemoradiotherapy was the most common treatment for HNSCC (56.0%), followed by surgery (17.2%), radiotherapy (14.9%), local resection (7.5%), and chemotherapy (4.5%). The tumor size of SESCC increased after HNSCC treatment in 18 patients (13.4%). Multivariate analysis revealed that an EGD interval of ≥ 120 days was significantly associated with increased tumor size in SESCC (odds ratio, 6.64; 95% confidence interval, 1.91-23.1). Tumor regrowth was observed in 70.6% of SESCCs that shrank with HNSCC treatment, mostly within six months. Tumor depth aggravation was rare (2.2%), but progression to advanced ESCC was observed in two patients.

Conclusions: Timely endoscopic follow-up, preferably within 120 days, is crucial for managing synchronous SESCC after HNSCC treatment to prevent tumor progression. Tumor regrowth should be monitored when SESCC shrinks with HNSCC treatment.