299 Background: Esophageal cancer is most often adenocarcinoma or squamous cell carcinoma, while rare histologies such as basaloid squamous carcinoma, sarcomatoid carcinoma, and neuroendocrine carcinoma (NEC) are poorly characterized. We aimed to evaluate incidence, treatment strategies, and survival outcomes of these unusual variants using a national cohort. Methods: We queried the National Cancer Database (2004–2019) for patients with esophageal cancer identified by ICD-O-3 morphology codes: basaloid squamous carcinoma (8083/3), sarcomatoid carcinoma (8033/3), and NEC (8013/3, 8246/3). Outcomes were compared with conventional squamous cell carcinoma (SCC) and adenocarcinoma (AC). Kaplan–Meier and multivariable Cox regression were used to estimate overall survival (OS). Results: Among 195,612 esophageal cancer cases, 682 (0.35%) were rare histologies: 231 basaloid SCC, 147 sarcomatoid carcinoma, and 304 NEC. Median age was 63 years, and 71% were male. Compared with SCC and AC, patients with rare histologies were more frequently diagnosed with advanced disease (56% vs 44%, p<0.01). Median OS for basaloid SCC was 15.8 months, similar to conventional SCC at 16.4 months (p=0.41). Sarcomatoid carcinoma had a median OS of 18.2 months, and outcomes improved significantly following surgical resection, with 3-year OS of 42% compared to 25% for non-surgical patients (p<0.01). NEC carried the poorest prognosis, with median OS of 10.6 months; however, patients receiving platinum-based chemotherapy demonstrated modestly improved outcomes (12.4 vs 7.8 months, p<0.01). On adjusted analysis, sarcomatoid carcinoma survival was comparable to SCC (HR 0.94, 95% CI 0.81–1.08), while NEC was independently associated with worse survival (HR 1.42, 95% CI 1.25–1.62). Conclusions: Rare histologic variants of esophageal cancer represent less than 0.5% of cases and are often diagnosed at advanced stage. Basaloid and sarcomatoid carcinomas demonstrate outcomes similar to conventional SCC when treated aggressively, while NEC carries a poor prognosis despite systemic therapy. Recognition of these subtypes is critical to guide management and inform clinical trial design for rare esophageal cancers.
Basharat et al. (Sat,) studied this question.