Oesophageal basaloid squamous cell carcinoma: a unique clinicopathological entity with telomerase activity as a prognostic indicator.

Oesophageal basaloid squamous cell carcinoma (BSCC) is uncommon and has been reported to have a worse prognosis than squamous cell carcinomas (SCCs), but this tumour has not been fully characterized. The aim of the present study was to analyse the clinicopathological features of a large cohort of patients with oesophageal BSCC treated at a single institution. The pathology of 756 primary oesophageal cancers treated between January 1989 and December 1998 was reviewed. Tumours that fulfilled the diagnostic criteria of BSCC were identified and were compared with SCC. Their expression of MIB-1, DNA ploidy, and telomerase activity were also studied. Thirty Chinese patients (25 men and five women) with BSCC were found, comprising 4% of patients with oesophageal cancer treated by surgical resection in the study period. Their median age was 67 years (range 40-78 years). Dysphagia was usually the main presenting symptom. Other concomitant malignant tumours were seen in three patients and paraneoplastic glomerulopathy in one. Five tumours were located in the upper third, 19 in the middle third, and six in the lower third. The median length was 5.8 cm (range 2-12 cm). The median MIB-1 score of BSCC was 750 (range 400-858) and was higher than that of SCC (p=0.003). The primary tumour and metastatic BSCC were aneuploid, as detected by flow cytometric analysis in nine patients. Telomerase activity was positive in 95% (19 out of 20) of the cases analysed. The 5-year survival of patients with BSCC was 12%. Distant metastases were seen in 53% (n=16); lung and liver were the most common sites. The median survival of patients with tumours which had a high level of telomerase activity was significantly shorter than those with low levels of telomerase activity (1 vs. 27 months) (p=0.001). The median survival of patients with BSCC and SCC was 26 and 16 months, respectively (p=0.3). In conclusion, BSCC has distinctive clinicopathological features and its long-term prognosis is no worse than SCC. The level of telomerase activity may have a prognostic role. Copyright 2001 John Wiley & Sons, Ltd.