BOSTON -- Patients with upper versus middle or lower tumor esophageal tumors treated with radiotherapy have better survival outcomes, according to a study presented at the American Society for Radiation Oncology (ASTRO) annual meeting.
The findings point toward integrating primary tumor site into individualized treatment planning, noted Dashan Ai, MD, of Fudan University Shanghai Cancer Center in China, and colleagues.
"These findings underscore the importance of integrating primary tumor site into personalized treatment planning and informing future TNM classifications for esophageal squamous cell carcinoma," the group wrote.
Tumor location has been embedded in the TNM staging system for esophageal cancer since 2009, the authors explained. Its independent effect on survival, however, particularly when treatment modality varies, remains uncertain, and no large multicenter datasets have systematically examined whether the prognostic weight of tumor location shifts between radiation-based and surgical approaches, they added.
To bridge the gap, the researchers analyzed two independent multicenter retrospective cohorts: a radiotherapy cohort of 2,773 patients and a surgery cohort of 1,153 patients, both with locoregional esophageal squamous cell carcinoma (ESCC). They used multivariate Cox regression, adjusted for sex, age, stage, grade, and diagnosis period, to assess the impact of upper, middle, or lower tumor location on overall survival. Findings were externally validated using the Surveillance, Epidemiology, and End Results (SEER) database data spanning 1973 to 2013.
According to the findings, in the radiotherapy cohort, upper esophageal tumors were associated with the best survival, while middle esophageal location carried significantly worse odds (hazard ratio [HR], 1.260; P < 0.001), as did lower esophageal location (HR, 1.514; P < 0.001). The pattern reversed in the surgery cohort, where lower ESCC showed a trend toward better survival compared to upper ESCC (HR, 0.726; P = 0.078), though the overall location effect did not reach statistical significance (P =0.178). SEER database validation confirmed both directional trends, the researchers reported.
"Superior outcomes are observed for upper esophageal cancers treated with radiotherapy and for lower esophageal cancers treated with surgery," the group wrote.
Ultimately, the study demonstrates that the association between tumor location and survival is significantly modified by treatment modality, the researchers noted. Yet whether these patterns hold across broader populations and contemporary regimens, including chemoradiation and minimally invasive surgical approaches, will require prospective evaluation, they concluded.
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