Postoperative radiotherapy did not improve survival beyond chemotherapy in pT3N0M0 oesophageal cancer

Adding postoperative radiotherapy to chemotherapy did not significantly improve survival after R0 resection of pT3N0M0 oesophageal squamous cell carcinoma.

KEY POINTS

  • This single-centre retrospective study reviewed 1,090 patients undergoing oesophagectomy between 2009 and 2020 and included 356 with R0-resected pT3N0M0 thoracic oesophageal squamous cell carcinoma who received adjuvant treatment.
  • Postoperative chemotherapy alone was given to 274 patients, while 82 received postoperative chemoradiotherapy. Propensity-score matching produced two groups of 82 patients with balanced measured clinicopathological characteristics.
  • Chemotherapy was predominantly cisplatin-based, with a median of three cycles. Postoperative radiotherapy delivered 45–60 Gy in 25–30 fractions to the tumour bed and high-risk lymphatic regions.
  • In the matched cohort, five-year overall survival was 65.3% with chemotherapy versus 71.4% with chemoradiotherapy (p = 0.90), while five-year disease-free survival was 63.3% versus 70.9% (p = 0.77).
  • The treatment strategy was not independently associated with overall survival after matching (hazard ratio 0.90; 95% confidence interval, 0.50–1.65; p = 0.70).
  • Locoregional recurrence occurred in 15 versus 8 patients after chemotherapy and chemoradiotherapy, respectively (p = 0.30). Distant metastases occurred in 13 versus 11 patients (p = 0.90).
  • An exploratory subgroup analysis associated chemoradiotherapy with better disease-free survival in lower-third tumours (hazard ratio 0.09; 95% confidence interval, 0.01–0.68; p = 0.020), but no subgroup showed a statistically significant overall-survival benefit. Treatment-related toxicity was not reported.

CLINICAL TAKEAWAY

Routine postoperative radiotherapy cannot be justified from these data for all patients with R0-resected pT3N0M0 disease already receiving chemotherapy. A possible reduction in locoregional recurrence and the lower-third tumour signal warrant prospective study, but residual confounding, limited subgroup size and absent toxicity data prevent a reliable benefit-risk assessment.

SOURCE

Radiation Oncology