Lower Radiation Levels Linked to Poorer Tumor Response in Esophageal Cancer

Illustration of tumor cell: © nevio - stock.adobe.com

April is Esophageal Cancer Awareness Month. This month, Targeted Oncology is highlighting research in the field of esophageal cancer treatment.

Achieving a pathologic complete response (pCR) was less common after patients with esophageal cancer underwent preoperative radiation at a dose of 41.4 Gy compared with higher doses, and the dose of radiation did not appear to affect postoperative morbidity, long-term survival, or disease recurrence.

Findings from this study were published in the Annals of Surgical Oncology. Study investigators sought to find if different doses of preoperative radiation were more or less effective for pCR or survival in patients with esophageal cancer. Doses of 41.4 Gy, 45 Gy, and 50.4 Gy were evaluated.

A pCR was observed in 15%, 30%, and 34% of patients at the 3 radiation dose levels, respectively. Only the 50.4 Gy dose was independently associated with pCR (OR, 2.78; 95% CI, 1.10-7.99). Among patients specifically with adenocarcinoma, 6.2% patients in the 41.4 Gy group, 29.2% in the 45 Gy group, and 22.7% in the 50.4 Gy group achieved a pCR.

Moreover, there were no significant differences in overall survival (OS) or disease-free survival (DFS). The median OS was 30.0 months (95% CI, 21-not evaluable) for patients in the lowest dose group, 31.6 months (95% CI, 25.5-37.5) in the middle dose group, and 30.0 months (95 CI, 9.9-50.1) in the highest dose group. The median DFS was 18.0 months (95% CI, 9.9-26.0), 26.0 months (95% CI, 15.9-36.1), and 24.0 months (95% CI, 9.0-38.9) for each of the dose levels, respectively.

“Our findings suggest that low-dose radiation is efficient in [squamous cell carcinoma]; a higher dose of 45–50.4 Gy may be needed for [adenocarcinoma] as it offers increased chances for pathological complete response, without compromising postoperative outcomes. These findings are of particular clinical relevance in candidates for the watch-and-wait strategy as they suggest low-dose [radiotherapy] to be potentially insufficient for [adenocarcinoma] lesions,” wrote study authors.

A total of 326 patients met the inclusion criteria for the study and were included in the analysis; 48 patients were treated at the 41.4 Gy dose level, 171 patients were at the 45 Gy level, and 107 patients were in the 50.4 Gy group. 

Regarding safety and postoperative outcomes, there were no reported differences in operative time, intraoperative blood loss, or postoperative complications among the different dose levels. In-hospital mortality was comparable between the arms, with 2%, 6%, and 3% (P =.352) of patients dying in the hospital postoperatively at the respective dose levels.

REFERENCE:

Mantziari S, Farinha HT, Messier, M. et al. Low-dose radiation yields lower rates of pathologic response in esophageal cancer patients. Ann Surg Oncol. 2024;31(4):2499-2508. doi:10.1245/s10434-023-14810-8