Improved Survival with Adjuvant External‐Beam Radiation Therapy in Lymph Node‐Negative Pancreatic Cancer

Artinyan et al1 indicated that a consensus in recommending adjuvant therapy for pancreatic carcinoma is lacking. In analyzing the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) registry, the authors indicated that the treatment of lymph node-negative pancreatic cancer with external-beam radiation therapy (EBRT) is associated with improved survival, and that adjuvant EBRT should be considered for patients with early-stage N0 disease. The authors exclude patients with lymph node-positive disease based on their perceived higher risk of metastatic disease, which should not benefit from radiation therapy. A significant proportion of patients have received combined treatment with radiation and chemotherapy directed at systemic disease. Indeed, Hazard et al,2 using the SEER data and a very similar analysis, arrived at a different conclusion, namely that patients with lymph node-positive disease benefited from radiation therapy whereas patients with lymph node-negative disease did not. In addition, Tomlinson et al3 and Schwarz and Smith,4 also using SEER data, demonstrated that lymph node positivity status is very much dependent on the number of lymph nodes retrieved by surgery or identified by the pathologist. The survival differences were found to have only marginal statistical significance, more so when the early deaths were excluded. Long–term survivors, as indicated by 3-year or 5-year survival rates, as well as local recurrence rates (which could further validate the effect of adjuvant treatment), were not discussed. Patients undergoing EBRT either preoperatively or postoperatively are inherently selected by their adequate performance status. Furthermore, patient selection bias in particular can account for the small differences in patient survival noted in the SEER data.5 The conclusions of these and other studies emphasize the need for further controlled studies and not the consideration of a particular choice of adjuvant therapy. David Z. Chu MD*, * cancersurgerysciences.com, Pasadena, California.