Adjuvant Radiotherapy Treatment Time Impacts Overall Survival in Gastric Cancer
Menée à partir de données portant sur 1 591 patients atteints d'un cancer gastrique traité entre 1998 et 2006, cette étude évalue la survie globale des patients en fonction de la durée de la radiothérapie adjuvante et des délais entre le traitement chirurgical et le début ou la fin de la radiothérapie
Purpose : Prolonged radiotherapy treatment time (RTT) is associated with worse survival in several tumor types. This study investigated whether delays during adjuvant radiotherapy impact overall survival (OS) in gastric cancer. Methods and Materials : The National Cancer Data Base was queried for patients with resected gastric cancer who received adjuvant radiotherapy with NCCN-recommended doses (45 or 50.4 Gy) from 1998-2006. Radiotherapy treatment time (RTT) was classified as standard (45 Gy: 33-36 days, 50.4 Gy: 38-41 days) or prolonged (45 Gy: >36 days, 50.4 Gy: >41 days). Cox-proportional hazards models evaluated the association between the following factors and OS: RTT, interval from surgery to radiotherapy initiation, interval from surgery to radiotherapy completion, radiotherapy dose, demographic/pathologic and operative factors, and other elements of adjuvant multimodality therapy. Results : Of 1591 patients, RTT was delayed in 732 (46%). Factors associated with prolonged RTT were non-private health insurance (OR 1.3, P=0.005) and treatment at non-academic facilities (OR 1.2, P=0.045). Median OS and five-year actuarial survival were significantly worse in patients with prolonged RTT compared with standard RTT (36 vs. 51 months, P=0.001; 39 vs. 47%, P=0.005); OS worsened with each cumulative week of delay (P<0.0004). On multivariable analysis, prolonged RTT was associated with inferior OS (HR 1.2, P=0.002); the intervals from surgery to radiotherapy initiation or completion were not. Prolonged RTT was particularly detrimental in patients with node positivity, inadequate nodal staging (<15 nodes examined), and those undergoing a cycle of chemotherapy prior to chemoradiotherapy. Conclusions : Delays during adjuvant radiotherapy appear to negatively impact survival in gastric cancer. Efforts to minimize cumulative interruptions to <7 days should be considered.