The professional seniority affects the clinical application of total neoadjuvant therapy for locally advanced rectal cancer.

e15590 Background: Total neoadjuvant therapy (TNT) integrates whole planned systemic chemotherapy within standard neoadjuvant protocols either before or after radiotherapy for locally advanced rectal cancer (LARC). Preference of neoadjuvant treatment type may vary among the medical oncologists. This study aimed to evaluate impact of professional seniority on TNT approach for LARC. Methods: A 20-item questionnaire was presented to medical oncologists as a cross-sectional survey during a national oncology congress via tablets. The evaluation was stratified by position; early-career oncologists (ECOs) and seniors. 2 questions were about experience regarding rectal cancer treatment. 5 questions were about physicians’ choice of screening and treatment in LARC and the factors affecting their treatment choices. 13 questions were about TNT approach (the sequencing of treatment, denominators of sequencing, chemotherapy choice, treatment response evaluation, operation preferences, adjuvant treatment and its denominators). Results: 189 medical oncologists were included (62.4% (n = 118) ECOs). An endorectal ultrasound was significantly preferred by the seniors (p = 0.039) in addition to conventional staging tools. 65.6% (n = 124) of the participants preferred long-course chemoradiation as their favorite neoadjuvant treatment approach. External sphincter invasion, threatened circumferential resection margin (CRM) and clinical stage were the most common denominators of TNT regardless of experience. ECOs favored short-course RT (p = 0.009) while the seniors chose long-course chemoradiotherapy (p = 0.041) as the index step of TNT. 57% (n = 108) of the physicians preferred to monitor treatment response for TNT at 8-weeks periods. Almost half of the participants (47.1%) reported pathological complete response (pCR) rates between 25-50% with TNT in their clinical practice. The physicians who prefer to give adjuvant treatment after completion of TNT make individualized decisions when surgical pathology reveals non-pCR, CRM and lymph node involvement. There was a significant difference between the ECOs and seniors (63.6 vs 45.1%, p = 0.013) in terms of choosing the adjuvant chemotherapy based on CRM positivity. Majority of the senior medical oncologists (88%) and ECOs (76.3%) agree that TNT should be the standardized neoadjuvant treatment approach for LARC. The preferred adjuvant chemotherapy after TNT was capecitabine-oxaliplatin (51.1%) or capecitabine alone (46%). Conclusions: TNT for LARC is well accepted among the medical oncologists and the professional seniority seems to affect its clinical application.