Assessing the practice of total neoadjuvant therapy for rectal cancer: an online survey among radiation oncology departments in Germany and German-speaking regions of Austria and Switzerland

Total neoadjuvant therapy (TNT) of rectal cancer improves rates of pathological complete remission and progression-free survival. With improved clinical response rates, interest grew in a non-operative approach/watch and wait (WaW) for this disease. In 2020, the working groups of ACO/AIO/ARO published a consensus statement on the use of TNT, including a non-operative approach. However, the best combination scheme remains unclear. Despite the increasing use of TNT, there is a lack of comprehensive data on its current implementation and practices. To address this knowledge gap, a multicenter survey was conducted to capture the use of TNT protocols in German-speaking radiotherapy departments. At the beginning of 2023, a GDPR-compliant online survey was conducted in Germany, Austria, and German-speaking Switzerland. The questionnaire comprised 43 questions covering various aspects of TNT, including chemotherapy and WaW concepts. Most respondents (98.4%) confirmed awareness of the consensus on TNT for rectal cancer. Institutions treated an average of 30.22 rectal cancer patients annually. Most respondents (76.2%) reported treating over 80% of patients neoadjuvantly. Regarding TNT, 33.3% treated 21-50% with such a protocol. No significant association was found between the institution type and TNT application. In 62/63 cases, tumor board discussion was standard before offering TNT. VMAT was the predominant technique (82.5%). For rectal cancer dosing, the 50/50.4Gy scheme was most common, followed by 45Gy with a boost and the 5 × 5Gy scheme. Dosing schemes for TNT varied slightly, with more participants reporting the use of 5 × 5Gy compared to radiation therapy for rectal cancer in general. CBCT was the primary IGRT method (88.9%). Larger hospitals typically administered chemotherapy themselves, while private practices collaborated with medical oncologists (p < 0.0001). The most common concurrent chemotherapy drugs were 5-fluorouracil/capecitabine (64.4%) and oxaliplatin (37.3%). A WaW strategy was reported to be institutional implemented by 63.8%. The timing of offering WaW was split, with 50% offering it after radiochemotherapy and 47% during the informed consent talk. For planned WaW, 62% prefer normofractionated TNT. TNT appears to be widely implemented in the German-speaking radio-oncological community, regardless of the type of institution. Image-guided therapy, multidisciplinary team decisions, and internal guidelines play an important role. TNT seems to have already altered treatment protocols for rectal cancer toward an organ-preserving approach in selected cases. In these WaW cases, normofractionation appears to be preferred over hypofractionation.