ESTRO 2022

Session Item

Monday

May 09

11:40 - 12:40

Room D1

Highlights of Proffered Papers - Latest Clinical Trials

Chair: , United Kingdom;

Chair: , The Netherlands

Session Code: 3290

Session Type: Proffered Papers

Track: Interdisciplinary

12:20 - 12:30

Total neoadjuvant therapy for Organ Preservation in Rectal Cancer: The CAO/ARO/AIO-16 phase II trial

Cihan Gani, Germany

Presentation Number: OC-0833

Abstract

Abstract Title:

Total neoadjuvant therapy for Organ Preservation in Rectal Cancer: The CAO/ARO/AIO-16 phase II trial

Authors:

Cihan Gani¹, Bülent Polat², Oliver Ott³, Elisabeth Germer⁴, Alfred Königsrainer⁵, Andreas Kirschniak⁶, Stephan Clasen⁷, Ulrich Grosse⁸, Markus Diefenhardt⁹, Michael Bitzer¹⁰, Joachim Reibetanz¹¹, Peter Martus¹², Michael Flentje², Rainer Fietkau³, Emmanouil Fokas⁹, Daniel Zips¹, Claus Michael Rödel⁹

¹University Hospital Tübingen, Department of Radiation Oncology, Tübingen, Germany; ²University Hospital Würzburg, Department of Radiation Oncology, Würzburg, Germany; ³University Hospital Erlangen, Department of Radiation Oncology, Erlangen, Germany; ⁴University Hospital Würzburg, Comprehensive Cancer Center, Würzburg, Germany; ⁵University Hospital Tübingen, Department of general, visceral and transplant surgery, Tübingen, Germany; ⁶Kliniken Maria Hilf , Surgical Department, Mönchengladbach, Germany; ⁷Klinikum am Steinenberg, Institute for Diagnostic and Interventional Radiology, Reutlingen, Germany; ⁸Spital Thurgau , Radiology, Frauenfeld, Switzerland; ⁹University Hospital Frankfurt, Department of Radiation Oncology, Frankfurt, Germany; ¹⁰University Hospital Tübingen, Department of Gastroenterology, Tübingen, Germany; ¹¹University Hospital Würzburg, Department of general, visceral and transplant surgery, Würzburg, Germany; ¹²University Hospital Tübingen, Institute for clinical epidemiology and applied biometry, Tübingen, Germany

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Purpose or Objective

Total neoadjuvant therapy (TNT) has recently shown to considerably increase pathological complete response (pCR) rates after surgery. However, data on the impact of TNT on clinical complete response (cCR) rates to facilitate subsequent organ preservation remain limited.

Material and Methods

This multicenter phase II trial assessed the clinical response after long-course radiochemotherapy (50.4 Gy and concomitant 5-FU/Oxaliplatin) followed by three cycles of consolidation chemotherapy with mFOLFOX6. Patients with stage II or III rectal cancer were enrolled. The primary endpoint was cCR rate on day 106 or day 196 (in case of a near CR on d106) after the start of treatment. Secondary endpoints include compliance, toxicity, pathological complete response, and long-term oncologic outcomes.

Results

A total of 93 patients were enrolled, 91 patients were evaluable. Of those 91 patients, 99% received full-dose radiotherapy, 70.3% received full-dose concomitant chemotherapy and 83% received all three cycles of consolidative chemotherapy. Grade III- IV toxicity during TNT was observed in 45% of patients. On day 106, 15% of patients had achieved a cCR and 38% were found to have a near cCR. After re-assessment on day 196, 21 of the 30 (70%) patients with a near cCR on day 106 had further regressed to a cCR. Another two patients underwent local excision after restaging on day 196 and were found to have a pCR. In total 36 of 91 (40%) patients qualified for omission of major surgery after TNT.

Conclusion

TNT with long-course radiotherapy and consolidative chemotherapy results in high cCR rate in patients with locally advanced rectal cancer. Results for sustained cCR and local regrowth rates require longer follow-up.

ClinicalTrials.gov Identifier: NCT03561142