eP811 - A Phase II Study of Total Neoadjuvant Therapy in Rectal Cancer

ePoster Presenter(s)

• 

  Po Chuan Chen, MD (he/him/his)

  Chief of colorectal surgery division
  Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  National Cheng Kung University Hospital
  Tainan, Tainan, Taiwan (Republic of China)

  All of the relevant financial relationships listed below have been mitigated.
  This individual has no financial relationships with ineligible companies.

Author(s)

• SC

  Shang-Hung Chen, M.D.

  Attending physician
  National Institute of Cancer Research, National Health Research Institutes, Tainan 70456, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• YY

  Yu-Min Yeh, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• RC

  Renhao Chan, M.D.

  Attending physician
  Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• PL

  Peng Chan Lin, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• HC

  Helen H.W. Chen, M.D., Ph.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• YW

  Yuan-Hua Wu, M.D.

  Chief of radio-oncology division
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• MT

  Mu-Hung Tsai, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• YC

  Yung-Jen Cheng, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• TP

  Tzu-Hui Pao, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• YH

  Ying-Tzu Huang, M.D.

  Attending physician
  Department of Oncology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.
• YS

  Yung-Yeh Su, M.D.

  Attending physician
  National Institute of Cancer Research, National Health Research Institutes, Tainan 70456, Taiwan
  Tainan, Tainan, Taiwan (Republic of China)

  Disclosure information not submitted.

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Purpose/Background: For non-metastatic stage II/II rectal adenocarcinoma, the current treatment paradigm has evolved from the traditional preoperative concurrent 5FU-based chemoradiotherapy followed by surgery and selective postoperative adjuvant chemotherapy to oxaliplatin-based total neoadjuvant chemoradiotherapy (TNT) followed by surgery. Until now, TNT for rectal adenocarcinoma using short course radiotherapy has been validated by a phase III RAPIDO trial and reported a superior pathological complete response rate, compared to 5FU-based concurrent chemoradiotherapy. However, there is currently a lack of data from clinical trials in the Chinese population to confirm the equivalent efficacy of this treatment modality. Therefore, in this clinical trial, we plan to evaluate the efficacy of a short-course radiotherapy followed by nine cycles of mFOLFOX6 chemotherapy and surgery in a Chinese cohort.Methods/Interventions: This is a single center, single-arm, open-label, phase II study to investigate the efficacy and toxicities of total neoadjuvant therapy in patients with middle or low rectal cancers. This study is conducted at National Cheng Kung University Hospital and planned to enroll patients for 2 years, and follow the clinical outcome for another 5 years. The clinicalTrials.gov Identifier is NCT06162650. Forty-two subjects will be enrolled. Patients who have newly diagnosed stage II/III, middle or low rectal adenocarcinoma will be recruited to receive the TNT treatment. The TNT includes the short-course radiotherapy (5×5 Gy over a maximum of 8 days) followed by chemotherapy with the regimen of mFOLFOX6 for a total of 9 cycles before surgery.
The primary endpoint of this study is the CR rate after the total neoadjuvant therapy. The CR rate includes the rate of patients whose tumor achieves either cCR or pCR. R0 resection, pathologic response, local recurrence, distant metastasis, and overall survival rates are secondary efficacy endpoints. Tumor measurements at the end of 9th cycle of mFOLFOX6 chemotherapy will be evaluated by digital rectal examination, colonoscopy, pelvic MRI and PET/CT scan (Figure 1). To evaluate the impacts on quality of life (QoL) of patients receiving TNT, two European Organization for Research and Treatment of Cancer (EORTC) questionnaires: the QLQ-C30 and QLQ-CR29 will be used for measurements. For exploratory purposes, 20 mL of blood will be collected at baseline, interim, and after surgery for cfDNA assessments. Tumor tissues at baseline and after surgery will also be gathered. These blood and tumor specimens will be utilized to analyze genetic variants and identify potential predictive biomarkers.Results/Outcomes: We started to entrol patietns since Dec 8, 2023. Until now, four mid/low, stage III rectal adenocarcinoma patients has been enrolled and MMR status were all preserved. One patient experienced grade 2 RT-related enteritis or proctitis. No grade 3 side effects were observed either during short course RT or FOLFOX chemotherapy. No patient has completed 9 cycles of neoadjuvant mFOLFOX6 so surgery has not been performed. cCR or pCR cannot be determined, tumor regression observed by comparing MRI and PET scan before surgery and genetic testing cannot be explored either. QoL data has also not been determined yet. However, safety profile looked good. The outcomes are waiting since we are still recruiting patients.Conclusion/

Discussion: We are eager to see the final results. However, since this is an ongoing clinical trial, the conclusion is undetermined.Figure 1 The study design and procedures