a Genome-based Platform to Predict Patients That Can Achieve Bladder Preservation in Muscle Invasive Bladder Cancer Patients

Overview

This study is aimed to develop a genome-based platform to predict patients who can achieve bladder preservation after neoadjuvant treatment. The main treatments for invasive bladder cancer are radical cystectomy and intrapelvic lymph node dissection, but 50% of patients experience recurrence within 2 years after surgery. The recurrence after surgery is associate with T3 stage, the presence of invading soft tissue around the bladder and N1, lymph node metastasis. Therefore, various methods are being tried to reduce recurrence and metastasis, among which preoperative chemotherapy has been reported to increase survival rate. Based on this, preoperative chemotherapy followed by radical cystectomy are also recommended. However, there are several limitations; The surgery may be delayed in case of non-responsive to chemotherapy, the difficulty of tolerance of chemotherapy as the patients are relatively old in bladder cancer. Therefore, the preoperative concurrent chemoradiotherapy can be considered as a treatment effectively lower the recurrence. In several retrospective study has reported that preoperative radiation induces the down-staging and leads to prolonged progression free survival. However, after radical cystectomy, there is discomfort for patients regarding the removal of the bladder. Treating the bladder while preserving the bladder is getting its attention. The representative treatment is performing neoadjuvant concurrent chemotherapy followed by transurethral resection of bladder tumor. The bladder preserving treatment is performed in patients who have unresectable, locally advanced bladder cancer or are not medically appropriate for surgery. The 5-year overall survival is reported to be around 50-60%. To date, no clinical trial has been conducted to compare whether concurrent chemoradiotherapy can achieve the comparable clinical outcome as radical cystectomy in operable conditions. Therefore, in order to perform the bladder preserving treatment, a platform selecting patients who can preserve the bladder from bladder preserving treatment in advance is needed. Responsiveness to radiotherapy is a combination of various factors, and radiation sensitivity of tumors is the most important. The recent study has been demonstrated that physician can predict radiation sensitivity using genomic data. In this study, we intend to develop a platform that can predict responsiveness to radiotherapy and select patients who can preserve bladder using genomic information.

The treatment in this study is one of the standard treatments suggested by the NCCN guidelines. Bladder is preserved when neoadjuvant concurrent chemoradiotherapy is performed after transurethral resection of bladder tumor and complete remission is achieved through the cystoscopy. If complete response is not achieved, additional chemotherapy is performed. In case that complete response is not achieved through the cystoscopy after additional chemotherapy, cystectomy is performed. If complete response is achieved, the bladder is preserved. Before treatment, the following are obtained; Medical history and physical examination, Tissue acquisition through transurethral resection of bladder tumor, Blood Test (CBC), Chemistry Test (SMA), staging through pelvic CT or MRI, cystoscopy, PET-CT or chest CT. Cisplatin based concurrent chemoradiotherapy is conducted 4 times during the radiotherapy. AFter radiotherapy, the gemcitabine/cisplatin or gemcitabine/carboplatin treatment is performed. The target delineation is performed in 3mm simulation CT for radiotherapy. To consider the uncertainty of breath, the 4D CT is taken. GTV includes primary lesions and lymph node based on diagnostic CT, MRI, and PET-CT. CTV covers the entire bladder with microscopic margin of GTV. PTV1 is defined as extending 1.5cm from the entire bladder. PTV2 is defined as extending 1.5cm from GTV. Radiotherapy is performed using 3D conformal radiotherapy, intensity-modulated radiotherapy, volumetric modulated Arc therapy. Radiotherapy is administered daily, five times a week according to the NCCN guidelines. Each treatment is performed with bladder empty. radiotherapy is performed 20 fractions in total. For the first 15 fractions, 2.65Gy administered for PTV1 including the entire bladder. For rest 5 fractions, 3 Gy for PTV2 is administered. Totally, 55 Gy is administered. If complete response is not achieved, the surgery and timing of surgery are determined by the urologist according to the location and severity of the primary cancer. The biopsy if performed using cystoscopy. If the findings are complete response, no additional treatment is performed, and if not, radical cystectomy is performed. The treatment response is evaluated based on standard treatment process. During the treatment, the regular check up is conducted to evaluate the acute toxicity regarding treatment. After bladder preserving treatment, the pelvic CT, MRI and cystoscopy is used for evaluation. The acquired specimens are ;used for RNA sequencing and organoid construction. The RNA sequencing is used to analyze the differentially expressed based on treatment response to neoadjuvant concurrent chemoradiotherapy.