Achieving complete clinical response in rectal cancer with chemoradiation and cryotherapy, a case study. These are our disclosures. The standard of care for rectal adenocarcinoma typically consists of neoadjuvant chemoradiation followed by surgical resection. However, curative surgery has high rates of morbidity with complications such as low anterior resection syndrome and in cases of abdominal perineal resection, permanent colostomy. Some patients are unable to undergo surgery due to medical comorbidities. Others find the permanent colostomy unacceptable and seek alternative treatment approaches. Multiple endoscopic ablative modalities are available, but they're not explored as part of multimodality cancer treatment. Our case is of a 57-year-old male with a history of smoking and type 2 diabetes who presented with unexplained weight loss and altered bowel habits. The index colonoscopy revealed a 2-centimeter ulcerated rectal mass located 5 centimeters from the anal verge. This was diagnosed as a T3N0M0, moderately differentiated invasive adenocarcinoma. He underwent chemoradiation, which led to significant reduction in the tumor size three months after completion of therapy, and the patient's post therapy initial clinical assessment showed ulceration with negative biopsies on flexible sigmoidoscopy. After four more months of chemotherapy, follow-up evaluation revealed recurrence of the ulcerated mass and biopsies were positive for adenocarcinoma. Abdominal perineal resection at this point was offered, but the patient declined. After a multidisciplinary discussion, the patient elected to try endoscopic cryoablation and with consolidative chemotherapy. Flexible sigmoidoscopy demonstrates the residual disease in the distal rectal adenocarcinoma, noted by ulceration here. Rectal ultrasound demonstrates the T3 staging. The estimated surface area was about 0.56 centimeter squares. The cryo balloon was used on an off-label basis for endoscopic ablation. Informed by recent multi-center data on cryo ablation and esophageal cancer, we performed three cycles of cryoablation per endoscopic session. Each cycle consisted of 14 seconds of freezing followed by direct observation of thawing. A total of three cycles were performed per session, and the patient underwent three treatment sessions. Thawing here is sped up in the interest of time. After completion of this thawing, the next treatment cycle will be undertaken, and this is demonstrated. Following treatment, changes that are expected to be seen include erythema around the area. Following treatment, changes that are expected to be seen include erythema around the area. Three months thereafter, the lesion is noted to have a broader base and superficial ulceration. Treatment again is undertaken per protocol, 14 seconds times three cycles per treatment session, and post-treatment changes are again appreciated. Three months thereafter, the lesion is noted to have a smaller footprint in terms of the ulcer with more superficial ulceration. Treatment again is undertaken to complete the third treatment session. Nine months after the initial treatment, the endoscopic examination reveals a scar without ulceration on the site. Biopsies show evidence of granulation tissue without adenocarcinoma or adenomatous tissue. Endoscopic ultrasound shows evidence of diffuse transmural injury without evidence of adverse events, suggesting that cryotherapy may be safe and effective in T3 lesions without adverse events such as perforations. In addition to imaging and biopsies, a circulating tumor DNA-based assay confirmed complete clinical response. This blood-based assay serves as a personalized molecular minimal residual disease assessment, which can be drawn periodically during surveillance. This case illustrates that in selected patients with low rectal cancer, complete clinical response might be achieved through chemoradiation followed by cryotherapy of the residual disease. This may be a potential alternative to surgery in selected patients. In the quest for organ preservation, multimodality treatment to achieve a complete clinical response could include endoscopic ablation. Further studies are warranted to evaluate the efficacy and safety of this approach in a broader patient population.

rectal cancer

chemoradiation

cryotherapy

endoscopic ablation

complete clinical response