Prediction of Neoadjuvant Chemoradiotherapy Response in Rectal Cancer Patients Using Harmonized Radiomics of Multcenter 18F-FDG-PET Image.

We developed machine and deep learning models to predict chemoradiotherapy in rectal cancer using 18F-FDG PET images and harmonized image features extracted from 18F-FDG PET/CT images. Patients diagnosed with pathologic T-stage III rectal cancer with a tumor size > 2 cm were treated with neoadjuvant chemoradiotherapy. Patients with rectal cancer were divided into an internal dataset (n = 116) and an external dataset obtained from a separate institution (n = 40), which were used in the model. AUC was calculated to select image features associated with radiochemotherapy response. In the external test, the machine-learning signature extracted from 18F-FDG PET image features achieved the highest accuracy and AUC value of 0.875 and 0.896. The harmonized first-order radiomics model had a higher efficiency with accuracy and an AUC of 0.771 than the second-order model in the external test. The deep learning model using the balanced dataset showed an accuracy of 0.867 in the internal test but an accuracy of 0.557 in the external test. Deep-learning models using 18F-FDG PET images must be harmonized to demonstrate reproducibility with external data. Harmonized 18F-FDG PET image features as an element of machine learning could help predict chemoradiotherapy responses in external tests with reproducibility.

A Patient-Derived Organoid-Based Radiosensitivity Model for the Prediction of Radiation Responses in Patients with Rectal Cancer.

Patient-derived tumor organoids closely resemble original patient tumors. We conducted this co-clinical trial with treatment-naive rectal cancer patients and matched patient-derived tumor organoids to determine whether a correlation exists between experimental results obtained after irradiation in patients and organoids. Between November 2017 and March 2020, we prospectively enrolled 33 patients who were diagnosed with mid-to-lower rectal adenocarcinoma based on endoscopic biopsy findings. We constructed a prediction model through a machine learning algorithm using clinical and experimental radioresponse data. Our data confirmed that patient-derived tumor organoids closely recapitulated original tumors, both pathophysiologically and genetically. Radiation responses in patients were positively correlated with those in patient-derived tumor organoids. Our machine learning-based prediction model showed excellent performance. In the prediction model for good responders trained using the random forest algorithm, the area under the curve, accuracy, and kappa value were 0.918, 81.5%, and 0.51, respectively. In the prediction model for poor responders, the area under the curve, accuracy, and kappa value were 0.971, 92.1%, and 0.75, respectively. Our patient-derived tumor organoid-based radiosensitivity model could lead to more advanced precision medicine for treating patients with rectal cancer.

Adjuvant chemotherapy does not provide survival benefits to elderly patients with stage II colon cancer.

To date, the effect of adjuvant chemotherapy after curative resection in patients with stage II colon cancer remains controversial. Still, little is known about the effects of adjuvant chemotherapy in patients with stage II colon cancer who are older than 70 years, as most studies did not focus on this population. This study aimed to investigate the oncologic outcomes of elderly patients with stage II colon cancer who underwent curative resection with or without postoperative adjuvant chemotherapy. We retrospectively reviewed medical records of patients older than 70 years who underwent curative resection of stage II primary colon cancer during 2002-2015. Patients were classified into surgery alone (SA) and adjuvant chemotherapy (AC) groups and propensity score-matched at a 1:1 ratio using a logistic regression. The end points were recurrence-free (RFS), cancer-specific (CSS) and overall survival (OS). Of the 623 patients who met the criteria, 145 were assigned to each arm after propensity score matching. The mean ages of the SA and AC groups were 74.3 and 74.0 years, respectively. A log-rank test revealed no significant inter-group differences in RFS (p = 0.202), CSS (p = 0.486) or OS (p = 0.299). In a Cox regression analysis, adjuvant chemotherapy was not found to be an independent factor affecting RFS (p = 0.206), CSS (p = 0.487) or OS (p = 0.301). Adjuvant chemotherapy does not appear to yield survival benefits in elderly patients with stage II colon cancer.

Safety of temporary ileostomy via specimen extraction site in rectal cancer patients who underwent laparoscopic low anterior resection.

If anastomotic site leakage is expected after laparoscopic low anterior resection (LAR), de-functioning ileostomy is required. However, there is controversy about the consequence of stoma formation via the specimen extraction site (SES). Therefore, we aimed to investigate stoma-related complication according to stoma formation via the SES. We enrolled rectal cancer patients who underwent laparoscopic LAR with temporary ileostomy between January 2013 and December 2017. Patients were divided into two groups: stoma through the SES (SES) and stoma through a new site (NS). The difference in the incidence of stoma-related complications was analysed. In total, 198 patients underwent laparoscopic LAR (SES = 141 patients, NS = 57 patients). The SES group had a shorter operation time (204.7 ± 74.4 min vs 229.5 ± 90.5 min, p = 0.049) and was associated with fewer cases of wound infection (0% vs 7%, p = 0.006) than the NS group. There was no statistically significant difference between the SES group and NS group in all-stoma complications (22.7% vs 12.3%, p = 0.095). The incidence of parastomal hernia also was not significantly different (11.3% vs 5.3%, p = 0.286). Stoma via the SES is feasible after laparoscopic LAR with temporary ileostomy, although stoma-related complication rate was higher, without a significant difference. It can shorten the operation time and reduce wound infection rate.

Oncologic outcomes after adjuvant chemotherapy with capecitabine compared to 5-fluorouracil/leucovorin for geriatric stage II colon cancer: a retrospective cohort study.

PURPOSE: After curative resection of stage II colon cancer, adjuvant chemotherapy with 5-fluorouracil/leucovorin (FL) or capecitabine is selectively recommended. However, there is little evidence of the effect of capecitabine on oncologic outcome in geriatric patients with stage II colon cancer compared to that of FL. The aim of this study was to determine the difference in recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) in patients older than 70 years of age with stage II colon cancer receiving capecitabine and FL. METHODS: Patients over 70 years of age diagnosed with primary pathologic stage II colon cancer at the Seoul National University Hospital from January 2005 to December 2015 were included. A prospectively collected database was analyzed retrospectively. Patients were separated into an FL group and a capecitabine group. The primary outcomes were RFS, CSS, and OS. RESULTS: Of the 154 included patients, 96 patients received FL and 58 patients received capecitabine. There was no difference between the two groups in RFS, CSS, or OS (p = 0.763, p = 0.221, and p = 0.470, respectively) as measured by Kaplan-Meier analysis with log-rank test. Administration of capecitabine as compared to FL was not a factor affecting RFS (hazard ratio [HR] 0.503, 95% confidence interval [CI] 0.145-1.745), CSS (HR 1.519, 95% CI 0.348-6.629), or OS (HR 0.941, 95% CI 0.290-3.053) on multivariable analysis. CONCLUSIONS: Capecitabine is a safe regimen in terms of oncologic outcomes compared with FL in older patients with stage II colon cancer.

Prognostic significance of sealed-off perforation in colon cancer: a prospective cohort study.

BACKGROUND: Perforated colon cancer is a rare complication, but has a high risk of recurrence. However, most studies have not distinguished sealed-off perforation from free perforation, and the prognosis is unclear. The aim of this study was to evaluate the oncologic outcome of colon cancer with sealed-off perforation. METHODS: Eighty-six consecutive patients who underwent resection for colon cancer with sealed-off or free perforation were included. We defined sealed-off perforation as a colon perforation with localized abscess identified on operative, computed tomography, or pathologic findings, with no evidence of free perforation, including fecal contamination and dirty fluid collection in the peritoneal cavity. Oncologic outcomes were compared between patients with colon cancer with sealed-off perforation and free perforation using a log-rank test and Cox regression analysis. RESULTS: The sealed-off perforation group included 62 patients, and 24 patients were in the free perforation group. TNM stage and lymphatic, venous, and perineural invasion were similar between the groups. The median follow-up period was 28.9 months (range 0-159). The sealed-off perforation group had better prognosis compared with the free perforation group in terms of progression-free survival (PFS) and overall survival (OS), although there were no statistically significant differences in PFS (5-year PFS 53.7% vs. 40.5%, p = 0.148; 5-year OS 53.6% vs. 22.9%, p = 0.001). However, in multivariable analysis using the Cox progression test, sealed-off perforation did not show a significant effect on cancer progression (p = 0.138) and OS (p = 0.727). CONCLUSIONS: Colon cancer with sealed-off perforation showed no difference in prognosis compared with free perforation.