Stratification of Stage II Colon Cancer Using Recurrence Prediction Value: A Multi-institutional International Retrospective Study.

OBJECTIVE: To create a recurrence prediction value (RPV) of high-risk factor and identify the patients with high risk of cancer recurrence. SUMMARY BACKGROUND DATA: There are several high-risk factors known to lead to poor outcomes. Weighting each high-risk factor based on their association with increased risk of cancer recurrence can provide a more precise understanding of risk of recurrence. METHODS: We performed a multi-institutional international retrospective analysis of patients with Stage II colon cancer patients who underwent surgery from 2010 to 2020. Patient data from a multi-institutional database were used as the Training data, and data from a completely separate international database from two countries were used as the Validation data. The primary endpoint was recurrence-free survival (RFS). RESULTS: A total of 739 patients were included from Training data. To validate the feasibility of RPV, 467 patients were included from Validation data. Training data patients were divided into RPV low (n = 564) and RPV high (n = 175). Multivariate analysis revealed that risk of recurrence was significantly higher in the RPV high than the RPV low (Hazard ratio (HR) 2.628; 95% confidence interval (CI) 1.887-3.660; P < 0.001). Validation data patients were divided into two groups (RPV low, n = 420) and RPV high (n = 47). Multivariate analysis revealed that risk of recurrence was significantly higher in the RPV high than the RPV low (HR 3.053; 95% CI 1.962-4.750; P < 0.001). CONCLUSIONS: RPV can identify Stage II colon cancer patients with high risk of cancer recurrence world-wide.

Delayed-Onset Organ/Space Surgical Site Infection Worsens Prognosis in High-Risk Stage II and III Colorectal Cancer.

BACKGROUND: It is unclear how early- and delayed-onset organ/space surgical site infections (SSIs) affect the long-term prognosis of patients with colorectal cancer, who are potential candidates for adjuvant chemotherapy. This study aimed to investigate the association between the timing of SSI onset and clinical outcome. METHODS: This retrospective, multicenter cohort study evaluated patients who were diagnosed with high-risk stage II or III colorectal cancer and underwent elective surgery between 2010 and 2020. Five-year recurrence-free survival (RFS) was the primary endpoint and was compared between early SSI, delayed SSI (divided based on the median date of SSI onset), and non-SSI groups. RESULTS: A total of 2,065 patients were included. Organ/space SSI was diagnosed in 91 patients (4.4%), with a median onset of 6 days after surgery. The early-onset SSI group had a higher proportion of patients with Clavien-Dindo grade ≥IIIb SSI than the delayed-onset SSI. Patients who received adjuvant chemotherapy (AC) had earlier organ/space SSI onset than those who did not. The adjusted hazard ratio of 5-year RFS in the delayed-onset SSI was 2.58 (95% confidence interval: 1.43-4.65; p = 0.002): higher than that in the early-onset SSI, with the non-SSI as the reference. CONCLUSIONS: Delayed-onset organ/space SSI worsened long-term prognosis compared to early-onset, and this may be due to delayed initiation of AC. Patients who are clinically suspected of having lymph node metastasis might need additional intervention to prevent delays in commencing AC due to the delayed SSI.

Cost-effectiveness analysis of pembrolizumab in patients with treatment-refractory metastatic colorectal cancer in Japan.

OBJECTIVE: The immune checkpoint inhibitor pembrolizumab has recently been recognized as a standard treatment regimen for patients with metastatic colorectal cancer and the microsatellite-instability-high/mismatch repair-deficient mutation. However, its cost-effectiveness in late-line treatment remains unclear. The aim of this study was to assess the cost-effectiveness of pembrolizumab for patients with microsatellite-instability-high/mismatch repair-deficient metastatic colorectal cancer. METHODS: Markov decision modeling using treatment costs, disease-free survival and overall survival was performed to examine the cost-effectiveness of pembrolizumab monotherapy compared with chemotherapy, and best supportive care. The Japanese healthcare payer's perspective was adopted. The outcomes were modeled on the basis of published literature. The primary outcome was the incremental cost-effectiveness ratio between the strategies. Sensitivity analyses were performed and the effects of uncertainty on the model parameters were investigated. RESULTS: Pembrolizumab monotherapy had incremental cost-effectiveness ratios of $408204.3 per quality-adjusted life-year gained compared with best supportive care and $489123.4 per quality-adjusted life-year gained compared with chemotherapy. Given a Japanese willingness-to-pay threshold of $69560.38 per quality-adjusted life-year, the base case results suggested that pembrolizumab monotherapy was not cost-effective. The sensitivity analysis results were in line with the base case results. CONCLUSION: Pembrolizumab monotherapy is not a cost-effective option in late-line treatment for patients with metastatic colorectal cancer and microsatellite-instability-high/mismatch repair-deficient mutation in the Japanese healthcare system. Further studies on its cost-effectiveness in first-line treatment are warranted.

Prognostic Impact of Main Lymph Node Metastasis in Patients with Colon Cancer.

BACKGROUND: Although extended lymph node dissection during colon cancer surgery is recommended in both Western and Eastern countries, the perception and clinical significance of main lymph node metastasis (MLNM) remains controversial. METHODS: In total, 1557 patients with colon cancer who underwent curative resection with D3 dissection were retrospectively analyzed. Clinicopathological factors associated with MLNM were analyzed. Kaplan-Meier survival analysis and log-rank tests were used to compare the prognosis between the MLNM and non-MLNM groups. RESULTS: Multivariate analysis showed that overall survival (OS) [hazard ratio, 2.117 (0.939-4.774), p = 0.071] and recurrence-free survival (RFS) [hazard ratio, 2.183 (1.182-4.031), p = 0.013] were affected by the MLNM status independent of the TNM stage. Survival analysis demonstrated that among patients with stage III disease, the OS and RFS rates were significantly different between patients with and without MLNM (OS: p = 0.0147, RFS: p = 0.0001). However, the OS and RFS rates were not significantly different between patients who had stage III disease with MLNM and patients who had stage IV disease (OS: p = 0.5901, RFS: p = 0.9610). CONCLUSIONS: MLNM is an independent prognostic factor for patients with colon cancer. The addition of the MLNM status to the current TNM classification may enhance the prognostic value of the TNM staging system and the clinical efficacy of adjuvant therapy in patients with colon cancer.

Metformin inhibits the development and metastasis of colorectal cancer.

Metformin is a commonly used drug for the treatment of diabetes. Accumulating evidence suggests that it exerts anti-cancer effects in many cancers, including colorectal cancer. However, the underlying molecular mechanisms of colorectal cancer metastasis remain unclear. Colorectal cancer cell lines were treated with metformin, and cell proliferation, invasion, and migration were analyzed in vitro. The relationship between metformin and the AMPK-mTOR axis was assessed by Western blot analysis and transfection with small interfering RNA. A colorectal cancer xenograft mouse model was used to observe the effects of metformin on liver metastasis. Immunohistochemical analysis was performed on liver metastatic tumors. In in vitro experiments, metformin significantly inhibited the proliferation, migration, and invasion only in HCT116 and SW837 cells, but not in HCT8 and Lovo cells. Only in HCT116 and SW837, a change in AMPK-mTOR expression was observed in a dose-dependent manner. In colorectal cancer xenograft mice, the liver metastatic rate (10% vs. 50%, p = 0.05) and the number of liver metastatic nodules (0.1/body vs. 1.2/body, p = 0.04) were significantly lower in the metformin group. Tumor proliferation and EMT were decreased and apoptosis was promoted only in metastatic liver tumors of mice treated with metformin. The molecular mechanism of the anti-cancer effects of metformin involves repression of mTOR pathways via AMPK activation. Moreover, the differences in metformin sensitivity depend on the response of the AMPK-mTOR pathway to metformin. Our study provides a theoretical basis for the anti-metastatic treatment of colorectal cancer using metformin.

Comprehensive risk score of the E-PASS as a prognostic indicator for patients after elective and emergency curative colorectal cancer surgery: A multicenter retrospective study.

OBJECTIVE: To evaluate the prognostic value of the comprehensive risk score (CRS) of the Estimation of Physiologic Ability and Surgical Stress for managing patients with colorectal cancer (CRC) who underwent elective and emergency colorectal cancer surgery with curative intent. SUMMARY BACKGROUND DATA: CRS, which is calculated based on both clinical and surgical factors, is a good predictor of postoperative complications and mortality. However, the impact of CRS in CRC prognosis remains unclear. METHODS: Patients with CRC who underwent curative resection between 2010 and 2019 were retrospectively enrolled in this study. The cohort was divided into the low and high CRS groups. The prognostic value of CRS was evaluated via Cox regression and Kaplan-Meier analyses. The CRS cutoff value was obtained using the Youden index applied to OS curves and have not been validated by any validation cohorts. RESULTS: In total, 2407 patients, including 1359 and 1048 patients with low and high CRS, respectively, were enrolled in this study. Multivariate analysis revealed that a CRS was an independent prognostic factor of overall and recurrence-free survival regardless of disease stage. Furthermore, adjuvant chemotherapy was beneficial for the survival of patients with stage III CRC in both high and low CRS groups; however, the survival benefit was limited in elderly high CRS patients. CONCLUSIONS: CRS was a strong prognostic factor for CRC regardless of disease stage and might be considered as a biomarker for selecting elderly patients who are eligible for adjuvant chemotherapy.

Long-term and short-term outcomes of laparoscopic versus open resection following tube decompression for obstructive colorectal cancer: a single-center retrospective study.

PURPOSE: The benefits of laparoscopic surgery over open surgery are well documented; however, the suitability of laparoscopic surgery for obstructive colorectal cancer is still controversial. The aim of this retrospective study was to compare the clinical benefits of laparoscopic surgery vs. open surgery for obstructive colorectal cancer after tube decompression. METHODS: We analyzed the outcomes of patients who underwent laparoscopic surgery vs. open surgery for curative resection after tube decompression for obstructive colorectal cancer at our hospital between January, 2007 and March, 2018. RESULTS: This study comprised 67 patients: 29 patients who underwent open surgery and 38 patients who underwent laparoscopic surgery. The morbidity within 30 days after surgery was comparable between the groups. The 3-year overall survival rates of the open and laparoscopic groups were 83.3 and 79.4%, respectively (p = 0.6244), and the 3-year disease-free survival rates were 59.3 and 71.2%, respectively (p = 0.3200). Multivariate analysis showed that nodal stage (p = 0.021) was an independent prognostic factor for OS and sex (p = 0.010) and side-ness (p = 0.048) were independent prognostic factors for DFS. CONCLUSION: If adequate decompression is achieved, laparoscopic resection following tube decompression for obstructive colorectal cancer can be a safe alternative to open surgery.

Cost-effectiveness of TAS-102 plus bevacizumab versus TAS-102 monotherapy in patients with metastatic colorectal cancer.

BACKGROUND: TAS-102 plus bevacizumab is an anticipated combination regimen for patients who have metastatic colorectal cancer. However, evidence supporting its use for this indication is limited. We compared the cost-effectiveness of TAS-102 plus bevacizumab combination therapy with TAS-102 monotherapy for patients with chemorefractory metastatic colorectal cancer. METHOD: Markov decision modeling using treatment costs, disease-free survival, and overall survival was performed to examine the cost-effectiveness of TAS-102 plus bevacizumab combination therapy and TAS-102 monotherapy. The Japanese health care payer's perspective was adopted. The outcomes were modeled on the basis of published literature. The incremental cost-effectiveness ratio (ICER) between the two treatment regimens was the primary outcome. Sensitivity analysis was performed and the effect of uncertainty on the model parameters were investigated. RESULTS: TAS-102 plus bevacizumab had an ICER of $21,534 per quality-adjusted life-year (QALY) gained compared with TAS-102 monotherapy. Sensitivity analysis demonstrated that TAS-102 monotherapy was more cost-effective than TAS-102 and bevacizumab combination therapy at a willingness-to-pay of under $50,000 per QALY gained. CONCLUSIONS: TAS-102 and bevacizumab combination therapy is a cost-effective option for patients who have metastatic colorectal cancer in the Japanese health care system.

Bridge to Surgery for Obstructing Colonic Cancer: A Comparison between Right- and Left-sided Lesions.

OBJECTIVES: Few studies have compared management and outcomes of bridge to surgery (BTS) for obstructive colonic cancer according to the location of the tumor. Additional information is needed about this procedure's characteristics and short-term and long-term outcomes. We aimed to compare patient and tumor characteristics, and outcomes of BTS for obstructive right-sided versus left-sided colonic cancers. METHODS: This was a retrospective, single center, cohort study. The study cohort comprised 149 patients, including 48 with right-sided and 101 with left-sided obstructive colonic cancers, who were treated with BTS between January 2007 and December 2017. Data on medical history, investigations, treatments, and prognosis were collected from an electronic database of a single hospital. The primary end points were overall (OS) and disease-free (DFS) survival and short-term surgical outcomes. RESULTS: Significantly more patients with right-sided cancers had postoperative complications (29.2% vs. 14.9%, p = 0.039). Additionally, postoperative chemotherapy was administered to a marginally significantly greater proportion of patients with left-sided cancers (29.2% vs 45.5%, p = 0.057). The long-term outcomes were comparable between the two groups (the 5-year OS rates were 67.6% and 80.9% [p = 0.117] and the 5-year DFS rates were 62.2% and 58.6% [p = 0.671]). Multivariate analyses using all studied variables showed that lymphovascular invasion, advanced T stage, and adjuvant chemotherapy were independent poor prognostic factors. CONCLUSIONS: The long-term outcome was not different between the right- and left-sided groups. In a BTS setting, postoperative complications may reduce the compliance of adjuvant chemotherapy in right-sided cancers and affect long-term outcomes.

Cost-effectiveness analysis of initial nonoperative management versus emergency laparoscopic appendectomy for acute complicated appendicitis.

BACKGROUND: The evidence regarding the safety and efficacy of nonoperative management is growing. However, the best treatment strategy for acute complicated appendicitis remains controversial. We aimed to evaluate the cost-effectiveness of treatment strategies for complicated appendicitis patients. This study sought to determine the most cost-effective strategy from the health care-payer's perspective. METHODS: The primary outcome was an incremental cost effectiveness ratio (ICER) using nonoperative management with or without interval laparoscopic appendectomy (ILA) as the intervention compared with operative management with emergency laparoscopic appendectomy (ELA) alone as the control. Model variables were abstracted from a literature review, and from data obtained from the hospital records of Tochigi Medical Center. Cost-effectiveness was evaluated using an ICER. We constructed a Markov model to compare treatment strategies for complicated appendicitis in otherwise-healthy adults, over a time horizon of a single year. Uncertainty surrounding model parameters was assessed via one-way- and probabilistic-sensitivity analyses. Threshold analysis was performed using the willingness-to-pay threshold set at the World Health Organization's criterion of $107,690. RESULTS: Three meta-analysis were included in our analysis. Operative management cost $6075 per patient. Nonoperative management with interval laparoscopic appendectomy (ILA) cost $984 more than operative management and produced only 0.005 more QALYs, resulting in an ICER of $182,587. Nonoperative management without ILA cost $235 more than operative management, and also yielded only 0.005 additional QALYs resulting in an ICER of $45,123 per QALY. Probabilistic sensitivity analysis with 1000 draws resulted in average ICER of $172,992 in nonoperative management with ILA and $462,843 in Nonoperative management without ILA. The threshold analysis demonstrated that regardless of willingness-to-pay, nonoperative management without ILA would not be most cost-effective strategy. CONCLUSIONS: Nonoperative management with ILA and Nonoperative management without ILA were not cost-effective strategies compared with operative management to treat complicated appendicitis. Based on our findings, operative management remains the standard of care and nonoperative management would be reconsidered as a treatment option in complicated appendicitis from economic perspective.

Effectiveness of active nasal surveillance culture for Methicillin-resistant Staphylococcus aureus in patients undergoing colorectal surgery.

OBJECTIVE: The aim of this study was to clarify the role of Methicillin-resistant Staphylococcus aureus (MRSA) carriers in the development of surgical site infection (SSI) after colorectal surgery. SUMMARY BACKGROUND DATA: MRSA is commonly implicated in hospital-acquired infections. Active surveillance culture (ASC) using the nasal swab test is useful to detect MRSA in surgical patients. We hypothesized that MRSA carriers would be more susceptible to SSI after colorectal surgery METHODS: Patients who underwent ASC between 2010 and 2013 were included in this study. The incidence of SSI was compared between MRSA carriers and non-carriers using the chi-square test. The odds ratio for SSI was computed using logistic regression analyses. RESULTS: Among 355 patients, 12 (3.4%) were identified as MRSA carriers and 343 as non-carriers. Of all the patients, 65 patients (18.3%) developed an SSI. Of these, 6 cases were in MRSA carriers and 59 cases were in non-carriers (p < 0.01). This meant that half of the 12 MRSA carriers developed an SSI, compared with only 17.2% of non-carriers (59 cases out of 343 patients). Therefore, MRSA carriers had a significantly higher risk of SSI (adjusted odds ratio = 4.77 [1.37 to 16.6], p = 0.01). CONCLUSIONS: Detection of MRSA via ASC is significantly associated with the development of SSI after colorectal surgery. These findings indicate that ASC for MRSA is useful to predict an SSI.