A risk-adjusted cumulative sum analysis of the progression from a novice to an expert surgeon at a single institution.

BACKGROUND/OBJECTIVE: Laparoscopic surgery for rectal cancer is challenging for novice surgeons because it requires a sharp dissection in a narrow pelvis with visual limitations. Therefore, this study aimed to analyze the learning curve and clinical outcomes of laparoscopic surgery for rectal cancer performed by a novice surgeon en route to becoming an expert. METHODS: In total, 119 patients who underwent laparoscopic surgery for rectal cancer performed by a single surgeon between June 2010 and December 2019 were analyzed. A single hybrid model based on the operative time, open conversion, complications, and resection margin involvement was generated to assess the success of laparoscopic surgery. Furthermore, the learning curve was evaluated using the risk-adjusted cumulative sum (RA-CUSUM) method. RESULTS: The learning period was categorized into three phases according to the RA-CUSUM method (phase 1, 1st-33rd cases; phase 2, 34th-84th cases; and phase 3, 85th-119th cases). Tumor size (p = 0.004), distal resection margin (p = 0.003), and the number of harvested lymph nodes (p < 0.001) significantly increased with the learning period. The time to tolerable soft diet became shorter according to the learning period (p = 0.017). Advanced T stage (p = 0.024) and adjuvant chemotherapy (p = 0.012) were more common in phase 3. CONCLUSIONS: This study suggested that the initial technical competence of laparoscopic surgery for rectal cancer was acquired in the 33rd case. Technical mastery was achieved in the 84th case. After mastering the technique, the surgeon tended to challenge more advanced cases, however, the complication rates did not increase.

Computed tomography-assessed presarcopenia and clinical outcomes after laparoscopic surgery for rectal cancer.

PURPOSE: Previous studies have reported that presarcopenia negatively affects rectal cancer treatment. However, most studies have analyzed patients including majority of open surgery, and the association between presarcopenia and clinical outcomes after laparoscopic rectal cancer surgery remains unclear. This study aimed to evaluate the impact of presarcopenia on the clinical and oncological outcomes after laparoscopic rectal cancer surgery. METHODS: Three hundred and one patients undergoing laparoscopic rectal cancer surgery between December 2009 and May 2016 were enrolled. Body composition was assessed using computed tomography by measuring the muscle and fat areas at the third lumbar (L3) vertebra. The L3 skeletal muscle area was used to calculate the skeletal muscle index and evaluate presarcopenia. RESULTS: Presarcopenia was more common in older ( ≥ 70 years, P = 0.008) or female patients (P = 0.045). Patients with presarcopenia had decreased skeletal muscle area (P < 0.001), lower hemoglobin level (P = 0.034), longer time to first flatus (P < 0.001), and more frequent surgical site infection (P = 0.001). However, survival rates were not significantly different between those with and without presarcopenia. CONCLUSION: Computed tomography-assessed presarcopenia was associated with delayed functional recovery and increased surgical site infection, although it was not revealed as a prognostic factor for oncological outcomes.

Mucocutaneous ulcer positive for Epstein-Barr virus, misdiagnosed as a small bowel adenocarcinoma: A case report.

BACKGROUND: Epstein-Barr virus (EBV)-positive mucocutaneous ulcers (MCUs) are an uncommon disorder characterized by ulcerative lesions in the skin, oral cavity or gastrointestinal tract in patients with iatrogenic or aging-induced immunosuppression. The nonspecific lesions are difficult to differentiate from small bowel adenocarcinomas. We present the case of a 69-year-old woman who was initially misdiagnosed with a small bowel adenocarcinoma but was later surgically diagnosed with and treated for EBV-MCU. Through this case, we aim to emphasize the importance of accurately distinguishing between the two conditions. CASE SUMMARY: The patient presented with an incidental finding of a small bowel tumor during computed tomography (CT) examination performed for hematuria. The CT scan showed irregular thickening of the distal ileum, which was suggestive of a malignant small bowel tumor. An exploratory laparotomy revealed an 8-cm mass in the distal ileum; thus, a segment of the small intestine, including the mass, was resected. Histopathological analysis revealed an ulceroinfiltrative mass-like lesion with luminal narrowing, marked inflammatory cell infiltration, and large atypical lymphoid cells (positive for EBV-encoded small RNA). A final diagnosis of an EBV-MCU was established. The postoperative course was uneventful, and the patient was discharged on postoperative day 7. The patient remained recurrence-free until 12 mo after surgery. CONCLUSION: This case highlights the diagnostic challenges for EBV-MCUs and emphasizes the importance of comprehensive evaluation and accurate histopathological analysis.

Comparative detection of syndecan-2 methylation in preoperative and postoperative stool DNA in patients with colorectal cancer.

BACKGROUND: Early detection of colorectal cancer (CRC) is essential to reduce cancer-related morbidity and mortality. Stool DNA (sDNA) testing is an emerging method for early CRC detection. Syndecan-2 (SDC2) methylation is a potential biomarker for the sDNA testing. Aberrant DNA methylation is an early epigenetic event during tumorigenesis and can occur in the normal colonic mucosa during aging, which can compromise the sDNA test results. AIM: To determine whether methylated SDC2 in sDNA normalizes after surgical resection of CRC. METHODS: In this prospective study, we enrolled 151 patients with CRC who underwent curative surgical resection between September 2016 and May 2020. Preoperative stool samples were collected from 123 patients and postoperative samples were collected from 122 patients. A total of 104 samples were collected from both preoperative and postoperative patients. Aberrant promoter methylation of SDC2 in sDNA was assessed using linear target enrichment quantitative methylation-specific real-time polymerase chain reaction. Clinicopathological parameters were analyzed using the results of SDC2 methylation. RESULTS: Detection rates of SDC2 methylation in the preoperative and postoperative stool samples were 88.6% and 19.7%, respectively. Large tumor size (3 cm, P = 0.019) and advanced T stage (T3-T4, P = 0.033) were positively associated with the detection rate of SDC2 methylation before surgery. Female sex was associated with false positives after surgery (P = 0.030). Cycle threshold (CT) values were significantly decreased postoperatively compared with preoperative values (P < 0.001). The postoperative negative conversion rate for preoperatively methylated SDC2 was 79.3% (73/92). CONCLUSION: Our results suggested that the SDC2 methylation test for sDNA has acceptable sensitivity and specificity. However, small size and early T stage tumors are associated with a low detection rate of SDC2 methylation. As the cycle threshold values significantly decreased after surgery, SDC2 methylation test for sDNA might have a diagnostic value for CRC.

Strangulated internal hernia through a defect of the broad ligament: a case report of laparoscopic surgery.

An internal hernia is defined as the protrusion of an internal organ through a defect in the abdominal cavity. Broad ligament hernia (BLH) is an extremely rare type of internal hernia that is difficult to diagnose preoperatively because the symptoms are nonspecific. However, early diagnosis is crucial, and early surgery is required to reduce complications such as strangulation. Laparoscopy has the advantage of enabling simultaneous diagnosis and treatment of BLH. With the advancement of the laparoscopic techniques, several cases of laparoscopic treatment of BLH have been reported. Nevertheless, open surgery is primarily performed in patients requiring bowel resection. We present a case of laparoscopic surgery for a strangulated internal hernia through a broad ligament defect. We successfully resected the strangulated small intestine and closed the defect of the broad ligament laparoscopically with a minor incision.

Apurinic/apyrimidinic endonuclease 1 is associated with poor prognosis after curative resection followed by adjuvant chemotherapy in patients with stage III colon cancer.

Purpose: Apurinic/apyrimidinic endonuclease 1 (APE1) is a key enzyme involved in the base excision repair pathway. It also has redox activity and maintains various transcription factors in an active reduced state. APE1 may be associated with chemoresistance. In the present study, we first investigated the expression level of APE1 protein and its correlation with oncologic outcomes of oxaliplatin-based chemotherapy in patients with stage III colon cancer. Further, we investigated the effects of human APE1 siRNA on the sensitivity of oxaliplatin in SNU-C2A colon cancer cells. Methods: Tissue specimens from tumor and normal colon of 33 patients with stage III colon cancer were obtained from 2006 to 2009. The patients received at least eight cycles of oxaliplatin-based chemotherapy. APE1 expression was analyzed by immunohistochemistry and Western blotting using a cultured SNU-C2A cell line. Cell viability and apoptosis were determined by Cell Counting Kit-8 and caspase-3 cleavage using Western blotting. Results: All the colon cancer tissues showed APE1 staining in the nucleus, whereas all the normal colon tissues were negative for APE1 staining in the cytoplasm. The group with a higher expression of APE1 demonstrated poorer prognosis than the group with low expression (P=0.026 for overall survival and P=0.021 for disease-free survival). Treatment with oxaliplatin resulted in a dose-dependent increase in APE1 expression in SNU-C2A cells. APE1 siRNA significantly enhanced oxaliplatin-induced growth inhibition, and also increased oxaliplatin-induced apoptosis in SNU-C2A cells. Conclusion: APE1 could be considered a prognostic factor in colon cancer patients treated with oxaliplatin-based chemotherapy.

Difference in Tumor Area as a Predictor of a Pathological Complete Response for Patients With Locally Advanced Rectal Cancer.

PURPOSE: This study was conducted to discover the clinical factors that can predict pathologically complete remission (pCR) after neoadjuvant chemoradiotherapy (CRT), so that those factors may help in deciding on a treatment program for patients with locally advanced rectal cancer. METHODS: A total of 137 patients with locally advanced rectal cancer were retrospectively enrolled in this study, and data were collected retrospectively. The patients had undergone a total mesorectal excision after neoadjuvant CRT. Histologic response was categorized as pCR vs. non-pCR. The tumor area was defined as (tumor length) × (maximum tumor depth). The difference in tumor area was defined as pre-CRT tumor area - post-CRT tumor area. Univariate and multivariate logistic regression analyses were conducted to find the factors affecting pCR. A P-value < 0.05 was considered significant. RESULTS: Twenty-three patients (16.8%) achieved pCR. On the univariate analysis, endoscopic tumor circumferential rate <50%, low pre-CRT T & N stage, low post-CRT T & N stage, small pretreatment tumor area, and large difference in tumor area before and after neoadjuvant CRT were predictive factors of pCR. A multivariate analysis found that only the difference in tumor area before and after neoadjuvant CRT was an independent predictor of pCR (P < 0.001). CONCLUSION: The difference in tumor area, as determined using radiologic tools, before and after neoadjuvant CRT may be important predictor of pCR. This clinical factor may help surgeons to determine which patients who received neoadjuvant CRT for locally advanced rectal cancer should undergo surgery.