Short-term and long-term outcomes after robotic radical surgery for rectal gastrointestinal stromal tumor.

BACKGROUND: The optimal approach for ensuring both complete resection and preservation of anal function in rectal gastrointestinal stromal tumor (GIST) remains unknown. The aim of this study was to clarify short-term and long-term outcomes after robotic radical surgery for rectal GIST. METHODS: A total of 13 patients who underwent robotic radical surgery for rectal GIST between December 2011 and April 2022 were included. All robotic procedures were performed using a systematic approach. A supplemental video of robotic radical surgery for rectal GIST is attached. The short-term outcome was the incidence of postoperative complications during the first 30 days after surgery. Surgical outcomes were retrieved from a prospective database. Long-term outcomes, including overall survival and recurrence-free survival, were determined in all patients. RESULTS: Median distance from the tumor to the anal verge was 4.0 cm. Surgical margins were negative in all patients. Two patients underwent neoadjuvant imatinib therapy. All patients underwent sphincter-preserving surgery. None underwent conversion to open or laparoscopic surgery. The incidence of postoperative Clavien-Dindo grade II and grade ≥ III complications was 7.7% and 0%, respectively. The median postoperative hospital stay was 7 days. Twelve patients (92.3%) underwent stoma closure within 5 months of the initial surgery. Median follow-up time was 76 months. The 5-year overall survival and recurrence-free survival rates were both 100%. None of the patients had recurrence. CONCLUSION: Short-term and long-term outcomes after radical robotic surgery for rectal GIST were favorable. Robotic surgery might be a useful surgical approach for rectal GIST.

Preoperative oral antibiotic administration in patients undergoing curative resection with stoma creation for colorectal cancer: effectiveness in preventing surgical site infection and the possibility of peristomal candidiasis induced by enterobacterial alteration.

AIM: There are many reports that preoperative oral antibiotics (OAs) are effective in preventing surgical site infections (SSIs) in colorectal surgery. However, there is no consensus on the optimal dose of OAs. In this study, we investigated the efficacy of OAs in preventing SSIs and the possibility that OAs induce enterobacterial alteration in the intestinal tract. METHOD: We performed a retrospective cross-sectional analysis of 389 patients who underwent R0 resection and stoma creation for colorectal cancer in our department between 2009 and 2020. We focused on the incidence of peristomal candidiasis (PSC) as an indicator of enterobacterial alteration and used kanamycin (KM) and metronidazole (MNZ) as the OAs. A low-dose group received 1000 mg/day of both KM and MNZ, and a high-dose group received 2000 mg/day of both KM and MNZ. RESULTS: SSI occurred in 60 of the 389 cases (15.4%). Regardless of stoma type, SSI was significantly more common in the non-OA group, while PSC was significantly less common. When examined by OA dose, the incidence of SSI was not significantly different between the low-dose and high-dose groups. However, PSC was significantly more common in the high-dose group than in the non-OA and low-dose groups. Analysis of bacterial and fungal levels in stool samples showed that bacterial levels after OAs were significantly lower than before OAs, while fungal levels increased. CONCLUSION: OAs significantly reduce SSI in colorectal cancer surgery. However, excess OAs were significantly associated with the occurrence of PSC without contributing to further reduction in SSI.

Use of a Powered Circular Stapler Can Prevent Anastomotic Air Leakage in Robotic Low Anterior Resection for Rectal Cancer.

Objectives: Preventing anastomotic complications during rectal cancer surgery is important. Compared with a manual circular stapler, a powered circular stapler is expected to reduce undesirable tension during anastomosis. However, whether a powered circular stapler can reduce anastomotic complications during robotic low anterior resection (Ro-LAR) remains unclear. We aimed to investigate whether the use of a powered circular stapler contributes to safe anastomosis in Ro-LAR. Methods: A total of 271 patients who underwent Ro-LAR for rectal cancer between April 2019 and April 2022 were included. Depending on the type of device employed, patients were divided into a powered circular stapler group (PCSG) and a manual circular stapler group (MCSG). Clinicopathological features and surgical outcomes were compared between the two groups. Results: There were no differences in clinicopathological characteristics and surgical outcomes, except for anastomotic outcomes, between the two groups. Patients with positive air leak tests were significantly more in the MCSG (p=0.026; PCSG, 1.5%; MCSG, 8.0%). Frequencies of anastomotic leakage (p=0.486; PCSG, 6.1%; MCSG, 8.9%) and anastomotic bleeding (p=1.000; PCSG, 0.7%; MCSG, 0.8%) were similar between the two groups. Multivariate analysis showed that the use of a powered circular stapler significantly increased the negative leak tests (p=0.020, odds ratio 6.74, 95% confidence interval 1.35-33.56). Conclusions: Use of a powered circular stapler in Ro-LAR for rectal cancer was significantly associated with a negative air leak test, suggesting that it contributes to stable and safe anastomosis.

The impact of mesorectal fat area on recurrence following total mesorectal excision for lower rectal cancer.

BACKGROUND: The mesorectal fat area (MFA) at the tip of the ischial spines on magnetic resonance imaging has been used to characterize mesorectal morphology. Recent studies reported that a larger MFA correlated with difficulties in rectal cancer surgery. However, the relationship between MFA and rectal cancer prognosis remains unclear. This study evaluated the impact of MFA on recurrence following robotic total mesorectal excision (TME) for rectal cancer. METHODS: Patients who underwent robotic TME for lower rectal cancer from December 2011 to December 2016 were enrolled. Cox regression analysis was performed to determine variables associated with relapse-free survival (RFS). Patients were divided into groups based on MFA, and RFS was compared. RESULTS: Of 230 patients, 173 (75.3%) were male. The median age was 63 years, and median MFA was 19.7 cm2. In multivariate analysis, smaller MFA (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.88-0.97; p < 0.01), p/yp stage II (HR, 3.81; 95% CI, 1.40-10.35; p < 0.01), and p/yp stage III (HR, 5.35; 95% CI, 1.88-15.27; p < 0.01) were independently associated with worse RFS. Sex, body mass index, and visceral fat area were not correlated with RFS. In the median follow-up period of 60.8 months, patients with MFA < 19.7 cm2 had a significantly lower 5-year RFS rate (72.7%) than those with MFA ≥ 19.7 cm2 (85.0%). CONCLUSIONS: Smaller MFA was associated with worse RFS in patients undergoing robotic TME for lower rectal cancer. MFA is considered to be a prognostic factor in rectal cancer.

Incidence and clinical significance of 491 known fusion genes in a large cohort of Japanese patients with colorectal cancer.

BACKGROUND: The clinical significance of fusion genes in colorectal cancer remains unclear. The purpose of this study was to determine the incidence of fusion genes in colorectal cancer and explore their clinical significance by screening for common fusion genes in a large Japanese cohort. METHODS: This study involved 1588 patients. The incidence of 491 fusion genes was examined using a designed fusion panel. In addition, the patients were classified into two groups (RSPO fusion-positive or -negative) according to the presence of RSPO fusions, and the clinicopathological and genetic characteristics of both groups were compared. Long-term outcomes were analyzed in patients without distant metastases. RESULTS: Fusion genes were detected in 2% (31/1588) of colorectal cancers. The incidence of RSPO fusions (such as PTPRK-RSPO3 and EIF3E-RSPO2) was 1.5% (24/1588), making them the most common fusions, whereas the incidence of other fusion genes was extremely low. The distribution of consensus molecular subtypes and frequency of APC mutations were significantly different between the RSPO fusion-positive and -negative groups. The 3-year cumulative incidence rate of recurrence was higher in the RSPO fusion-positive group than in the RSPO fusion-negative group (positive, 31.2% vs. negative, 13.5%, hazard ratio = 2.357; p = 0.040). CONCLUSION: Broad screening for fusion genes showed that RSPO fusions were the most common in colorectal cancer, with an incidence of 1.5%. RSPO fusions may be clinically significant in identifying patients at a high risk of recurrence who would be responsive to specific treatments.

Feasibility of two laparoscopic surgeries for colon cancer performed by the same surgeon on a single day.

BACKGROUND: Although the proportion of laparoscopic colectomies (LCs) for colon cancer is increasing, the feasibility of the same surgeon performing two LCs on a single day remains unknown. This study was conducted to clarify the feasibility of this practice by evaluating short-term and long-term outcomes. METHODS: This retrospective analysis enrolled patients with pathological stage I-III colon cancer who underwent LC at the Shizuoka Cancer Center between 2010 and 2020. Patients were divided into two groups based on the timing of the surgery for the surgeon. The first group (n = 1485) comprised patients who underwent LC as the first surgery of the day for the surgeon. The second group (n = 163) comprised patients who underwent LC as the second LC of the day for the surgeon. Propensity score matching was performed to balance the baseline characteristics of the first and second groups. The short-term and long-term outcomes of the two groups were compared. RESULTS: After propensity score matching, there were no significant differences in the incidence of postoperative complications of Clavien-Dindo classification grade II or higher between the first (10.4%, 17/163) and second groups (5.5%, 9/163). There were no significant differences in other perioperative outcomes, including operative time, intraoperative blood loss, and incidence of conversion to open surgery, between the two groups. Regarding long-term outcomes, there were no significant differences in overall survival or relapse-free survival between the two groups both in the full cohort and in the propensity score-matched cohort. In the propensity score-matched cohort, 5-year overall survival was 92.7% in the first group and 94.4% in the second group; 5-year relapse-free survival was 87.1% and 90.3%, respectively. CONCLUSION: Our results suggest that the same surgeon performing two LCs for colon cancer on a single day is feasible in terms of short-term and long-term outcomes.

Long-term outcomes of upfront robotic rectal cancer surgery: a single-center, retrospective cohort study in Japan.

PURPOSE: The purpose of this study was to evaluate the long-term outcomes of robotic rectal cancer surgery and to examine the risk factors for recurrence. METHODS: In a high-volume center in Japan, we retrospectively enrolled patients with pStage I-III rectal cancer within 15 cm of the anal verge who underwent robotic surgery from 2011 to 2017. Almost all patients underwent upfront surgery, and lateral lymph-node dissection (LLND) was performed for patients with locally advanced lower rectal cancer. We evaluated the 5-year overall survival (OS), relapse-free survival (RFS), and cumulative local recurrence (LR) rates and examined the risk factors for the RFS. RESULTS: We evaluated 488 patients who underwent robotic rectal cancer surgery, including 5.1% who underwent preoperative chemoradiotherapy to obtain clear resection margins and 33.6% who underwent LLND. There were 203, 87, and 198 patients with pStage I, II, and III, respectively, and the positive resection margin rate was 1.0%. The 5-year OS, RFS, and LR rates were 95.5%, 81.7%, and 2.2%, respectively. The independent risk factors for the RFS were the presence of venous invasion, extramural tumor deposits without lymph-node structure, and pT ≥ 3. CONCLUSION: This study demonstrated the favorable long-term outcomes of robotic rectal cancer surgery.

Lymph node metastasis in T1 colorectal cancer with the only high-risk histology of submucosal invasion depth ≥ 1000 µm.

PURPOSE: The number of patients undergoing additional surgery after endoscopic resection (ER) for T1 colorectal cancer (CRC) is increasing. Regarding high-risk histology of lymph node metastasis (LNM) in T1 CRC, a submucosal invasion depth ≥ 1000 µm (T1b) alone may be related to a low incidence of LNM. This study was conducted to clarify the incidence of LNM and to identify factors associated with LNM in T1 CRC with high-risk histology characterized only by T1b. METHODS: We retrospectively investigated patients with pathological T1b CRC who underwent colorectal resection between 2010 and 2020. Patients were divided into two groups with high-risk histology: those in whom the only high-risk feature was T1b (low-risk T1b group, n = 263), and those with T1b as well as lymphovascular invasion, tumor budding, or poorly differentiated or mucinous adenocarcinoma (high-risk T1b group, n = 289). The incidences of LNM and recurrence were compared. Multivariate analysis was performed to identify factors associated with LNM in the low-risk T1b group. RESULTS: The incidences of LNM were 3.8% and 21.6% in the Low- and High-risk T1b groups, respectively (p < 0.01), while the 5-year recurrence rates in the two groups were 0.6% and 3.4%, respectively (p = 0.10). Multivariate analysis revealed that only a predominant histological type of moderately differentiated adenocarcinoma (p = 0.04) was independently associated with LNM in the low-risk T1b group. CONCLUSION: When considering the omission of additional surgery after ER in cases of T1 CRC whose only high-risk histological feature is T1b, attention should be paid to the predominant histological type.

Long-term outcomes of D2 vs. D3 lymph node dissection for cT2N0M0 colorectal cancer: a multi­institutional retrospective analysis.

BACKGROUND: According to Japanese guidelines, D2 or D3 lymph node dissection (LND) is indicated for cT2N0M0 colorectal cancer (CRC). In this study, we retrospectively compared the long-term outcomes between D2 and D3 LND among patients with cT2N0M0 CRC. METHODS: Our sample included 515 patients from the Japanese Study Group for Postoperative Follow-Up of Colorectal Cancer database, who underwent surgical resection for cT2N0M0 CRC between January 2009 and December 2012, 195 (37.9%) of whom underwent D2 LND and 320 (62.1%) D3 LND. The D2 and D3 groups were retrospectively compared in terms of long-term outcomes including overall survival (OS) and relapse-free survival (RFS). The prognostic factors for these outcomes were also evaluated. RESULTS: The D2 group had significantly older patients and higher proportion of men than the D3 group. The rates of OS (5-year OS; 94.8% in the D3 group vs. 93.4% in the D2 group, p = 0.38) and RFS (5-year RFS; 89.3% in the D3 group vs. 89.1% in the D2 group, p = 0.91) were comparable for both groups. On multivariate analysis, age ≥ 80 years was significantly associated with poor OS. The extent of LND was not associated with either OS or RFS. Long-term outcomes were similar between the two groups, independent of tumor location. CONCLUSION: The long-term outcomes did not differ between the D2 and D3 groups and the extent of LND was not associated with prognosis for cT2N0M0 CRC. Therefore, D2 LND may be sufficient for cT2N0N0 CRC treatment.

The Effectiveness of Machine Learning in Predicting Lateral Lymph Node Metastasis From Lower Rectal Cancer: A Single Center Development and Validation Study.

AIM: Accurate preoperative diagnosis of lateral lymph node metastasis (LLNM) from lower rectal cancer is important to identify patients who require lateral lymph node dissection (LLND). We aimed to create an effective prediction model for LLNM using machine learning by combining preoperative information. METHODS: We retrospectively examined patients who underwent primary rectal cancer surgery with unilateral or bilateral LLND between April 2010 and March 2020 at a single institution. Using the machine learning software "Prediction One" (Sony Network Communications), we developed a prediction model in the training cohort that included 267 consecutive patients (500 sides) from April 2010. Clinicopathological data obtained from the preoperative examinations were used as the learning items. In the validation cohort that included subsequent patients until March 2020, we compared the discriminating powers of the prediction model and the conventional method using the short-axis diameter of the largest lateral lymph node, as detected on magnetic resonance imaging. RESULTS: The area under the receiver operating characteristic curve (AUC) of the prediction model was 0.903 in the validation cohort comprising 56 patients (107 sides). This indicated significantly higher predictive power than that of the conventional method (AUC = 0.754; P = .022). Using the cutoff values defined in the training cohort, the accuracy, sensitivity, and specificity of the prediction model were 80.4%, 90.0%, and 79.4%, respectively. The model was able to correctly predict four of five sides comprising LLNM with the short-axis diameters ≤4 mm. CONCLUSION: Machine learning contributed to the creation of an effective prediction model for LLNM.

Efficacy of a robotic stapler on symptomatic anastomotic leakage in robotic low anterior resection for rectal cancer.

PURPOSE: Clinical evidence demonstrating risk factors for anastomotic leakage including robotic staplers has remained limited, even though the use of robotic surgery has increased substantially. The purpose of this study was to evaluate the effects of robotic staplers on symptomatic anastomotic leakage in robotic low anterior resection for rectal cancer. METHODS: A total of 427 consecutive patients with primary rectal cancer who underwent robotic low anterior resection without diverting stoma were investigated retrospectively. Symptomatic anastomotic leakage was defined as anastomotic leakage of Clavien-Dindo Grade ≥ II. We compared the symptomatic anastomotic leakage rates between manual and robotic staplers using propensity score matching and investigated the risk factors for symptomatic anastomotic leakage. RESULTS: After propensity score matching, 168 pairs of manual and robotic stapler cases were selected. The symptomatic anastomotic leakage rate was significantly higher for manual staplers (6.5%) than for robotic staplers (1.2%, p = 0.02). In a multivariate analysis, the use of a manual stapler (p = 0.04, OR 4.86, 95% CI 1.08-21.8) and anastomosis < 4 cm from the anal verge (p < 0.01, OR 4.36, 95% CI 1.48-12.9) were identified as independent risk factors for symptomatic anastomotic leakage. CONCLUSIONS: Robotic stapler use was associated with a significantly decreased rate of anastomotic leakage in robotic low anterior resection without diverting stoma for rectal cancer.

Reduction of perioperative venous thrombus formation by antithrombotic peripherally inserted central catheter in esophageal cancer.

PURPOSE: Although a central venous catheter (CVC) is often needed perioperatively for intraoperative and nutritional management of esophageal cancer (EC), the catheter placement impacts the risk of venous thrombosis. We examined the risks of thrombus formation by catheter type, placement, and duration. METHODS: In total, 226 patients with EC were enrolled in this retrospective study. Patients were classified into one of three groups: those with a conventional CVC (cCVC), a peripherally inserted central catheter (PICC), or an antithrombogenic agent-coated PICC (secPICC). The thrombus formation and clinicopathological features were examined. RESULTS: The frequency of all types of thrombosis was significantly lower in the secPICC group (p < 0.01). Although deep vein thrombosis was frequent in the cCVC group, catheter thrombosis was frequent in the PICC group. In a univariate analysis in patients with the PICC and secPICC groups, less thrombus formation was observed in the secPICC (p = 0.01), short placement time (p = 0.02), and right-sided placement (p < 0.01). Furthermore, a multivariate analysis revealed that secPICC (p = 0.049) and right-sided placement (p = 0.04) significantly reduced rates of thrombus formation. CONCLUSION: In patients with EC, secPICC and right-sided placement reduce perioperative venous thrombus formation.

Clinical outcomes following colorectal resection of colorectal cancer with simultaneous hepatic and pulmonary metastases at the time of diagnosis.

PURPOSE: There are no established treatment strategies for patients with hepatic and pulmonary metastases at the time of primary colorectal cancer (CRC) diagnosis. This study assessed patients undergoing complete resection of primary CRC and hepatic and pulmonary metastases, to evaluate long-term outcomes and clarify clinicopathological factors associated with failure of complete resection. METHODS: This retrospective analysis enrolled patients at Shizuoka Cancer Center between 2002 and 2018 who underwent colorectal resection with curative intent for primary CRC with hepatic and pulmonary metastases. The curative resection (CR) group comprised patients who underwent complete resection of the primary tumor and metastatic lesions, and the non-curative resection (Non-CR) group consisted of those in whom resection of the metastatic lesions was not performed. Univariate and multivariate analyses were conducted to determine clinicopathological factors associated with non-curative resection. RESULTS: Of 26 total patients, the CR and Non-CR groups consisted of 14 (54%) and 12 patients (46%), respectively. In the CR group, the 3-year overall and relapse-free survival rates were 92.9% and 28.6%, respectively. Multivariate analysis showed that pathological stage T4 (odds ratio 8.58, 95% confidence interval 1.13-65.20, p = 0.04) was independently associated with non-curative resection. CONCLUSION: The percentage of patients undergoing complete resection of primary CRC and metastatic lesions was 56%, and the 3-year OS rate was 92.9%. Resection of primary CRC and metastatic lesions was considered to be appropriate in this population, and pathological stage T4 tumor was associated with incomplete resection of metastatic tumors.

Circulating circERBB2 as a potential prognostic biomarker for gastric cancer: An investigative study.

Circular RNA is a novel endogenous non-coding RNA that can serve as a biomarker because of its stable loop structure. We investigated and examined the utility of plasma circERBB2 as a prognostic biomarker in 70 patients with gastric cancer who underwent gastrectomy. We investigated by real-time quantitative PCR the circERBB2 concentrations in the preoperative and postoperative plasma and the circERBB2 expression in the resected tumors. The relationships between circERBB2 concentration in plasma and the clinicopathological features and prognosis were analyzed. circERBB2 was detected in the preoperative plasma samples of 37 patients. The presence of circERBB2 in preoperative plasma (high group) was significantly correlated with lymph node metastasis (P = .035) and tended to be correlated with men (P = .069). Both relapse-free and overall survival were significantly poor in the high group (P = .001 and P = .009, respectively). The Cox proportional-hazard model revealed that the high group was an independent prognostic factor of relapse-free survival (P = .038). Among 16 patients of the high group, 13 patients did not show circERBB2 in the postoperative plasma. The concentration of circERBB2 in plasma was significantly higher in patients with recurrent cancer than those recurrence-free patients (P < .001). In 2 patients with recurrent cancer, plasma circERBB2 concentrations were increased, whereas, in 2 recurrence-free patients, these concentrations hardly changed during the treatment progress. The circERBB2 concentrations in preoperative plasma samples can be considered as a noninvasive prognostic biomarker for gastric cancer. Furthermore, monitoring the postoperative plasma circERBB2 concentrations may be useful for detecting gastric cancer recurrences.

Diagnostic accuracy of the gastric cancer T-category with respect to tumor localization.

PURPOSE: Diagnosing early gastric cancer (EGC) or advanced gastric cancer (AGC) according to T-category is important for optimal GC treatment; however, the clinical and pathological diagnosis of tumor depths can sometimes vary. This study investigated the accuracy of clinical diagnosis of the tumor depth from the viewpoint of tumor localization and prognosis of patients with GC with discordance between clinical and pathological findings. METHODS: This study enrolled 741 patients with primary GC who underwent curative gastrectomy. Based on the clinical and pathological diagnosis of T-category, the patients were classified into four groups: Early-look EGC, Early-look AGC, Advanced-look EGC, and Advanced-look AGC. Tumor localization was classified longitudinally (the upper [U], middle [M], and lower [L] parts and cross-sectionally (the anterior [Ant] and posterior [Post] walls, and the lesser [Less] and greater [Gre] curvatures). RESULTS: Of the 462 clinical EGC cases, 52 were Early-look AGC cases that exhibited a significant association of tumor localization with the Post and Less in the U and M locations (UM-PL; p = 0.037). An Advanced-look EGC (p = 0.031) and Advanced-look AGC (p = 0.025) were independent prognostic factors for relapse-free survival each in pathological EGC and AGC, respectively. CONCLUSIONS: Patients with clinically diagnosed EGC but with pathologically diagnosed AGC more frequently presented tumor in the UM-PL than in any other location. Selection of therapeutic strategy according to the clinical diagnosis might be critical; however, it should be also considered that the accuracy of preoperative assessments varies with tumor localization.

Involvement of Intracellular and Extracellular High-Mobility Group Box-1 in the Progression of Esophageal Squamous Cell Carcinoma.

BACKGROUND: High-mobility group box-1 (HMGB1) is involved in a broad range of inflammatory responses and the progression of various types of malignancy. However, the roles of HMGB1 in the progression of esophageal squamous cell carcinoma (ESCC) are unclear. The aim of this study was to investigate the significance of intracellular and extracellular HMGB1 in ESCC. METHODS: HMGB1 levels were measured in the tissue and plasma of patients with ESCC, or in ESCC cell lines and their conditioned medium. The effects of downregulation of intracellular HMGB1 or upregulation of extracellular HMGB1 on proliferation, cell migration, and invasion were evaluated using proliferation, transwell, and wound healing assays. RESULTS: Downregulation of HMGB1 expression inhibited cell proliferation, migration, and invasion. On the other hand, upregulation of extracellular HMGB1 level by addition of recombinant HMGB1 promoted the migratory and invasive abilities of ESCC cells through increases of phosphorylation of the signal-regulated kinase 1/2 and NF-κBp65 proteins. These effects of extracellular HMGB1 were attenuated by treatment with recombinant soluble thrombomodulin, which adsorbs HMGB1. The expression of HMGB1 was significantly higher in tumor tissue (p = 0.008), and the concentration of HMGB1 in the plasma was significantly higher in patients with ESCC than in healthy volunteers (p = 0.04). Cancer-specific survival was worse in patients with high concentration of plasma HMGB1 (p = 0.01). CONCLUSION: Increase of HMGB1 levels in tumor cells or plasma plays a crucial role in the malignant potential of ESCC. Intracellular and extracellular HMGB1 may be a therapeutic target in ESCC.

[A Case of Early Duodenal Cancer with Lymph Node Involvement Confirmed by Laparoscopic Lymph Node Sampling].

The patient was a 67-year-old man. A Type 0-Ⅱa+Ⅱc tumor, 20mm in size was observed in the 1st portion of the duodenum under magnifying endoscopy. Mucosal cancer was suspected and endoscopic resection was performed, with pathological findings as follows: Type 0-Ⅱa+Ⅱc, 19×12 mm, tub1, pT1b(SM2: 700 mm), pUL0, Ly0, V0, pHM0, pVM0. He refused subtotal stomach-preserving pancreaticoduodenectomy(SSPPD)because of the high morbidity and mortality rates. Instead, he underwent only laparoscopic sampling of No. 5, 6, 12b, and 13a lymph nodes, and metastasis in a No. 6 node was pathologically confirmed. He eventually underwent SSPPD with D2, but no metastases were found in other lymph nodes. Pancreaticoduodenectomy is currently considered the best treatment option for complete removal of regional lymph nodes in duodenal cancer despite high morbidity and mortality rates. Further studies are needed to determine the pattern and incidence of lymph node metastasis by location and depth of the primary tumor, to establish optimal treatment guidelines for duodenal cancer.

[A Case of Advanced Gastric Cancer with Extensive Lymph Node Metastasis That Showed pCR to Preoperative Chemotherapy ContainingXP].

A 67-year-old man was admitted to our hospital because of a type 2 tumor on the posterior wall of the cardia, and a biopsy resulted in a diagnosis of moderately differentiated tubular adenocarcinoma. Abdominal CT revealed swelling of the No. 1, 3, 11p(bulky N), and No.16a2lat lymph nodes. He was diagnosed with gastric cancer, T4aN2M1(LYM), cStage ⅣB, and was administered chemotherapy. After 2 courses of chemotherapy containing capecitabine plus cisplatin(XP), both the primary tumor and lymph nodes markedly decreased in size; then, total gastrectomy with D2+No.16a2lat was performed. Pathological examinations showed no residual cancer cells both in the primary lesion and lymph nodes; thus, the treatment effect of chemotherapy was Grade 3. Some gastric cancer patients may undergo curative resection even with extensive lymph node metastases when effective chemotherapy has been administered. Further discussions are needed about optimal chemotherapeutic regimens and surgical procedures.

[A Case of GIST with Extensive Peritoneal Dissemination Controlled over Long-Term by Low-Dose, Intermittent Administration of Imatinib after Weight Loss Surgery].

A 67-year-old man presented with abdominal pain and fever. Many abdominal tumors were detected by enhanced computed tomography(CT). The largest tumor, measuring 20 cm, had perforated the ileum and formed an abscess. Emergency surgery was performed to remove multiple tumors in the peritoneal cavity as much as possible. Immunostaining showed c-kit and CD34 positivity, and the tumors were diagnosed as gastrointestinal stromal tumor(GIST). During postoperative imatinib therapy for the residual tumor, low-dose intermittent administration was required due to side effects, but the disease was controlled for over 91months. For advanced GIST with peritoneal dissemination, 200mg/day imatinib or intermittent administration after volume reduction surgery might be effective depending on the patient's general condition.

[A Case of Resection for Metastatic Osseous Tumor from Rectal Cancer].

A 67-year-old male was referred to our hospital for further investigation of fecal occult blood. We diagnosed him with rectal cancer with osseous metastasis. Chemo-and radiation therapy were administered following resection of the rectal cancer. There were no other lesions except for the osseous metastasis remaining after these interventions. The osseous lesion was then resected. There have no signs of recurrence for 1 year and 9 months since the last operation. We report a case of successful resection of osseous metastasis from rectal cancer.