Dynamics of surgical smoke in the operating room during spinal surgery: Comparison of particulate matter 2.5-air concentration between the electric scalpel with and without a smoke evacuation pencil: A cross-sectional study.

BACKGROUND: Surgical smoke is a vaporous by-product generated during tissue incision and cauterization with an electric scalpel. This smoke contains tissue- and blood/vascular-derived substances, bacteria, viruses, and chemical substances. Among them, it contains many fine particles called particulate matter (PM) 2.5, which are harmful and hazardous to the human body. We aimed to investigate the occurrence of PM2.5 in surgical smoke produced during spinal surgery and to evaluate the efficacy of an electric scalpel with a smoke evacuation pencil. METHODS: In this retrospective observational study, 89 patients who underwent spinal surgery between June 2019 and May 2021 were included. A dust monitor was installed in the operating room to measure the PM2.5 air concentration during the surgery. During each surgery, the total amount of PM2.5, the maximum PM2.5 air concentration, the exposure time to PM2.5, and the average value of PM2.5 air concentration from the start to the end of the surgery were calculated. RESULTS: We found that in 29 of the 89 cases (32.6%), the air concentration of PM2.5 increased to a level that could cause health damage during the surgery. Twelve cases (13.4%) reached the level that could cause serious health damage, and 8 cases (9%) reached an emergency warning level. The total amount and the maximum and average levels of PM2.5 were significantly suppressed in the surgery with a smoke evacuation pencil group than in the surgery without a smoke evacuation pencil group. CONCLUSION: We detected hazardous levels of PM2.5 in the air during spinal surgery, highlighting the importance of considering smoke control or reduction during spinal surgery. We recommend using an electric scalpel with a smoke evacuation pencil for regulating PM2.5 levels in the operating room.

Comparison of surgical smoke between open surgery and laparoscopic surgery for colorectal disease in the COVID-19 era.

BACKGROUND: Surgical smoke during operation is a well-known health hazard for medical staff. This study aimed to investigate the dynamics of surgical smoke during open surgery or laparoscopic surgery for colorectal disease. METHODS: This study quantitated particulate matter (PM) counts as part of surgical smoke in 31 consecutive patients who underwent colectomy at the Niigata City General Hospital using a laser particle counter. Particles were graded by size as ≤ 2.5 µm PM (PM2.5) or > 2.5 µm PM (large PM). Operative procedures were categorized as either open surgery (n = 14) or laparoscopic surgery (n = 17). RESULTS: The median patient age was 72 (range 41-89) years and 58.1% were male. The total PM2.5, PM2.5 per hour, and maximum PM2.5 per minute counts during operation were significantly higher in open surgery than in laparoscopic surgery (P = 0.001, P < 0.001, and P = 0.029, respectively). Large PM counts (total, per hour, and maximum per minute) were also higher in the open surgery group than in the laparoscopic surgery group. The maximum PM2.5 concentration recorded was 38.6 µm/m3, which is considered "unhealthy for sensitive groups" according to the U.S. Environment Protection Agency air quality index standards, if it was a 24-h period mean value. CONCLUSION: Exposure to surgical smoke is lower during laparoscopic surgery than during open surgery for colorectal diseases.

Is radiological psoas muscle area measurement a predictor of postoperative complications after rectal resection for rectal cancer? A retrospective study.

PURPOSE: Previous studies have reported that sarcopenia increases the risk of postoperative complications following colorectal resection. This retrospective study assessed the postoperative complications of rectal resection associated with sarcopenia. METHODS: We retrospectively analyzed 262 patients who underwent curative low anterior resection for primary rectal cancer from January 2008 to May 2020 at our institution. The patients were divided into a sarcopenia group (normalized total psoas muscle area < 6.36 cm2/m2 in males and < 3.92 cm2/m2 in females; N = 49) and a non-sarcopenia group (N = 213). RESULTS: The overall rate of postoperative complications within 30 days of surgery was higher in the sarcopenia group than in the non-sarcopenia group (46.9 vs. 29.6%; P = 0.028). The rate of postoperative remote infections was higher in the sarcopenia group than in the non-sarcopenia group (12.2 vs. 2.8%; P = 0.012). Sarcopenia was found to be a predictor of remote infection by a multivariate analysis (odds ratio, 4.08; 95% confidence interval, 1.12-14.80; P = 0.033). CONCLUSION: Sarcopenia diagnosed using the psoas muscle index was found to be an independent predictive factor for postoperative remote infection after curative low anterior resection for rectal cancer.

[A Case of Suspected Lynch Syndrome Due to Radical Resection for Descending Colon Cancer and Renal Pelvic Cancer].

A 60-year-old woman was admitted on account of presenting with bloody stools. She had a history of endometrial cancer surgery. Family history revealed 3 colorectal cancer cases among the first or second relatives. Colonoscopy and contrast- enhanced computed tomography revealed descending colon cancer and left renal pelvic cancer. We performed partial resection of the descending/transverse colon with D3 lymph node dissection and total resection of the left kidney and ureter with curative intent. Postoperative pathological diagnosis revealed descending colon cancer(pT4bN0M1c, pStage Ⅳc)and left renal pelvic cancer (T1N0M0, Stage Ⅰ). In this case, Lynch syndrome was suspected based on the family history and medical history. The clinical findings were consistent with Amsterdam Criteria Ⅱ. The microsatellite instability(MSI)test result was MSI-H and the BRAF genetic test result showed a wild type. Immunohistochemical staining of descending colon cancer tissue showed loss of expression of MSH2 and MSH6 proteins. Genetic counseling was provided because Lynch syndrome was strongly suspected. Capecitabine plus oxaliplatin therapy was performed for 6 months for descending colon cancer. Nine months postoperatively, the patient remained recurrence-free for both colon cancer and renal pelvic cancer. We report a case of suspected Lynch syndrome triggered by double cancer of the descending colon and renal pelvis.

Clinical Significance of Mesenteric Lymph Node Involvement in the Pattern of Liver Metastasis in Patients with Ovarian Cancer.

BACKGROUND: Mesenteric lymph node (MLN) involvement is often observed in ovarian cancer (OC) with rectosigmoid invasion. This study aimed to investigate the clinical significance of MLN involvement in the pattern of liver metastasis in patients with OC. METHODS: We included 85 stage II-IV OC patients who underwent primary or interval debulking surgery. Twenty-seven patients underwent rectosigmoid resection, whose status of MLN involvement was judged from hematoxylin and eosin (H&E) staining of resected specimens. The prognostic significance of clinicopathological characteristics, including MLN involvement, was evaluated using univariate and multivariate analyses. RESULTS: MLN involvement was detected in 14/85 patients with stage II-IV OC. Residual tumor status, cytology of ascites, and MLN involvement were independent prognostic factors for progression-free survival (PFS; p = 0.033, p = 0.014, and p = 0.008, respectively). When patients were classified into three groups (no MLN, one MLN, two or more MLNs), the number of MLNs involved corresponded to three distinct groups in PFS (p = 0.001). The 3-year cumulative incidence of liver metastasis of patients with MLN involvement was significantly higher than that of patients without MLN involvement (61.1% vs. 8.9%, p < 0.001). MLN involvement was significantly associated with liver metastasis of hematogenous origin (p < 0.001) compared with peritoneal disseminated origin. CONCLUSION: MLN involvement is an important prognostic factor in OC, predicting poor prognosis and liver metastasis of hematogenous origin.

The clinical significance of distal spread differs according to the primary tumor location in rectal cancer.

PURPOSE: Treatment strategies of rectal cancer differ between tumors located above (RS/Ra) and below (Rb) the peritoneal reflection. Based on the extent of distal spread (DS), the Japanese Society for Cancer of Colon and Rectum proposed an optimal distal margin in RS/Ra and Rb tumors. In this study, we investigated the clinical significance of DS between RS/Ra and Rb tumors. METHODS: We analyzed 287 stage I-III rectal cancer patients who underwent curative intent resection without preoperative therapy. DS and other pathological factors were evaluated using whole-mount sections. To investigate the clinical significance of DS in RS/Ra and Rb tumors, clinicopathological variables, including DS, were analyzed for the survival outcome according to the tumor group. RESULTS: DS was detected in 20 out of 185 (11%) patients with RS/Ra tumors and 8 out of 102 (8%) patients with Rb tumors. DS was not significantly associated with the overall survival (OS) or relapse-free survival (RFS) in RS/Ra tumors, but was an independent prognostic factor for the OS and RFS in Rb tumors (P = 0.002 and 0.007, respectively). CONCLUSIONS: The clinical significance of DS differs between RS/Ra and Rb tumors. DS is associated with a worse survival in Rb tumors, but not in RS/Ra tumors.

[A Case of High-Frequency Microsatellite Instability in Colorectal Cancer with MSH2 Mutation Detected Using Gene Panel Testing with a Next-Generation Sequencer].

Here, we report about a woman in her 30s who had peritoneal dissemination and multiple colon cancer with high-frequency microsatellite instability(MSI-H). Her father, paternal grandfather, and maternal grandmother had a history of colorectal cancer treatment. Thus, Lynch syndrome was suspected. We performed R0 resection for peritoneal dissemination and subsequent peritoneal dissemination. A 435-gene panel testing using a next-generation sequencer identified MSH2 and other mutations in the tumor. Hence, we speculated that she could have a germline mutation of MSH2, which causes Lynch syndrome. In the future, if she wishes to receive genetic counseling and undergo germline testing for variants to confirm the diagnosis of Lynch syndrome, we will perform them after receiving informed consent.

Next generation sequencing-based gene panel tests for the management of solid tumors.

Next generation sequencing (NGS) has been an invaluable tool to put genomic sequencing into clinical practice. The incorporation of clinically relevant target sequences into NGS-based gene panel tests has generated practical diagnostic tools that enable individualized cancer-patient care. The clinical utility of gene panel testing includes investigation of the genetic basis for an individual's response to therapy, such as signaling pathways associated with a response to specific therapies, microsatellite instability and a hypermutated phenotype, and deficiency in the DNA double-strand break repair pathway. In this review, we describe the concept of precision cancer medicine using target sequences in gene panel tests as well as the importance of the control of sample quality in routine NGS-based genomic testing. We describe geographic and ethnic differences in cancer genomes, and discuss issues that need to be addressed in the future based on our experiences in Japan.

SMAD4 alteration associates with invasive-front pathological markers and poor prognosis in colorectal cancer.

AIMS: SMAD4 acts as a tumour suppressor, and the loss of SMAD4 is associated with poor prognosis in colorectal cancer (CRC) patients. Although next-generation sequencing (NGS) enabled us to detect numerous genetic alterations in a single assay, the clinical significance of SMAD4 alteration detected with NGS has not been fully investigated. The aim of this study was to evaluate the clinicopathological characteristics and clinical significance of SMAD4 alteration detected with NGS in CRC. METHODS AND RESULTS: We retrospectively investigated 201 patients with stage I-IV CRC, by using a 415-gene panel. To analyse the relationship between SMAD4 alteration and other clinicopathological characteristics, we evaluated clinicopathological variables, including invasive-front pathological markers: tumour budding, poorly differentiated cluster, and Crohn-like lymphoid reaction. Fifty-six patients (28%) had SMAD4 alteration: 24 and 32 patients had SMAD4 mutation and deletion, respectively. SMAD4 alteration was significantly associated with T category (P = 0.027), N category (P = 0.037), M category (P = 0.028), and invasive-front pathological markers, such as poorly differentiated cluster grade 3 (P = 0.020) and absence of Crohn-like lymphoid reaction (P = 0.004). Immunohistochemistry revealed that SMAD4 alteration was significantly associated with loss of SMAD4 (P = 0.023). In 90 patients with stage I-III disease, SMAD4 alteration was significantly associated with poor prognosis for relapse-free and overall survival (P = 0.047; P = 0.022, respectively). Conversely, in 111 patients with stage IV disease, SMAD4 alteration was not significantly associated with overall survival. CONCLUSION: SMAD4 alteration is associated with invasive-front pathological markers and poor prognosis in stage I-III CRC patients.

[Digestive Surgery Intervention for Gynecological Malignant Tumor].

AIM: This study aimed to determine surgical outcomes in patients with gynecological cancers for whom surgery was performed by gynecologists and digestive surgeons. METHODS: Seventy-three patients who underwent surgery for a gynecological malignant tumor from January 2010 to December 2014 were included in this retrospective study. Data on the definitive diagnosis, operative procedures, postoperative complications, stoma settings, length of hospital stay, and prognosis was collected for each patient. RESULTS: The median age of this female-only cohort was 60 years. Emergency surgery was performed in 8(11.0%)patients. Ovarian cancer was diagnosed in 56(76.7%)patients, and among these patients, the clinical disease Stage was Ⅰ, Ⅱ, Ⅲ, and Ⅳ in 4, 4, 20, and 11 patients, respectively. Moreover, 17 patients had recurrent ovarian cancer. Intestinal resection with anastomosis was performed in 25(34.2%)patients. Stoma formation was performed in 22 (30.1%)patients, however no patient underwent stoma closure surgery in the current study. The median operative time was 252 minutes, and the median blood loss was 1,190 mL. Regarding postoperative complications, ileus, pelvic abscess, and anastomotic leakage developed in 6(8.2%), 4(5.5%), and 2(2.7%)patients, respectively. The postoperative median survival time in patients with ovarian cancer was 1,399 days. CONCLUSION: These results suggest that tumor debulking, including intestinal tract resection, may contribute to the prolonged prognosis of gynecological tumors, although stoma closure is difficult to perform.

[A Case of Esophageal Cancer Achieving a Pathological Complete Response after Preoperative Docetaxel, Cisplatin, and 5-Fluorouracil Therapy].

A 66-year-old man with middle thoracic esophageal squamous cell carcinoma with supraclavicular lymph node metastasis visited our hospital. He underwent 3 courses of preoperative chemotherapy with docetaxel, cisplatin, and 5-FU(DCF)with a clinically-determined partial response. Minimally-invasive esophagectomy with 3-fieldlymphad enectomy was subsequently performed. Histopathologic examination revealedno viable tumor cells in the resectedesophagus andsupraclavicular lymph node. DCF is a promising preoperative chemotherapy regimen for locally advanced esophageal cancer because of its higher complete response rate comparedto that for cisplatin plus 5-FU.

[A Case of Long-Term Survival after Resection for Metachronous Liver and Lung Metastases of Rectal Cancer Associated with Familial Adenomatous Polyposis].

A 37-year-old man was admitted to our hospital for the treatment of familial adenomatous polyposis and rectal carcinoma. He underwent total colectomy with ileoanal anastomosis(pT3N1M0, pStage Ⅲa)followed by adjuvant therapy with S-1. Three months after primary surgery, CT and MRIrevealed liver metastases(S5, S6). Laparoscopic partial hepatectomy was performed. Two years after primary surgery, new liver metastases(S2, S8)were found and we performed open partial hepatectomy and administered mFOLFOX6. Three years and 5 months after primary surgery, right lung metastases(S6, S9) were detected and the patient underwent a thoracoscopic-assisted right lung wedge resection. Repeated resection of metastases might have contributed to the long-survival in our case.

[A Case of Esophageal Primary Malignant Melanoma That Developed During the Follow-Up of Esophageal Melanocytosis].

A 78-year-old woman was endoscopically followed up for benign melanocytosis in the middle thoracic esophagus that was detected 3 years prior. She presented with chest tightness, and an endoscopic examination revealed a protruding tumor at the melanotic lesion. She was histologically diagnosedwith an esophageal primary malignant melanoma. Computedtomography showedno metastatic lesions. She underwent minimally invasive esophagectomy with 2-fieldlymphad enectomy. Immunotherapy with nivolumab is ongoing for liver metastasis, which developed1 year and6 months after esophagectomy. Careful follow-up for esophageal melanocytosis is important for early diagnosis of esophageal primary malignant melanoma.

[A Case of Peritoneal Metastases after Radiofrequency Ablation for Liver Metastasis from a Pancreatic Neuroendocrine Tumor].

A 77-year-old woman presented with peritoneal metastases from a pancreatic neuroendocrine tumor(p-NET). At the age of 56 years, she underwent distal pancreatectomy for p-NET, which was pathologically diagnosed as G2. She underwent right hemihepatectomy for liver metastasis(S6)from the p-NET 10 years post-pancreatectomy. Eight years post-hepatectomy, radiofrequency ablation(RFA)was attempted for liver metastasis(S4)from the p-NET. However, RFA was not completed because of hematoma development along the needle tract of RFA. She underwent partial hepatectomy for this lesion 6 months post-RFA. Two years post-RFA, localized peritoneal metastases on the right diaphragm were detected. She underwent en bloc tumor resection with partial resection of the diaphragm. She remains alive and well with no evidence of disease 2 years post-resection of the peritoneal metastases from the p-NET.

[A Case of Long-Term Survival in a Patient with Advanced Rectal Cancer and Paraaortic and Lateral Lymph Node Metastases].

A 65-year-old woman was referred for further examination following positive results on a fecal occult blood test. Colonoscopy revealed type 0-Ⅱa cancer, with a lesion measuring 2 cm in diameter in the rectosigmoid colon, and type 5 cancer, with a lesion measuring 6 cm in diameter in the upper rectum. Computed tomography(CT)and positron emission tomography (PET)-CT revealed mesorectal lymph node metastases. Therefore, she was diagnosed with rectosigmoid colon cancer(Stage Ⅰ)and upper rectal cancer(Stage Ⅲa). However, PET-CT also revealed slight fluorodeoxyglucose uptake in the paraaortic and lateral lymph node lesions; hence, the possibility ofmetastasis could not be ruled out. Given that chemotherapy was restricted due to renal dysfunction, low anterior resection was performed as the first choice. Analysis of intraoperative frozen sections showed paraaortic and lateral lymph node metastases; thus, we performed lymph node dissection of these lesions. Pathological examination ofthe resected lymph nodes revealed that 21 of 37 lesions were cancer metastases. S-1 was administered as adjuvant chemotherapy for 5 months. Mediastinal lymph node metastases was suspected on chest CT 5 months and 3 years post-surgery; thus, panitumumab was administrated. These lymph nodes decreased in size immediately. Six years after the first surgery, the patient was well without any signs of recurrence.

[A Case of Pathological Complete Response with Neoadjuvant Chemotherapy for Advanced Rectal Cancer].

A 62-year-old man was admitted with complaints of bloody stool. Colonoscopy revealed a 5 cm diameter type 2 tumor in the lower rectum close to the anal canal. Tumor biopsy indicated a well-differentiated tubular adenocarcinoma. Computed tomography revealed locally advanced rectal cancer with mesorectal lymph node metastases(cT3N1P0M0, Stage Ⅲa, JSCCR 8th). The patient was treated with neoadjuvant chemotherapy(NAC)after transverse colostomy as an anus-preserving procedure. For the NAC, 12 courses of capecitabine plus oxaliplatin(CapeOX)and bevacizumab(BV)were administered. Colonoscopy after NAC revealed that the main tumor had considerably shrunk. No malignant tissues were found on biopsy. However, rectal wall thickness remained unchanged. Therefore, response evaluation for chemotherapy indicated partial response. Intersphincteric resection(ISR)with diverting loop ileostomy was performed as an anus-preserving surgical procedure. No remnant tumor in the rectum or lymph node metastases were found upon the pathological examination of resected specimens. Ileostomy closure was performed at 6 months post-ISR. At 12 months post-ISR, the patient was well and showed no signs of recurrence. This case demonstrated that NAC with CapeOX and BV can be a promising option for treating locally advanced lower rectal cancer and preserving the anus.

[Surgical Resection after Transarterial Chemoembolization for Hepatocellular Carcinoma with Bile Duct Tumor Thrombus-Report of a Long-Term Survivor].

A 78-year-old woman with jaundice was referred to our hospital. On admission, serological testing for viral hepatitis was negative and serum levels of AFP and PIVKA-Ⅱ were elevated(925 ng/mL and 6,820 mAU/mL, respectively). Computed tomography revealed a main tumor measuring 3 cm in size at segment 1 of the liver and bile duct tumor thrombus extending to the right hepatic duct. A diagnosis of hepatocellular carcinoma with a bile duct tumor thrombus was made. After endoscopic biliary drainage for obstructive jaundice and transarterial chemoembolization for the lesions, she underwent left hepatectomy, resection of the caudate lobe, extrahepatic bile duct resection, and cholecystectomy. The hepatic side of the extrahepatic bile duct was transected at the confluence of the right anterior and posterior ducts because invasion of the tumor thrombus to the right hepatic duct was suspected on cholangioscopy. Histological examination revealed the tumor to be a moderately differentiated hepatocellular carcinoma with bile duct tumor thrombus. Surgical margins were negative, and vascular invasion was not found. She remains alive and well with no evidence of disease 64 months after hepatectomy.

[A Case of Peritoneal Recurrence of Invasive Ductal Carcinoma Derived from Intraductal Papillary Mucinous Neoplasm after Surgery Treated with Palliative Radiation Therapy and Chemotherapy].

An 82-year-old man with a diagnosis ofintraductal papillary mucinous carcinoma(IPMC)underwent pancreaticoduodenectomy followed by adjuvant chemotherapy with S-1. Six months after surgery, he had upper abdominal pain, and CT demonstrated a recurrent intraabdominal tumor located at the surgical incision scar. It was diagnosed as a solitary peritoneal recurrence, and palliative radiation therapy at a dose of 30 Gy was performed for the relief of abdominal pain after administration ofoxycodone. He was free ofpain without pharmacological therapy and received subsequent chemotherapy with nabpaclitaxel plus gemcitabine(GnP). He remains free ofpain and alive without progression ofthe disease 24 months after recurrence. Hypofractionated-accelerated radiotherapy is feasible and results in pain relief for local recurrence of IPMC.

Upregulation of phosphorylated sphingosine kinase 1 expression in colitis-associated cancer.

BACKGROUND: Colitis-associated cancer (CAC) is the most serious complication of inflammatory bowel disease. Sphingosine-1-phosphate (S1P) is a bioactive lipid mediator that is generated by sphingosine kinase 1 (SphK1) and is known to play an important role in inflammation and cancer progression. Moreover, SphK1 and S1P act as upstream mediators of proinflammatory cytokine interleukin 6 (IL-6) and signal transducer and activator of transcription-3 (STAT3). We hypothesized that the expression levels of phosphorylated SphK1 (pSphK1), phosphorylated STAT3 (pSTAT3), and IL-6 are universally higher in CAC patients than in sporadic colorectal cancer (CRC) patients because all of these factors are associated with inflammation. In this study, we determined the expression levels of pSphK1 in patients with sporadic CRC and CAC and clarified the importance of S1P in CAC patients. MATERIALS AND METHODS: We randomly selected 10 sporadic CRC patients and 10 CAC patients who underwent curative resection, and we examined their surgical specimens by immunohistochemistry. We determined the expression levels of pSphK1, pSTAT3, and IL-6 in these samples. RESULTS: We found pSphK1 expression to be more prevalent in CAC patients (P = 0.019) and to have a higher immunohistochemistry score (P = 0.005) than in sporadic CRC patients. However, the expression of pSTAT3 and IL-6 did not differ between the patient groups. CONCLUSIONS: To our knowledge, this is the first report comparing pSphK1 expression levels in CAC with those in sporadic CRC. The high levels of pSphK1 expression in CAC suggest an important role of S1P in the disease process of CAC.

Carcinoma in the Remnant Stomach During Long-Term Follow-up After Distal Gastrectomy for Gastric Cancer: Analysis of Cumulative Incidence and Associated Risk Factors.

BACKGROUND: The number of patients with remnant gastric cancer following resection of gastric cancer may increase. The aims of this study were to investigate the development of remnant gastric cancer after distal gastrectomy for gastric cancer and to examine its cumulative incidence, clinicopathological characteristics, and risk factors. METHODS: We examined 437 patients with relapse-free survival for 5 years or more after distal gastrectomy with Billroth I reconstruction for gastric cancer performed between 1985 and 2005. RESULTS: A total of 17 patients suffered from remnant gastric cancer. The cumulative incidence was 3.7% at 10 years and 5.4% at 20 years. The median time until development of remnant gastric cancer was 79 months (range 30-209 months). The presence of synchronous multiple gastric cancers was a significant independent risk factor for remnant gastric cancer (hazard ratio 4.036; 95% confidence interval 1.478-11.02; P = 0.006). Of the 17 patients, the 13 whose remnant gastric cancer was detected via regular endoscopy showed better prognoses than the patients detected by other means (P < 0.001). CONCLUSION: The cumulative incidence of remnant gastric cancer was 5.4% at 20 years. In particular, patients who had multiple gastric cancers at initial gastrectomy were at higher risk for remnant gastric cancer. Therefore, long-term endoscopic surveillance is important.