Taeil Son

Clinical implication of an insufficient number of examined lymph nodes after curative resection for gastric cancer

The seventh edition of the tumor, lymph node (LN), metastasis (TNM) staging system increased the required number of examined LNs in gastric cancer from 15 to 16. However, the same staging system defines lymph node‐negative gastric cancer regardless of the number of examined LNs. In this study, the authors evaluated whether gastric cancer can be staged properly with fewer than 15 examined LNs.

Minimally Invasive Surgery for Gastric Cancer Treatment: Current Status and Future Perspectives

Minimally invasive surgery, which has been extensively used to treat gastric adenocarcinoma, is now regarded as one of the standard treatments for early gastric cancer, and its suitability for advanced gastric cancer is being investigated. The use of cutting-edge techniques for minimally invasive surgery enables surgeons to deliver various treatment options to minimize a patients distress and to maintain oncologic safety. Ongoing multicenter prospective studies aim to validate the efficacy of these surgical techniques and to expand the indications of minimally invasive surgery for the treatment of gastric cancer. In this review, we summarize the current status and issues regarding minimally invasive surgery for the treatment of gastric cancer.

Method of reconstruction governs iron metabolism after gastrectomy for patients with gastric cancer

Objective: Anemia after gastrectomy is commonly neglected by clinicians despite being an important and frequent long-term metabolic sequela. We hypothesized that the incidence and timing of the occurrence of iron deficiency after gastrectomy is closely associated with the extent of gastrectomy and the reconstruction method, and we investigated the treatment outcomes of iron supplementation to understand iron metabolism and determine the optimal reconstruction method after gastrectomy. Patients and Methods: Using a prospective gastric cancer database, we identified 381 patients with early gastric cancer with complete hematologic parameters who underwent gastrectomy between January 2004 and May 2008. Kaplan-Meier methods, Cox regression, and logistic regression were used to evaluate the associations of the extent of gastrectomy and reconstruction method with iron metabolism. Results: The prevalence of iron deficiency 3 years after gastrectomy was 69.1%, and iron-deficiency anemia was observed in 31.0% of patients. Iron deficiency developed in 64.8% and 90.5% of patients after distal gastrectomy and total gastrectomy within 3 years after surgery (P < 0.0001), respectively. Iron deficiency was significantly more frequent in women than in men (P < 0.0001) and after gastrojejunostomy than after gastroduodenostomy (P < 0.0001). Serum ferritin levels were different according to the extent of gastrectomy and reconstruction method. The proportion of patients treated for iron-deficiency anemia was also significantly different according to the extent of gastrectomy (P = 0.020). Conclusions: Iron deficiency occurs in most patients with gastric cancer after gastrectomy, and its incidence was different according to the extent of gastrectomy and reconstruction method. To improve iron metabolism after distal gastrectomy, gastroduodenostomy would be the method of reconstruction whenever possible.

Laparoscopic gastric cancer surgery: Current evidence and future perspectives.

Laparoscopic gastrectomy has been widely accepted as a standard alternative for the treatment of early-stage gastric adenocarcinoma because of its favorable short-term outcomes. Although controversies exist, such as establishing clear indications, proper preoperative staging, and oncologic safety, experienced surgeons and institutions have applied this approach, along with various types of function-preserving surgery, for the treatment of advanced gastric cancer. With technical advancement and the advent of state-of-the-art instruments, indications for laparoscopic gastrectomy are expected to expand as far as locally advanced gastric cancer. Laparoscopic gastrectomy appears to be promising; however, scientific evidence necessary to generalize this approach to a standard treatment for all relevant patients and care providers remains to be gathered. Several multicenter, prospective randomized trials in high-incidence countries are ongoing, and results from these trials will highlight the short- and long-term outcomes of the approach. In this review, we describe up-to-date findings and critical issues regarding laparoscopic gastrectomy for gastric cancer.

Complicated benign cystic mesothelioma of mesoappendix misdiagnosed as an appendiceal abscess in a postpartum period woman

Benign cystic mesothelioma is an uncommon tumor arising from the peritoneal mesothelium. It is characterized by multilocular grapelike, thin-, and translucent-walled cysts, or a unilocular cyst lined by benign mesothelial cells. It occurs predominantly in women of reproductive age, and shows a predilection for the surface of the pelvic peritoneum or visceral peritoneum. Patients usually present abdominal pain and palpable mass, but many cases have been found incidentally during laparotomy. Definite preoperative diagnosis is known to be difficult. Benign cystic mesothelioma has a tendency towards local recurrence, although the gross microscopic features are benign. Moreover, there is controversy over whether this disease is neoplastic or reactive. Initial complete surgical resection and cytoreductive surgery for recurred cases are standard treatments. In the following report, we describe a case of complicated benign cystic mesothelioma in a postpartum woman, involving the pelvic peritoneum and mesoappendix, which was initially misdiagnosed as a periappendiceal abscess.

Robotic gastrectomy for gastric cancer: Robotic Gastrectomy

Robotic surgery for gastric cancer overcomes technical difficulties with laparoscopic gastrectomy. Its benefits include reduced intraoperative bleeding and shorter hospital stays; it is also easier to learn. Because accuracy increases during lymphadenectomy, a larger number of lymph nodes is likely to be retrieved using robotic gastrectomy. Higher costs and longer operation times have hindered the widespread adaptation and use of robotic surgery. In this review, we summarize the current status and issues regarding robotic gastrectomy. J. Surg. Oncol. 2015; 112:271–278.

Elevated high-sensitivity C-reactive protein, a marker of advanced stage gastric cancer and postgastrectomy disease recurrence

Gastric cancer recurrence after curative surgery remains high. Although no preoperative marker of gastric cancer progression after radical gastrectomy exists, recent studies suggest that C‐reactive protein (CRP) is associated with cancer progression. Our study evaluated the significance of preoperative high‐sensitivity CRP (hs‐CRP) levels as a marker of disease progression after radical gastrectomy.

Comprehensive expression profiles of gastric cancer molecular subtypes by immunohistochemistry: Implications for individualized therapy

Gastric cancer (GC) is a leading cause of death. We aim to establish a clinically relevant assay that encompasses recent molecular classifications and provides useful clinical information in a large cohort of GC patients. A consecutive series of 438 GC patients that underwent palliative chemotherapy between 2014 and 2015 were assessed using 10 GC panels: EBER in-situ hybridization, immunohistochemistry for mismatch repair (MMR) proteins (MLH1, PMS2, MSH2, and MSH6), receptor tyrosine kinases (RTKs; HER2, EGFR, and MET), PTEN, and p53 protein. With a median of one aberration, 3.3 % of samples analyzed were Epstein-Barr virus (EBV)-positive; 4.8%, MMR-deficient. RTKs were overexpressed in 218 patients; EGFR was most commonly overexpressed (39.9%), followed by HER2 (13.5%) and MET (12.1%). Furthermore, 2.5 % and 10.7 % of cases had simultaneous overexpression of three and two RTKs, respectively. p53 overexpression/null tumors were identified in 259 patients (59.1%), and PTEN loss was identified in 89 patients (20.3%). EBV-positivity was mutually exclusive with MMR-deficiency, predominantly identified in male patients, and these tumors were undifferentiated with proximal location. p53 mutant type was significantly found predominantly in the EBV-negative (60.6% vs 14.3%, P=0.001) and HER2-positive (78.0% vs 56.2%, P=0.002) groups. We described a molecular spectrum of distinct GC subtypes using clinically applicable assay. This assay will provide a convenient screening tool and facilitate the development of targeted agents in clinical trials.

A Novel Prediction Model of Prognosis After Gastrectomy for Gastric Carcinoma: Development and Validation Using Asian Databases.

Objective: The prognoses of gastric cancer patients vary greatly among countries. Meanwhile, tumor-node-metastasis (TNM) staging system shows limited accuracy in predicting patient-specific survival for gastric cancer. The objective of this study was to create a simple, yet universally applicable survival prediction model for surgically treated gastric cancer patients. Summary Background Data: A prediction model of 5-year overall survival for surgically treated gastric cancer patients regardless of curability was developed using a test data set of 11,851 consecutive patients. Methods: The models coefficients were selected based on univariate and multivariate analysis of patient, tumor, and surgical factors shown to significantly impact survival using a Cox proportional hazards model. For internal validation, discrimination was calculated with the concordance index (C-statistic) using the bootstrap method and calibration assessed. The model was externally validated using 4 data sets from 3 countries. Results: Our models C-statistic (0.824) showed better discrimination power than current tumor-node-metastasis staging (0.788) (P < 0.0001). Bootstrap internal validation demonstrated that coefficients remained largely unchanged between iterations, with an average C-statistic of 0.822. The model calibration was accurate in predicting 5-year survival. In the external validation, C-statistics showed good discrimination (range: 0.798–0.868) in patient data sets from 4 participating institutions in 3 different countries. Conclusions: Utilizing clinically practical patient, tumor, and surgical information, we developed a universally applicable prediction model for accurately determining the 5-year overall survival of gastric cancer patients after gastrectomy. Our predictive model was also valid in patients who underwent noncurative resection or inadequate lymphadenectomy.

Robotic surgery for gastric tumor: current status and new approaches

Surgical techniques have evolved tremendously over this past century. To maximize the efficacy and minimize the invasiveness of laparoscopic surgery, researchers have sought to implement wider application of robotics. Nevertheless, both optimism without sound evidence and fear of new technology obscure the appropriate uses of robotic surgery. In the present review, we attempted to provide a balanced perspective on the current state of robotic gastrectomy, outlining evidence and opportunities for the use thereof. Although evidence is limited, the use of robotics is feasible for gastric cancer surgery, and less than 10 cases of robotic surgery are needed to become proficient therein. Compared to the clinical impact of laparoscopy on gastric cancer surgery, the additional benefits of robotic surgery to patients seem to be limited. Despite additional costs and longer surgeries, robotic surgery reportedly does not offer surgical outcomes superior to those for laparoscopic surgery, according to a recent multicenter study. Meanwhile, however, our in-depth review of retrospective and prospective reports revealed that robots could expand the indications of minimally invasive gastrectomy for patients requiring total gastrectomy and D2 lymph node dissection. Moreover, we found that robotic gastrectomy is associated with a higher number of retrieved lymph nodes, less bleeding, fewer complications, and shorter hospital stay, compared to laparoscopic gastrectomy. Accordingly, new surgical approaches using advanced technologies, such as near infrared detectors, the Tilepro® multi-input display, dual consoles, and the Single-Site® system, are under investigation. In conclusion, measuring the additional benefits of robotic over laparoscopic surgery would be difficult and clinically insignificant. Thus, developing new surgical procedures that extend the benefits of conventional laparoscopic surgery to patients in whom minimally invasive surgery would not be possible is necessary to justify the greater use of robotic surgery.