Wider indications for the local resection of gastric cancer by adjacent lymphadenectomy

Clinical implication of endoscopic gross appearance in early gastric cancer: revisited

BACKGROUND

The macroscopic appearance of early gastric cancer (EGC) is known to reflect its growth patterns. The purpose of this study was to investigate the role of the endoscopic appearance as a predictor of clinical behavior in EGC.

METHODS

Between January 2005 and December 2008, 1,845 patients were diagnosed with EGC and underwent surgery. The clinicopathologic characteristics were retrospectively analyzed according to gross appearance. Endoscopic findings were classified by predominant type as elevated, flat, or depressed. Flat and depressed types were categorized together as nonelevated type.

RESULTS

The proportions of elevated, flat, and depressed types were 16.6, 28.6, and 54.8 %. The gross appearance of the elevated type predominantly showed well/moderate differentiation, whereas the flat and depressed types showed signet-ring cells and poor differentiation, respectively. When the elevated and nonelevated types were compared, submucosal invasion, lymphovascular invasion (LVI), and lymph-node metastasis (LNM) were higher in elevated than in nonelevated type. In differentiated EGC, submucosal invasion, LVI, LNM, and multiplicity were significantly higher in the elevated than the nonelevated type. These patterns were significantly common in the order elevated, depressed, and flat types. In undifferentiated EGC, submucosal invasion, LVI, and perineural invasion were significantly higher in elevated than in nonelevated type. These patterns were significantly common in the order elevated, depressed, and flat types. However, LNM was not significantly different based on gross appearance in undifferentiated EGC.

CONCLUSIONS

Clinical behavior differs according to endoscopic appearance in EGC. The endoscopic appearance of EGC may facilitate prediction of clinical behavior, particularly in differentiated EGC.

Clinicopathological characteristics and treatment strategies in early gastric cancer: a retrospective cohort study

Background

Both endoscopic and surgical approaches are employed in the treatment of early gastric cancer (EGC). The aim of this study was to establish appropriate treatment strategies for early gastric cancer.

Methods

We retrospectively examined clinicopathological data of EGC patients who had undergone surgery.

Results

A total of 327 patients (204 males and 123 females, mean age 63.2 years) were eligible for inclusion in the study. The median follow-up period was 31 months. Of 161 mucosal (pT1a) tumors, 87 were mainly undifferentiated and 110 had an undifferentiated component. Four patients with pT1a tumors had lymph node metastases; all these tumors were signet-ring cell carcinomas and were macroscopic type 0-IIc with ulceration, and only one of them had lymphatic invasion. Among patients with submucosal tumors, four of 43 patients with pT1b1 tumors and 37 of 123 patients with pT1b2 tumors had nodal metastases. Lymph node metastases were significantly higher in mixed undifferentiated type group than differentiated type group for both groups, pT1a-pT1b1 (p = 0.0251) and pT1b2 (p = 0.0430) subgroups. Only four of 45 patients with nodal metastases were diagnosed preoperatively by computed tomography (sensitivity 8.9%, specificity 96.2%). Nine patients with pT1b tumors had recurrence after surgery, and died. The sites of initial recurrence were liver, bone, peritoneum, distant nodes, and the surgical anastomosis.

Conclusions

The incidence of nodal metastases was approximately 5% in undifferentiated type mucosal (pT1a) tumors, and higher in submucosal (pT1b) tumors. The sensitivity of preoperative diagnosis of nodal metastases in EGC using computed tomography was relatively low in this study. Therefore at present surgery with adequate lymphadenectomy should be performed as curative treatment for undifferentiated type EGC.

Comparative study of complete and partial omentectomy in radical subtotal gastrectomy for early gastric cancer

PURPOSE

Curative surgery for patients with advanced or even early gastric cancer can be defined as resection of the stomach and dissection of the first and second level lymph nodes, including the greater omentum. The aim of this study was to evaluate the short- and long- term outcomes of partial omentectomy (PO) as compared with complete omentectomy (CO).

MATERIALS AND METHODS

Seventeen consecutive open distal gastrectomies with POs were initially performed between February and July in 2006. The patients' clinicopathologic data and post-operative outcomes were retrospectively compared with 20 patients who underwent open distal gastrectomies with COs for early gastric cancer in 2005.

RESULTS

The operation time in PO group was significantly shorter than that in CO group (142.4 minutes vs. 165.0 minutes, p=0.018). The serum albumin concentration on the first post-operative day in PO group was significantly higher than CO group (3.8 g/dL vs. 3.5 g/dL, p=0.018). Three postoperative minor complications were successfully managed with conservative treatment. Median follow-up period between PO and CO was 38.1 and 37.7 months. All patients were alive without recurrence until December 30, 2009.

CONCLUSION

PO during open radical distal gastrectomy can be considered a more useful procedure than CO for treating early gastric cancer. To document the long-term technical and oncologic safety of this procedure, a large-scale prospective randomized trial will be needed.

Physiological evaluation of residual stomach motility after local resection in conscious dogs

PURPOSE

To investigate the phenomenon of remnant gastric motility and emptying after local resection.

METHODS

Fifteen dogs were divided into three groups: a control (CONT) group, a group that underwent local resection of the greater (GREAT) curvature, and a group that underwent resection of the lesser (LESS) curvature. We conducted a strain gauge force transducer study, a [(13)C]octanoic acid breath test ((13)C-OBT), and a mosapride citrate effect test. Based on these results, we worked out the receptive relaxation (RR), motility index (MI), and postprandial period (PP) in the postprandial state, and the frequency, duration, and MI of phase III in the fasted state. The half emptying time (T (1/2)) of (13)C-OBT was also calculated. The MI was compared according to the mosapride effect test results.

RESULTS

Postprandial RR, antro-pyloro-duodenal coordination, and fasting contractions were maintained in all three groups. Receptive relaxation was significantly shorter in the LESS group than in the other groups. Motility index was significantly lower in both treatment groups than in the CONT group. The PP was significantly longer in the GREAT group than in the other two groups. The (13)CO(2) excretion curves did not differ significantly among the groups. The duration of phase III was remarkably less in the treatment groups than in the CONT group, and MI was significantly lower in the LESS group than in the other groups in the fasted state. The MI increased remarkably after mosapride administration in the CONT group, showing no differences in other objective groups.

CONCLUSION

Gastric function was maintained after gastric local resection, although its motility decreased.

[Surgical treatment of gastric carcinoma]

The gastric cancer is the most common cancer in Korea. The only treatment modality showing improved survival for gastric cancer is curative surgical resection, which comprises the resection of stomach, proper lymphadenectomy, and reconstruction. However, specific surgical procedures should be decided according to the location of the cancer, advancement of the tumor, and patients condition. Surgical treatment for gastric cancer has been developed toward two directions that are minimal invasive surgery for early gastric cancer and multi-disciplinary approach for advanced gastric cancer. Laparoscopic surgery for early gastric cancer has been accepted for minimally invasive surgery. Moreover, the advancement of diagnostic tools to assess biological aggressiveness of the tumor enables physicians to perform endoscopic resection or minimized resection for early gastric cancer. Recently, surgeons try to extend the application of laparoscopic gastric resection and D2 lymphadenectomy to advanced gastric cancer. However, technical and oncological evidences based on clinical trials should be filed up before adopting it as a standard therapy. In case of advanced gastric cancer, in addition to radical surgery, various treatment modalities including chemotherapy, radiation, and molecular target therapy also have been applied in many clinical trials. However, it should be stressed that a prerequisite for precise evaluation of the efficacy of these combined treatment modalities would be the standardization of surgical procedure.

Predicting lymph node status in early gastric cancer

Accurate prediction of lymph node (LN) status is of crucial importance for appropriate treatment planning in patients with early gastric cancer (EGC). However, there is no definitive consensus yet on which patient and/or tumor characteristics are associated with LN metastasis. A systematic search for studies investigating the relationship between patient and/or tumor characteristics and LN metastasis in EGC was performed in PubMed/MEDLINE. Patient and/or tumor characteristics associated with LN metastasis were identified by meta-analyzing results of individual studies. Forty-five studies were included. Variables significantly associated with LN metastasis in gastric cancer limited to the mucosa were: age younger than 57 years, tumor location in the middle part of the stomach, larger tumor size, macroscopically depressed tumor type, tumor ulcerations, undifferentiated tumors, diffuse tumor type according to the Lauren classification, lymphatic tumor invasion, tumors with a proliferating cell nuclear antigen (PCNA) labeling index of more than 25%, and matrix metalloproteinase-9-positive tumors. Variables significantly associated with LN metastasis in gastric cancer limited to the submucosa were: female sex, tumor location in the lower part of the stomach, larger tumor size, undifferentiated tumors, increasing depth of submucosal invasion, lymphatic tumor invasion, vascular tumor invasion, increased submucosal vascularity, tumors with a PCNA labeling index of more than 25%, tumors with a gastric mucin phenotype, and vascular endothelial growth factor-C-positive tumors. We identified several variables associated with LN metastasis in EGC. These variables should be included in future research, in order to assess which of these variables remain as significant predictors of LN metastasis.

Concepts, rationale, and current outcomes of less invasive surgical strategies for early gastric cancer: data from a quarter-century of experience in a single institution

Previously proposed criteria of less invasive surgery for early gastric cancer (EGC) were based mainly on the pathological analyses of the resected specimens; however, preoperative and intraoperative information are also obviously essential for decision making on stage-dependent patient management. Furthermore, most indications and treatment options have not been systematically integrated or evaluated by treatment outcomes. We investigate in this report the rationality of less invasive surgery employed for EGC. Distribution analyses of positive nodes were investigated among 684 patients with primary solitary EGC (379 mucosal and 305 submucosal) who underwent curative resection between 1976 and 2000. Clinicopathological factors highlighted and analyzed included clinical (preoperative and intraoperative) and pathological (postoperative) cancer depth and nodal involvement, gross form, histological type, and maximum cancer diameter, as well as postoperative morbidity and mortality. The scope of lymphadenectomy can be reduced to a modified D1 for clinically mucosal, node-negative, nonpalpable gastric cancer, or for clinically submucosal, node-negative gastric cancer < or = 1.5 cm for intestinal type, or < or = 1.0 cm for diffuse type. Otherwise, a modified D2 lymphadenectomy is sufficient. Local resection can be recommended for clinically mucosal, node-negative gastric cancer without apparent ulceration < or = 4 cm if adjacent lymph nodes are proved cancer negative by a frozen section examination. If the gastric cancer has spread beyond the above criteria, a pylorus-preserving gastrectomy (PPG) can be recommended for tumors located in the middle or lower third of the stomach, provided the distal margin of the cancer is at least 4.5 cm from the pyloric ring. The PPG can be accompanied by a modified D1 or a modified D2 lymphadenectomy according to the respective dissection criteria. Results of these less invasive strategies showed reduced morbidity and mortality, as well as no recurrence or cancer-related deaths. These results suggest that each of our criteria for less invasive surgery for EGC is realistic, well stratified, and satisfactory.

Accuracy of linear-array EUS for preoperative staging of gastric cardia cancer

BACKGROUND

The feasibility of a less invasive operation for early stage cancer of the gastric cardia with a low frequency of lymph node involvement has been previously demonstrated by us. Precise discrimination among mucosal, submucosal, and advanced cancers, as well as accurate evaluation of the proximal tumor margin are prerequisites for such stage-specific treatment. EUS is considered the most reliable staging modality. However, there is no EUS study specifically of cardia cancer.

METHODS

Forty-five patients with gastric cardia cancer who underwent gastrectomy with at least first-tier lymphadenectomy were retrospectively analyzed. The results of preoperative linear-array echoendoscopy (7.5 MHz) with respect to cancer depth, lymph node involvement, and esophageal invasion were compared with postoperative histopathologic findings.

RESULTS

Overall diagnostic accuracy for depth of invasion was 71%. Sensitivity for T1, T2, and T3 lesions was 100%, 31% and 75%, respectively. Overstaging of T2 cancers was the main diagnostic error. Mucosal (pT1-m) and submucosal (pT1-sm) cancers were correctly discriminated in 81% of patients. Diagnostic accuracy for lymph node involvement was 80%. EUS had positive and negative predictive values of 90% and 80%, respectively, for esophageal invasion.

CONCLUSIONS

For gastric cardia cancer, the linear-array echoendoscope yielded satisfactory results with respect to depth of invasion, lymph node involvement, and esophageal invasion evaluation. The information obtained is useful to the performance of stage-specific treatment.

Treatment strategy of limited surgery in the treatment guidelines for gastric cancer in Japan

Surgical practice for gastric cancer in Japan is based on the Gastric Cancer Treatment Guidelines issued in 2001 by the Japanese Gastric Cancer Association. These recommendations list options for treatment of each stage of cancer, with clear distinctions between interventions recommended for routine use and those that should be confined to trial settings until further evidence for their curative potential becomes available. In this review, we discuss standard surgery, local resection, segmental resection, and pylorus-preserving gastrectomy (PPG) as examples of limited resection and describe in detail the indications for limited lymph-node dissection in cases of early-stage gastric cancer. At present, evidence does not support the conclusion that limited surgery is effective for local resection or for improving quality of life. Thus, use of limited surgery should be considered an experimental approach both in Japan and the West. We conclude that surgeons who are familiar with the criteria for selecting surgical procedures should decide on a case-by-case basis which technique is most appropriate. Choices should be made with consideration of the stage of the cancer, invasiveness of the surgical procedure, and the patient's history. For all procedures, the patient must give informed consent and the surgeons must accurately assess the success of the operation after surgery.

Indications of a minimized scope of lymphadenectomy for submucosal gastric cancer

BACKGROUND

A recent trend for less invasive surgery has increased consideration for a minimized scope of lymphadenectomy for submucosal cancer; however, feasibility criteria have not been precisely established.

METHODS

Patterns and sites of nodal involvement were retrospectively investigated in 294 patients with solitary submucosal gastric cancer in association with other clinicopathologic characteristics, including pre- and intraoperative evaluations of cancer depth (cT) and nodal involvement (cN).

RESULTS

Among the early (cT1) and node-negative (cN0) cancer, intestinal (< or =1.5 cm) and diffuse types (< or =1.0 cm) of submucosal cancer showed low incidences of nodal involvement (3%) confined to the first tier. When the cancer exceeded these cutoff diameters, positive nodes of the second tier were confined to three priority stations (left gastric, common hepatic, and celiac arteries) at an incidence of 2.3%. Perigastric and preferential dissection of these three node stations (modified D2 dissection) showed survival benefits identical to those of a conventional D2 dissection.

CONCLUSIONS

When submucosal cancer is evaluated as cT1cN0, a virtually sufficient minimized scope of lymphadenectomy is a D1 dissection for that within the cutoff diameter and a modified D2 dissection for that exceeding the cutoff diameter. These two types of dissection can even cover the infrequently observed node-positive stations and can realize no residual disease at surgery.

Is there a role for nontraditional resection of early gastric cancer?

Current trends in the treatment of gastric cancer indicate the emergence of a more sophisticated approach, with tailored therapy applied to individual cases. Treatment includes a broader spectrum of therapeutic options (Fig. 3), including EMR, laparoscopic or laparoscopy-assisted surgery, modified radical surgery, and typical radical surgery with lymph node dissections. Precise characterization of the lesions, especially the depth of invasion in the gastric wall, its size, histology and whether there is ulceration, is the key to successful treatment of N0 mucosal cancer. Micrometastasis and metastasis at the molecular level are issues that require further investigation. Laparoscopic surgery may be more widely accepted. The limitations of nodal dissection based on the concept of a sentinel node should be carefully evaluated in future studies. [figure: see text] Many treatment options, ranging from minimally invasive surgery to D2 node dissection, are available to the surgical oncologist who is treating EGC. As more information is gathered, surgeons will be better able to select patients who are good candidates for minimal surgical procedures.