Preoperative chemotherapy for stage III-IV gastric carcinoma: feasibility, response and outcome after complete resection

Changes in P-glycoprotein expression in gastric carcinoma with respect to distant gastric mucosa may be influenced by p53

BACKGROUND

The effectiveness of some chemotherapeutic agents used to treat gastric carcinoma patients may be impaired by the presence of P-glycoprotein (P-gp) and the status of p53. A modulation of P-gp expression by p53 or other alterations during tumorigenesis have been reported. The authors analyzed P-gp expression in relation to p53 and histopathologic features in gastric carcinoma.

METHODS

Forty-one resected gastric carcinomas and mucosa distant from the tumor were assessed for P-gp expression by immunohistochemistry with C494 and JSB-1 antibodies. p53 expression was also immunohistochemically assessed by DO7 antibody in tumor samples. P-gp and p53 expression were semiquantitatively analyzed according to the percentage of stained cells. Histologic type, grade, vessel invasion, and stage were also studied.

RESULTS

Moderate or high P-gp expression was detected in gastric carcinoma in 29 cases (71%) and in gastric mucosa remote from the tumor in 36 cases (88%). This reduction in P-gp expression was observed in 22% of the carcinomas, all but 1 being p53 immunonegative tumors. Thus, 8 (42%) of the p53 immunonegative carcinomas showed a loss of P-gp expression compared with their distant gastric mucosa. All p53 immunopositive carcinomas coexpressed P-gp. No correlation between P-gp expression and histologic type, grade, vessel invasion, or stage was found.

CONCLUSIONS

P-gp expression in gastric carcinomas is frequent and coexpression with p53 is found. The analysis of P-gp expression in carcinomas and distant mucosa show that it is not regulated by p53, but a loss of P-gp detected in some of these carcinomas is mainly associated with a lack of p53 protein accumulation.

Multidisciplinary approach to esophageal and gastric cancer

Despite marked advances in surgical therapy for patients with esophageal, esophagogastric, and gastric cancers, the overall prognosis of these patients has not markedly improved during the past decades. Multidisciplinary approaches using adjuvant postoperative and neoadjuvant preoperative therapeutic principles have received increasing attention with regard to the management of these patients. A series of randomized, prospective trials has demonstrated that adjuvant postoperative radiation or chemotherapy does not result in a convincing survival advantage after complete tumor resection in esophageal, esophagogastric junction, or gastric cancer. The available data on the role of neoadjuvant preoperative therapy are not yet conclusive. Although neoadjuvant therapy may reduce the tumor mass in many patients, several randomized, controlled trials have shown that, compared with primary resection, a multimodal approach does not result in a survival benefit in patients with locoregional, that is, potentially resectable, tumors. In contrast, in patients with locally advanced tumors, that is, patients in whom complete tumor removal with primary surgery seems unlikely, neoadjuvant therapy increases the likelihood of complete tumor resection on subsequent surgery, but only patients with objective histopathologic response to preoperative therapy seem to benefit from this approach. Consequently, in the future, improvements in the overall survival of patients with esophageal, esophagogastric junction, or gastric cancer most likely will be achieved only by tailored therapeutic strategies that are based on the individual tumor location, tumor stage, and consideration of established prognostic factors. A clear classification of the underlying tumor entity, a profound knowledge of the prognostic factors applicable, a thorough preoperative staging, and identification of parameters that allow for the prediction of response to preoperative therapy will become essential for the selection of the optimal therapeutic modality for individual patients.

Surgical resection for cancer of the cardia

From the pathogenic and therapeutic point of view, adenocarcinomas of the esophagogastric junction (AEG) should be classified into adenocarcinoma of the distal esophagus (Type I), true carcinoma of the cardia (Type II), and subcardial carcinoma (Type III). This classification can be easily performed by summarizing the information available from contrast radiography, endoscopy, and intra-operative findings; it allows comparison of data between various centers and facilitates the choice of surgical therapy. A complete removal of the primary tumor and its lymphatic drainage has to be the primary goal of any surgical approach to adenocarcinoma of the esophagogastric junction. In patients with potentially resectable, true carcinoma of the cardia (AEG Type II), this can be achieved by a total gastrectomy with transhiatal resection of the distal esophagus and en bloc removal of the lymphatic drainage in the lower posterior mediastinum and along the celiac axis and superior border of the pancreas. This approach is associated with lower morbidity and provides equal long-term survival as compared to the more radical transmediastinal or abdominothoracic esophagogastrectomy. Whether a routine splenectomy for lymphadenectomy in the splenic hilus offers a survival benefit in these patients is questionable. In patients with early tumors staged as uT1 on pre-operative endosonography, a limited resection of the proximal stomach, cardia, and distal esophagus with interposition of a pedicled isoperistaltic jejunal segment appears justified since this procedure allows a complete tumor removal with adequate lymphadenctomy and offers excellent functional results. Multimodal therapy with pre-operative polychemotherapy or combined radio-chemotherapy appears to offer a significant survival benefit in patients with locally advanced tumors. With this tailored approach, extensive pre-operative staging becomes mandatory for an adequate selection of the appropriate therapeutic concept.

Neoadjuvant chemotherapy for patients with locally advanced gastric carcinoma: effect on tumor cell microinvolvement of regional lymph nodes

BACKGROUND

In a previous study the authors demonstrated, using immunohistochemical methods for epithelial antigens, that the regional lymph nodes of gastric adenocarcinoma contained individual tumor cells or small clusters of these cells (tumor cell microinvolvement [TCM]) in over 90% of cases. In the current study the authors used the same method to investigate a series of gastric adenocarcinoma cases treated with neoadjuvant chemotherapy prior to tumor resection; their aim was to determine the effect of chemotherapy on TCM in regional lymph nodes.

METHODS

Resection specimens from 17 patients with adenocarcinoma of the stomach, resected after neoadjuvant treatment and classified by routine histology as ypN0, were included in this study. One section from each of the 622 lymph nodes dissected from these specimens was stained by immunohistochemical methods for cytokeratins and Ber-Ep4.

RESULTS

Six patients (35%) and 25 of the 622 lymph nodes (4.0%) had TCM, compared with 93% of patients and 21.8% of lymph nodes in the previous study of patients treated with surgery alone. The lymph node response to chemotherapy correlated with the pathologic response of the primary tumor. Specifically, none of 5 patients with a complete or major pathologic response versus 6 of 12 (50%) patients with minor, partial, or no response had lymph node microinvolvement.

CONCLUSIONS

In comparison to our previous study, this study indicates that chemotherapy has a marked effect on tumor cells in regional lymph nodes and that the extent of this effect can be correlated with the degree of pathologic response of the primary tumor to chemotherapy.

Current advances and changes in treatment strategy may improve survival and quality of life in patients with potentially curable gastric cancer

BACKGROUND

The treatment strategy for gastric cancer is determined by the stage of disease. Advances in diagnostic techniques such as endoscopic ultrasound (EUS) and in staging have increased the accuracy of pretreatment staging. Correct staging is a prerequisite for the optimal treatment of gastric cancer patients. Long-term expected survival and quality of life (QOL) are the major criteria determining the therapeutic strategy.

RESULTS

Surgical resection offers excellent survival rates for early gastric cancer (EGC) patients. D1 resection is sufficient for mucosal cancers (T1m) and for most submucosal cancers (Tlsm); however, for the rest (about 5%) of these patients with N2 disease a D2 resection is required for complete tumor resection (R0). Considering QOL, endoscopic mucosal resection (EMR) or laparoscopic wedge resection is the best front-line therapy for several mucosal cancers. Prediction and selection of node-negative patients with the help of certain macroscopic and histologic criteria can eliminate the possibility for residual disease in perigastric lymph nodes. However, long-term survival data are needed before these new techniques become more generally accepted. In contrast, an aggressive approach is necessary for the treatment of advanced gastric cancer. Total gastrectomy, with the exception of distal tumors that can be treated by subtotal gastrectomy, is the procedure of choice. Splenectomy is indicated for proximal advanced tumors. Distal pancreatectomy should be avoided, however, because its adverse effect has been documented in all randomized trials. Although the survival benefit of extended (D2) lymphadenectomy is unproven in randomized trials, D2 resection increases the R0 resection rate and may improve survival in some selected node-positive patients. D2 resection has little effect on preventing peritoneal tumor spread and liver metastasis, and the traditional late administration of chemotherapeutic drugs has been proven ineffective. Current data suggest a possible beneficial effect of combined treatment for patients with local advanced gastric cancer (LAGC). Ongoing phase-III randomized trials will prove whether patients with LAGC treated by neoadjuvant chemotherapy plus D2 resection versus surgery alone or surgery plus intraoperative intraperitoneal chemotherapy derive any benefit from these combined treatment modalities.

CONCLUSION

Evaluation of all information concerning tumor stage, location, histologic type, expected survival, and QOL after resection is of paramount importance for the surgeon planning the extent of surgery. The therapeutic approach should be stratified according to the stage of disease.

Prognostic factors in a series of 297 patients with gastric adenocarcinoma undergoing surgical resection

BACKGROUND

Gastric cancer has a poor prognosis. The aim of this study was to determine the influence of several clinicopathological variables on outcome in a series of 297 Western patients undergoing surgical resection for gastric adenocarcinoma.

METHODS

The results were analysed retrospectively and prognostic factors were identified in a univariate and Cox proportional hazards regression model. Mean patient age at the time of operation was 61.9 years; 65.7 per cent were men. Mean follow-up was 7.8 (range 1-15) years. Of the 297 patients undergoing surgery, 70 per cent had subtotal gastrectomy, 26.3 per cent underwent total gastrectomy and 3.7 per cent had proximal gastrectomy.

RESULTS

The overall survival rate was 38.9 per cent at 5 years. In th univariate analysis, survival-related factors were weight loss (P < 0.05), abdominal mass (P < 0.01), dysphagia (P < 0.001), type of gastrectomy (subtotal gastrectomy versus total gastrectomy, P < 0.001), intention of resection (curative versus palliative resection, P < 0.001), tumour site (P < 0.001), histopathological grade (low versus high grade, P < 0.05), tumour diameter less than 3 cm (P < 0.001), degree of gastric wall invasion (P < 0.001), degree of lymph node invasion (P < 0.001) and stage of the neoplasia (P < 0.001). Other variables had no significant influence. In the multivariate analysis, degree of gastric wall invasion, lymph node invasion, tumour size and dysphagia at presentation were the only independent prognostic variables.

CONCLUSION

From these data it was possible to derive a prognostic index with which patients could be classified as at low, intermediate or high risk.

Barrett's cancer: indications, extent, and results of surgical resection

In the Western world, the prevalence of Barrett's carcinoma, i.e., adenocarcinoma of the distal esophagus arising from specialized columnar epithelial metaplasia, has risen dramatically in the past two decades. High-grade dysplasia in the columnar epithelium has been identified as the precursor of malignant carcinoma. Whether an esophagectomy should be performed in patients with high-grade dysplasia remains controversial. Surgical resection is the mainstay of therapy in patients with invasive adenocarcinoma who are fit for surgery. Complete removal of the primary tumor and its lymphatic drainage has to be the primary goal of any surgical approach to adenocarcinoma of the distal esophagus. In patients with tumors located in the distal esophagus, this can be achieved by a radical transhiatal esophagectomy and proximal gastric resection with en bloc removal of the lymphatic drainage in the lower posterior mediastinum and along the celiac axis. Early adenocarcinoma can be cured by this approach. The value of multimodality therapy in patients with advanced tumors needs to be confirmed in well-designed randomized prospective trials.

Accuracy of laparoscopic ultrasonography in the staging of upper gastrointestinal malignancy

Laparoscopic ultrasonographic staging was compared prospectively with conventional computed tomography (CT) and ultrasonographic staging of 24 lower-third oesophageal tumors and 20 gastric malignancies. Following laparoscopic ultrasonography, seven patients regarded as being resectable after conventional imaging were excluded from surgical exploration because of ascites with peritoneal deposits (four patients), liver metastases (one), advanced local disease (one) and poor tolerance of general anaesthesia (one). Preoperative T and N stages were compared with the pathological staging following resection in 34 patients. Laparoscopic ultrasonography was significantly more accurate than conventional CT and ultrasonography in assessment of the primary tumour (91 versus 64 per cent, P < 0.01) and nodal status (91 versus 62 per cent, P < 0.05). The addition of laparoscopic ultrasonography to conventional procedures for staging upper gastrointestinal malignancy improved the overall accuracy of staging. Although this may have future implications for the selection of patients for multimodality treatment, management decisions are currently based on laparoscopic findings, which in this study resulted in a resection rate of 97 per cent.

Preoperative chemotherapy in gastric cancer

Even with extended surgery, including systematic lymphadenectomy of the lymph node compartment II, only half of the patients with locally advanced gastric cancer (LAGC)-which comprises stages IIIA, IIIB, and IV-undergo macroscopic and microscopic tumor-free resection (i.e., R0 resection, according to UICC 1987/AICC 1988). An improvement in this situation is best accomplished by preoperative treatment modalities to increase the R0 resection rate and by preoperative and postoperative treatment to reduce local recurrences and distant metastases. For LAGC, which includes approximately two thirds of patients with locoregionally confined tumors, preoperative chemotherapy (CTx) represents a promising approach. Among a group of patients with surgically or clinically staged unresectable LAGC, approximately half underwent R0 resection after downstaging induced by active CTx. The long-term survival of these patients seems to be improved. Even in patients who had primarily unresectable tumors as defined by explorative laparotomy, the long-term survival was about 20% after preoperative CTx and subsequent surgery. Based on these experiences, randomized trials investigating preoperative CTx versus surgery alone are clearly needed to define whether such an approach has an impact on RO resection rates and survival of patients with LAGC. Preconditions for such trials are clinical staging procedures, including endoscopic ultrasonography (T category) and surgical laparoscopy plus lavage (excluding peritoneal carcinomatosis), and a standardized surgical procedure.