The Essentials of Locoregional Control in the Treatment of Gastric Cancer

Synergistic antitumor activity of a DLL4/VEGF bispecific therapeutic antibody in combination with irinotecan in gastric cancer

Notch signaling has been identified as a critical pathway in gastric cancer (GC) progression and metastasis, and inhibition of Delta-like ligand 4 (DLL4), a Notch ligand, is suggested as a potent therapeutic approach for GC. Expression of both DLL4 and vascular endothelial growth factor receptor 2 (VEGFR2) was similar in the malignant tissues of GC patients. We focused on vascular endothelial growth factor (VEGF), a known angiogenesis regulator and activator of DLL4. Here, we used ABL001, a DLL4/VEGF bispecific therapeutic antibody, and investigated its therapeutic effect in GC. Treatment with human DLL4 therapeutic antibody (anti-hDLL4) or ABL001 slightly reduced GC cell growth in monolayer culture; however, they significantly inhibited cell growth in 3D-culture, suggesting a reduction in the cancer stem cell population. Treatment with anti-hDLL4 or ABL001 also decreased GC cell migration and invasion. Moreover, the combined treatment of irinotecan with anti-hDLL4 or ABL001 showed synergistic antitumor activity. Both combination treatments further reduced cell growth in 3D-culture as well as cell invasion. Interestingly, the combination treatment of ABL001 with irinotecan synergistically reduced the GC burden in both xenograft and orthotopic mouse models. Collectively, DLL4 inhibition significantly decreased cell motility and stem-like phenotype and the combination treatment of DLL4/VEGF bispecific therapeutic antibody with irinotecan synergistically reduced the GC burden in mouse models. Our data suggest that ABL001 potentially represents a potent agent in GC therapy. Further biochemical and pre-clinical studies are needed for its application in the clinic.

Gastrectomy and D2 Lymphadenectomy for Gastric Cancer: A Meta-Analysis Comparing the Harmonic Scalpel to Conventional Techniques

The ultrasonic Harmonic scalpel has demonstrated clinical and surgical benefits in dissection and coagulation. To evaluate its use in gastrectomy, we conducted a systematic review and meta-analysis of randomized controlled trials comparing the Harmonic scalpel to conventional techniques in gastrectomy for patients with gastric cancer. International databases were searched without language restrictions for comparisons in open or laparoscopic gastrectomy and lymphadenectomy. The meta-analysis used a random-effects model for all outcomes; continuous variables were analyzed for mean differences and dichotomous variables were analyzed for risk ratios. Sensitivity analyses were conducted for study quality, type of conventional technique, and imputation of study results. Ten studies (N = 935) met the inclusion criteria. Compared with conventional hemostatic techniques, the Harmonic scalpel demonstrated significant reductions in operating time (−27.5 min; P < 0.001), intraoperative blood loss (−93.2 mL; P < 0.001), and drainage volume (−138.8 mL; P < 0.001). Results were numerically higher for conventional techniques for hospital length of stay, complication risk, and transfusions but did not reach statistical significance. Results remained robust to sensitivity analyses. This meta-analysis demonstrates the clear advantages of using the Harmonic scalpel compared to conventional techniques, with improvements demonstrated across several outcome measures for patients undergoing gastrectomy and lymphadenectomy.

Clinical implications of DLL4 expression in gastric cancer

BACKGROUND

Delta-like ligand 4 (DLL4)-Notch signaling plays a key role in tumor neovascular development and angiogenesis during tumor growth. The clinical significance of DLL4 expression in gastric cancer has not been clarified.

METHODS

Gastric cancer cell lines and 180 gastric cancer patients were enrolled. DLL4 expression in gastric cancer cells and stroma was identified and evaluated immunohistochemically. The association between DLL4 and clinicopathological factors was also assessed.

RESULTS

DLL4 expression was identified in the cellular membrane and cytoplasm of gastric cancer cells by immunoblotting and immunohistochemical staining. DLL4 positivity in cancer cells and stroma was found in 88 (48%) and 41 (22%) of the 180 gastric cancer patients respectively. Both cancer and stromal DLL4 expression significantly correlated with more advanced tumor depth, nodal involvement, and lymphatic and venous invasion. A strongly positive association between cancerous and stromal DLL4 expression was identified (p < 0.01). Both cancerous and stromal DLL4 expression were prognostic markers in gastric cancer as determined by univariate analysis.

CONCLUSIONS

Cancerous and stromal DLL4 expression was found in 48% and 22% in gastric cancer, and significantly affected postoperative clinical outcomes. Cancerous and stromal DLL4 expression may be an effective target of anti-DLL4 treatment in gastric cancer.

Gastric cancer eastern experience

Several guidelines are used for cancer therapy throughout the world. The Japan Gastric Cancer Association guideline, whereby standard surgery for T2 to T4 curable gastric cancer is defined as more than two-thirds gastrectomy with D2 dissection, are widely followed, with further data being gathered from either single institutions or nationwide registry. In the East, D2 dissection shows much better results than less extended surgery followed by adjuvant treatment. Adjuvant chemotherapy without radiotherapy shows significantly better survival results than surgery alone only when D2 dissection is applied. Without good local control, including regional lymph node metastasis, the cure rate cannot be high.

Improved survival after resectable non-cardia gastric cancer in The Netherlands: the importance of surgical training and quality control

BACKGROUND

In The Netherlands, standardised limited D1 and extended D2 lymph node dissections in the treatment of resectable gastric cancer were introduced nationwide within the framework of the Dutch D1-D2 Gastric Cancer Trial between 1989 and 1993. In a population-based study, we evaluated whether the survival of patients with resectable gastric cancer improved over time on a regional level.

METHODS

We compared 5-year overall and relative survival of patients with curatively resected non-cardia gastric cancer in the regional cancer registry of the Comprehensive Cancer Centre West in The Netherlands before the Dutch D1-D2 trial (1986 to mid 1989; n = 273), during the trial period (mid 1989 to mid 1993; n = 255), and after the trial (mid 1993 to 1999; n = 219), adjusting for prognostic variables.

RESULTS

Unadjusted survival was highest in the post-trial period: 5-year overall and relative survival were 42% and 52%, respectively, compared to 34% and 41% in the pre-trial period, and 39% and 46% in the trial period (p = 0.31 and p = 0.06, respectively). After adjustment for age, gender, tumour site, pT-stage, nodal status and hospital volume, the effect of period on survival was more apparent (p = 0.009). Compared to the pre-trial period, the hazard ratio was 0.83 (95% confidence interval, 0.68-1.02) for the trial period, and 0.72 (0.58-0.89) after the trial. Less than 1% of the patients received adjuvant therapy.

CONCLUSION

Survival of patients with curatively resected non-cardia gastric cancer has improved. Standardisation and surgical training in D1 and D2 lymph node dissection are the most likely explanation for this improvement.

The multidisciplinary management of gastrointestinal cancer. Multimodal treatment of gastric cancer

Although radical surgical R0 resections are the basis of cure for gastric cancer, surgery alone only provides long-term survival in 20-30% of patients with advanced-stage disease. Thus, in Western and European countries, advanced gastric cancer has a high risk of recurrence and metachronous metastases. Very recently, multimodal strategies combining different neoadjuvant and/or adjuvant protocols have improved the prognosis of gastric cancer when combined with surgery with curative intent. As used in palliative regimens, the combination of cisplatin with intravenous or oral fluoropyrimidines has been the integral component of such (neo)adjuvant strategies. However, the cytotoxic agents docetaxel, oxaliplatin and irinotecan and new targeted biologicals such as cetuximab, bevacizumab or panitumumab are currently under investigation, with or without irradiation, in multimodal treatment regimens. These studies may further increase R0 resection rates, and prolong disease-free and overall survival times in the treatment of advanced gastric cancer. This article reviews the most relevant literature on multimodal treatment of gastric cancer, and discusses future strategies to improve locoregional failures.