Lymphadenectomy for gastric cancer

Evolution of Gastric Cancer Treatment: From the Golden Age of Surgery to an Era of Precision Medicine

Gastric cancer imposes a global health burden. Although multimodal therapies have proven to benefit patients with advanced diseases after curative surgery, the prognosis of most advanced cancer patients still needs to be improved. Surgical extirpation is the mainstay of gastric cancer treatment. Indeed, without curative surgery, variations and combinations of chemotherapy and/or radiation cannot bring clinically meaningful success. Centered around D2 surgery, adjuvant and peri-operative multimodal therapies have improved survival in a certain group of gastric cancer patients. Moving toward a personalized cancer therapy era, molecular targeted strategies have been tested in clinical trials for gastric cancer. With some success and failures, we have learned valuable lessons regarding the biology of gastric cancer and the clinical relevance of biological therapies in addition to conventional treatments. Future treatment of gastric cancer will be shifted to molecularly tailored and genome information-based personalized therapy. Collaboration across disciplines and actively adopting emerging anti-cancer strategies, along with in-depth understanding of molecular and genetic underpinnings of tumor development and progression, are imperative to realizing personalized therapy for gastric cancer. Although many challenges remain to be overcome, we envision that the era of precision cancer medicine for gastric cancer has already arrived and anticipate that current knowledge and discoveries will be transformed into near-future clinical practice for managing gastric cancer patients.

Optimal management of resectable gastric adenocarcinoma

The worldwide incidence of gastric adenocarcinoma has rapidly declined in the past century, but gastric cancer remains the fifth most common malignancy in the world. Approximately half of all cases of gastric cancer are diagnosed in Eastern Asia. In this review, we provide an overview of the landmark studies investigating neoadjuvant and adjuvant therapies in resectable gastric cancer and highlight ongoing efforts to define optimal population-adapted management strategies.

Personalized Surgery for Gastric Adenocarcinoma: A Meta-analysis of D1 versus D2 Lymphadenectomy

BACKGROUND

The recent publication of 5-year survival data for the Italian Gastric Cancer Study Group (IGCSG) D1 versus D2 lymphadenectomy for gastric cancer trial adds important data for analysis of whether a D2 lymphadenectomy improves survival.

METHODS

Systematic searches were conducted using Medline, Embase, and the Cochrane Central Register of Controlled Trials from January 1, 1985 to February 1, 2014. Meta-analyses were performed using RevMan version 5 software. Long-term outcomes were analyzed. Subgroup analyses of T and N stage were performed.

RESULTS

Outcomes of four randomized, controlled trials involving 1,599 patients (823 D1: 776 D2) enrolled from 1982 to 2005 were included for qualitative analysis and quantitative meta-analysis. Despite the addition of long-term survival data from the IGCSG, 5-year overall and nodal status survival was similar between D1 and D2 trials. However, subgroup analysis revealed a survival benefit for T3 patients (odds ratio 1.64, 95 % confidence interval 1.01-2.67) and a trend for survival benefit for advanced nodal stage (odds ratio 1.36, 95 % confidence interval 0.98-1.87) with D2 compared with D1 lymphadenectomy.

CONCLUSIONS

As recent studies have demonstrated comparable short-term surgical outcomes for both D1 and D2 lymphadenectomies, consideration should be made for more extensive lymph node dissection among patients with advanced stage.

Lymph node dissection for gastric cancer: a critical review

Gastric cancer is one of the most common neoplasms and an important cause of cancer-related death worldwide. Efforts to reduce its high mortality rates are currently focused on multidisciplinary management. However, surgery remains a cornerstone in the management of patients with resectable disease. There is still some controversy as to the extent of lymph node dissection for potentially curable stomach cancer. Surgeons in eastern countries favor more extensive lymph node dissection, whereas those in the West favor less extensive dissection. Thus, extent of lymph node dissection remains one of the most hotly discussed aspects of gastric surgery, particularly because most stomach cancers are now often comprehensively treated by adding some perioperative chemotherapy or chemo-radiation. We provide a critical review of lymph nodes dissection for gastric cancer with a particular focus on its benefits in a multimodal approach.

Is there a role for surgery with adequate nodal evaluation alone in gastric adenocarcinoma?

INTRODUCTION

The extent of lymphadenectomy and protocol design in gastric cancer trials limits interpretation of survival benefit of adjuvant therapy after surgery with adequate lymphadenectomy. We examined the impact of surgery with adequate nodal evaluation alone on gastric cancer survival.

METHODS

Using 2001-2008 California Cancer Registry, we identified 2,229 patients who underwent gastrectomy with adequate nodal evaluation (≥15 lymph nodes) for American Joint Committee on Cancer stage I-IV M0 gastric adenocarcinoma. Cox proportional hazard analyses were used to evaluate the impact of surgery alone on survival.

RESULTS

Nearly 70% of our cohort had T1/2 tumors and 29% had N0 disease. Forty-nine percent of the cohort underwent surgery alone. These patients were more likely to be older, Medicare-insured, with T1 and N0 disease. On unadjusted analyses, persons who underwent surgery alone for stage I or N0 disease experienced 1- and 3-year overall and cancer-specific survival comparable to those who received adjuvant therapy. On multivariate analyses for stage I or N0 disease, surgery alone predicted superior survival outcomes than when combined with adjuvant therapies.

CONCLUSION

Surgery alone with adequate nodal evaluation may have a role in low-risk gastric cancer. To corroborate these findings, surgery with adequate lymphadenectomy alone (as treatment arm) deserves consideration in the design of gastric cancer trials to provide effective yet resource-conserving, rather than maximally tolerated, treatments.

Adjuvant chemotherapy: an option for Asian patients only?

Survival rates following curative resection for gastric cancer are higher in East Asia than in Europe and the US. The aggressive surgical approach adopted in East Asia may explain these observations. In Japan and Korea, gastrectomy with extended lymphadenectomy (D2 gastrectomy) has been standard of care for many years, whereas gastrectomy with lymphadenectomy of the perigastric lymph nodes (D1 surgery) has been favored in Europe and the US until recently. D2 surgery is now recommended globally based on the 15-year findings from the large Dutch D1D2 study, which showed a reduction in cancer-related deaths with D2 versus D1 surgery. Improved outcomes are now being reported in the US and Europe as D2 surgery becomes more widely used. In addition to surgery, systemic therapy is also required to control recurrences, although the preferred regimen differs by region. Given that some of the studies on which these preferences are based predate the widespread acceptance of D2 surgery, the optimal regimen should be considered carefully. Recent studies from East Asia support the use of adjuvant chemotherapy after D2 surgery. Adjuvant chemotherapy should also be considered a valid approach in other regions now that the benefits of D2 surgery have been demonstrated unequivocally.

Meta-analysis of D1 versus D2 gastrectomy for gastric adenocarcinoma

OBJECTIVES

To conduct a meta-analysis of randomized controlled trials evaluating the efficacy and drawbacks of limited (D1) versus extended lymphadenectomy (D2) for proven gastric adenocarcinoma.

METHODS

A search of Cochrane, Medline, PubMed, Embase, Science Citation Index and Current Contents electronic databases identified randomized controlled trials published in the English language between 1980 and 2008 comparing the outcomes of D1 versus D2 gastrectomy for gastric adenocarcinoma. The meta-analysis was prepared in accordance with the Preferred Reporting Items for Systematic reviews and Meta-analyses statement. The 6 outcome variables analyzed included length of hospital stay; overall complication rate; anastomotic leak rate; reoperation rate; 30-day mortality rate and 5-year survival rate. Random effects meta-analyses were performed using odds ratios (OR) and weighted mean differences (WMD).

RESULTS

Six trials totaling 1876 patients (D1 = 946, D2 = 930) were analyzed. In 5 of the 6 outcomes the summary point estimates favored D1 over D2 group with a statistically significant reduction of (i) 6.37 days reduction in hospital stay (WMD -6.37, confidence interval [CI] -10.66, -2.08, P = 0.0036); (ii) 58% reduction in relative odds of developing postoperative complications (OR 0.42, CI 0.27, 0.66, P = 0.0002); (iii) 60% reduction in anastomotic breakdown (OR 0.40, CI 0.25, 0.63, P = 0.0001); (iv) 67% reduction in reoperation rate (OR 0.33, CI 0.15, 0.72, P = 0.006); and (v) 41% reduction in 30-day mortality rate (OR 0.59, CI 0.40, 0.85, P = 0.0054). Lastly there was no significant difference in the 5-year survival (OR 0.97, CI 0.78, 1.20, P = 0.7662) between D1 and D2 gastrectomy patients.

CONCLUSIONS

On the basis of this meta-analysis we conclude that D1 gastrectomy is associated with significant fewer anastomotic leaks, postoperative complication rate, reoperation rate, decreased length of hospital stay and 30-day mortality rate. Finally, the 5-year survival in D1 gastrectomy patients was similar to the D2 cohort.

Results of specialization in the surgical treatment of gastric cancer in Peru

BACKGROUND

The best results in the surgical treatment of gastric cancer are those obtained by the Japanese surgical school that emphasizes D2 lymphadenectomy as a fundamental principle for obtaining better local control of the disease. However, this technique has not gained wide acceptance in the West, owing to the fact that the results of Japanese studies have not been reproduced frequently in Western countries. In recent years, a series of studies have recommended the centralization of gastric cancer treatment in specialized surgical units in order to obtain results similar to those achieved by Japanese centers. The objective of this study was to describe the specialization process and to show the short-term results obtained in the surgical treatment of gastric cancer in the Specialized Unit of the Rebagliati National Hospital, the largest general referral hospital in Lima, Peru.

METHODS

In the year 2000 a specialized service was created for the surgical treatment of gastric cancer, initiating a process that included the establishment of surgical treatment guidelines, training in the Japanese surgical technique, and progress along the learning curve for D2 lymphadenectomy. Clinical, surgical, and pathological data were recorded prospectively in a fixed format, considering that strict documentation of cases was also an important step within this process.

RESULTS

Between January 1, 2004, and December 31, 2005, 243 consecutive patients with a proven diagnosis of gastric adenocarcinoma were admitted to the operating theater for surgical treatment. During this study period, morbidity was 22.7% and hospital mortality, 2.8%. The numbers (mean +/- SD) of resected lymph nodes for distal gastrectomy and total gastrectomy were 37.3 +/- 12.4 and 45.3 +/- 14.5, respectively. Hospital stay was 13 days for distal gastrectomy as well as for total gastrectomy.

CONCLUSION

According to our results, adequate training in the Japanese surgical technique, progress along the learning curve for D2 lymphadenectomy, and the establishment of specialized units are highly recommended for the surgical treatment of gastric cancer in Western referral hospitals.

Disparities in gastric cancer chemotherapy between the East and West

There are still remarkable disparities in the treatment of gastric cancer between the East and West. Treatment outcomes for this disease have improved in Japan due to early detection and surgical resection with systematic node dissections, such as D2, whereas gastric cancer remains a virulent disease in Western countries. Differences in the types of surgery and their outcomes affect how adjuvant trials are conducted and interpreted. Recent Western randomized trials demonstrated the significant survival benefit of adjuvant chemoradiotherapy or intensive combination chemotherapy. However, baseline surgical quality and outcomes were quite different from those in Japan, and Japanese surgical/medical oncologists have not accepted the Western results. Several disparities are also evident in the results of chemotherapy trials for advanced gastric cancer. Although similar results were obtained with randomized studies using older regimens, the interpretation of the results differed between Japan and other countries. A combination of cisplatin and fluorouracil was used as the reference arm in ongoing randomized trials in most countries, whereas single-agent fluorouracil or S-1 alone was used in Japanese trials. Two triplet regimens have already demonstrated significant prolongation of survival in Western studies. However, these benefits seem to be marginal and these regimens may be replaced by newer regimens, which will soon be available in Europe and Asia, where a total of 2,600 patients have been accrued. Although these disparities between regions must be overcome, it is time for both Eastern and Western investigators to pursue further benefits by incorporating new agents into treatment regimens.

Role of radiation therapy in gastric adenocarcinoma

Outcomes in patients with gastric cancer in the United States remain disappointing, with a five-year overall survival rate of approximately 23%. Given high rates of local-regional control following surgery, a strong rationale exists for the use of adjuvant radiation therapy. Randomized trials have shown superior local control with adjuvant radiotherapy and improved overall survival with adjuvant chemoradiation. The benefit of adjuvant chemoradiation in patients who have undergone D2 lymph node dissection by an experienced surgeon is not known, and the benefit of adjuvant radiation therapy in addition to adjuvant chemotherapy continues to be defined.

In unresectable disease, chemoradiation allows long-term survival in a small number of patients and provides effective palliation. Most trials show a benefit to combined modality therapy compared to chemotherapy or radiation therapy alone.

The use of pre-operative, intra-operative, 3D conformal, and intensity modulated radiation therapy in gastric cancer is promising but requires further study.

The current article reviews the role of radiation therapy in the treatment of resectable and unresectable gastric carcinoma, focusing on current recommendations in the United States.

Optimal locoregional treatment in gastric cancer

Worldwide, gastric cancer is one of the leading causes of cancer-related death. The mainstay of curative treatment is radical surgery. But even with optimal surgical resection, the prognosis remains modest in the Western world. Numerous attempts have been undertaken to improve clinical outcome. More extensive lymph node dissection, adjuvant radiotherapy and adjuvant chemotherapy did not result in a survival benefit in randomized trials. Only postoperative chemoradiotherapy has proven to be valuable in prospective randomized trials. Questions are to be answered about optimization of surgery, radiotherapy and chemotherapy, and fine tuning of the three modalities. One of the key issues that should be addressed is whether pre- or postoperative chemoradiotherapy will benefit survival or locoregional control in the case of optimal surgery with an "over-D1" lymphadenectomy and without splenectomy. In this article the most relevant literature on locoregional treatment in operable gastric cancer will be reviewed and future strategies will be discussed.