Optimal surgery for advanced gastric cancer

Significance of nodal dissection and nodal positivity in gastric cancer

Lymphadenectomy is a central component of surgery for gastric cancer. However, controversies over the optimal extent of lymphadenectomy in gastric cancer surgery have persisted for several decades. In Eastern countries where the incidence of gastric cancer is high, surgeons have performed extensive lymphadenectomy (D2 lymphadenectomy) with low morbidity and mortality, while most Western surgeons have advocated for more limited lymphadenectomies according to the results of Dutch trial and MRC trial. Initially, these trials had failed to show survival benefit of D2 procedure and instead, found pancreaticosplenectomy performed as part of the D2 procedure associated with high incidence of morbidity and mortality. Subsequently, superiority of D2 lymphadenectomy on survival was demonstrated based on updated results. Moreover, spleen and pancreas preserving D2 lymphadenectomy are being performed safely in Western countries. Today, there is an international consensus on performing D2 lymphadenectomy as the standard procedure for advanced gastric cancer and is widely accepted as the standard procedure for gastric cancer surgery. The significance of the extent of lymphadenectomy is intimately associated with the prognostic importance of nodal metastases as the most powerful indicator of recurrence and survival for patients after curative gastrectomy. Maruyama computer program could be used to estimate the risk of lymph node metastasis in each nodal station. The Maruyama Index could be used to assess the adequacy of lymphadenectomy in gastric cancer. Positive lymph node ratio is calculated as the ratio of positive lymph nodes to all harvested lymph nodes, which might be a more precise predictor of prognosis than the absolute number of positive lymph nodes. While D2 lymphadenectomy enables the accurate staging of the disease, reduces the incidence of locoregional recurrences and thus contribute to an improved overall survival; performing lymphadenectomy beyond D2 is unlikely to improve survival. Therapeutic D2+ lymphadenectomy for advanced gastric cancer requires further evaluations, especially for patients receiving neo-adjuvant or conversion treatments.

Evolution in the surgical management of gastric cancer: is extended lymph node dissection back in vogue in the USA?

BACKGROUND

Gastric cancer remains a formidable treatment challenge. For decades, treatment consisted mostly of surgical intervention for this deadly disease. With improvements in the multi-disciplinary management of solid organ malignancies, the approach to this disease is being stepwise refined.

MAIN BODY

One of the prevalent controversies in the surgical management of gastric cancer rests on the need for adequate harvesting of lymph nodes. For decades, lymph node dissection is regarded as a staging technique useful in only upstaging the disease. The adoption of D2 lymphadenectomy has been particularly slow to mature. But with prevailing data from Asia consistently demonstrating a survival benefit from lymphadenectomy, it calls into question the notion of lymphadenectomy as being solely a staging procedure.

CONCLUSIONS

As gastric resection techniques are being better defined in western countries and surgical morbidities lowered on its execution, D2 lymphadenectomy is becoming more accepted as the new standard in the management of gastric cancer.

Decreased RNA-binding motif 5 expression is associated with tumor progression in gastric cancer

RNA-binding motif 5 is a putative tumor suppressor gene that modulates cell cycle arrest and apoptosis. We recently demonstrated that RNA-binding motif 5 inhibits cell growth through the p53 pathway. This study evaluated the clinical significance of RNA-binding motif 5 expression in gastric cancer and the effects of altered RNA-binding motif 5 expression on cancer biology in gastric cancer cells. RNA-binding motif 5 protein expression was evaluated by immunohistochemistry using the surgical specimens of 106 patients with gastric cancer. We analyzed the relationships of RNA-binding motif 5 expression with clinicopathological parameters and patient prognosis. We further explored the effects of RNA-binding motif 5 downregulation with short hairpin RNA on cell growth and p53 signaling in MKN45 gastric cancer cells. Immunohistochemistry revealed that RNA-binding motif 5 expression was decreased in 29 of 106 (27.4%) gastric cancer specimens. Decreased RNA-binding motif 5 expression was correlated with histological differentiation, depth of tumor infiltration, nodal metastasis, tumor-node-metastasis stage, and prognosis. RNA-binding motif 5 silencing enhanced gastric cancer cell proliferation and decreased p53 transcriptional activity in reporter gene assays. Conversely, restoration of RNA-binding motif 5 expression suppressed cell growth and recovered p53 transactivation in RNA-binding motif 5-silenced cells. Furthermore, RNA-binding motif 5 silencing reduced the messenger RNA and protein expression of the p53 target gene p21. Our results suggest that RNA-binding motif 5 downregulation is involved in gastric cancer progression and that RNA-binding motif 5 behaves as a tumor suppressor gene in gastric cancer.

Problems faced by evidence-based medicine in evaluating lymphadenectomy for gastric cancer

Gastric cancer surgical management differs between Eastern Asia and Western countries. Extended lymphadenectomy (D2) is the standard of care in Japan and South Korea since decades, while the majority of United States patients receive at most a limited lymphadenectomy (D1). United States and Northern Europe are considered the scientific leaders in medicine and evidence-based procedures are the cornerstone of their clinical practice. However, surgeons in Eastern Asia are more experienced, as there are more new cases of gastric cancer in Japan (107898 in 2012) than in the entire European Union (81592), or in South Korea (31269) than in the entire United States (21155). For quite a long time evidence-based medicine (EBM) did not solve the question whether D2 improves long-term prognosis with respect to D1. Indeed, eastern surgeons were reluctant to perform D1 even in the frame of a clinical trial, as their patients had a very good prognosis after D2. Evidence-based surgical indications provided by Western trials were questioned, as surgical procedures could not be properly standardized. In the present study we analyzed indications about the optimal extension of lymphadenectomy in gastric cancer according to current scientific literature (2008-2012) and surgical guidelines. We searched PubMed for papers using the key words “lymphadenectomy or D1 or D2” AND “gastric cancer” from 2008 to 2012. Moreover, we reviewed national guidelines for gastric cancer management. The support to D2 lymphadenectomy increased progressively from 2008 to 2012: since 2010 papers supporting D2 have achieved a higher overall impact factor than the other papers. Till 2011, D2 was the procedure of choice according to experts’ opinion, while three meta-analyses found no survival advantage after D2 with respect to D1. In 2012-2013, however, two meta-analyses reported that D2 improves prognosis with respect to D1. D2 lymphadenectomy was proposed as the standard of care for advanced gastric cancer by Japanese National Guidelines since 1981 and was adopted as the standard procedure by the Italian Research Group for Gastric Cancer since the Nineties. D2 is now indicated as the standard of surgical treatment with curative intent by the German, British and ESMO-ESSO-ESTRO guidelines. At variance American NCCN guidelines recommend a D1⁺ or a modified D2 lymph node dissection. In conclusion, D2 lymphadenectomy, originally developed by Eastern surgeons, is now becoming the procedure of choice also in the West. In gastric cancer surgery EBM is lagging behind national guidelines, rather than preceding and orienting them. To eliminate this lag, EBM should value to a larger extent Eastern Asian literature and should evaluate not only the quality of the study design but also the quality of surgical procedures.

Does neoadjuvant chemotherapy improve outcomes for patients with gastric cancer?

BACKGROUND

The role of neoadjuvant and adjuvant therapy for gastric cancer remains undefined. We compared the outcomes for patients treated with surgery alone or with the addition of adjuvant or neaodjuvant treatment.

METHODS

A single-institution, retrospective evaluation of a prospective database of gastric cancer patients treated from 2000 to 2008 was performed.

RESULTS

Overall, 173 patients with gastric cancer underwent surgical extirpation. Of the 173 patients, 43% had early-stage disease (less than stage 2) and 57% had late-stage disease (stage 2 or greater; American Joint Committee on Cancer, 2010). The median survival from the date of diagnosis for those treated with neoadjuvant chemotherapy (NAC) (n = 35), adjuvant chemotherapy (n = 21), adjuvant chemoradiotherapy (n = 18), both NAC and adjuvant chemotherapy (n = 11), or surgery alone (n = 88) was 26.3, 17.3, greater than 60, greater than 60, and 50.3 months, respectively. The addition of NAC to surgery was detrimental to survival in those with early-stage disease (P = 0.002) and did not improve survival in those with late-stage disease (P = 0.687). For those with late-stage disease, surgery with adjuvant chemoradiotherapy exhibited the best overall survival compared with surgery alone (P = 0.021) or surgery with adjuvant chemotherapy (P = 0.01). Patients treated with NAC had a greater rate of R0 resection compared with surgery alone (P = 0.049).

CONCLUSIONS

NAC for patients with gastric cancer does not significantly improve the overall outcomes for those with late-stage disease and could be detrimental to survival for those with early-stage disease. However, treatment with NAC resulted in an improved rate of R0 resection.

The effect of continuous jejunal interposition on gastrointestinal hormones after distal gastrectomy

The objective of our study was to determine the effect of continuous jejunal interposition on gastrointestinal hormones after distal gastrectomy, and lay a foundation for surgical management.Distal subtotal gastrectomy experimental model were established on 24 adult Beagle dogs. Digestive tract reconstruction of the dogs was randomly divided into continuous jejunal interposition group, Billroth II anastomosis group and isolated jejunum interposition group. The content of serum gastrin, plasma motilin and cholecystokinin after different digestive tract reconstructions was detected and compared by enzyme-linked immunosorbent assay. In the dogs which received continuous jejunal interposition, postoperative serum gastrin level was significantly lower than before surgery either in fasting or postprandial state (all p<0.05). The serum gastrin level of continuous jejunal interposition group was significantly higher than the other groups in postprandial state (all p<0.05), and was significantly higher than Billroth II -type anastomosis group in fasting state (p<0.05). Furthermore, the postoperative plasma motilin and cholecystokinin levels were significantly higher than before surgery either in fasting or postprandial in dogs received continuous jejunal interposition (all p<0.05). The postoperative plasma motilin level of continuous jejunal interposition group was significantly higher than the other groups in postprandial state (all p<0.05), and was significantly higher than Billroth II -type anastomosis group in fasting state (p<0.05). However, the postoperative cholecystokinin level of continuous jejunal interposition group was significantly lower than the other groups (all p <0.05).Continuous jejunal interposition after distal gastrectomy could maintain the postoperative plasma motilin and serum gastrin in a relatively high level, while cholecystokinin in a low level.