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Page 2 of 11 Pergolini et al. J Cancer Metastasis Treat 2018;4:33 I http://dx.doi.org/10.20517/2394-4722.2017.84

INTRODUCTION
Gastric carcinoma is the second leading cause of cancer-related death worldwide . The 5-year survival for
[1]
patients with gastric cancer is 30.6%. This decreases to 5.2% in patients with distant metastases, who comprise
35% of total patients with a diagnosis of gastric cancer . Liver metastases occur in 4%-14% of cases, while
[2,3]
[4,5]
around 15% of patients develop pulmonary metastases . Approximately 70% of patients are considered
ineligible for surgical treatment with curative intent at the time of presentation, due to the presence of locally
[2]
advanced disease or distant metastases . In addition, recurrence occurs in 30%-50% of cases, even after
curative R0 resection, mainly in the first two years after gastrectomy .
[6,7]
In this setting, neoadjuvant chemotherapy offers new perspectives in controlling systemic disease and down-
staging locally advanced gastric cancer prior to surgery . Moreover, several studies have reported promising
[8]
outcomes of surgical resection in patients with advanced gastric cancer with hepatic or pulmonary
metastases. However, the current guidelines are not consistent regarding the most appropriate treatment
strategy. The Japanese Gastric Cancer Association (JGCA) and the National Comprehensive Cancer
Network (NCCN) guidelines [9,10] do not recommend surgery with curative intent in these patients, leading
most patients with metastatic gastric cancer to receive palliative treatment. By contrast, the Guidelines
Committee of the JGCA recently reconsidered the treatment of potentially resectable M1 disease in highly
selected patients [9,11] . The definition of "stage IV" gastric cancer has varied greatly over the last few years;
the 7th and 8th versions [12,13] of the American Joint Committee on Cancer (AJCC)/Union for International
Cancer Control (UICC) 2010 tumor-node-metastasis (TNM) staging system clearly defined stage IV as any
[14]
lesion with hematogenous metastases (M1), while previous versions have also included "locally advanced"
cases, such as lesions with massive (> 15) lymph node metastases (N3) or with direct invasion of adjacent
structures (T4). The Japanese Classification of Gastric Cancer did not classify pancreatic head (station 13 and 17)
and para-aortic (station 16) lymph node metastases as "distant" (M1) up until the 3rd English Edition in
2011 , whereas western staging systems had accepted this concept long before . Which patients with stage IV
[14]
[15]
gastric cancer (either locally advanced or with M1) should be offered a surgical resection and the exact
survival benefit of this remain unclear.

This study sought to systematically review the literature in order to evaluate the outcomes of surgical
treatment for stage IV gastric cancer and to provide an update on the surgical treatment strategies for
this condition.

METHODS
A systematic literature search was carried out on October 9th, 2017. All references from 2002 to 2017 were
potentially eligible for inclusion in the study. The following search strategy was used in PubMed, MEDLINE
and Embase: ((((((((((“gastric cancer”) OR “gastric carcinoma”) OR “gastric neoplasm”) OR “stomach cancer”)
OR “stomach carcinoma”) OR “stomach neoplasm”)) AND ((“metastatic”) OR metastas*)) AND ((((“liver”)
OR “hepatic”) OR “lung”) OR “pulmonary”)) AND (((((“surgery”) OR “resection”) OR “palliative surgery”)
OR “palliative gastrectomy”) OR “surgical”)).

A title search was conducted with title review of all identified references. Studies deemed unrelated to study
aims were excluded. Abstracts for the remaining studies were retrieved and screened for relevance. Full
papers were retrieved for all abstracts deemed potentially eligible. Full papers underwent authors’ review
and assessment of inclusion/exclusion criteria. Any disagreement during the search and selection process
was resolved by consensus.

Inclusion criteria
• Papers presenting data regarding liver and pulmonary metastasis resection in patients with gastric cancer,
without evidence of peritoneal metastases or metastases to other organs.