Cytoreductive Gastrectomy After Systemic Therapy Versus Systemic Therapy Alone For Limited Metastasis Gastric Cancer

Prior treatment

• Uncontrolled concurrent illness including but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia
• Prior surgical treatment for GC involving resection

Other illness

• Past history of malignancy other than gastric cancer diagnosed in the last 5 years except for basal cell carcinoma of skin or preinvasive cancer of cervix
• Significant disease or conditions which, in the investigator's opinion, would exclude patient from the study
• Psychiatric illness/social situations that would limit compliance with study requirements
• Clinical or radiological progression during 1st line systemic treatment
  • Patients with radiological progression of LM (determined by RECIST criteria) to be excluded as disease is likely not responding well to 1st line treatment.
  • Patients with clinical progression of LM as defined by increasing ascites requiring intervention (ascitic tap/drain, hospital admission etc) or causing significant symptoms to the patient (tense distended abdomen, early satiety, shortness of breath etc).
  • Ascites volume as a reflection of disease control is difficult to assess and quantify or a reflection of disease progression. (15)
• Any patient deemed unresectable or requiring extensive resection beyond procedure approved in the study protocol
  • PCI \> 12
  • Extensive bowel / mesentery involvement requiring \>2 separate / non-contiguous small or large bowel resections in addition to the gastrectomy
  • Involvement of the head of pancreas or bile duct
  • PM or nodal disease in the hepatoduodenal ligament
  • Involvement of major vascular structures
  • Involvement of esophagus precluding a reasonable chance of R0 resection by transhiatal approach Withdrawal Criteria

Age

• Patients in the reproductive age who declined to use an adequate means of contraception

Other

• Any extra-abdominal metastasis at diagnosis or during systemic treatment.
• Pregnant and lactating females
• Patient decides to withdraw from the study, or
• The investigator concludes that it is in the patient's best interest to discontinue study treatment.

• Age 18-75
• GCLM detected on surgical exploration and demonstrated by histology or cytology
• Localized peritoneal carcinomatosis (P1 or P2 score), according to the classification of the Japanese Research Society for Gastric Cancer
• Liver metastasis lesions of maximum diameter ≤5 cm
• Para-aortic lymph node metastasis below the coeliac axis or above the inferior mesenteric artery (lymph node 16a1/b2 of maximum diameter≥1cm)
• Bilateral or unilateral Krukenberg tumors were allowed and considered 1 incurable organ site
• The accepted patient has two metastases
• Baseline Eastern Cooperative Oncology Group (ECOG) performance status \< 1
• Basic laboratory tests demonstrating adequate bone marrow function (neutrophil count \> 1500mm3, haemoglobin \> 8g/dL, platelet count \> 100,000/mm3), adequate liver function (bilirubin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) within upper limits of normal), adequate renal function (serum creatinine within the upper limit of normal)
• Expected survival \> 3 months
• Able to tolerate enteral nutrition and adequate mental capacity to give informed consent
• Completed 4 cycles of first-line standard-of systemic therapy
• Repeat diagnostic laparoscopy after first-line treatment prior to randomization demonstrating feasible resection.
  • Eligibility criteria for resection \& extent of proposed resection
• Staging scans (cross-sectional imaging) demonstrating no extra metastases (lung, bone,...)
• Cross-sectional imaging demonstrating no local progression of PM
• PCI score \<12
• Cytology +ve alone (no gross PM) permissible for enrolment
• Feasible R0 resection (reasonable chance of negative margins on histology)
• Feasible D1, D1+ or D2 lymphadenectomy