GASTRIC CANCER: OPTIMIZATION OF MANAGEMENT P0050 Oleg Kshivets Surgery Department, Siauliai Public Hospital, Lithuania

OBJECTIVE: Search of best treatment plan for gastric cancer (GC) patients (GCP) was realized.

METHODS: In trial (1975-2010) the data of consecutive 612 GCP after complete gastrectomies (R0) (age=56.6±9.4 years; male=422, female=190; tumor diameter: D=5.7±3.0 cm; distal gastrectomies=364, proximal gastrectomies=132, total gastrectomies=116, combined procedures with resection of pancreas, liver, diaphragm, colon, splenectomy, etc=209; only surgery-S=505, adjuvant chemoimmunotherapy-AT=107: 5FU+thymalin/taktivin; T1=168, T2=182, T3=127, T4=135; N0=303, N1=84, N2=225; G1=175, G2=104, G3=333) was reviewed. Variables selected for 5- year survival (5YS) study were input levels of blood, biochemic and hemostatic factors, sex, age, TNMG, D. Survival curves were estimated by Kaplan-Meier method. Differences in curves between groups were evaluated using a log-rank test. Neural networks computing, Cox regression, clustering, structural equation modeling, Monte Carlo and bootstrap simulation were used to determine any significant regularity.

RESULTS: For total of 612 GCP overall life span (LS) was 2015.5±2208.5 days and cumulative 5YS reached 50.9%, 10 years – 44.2%, 20 years – 32.6%. 222 GCP (LS=4316.2±2214.9 days) lived more than 5 years without GC progressing. 287 GCP (LS=694.1±372.4 days) died because of GC during first 5 years after surgery. 5YS of GCP was superior significantly after AT (69.6%) compared with S (48.9%) (P=0.005 by log-rank test). Cox modeling displayed that 5YS significantly depended on: phase transition (PT) “early-invasive GC”, PT N0-N12, T1-4, GC growth, blood cell subpopulations, cell ratio factors (ratio between blood cells and GC cells), ESS, prothrombin index, bilirubin, chlorides (P=0.000-0.036). Neural networks computing, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT “early-invasive GC” (rank=1), PT N0-N12 (rank=2), AT, T1-4, G1-3, cell ratio factors. Correct prediction of 5YS was 100% by neural networks computing.

CONCLUSION: Optimal treatment strategies for GCP are: 1) screening and early detection of GC; 2) availability of experienced surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymphadenectomy for completeness; 4) precise prediction; 5) adjuvant chemoimmunotherapy for GCP with unfavorable prognosis.

Survival FunctionComplete Censored

Survival of Gastric Cancer Patients after Complete Gastrectomies, n=612

Years after Gastrectomies

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Cumulative Proportion Surviving (Kaplan-Meier)Complete Censored

P=0.000 by Log-Rank Test

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Invasive GCP, n=515 Early GCP, n=97

Cumulative Proportion Surviving (Kaplan-Meier)Complete Censored

P=0.000 by Log-Rank Test

Years after Gastrectomies

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1.0GCP with N1-2, n=309 GCP with N0, n=303

Cumulative Proportion Surviving (Kaplan-Meier)Complete Censored

P=0.005 by Log-Rank Test

Years after Gastrectomies

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GCP without Adjuvant CHIT, n=505 GCP after Adjuvant CHIT, n=107