Background: Preoperative therapy has gained wide interest in advanced gastric cancer patients due to its potential advantages of improved disease control. Selection of high risk patients based on preoperative staging is crucial to choose the candidates for neoadjuvant therapy.
Methods: Our institutional review board approved this retrospective study and waived the requirement for patient consent. We searched 394 advanced gastric cancer patients (pT2-4) who underwent curative resection in 2010 without neoadjuvant therapies. Two abdominal radiologists independently reviewed the preoperative CT including tumor depth on CT (CT-tumor depth), which was categorized as follows: intramural, minimal extramural(<1mm), spiculated extramural(≥1mm) and nodular extramural infiltration. The impact of clinicoradiologic factors on disease recurrence and disease free survival (DFS) was evaluated. Recursive partitioning analysis was performed to suggest prediction models for recurrence.
Results: Of total 394 patients, 86 patients (21.8%) experienced recurrence. Spiculated (≥1mm) and nodular extramural tumor infiltration and CT size of 5-10cm were independent predictors of disease recurrence and significantly associated with worse DFS. Lymph node involvement on CT was not significantly associated with patient outcome. Among patients with same pT4a stage, the recurrence rate rises and DFS gets worse as the extramural tumor infiltration progresses (P < 0.001). The prediction model for recurrence revealed that size and CT-tumor depth were the two major discriminating factors.
Conclusion: CT-tumor depth and size could be used as independent predictors for prognosis. Preoperative CT can be used for prognostic stratification to select high risk patients for whom neoadjuvant therapies might be considered.