Utility of endoscopic ultrasonography elastography as a predictive tool for post-treatment recurrence of resectable pancreatic cancer treated with neoadjuvant and adjuvant chemotherapy: a retrospective study in Japan

BACKGROUND: Post-treatment recurrence frequently occurs even in patients with resectable pancreatic cancer (PC) who receive neoadjuvant chemotherapy (NAC), surgery, and adjuvant chemotherapy (AC). This study aimed to evaluate whether endoscopic ultrasonography elastography (EUS-EG) of PC lesions is useful in predicting post-treatment recurrence in such patients. METHODS: We retrospectively analyzed 44 of 164 consecutive patients with resectable PC who underwent NAC, surgery, and AC after EUS-EG. The endpoints were associations between EUS-EG stiffness classification (soft/stiff) and pathological response, post-treatment recurrence, and recurrence-free survival (RFS). RESULTS: In the soft vs. stiff groups, the median pathological response rate was 30% (20%-75%) vs. 20% (10%-65%) (p=0.022), post-treatment recurrence rate was 25% vs. 59% (p=0.042), and the median RFS was NR (not reached) days vs. 683 days (p=0.039). In the multivariate analysis, stiffness classification was the only factor significantly associated with RFS (hazard ratio, 4.2; p=0.025). CONCLUSIONS: To the best of our knowledge, this is the first study to indicate that EUS-EG stiffness classification may predict recurrence in resectable PC treated with NAC, surgery, and AC. Patients with stiff lesions on EUS-EG tend to have a higher risk of recurrence and may require more careful post-treatment follow-up and novel treatment strategies.