151P - Relationship between depth of response and early tumor shrinkage with overall survival in advanced pancreatic cancer

Background

Depth of response (DpR) and early tumor shrinkage (ETS) are established predictors of overall survival (OS) in colorectal and gastric cancer; however, data for pancreatic cancer (PC) are limited.

Methods

This study was conducted as part of two multicenter retrospective studies (NAPOLEON and NAPOLEON-2) of patients (pts) with measurable advanced PC tumors. Cohort 1 included 292 pts treated with gemcitabine/nab-PTX (GnP, 184 pts) and FOLFIRINOX (FFX, 108 pts) as first-line chemotherapy, and Cohort 2 included 88 pts treated with nanoliposomal irinotecan, fluorouracil and folinic acid as second-line chemotherapy. DpR was defined as the maximum tumor shrinkage percentage on imaging compared with the pre-treatment level. Pts were divided by DpR into three groups: control (Group A), responder (Group B), and deep responder (Group C). ETS was defined as ≥20% reduction from the start of treatment to the second evaluation.

Results

In Cohort 1, DpR was −2.3 to +1550% in Group A, −28.6 to −2.5% in Group B, and −100.0 to −28.6% in Group C. The baseline C-reactive protein/albumin ratio differed significantly by group (p=0.04). The median OS (mOS) was significantly longer in Group C (17.2 months) and Group B (11.5 months) than in Group A (8.4 months), (hazard ratio [HR], 95% confidence interval [CI]: 0.30, 0.22–0.42, p<0.01; and 0.58, 0.43–0.79, p<0.01, respectively). The mOS was also significantly longer in the ETS group overall (HR 0.46, 95% CI 0.35–0.61, p<0.01) and in both the GnP and FFX subgroups. In Cohort 2, DpR was +18.4 to +128.6% in Group A, −2.9 to +17.9% in Group B, and −80.0 to −3.2% in Group C. The baseline prevalence of ascites differed significantly by group (p=0.04). The mOS was significantly longer in Group C (10.9 months) than in Group A (4.6 months; HR 0.33, 95% CI 0.17–0.65, p<0.01), but mOS in Group B (6.8 months) did not differ significantly from Group A (p=0.10).

Conclusions

This is the first report that DpR and ETS might be predictors of OS in pts with PC on standard chemotherapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.