Treatment and Survival for Unresectable Pancreatic Adenocarcinoma in Queensland, Australia, 2018–2022

Background

The three main chemotherapy regimens for people with unresectable pancreatic cancer include modified FOLFIRINOX (comprising oxaliplatin, irinotecan and fluorouracil, denoted mFFX), gemcitabine with nab-paclitaxel (GnP), and single-agent gemcitabine (GEM). We explored characteristics associated with the type of chemotherapy and variations in survival.

Materials and Methods

Records for people with unresected pancreatic adenocarcinoma between 2018 and 2022 treated with first-line mFFX, GnP or GEM were extracted from the population-based Queensland Oncology Repository. Multivariable Poisson models were fitted to determine factors associated with each type of chemotherapy, expressed as relative likelihoods (RLs). Variations in three-year observed survival were assessed using flexible parametric modelling and reported in terms of adjusted excess mortality hazard ratios (HRs).

Results

Of the 766 people in the study cohort, 59% were treated with GnP, 27% with mFFX, and 15% with GEM. After adjustment, treatment with mFFX was far more likely in selected private facilities compared to public hospitals (RL = 2.33, 95% CI 1.84–2.96), whereas the GEM regimen was used more often for those from outer regional/remote areas (RL = 2.20 compared to people living in major cities, 95% CI 1.45–3.34; p < 0.001). Three-year survival was very poor at just 5% (95% CI 3%–7%). Nonetheless, adjusted mortality was higher for GnP (HR = 1.30, 95% CI 1.07–1.59) and GEM (HR = 1.53, 95% CI 1.17–2.01) compared to mFFX.

Conclusions

Apart from clinical indications, there should be equity in the treatment received for unresectable pancreatic cancer. Our results suggest, however, that where a person lives and the type of facility at which they are treated may influence their chemotherapy regimen.