TOPLINE:
a multicenter cohort study found. Several factors, including treatment type and tumor features, influenced the outcomes.
METHODOLOGY:
- Preoperative chemo(radio)therapy is increasingly used in patients with localized pancreatic adenocarcinoma and may improve the chance of a pathologic complete response. Achieving a pathologic complete response is associated with improved overall survival.
- However, the evidence on pathologic complete response is based on large national databases or small single-center series. Multicenter studies with in-depth data about complete response are lacking.
- In the current analysis, researchers investigated the incidence and factors associated with pathologic complete response after preoperative chemo(radio)therapy among 1758 patients (mean age, 64 years; 50% men) with localized pancreatic adenocarcinoma who underwent resection after two or more cycles of chemotherapy (with or without radiotherapy).
- Patients were treated at 19 centers in eight countries. The median follow-up was 19 months. Pathologic complete response was defined as the absence of vital tumor cells in the patient’s sampled pancreas specimen after resection.
- Factors associated with overall survival and pathologic complete response were investigated with Cox proportional hazards and logistic regression models, respectively.
TAKEAWAY:
- Researchers found that the rate of pathologic complete response was 4.8% in patients who received chemo(radio)therapy before pancreatic cancer resection.
- Having a pathologic complete response was associated with a 54% lower risk for death (hazard ratio, 0.46). At 5 years, the overall survival rate was 63% in patients with a pathologic complete response vs 30% in patients without one.
- More patients who received preoperative modified FOLFIRINOX achieved a pathologic complete response (58.8% vs 44.7%). Other factors associated with pathologic complete response included tumors located in the pancreatic head (odds ratio [OR], 2.51), tumors > 40 mm at diagnosis (OR, 2.58), partial or complete radiologic response (OR, 13.0), and normal(ized) serum carbohydrate antigen 19-9 after preoperative therapy (OR, 3.76).
- Preoperative radiotherapy (OR, 2.03) and preoperative stereotactic body radiotherapy (OR, 8.91) were also associated with a pathologic complete response; however, preoperative radiotherapy did not improve overall survival, and preoperative stereotactic body radiotherapy was independently associated with worse overall survival. These findings suggest that a pathologic complete response might not always reflect an optimal disease response.
IN PRACTICE:
Although pathologic complete response does not reflect cure, it is associated with better overall survival, the authors wrote. Factors associated with a pathologic complete response may inform treatment decisions.
SOURCE:
The study, with first author Thomas F. Stoop, MD, University of Amsterdam, the Netherlands, was published online on June 18 in JAMA Network Open.
LIMITATIONS:
The study had several limitations. The sample size and the limited number of events precluded comparative subanalyses, as well as a more detailed stratification for preoperative chemotherapy regimens. Information about patients’ race and the presence of BRCA germline mutations, both of which seem to be relevant to the chance of achieving a major pathologic response, was not collected or available.
DISCLOSURES:
No specific funding was noted. Several coauthors have industry relationships outside of the submitted work.
A version of this article first appeared on Medscape.com.