Efficacy of platinum chemotherapy agents in the adjuvant setting for adenosquamous carcinoma of the pancreas

Abstract

Background: Pancreatic adenosquamous carcinoma (PASC) accounts for only 1-4% of all exocrine pancreatic cancers and carries a particularly poor prognosis. This retrospective study was performed to determine whether inclusion of a platinum agent as part of adjuvant therapy is associated with improved survival in patients with resected PASC.

Methods: Records of all patients who underwent pancreatic resection at Johns Hopkins Hospital from 1986 to 2012 were reviewed to identify those with PASC. Multivariable Cox proportional hazards modeling was used to assess for significant associations between patient characteristics and survival.

Results: In total, 62 patients (1.1%) with resected PASC were identified among 5,627 cases. Median age was 68 [interquartile range (IQR), 57-77] and 44% were female. Multivariate analysis revealed that, among all patients (n=62), the following factors were independently predictive of poor survival: lack of adjuvant therapy [hazard ratio (HR) =3.6; 95% confidence interval (CI), 1.8-7.0; P<0.001], margin-positive resection (HR =3.5; 95% CI, 1.8-6.8; P<0.001), lymph node involvement (HR =3.5; 95% CI, 1.5-8.2; P=0.004), and age (HR =1.0; 95% CI, 1.0-1.1; P=0.035). There were no significant differences between patients who did and did not receive adjuvant therapy following resection (all P>0.05). A second multivariable model included only those patients who received adjuvant therapy (n=39). Lack of inclusion of a platinum agent in the adjuvant regimen (HR =2.4; 95% CI, 1.0-5.8; P=0.040) and larger tumor diameter (HR =1.3; 95% CI, 1.0-1.6; P=0.047) were independent predictors of inferior survival.

Conclusions: Addition of a platinum agent to adjuvant regimens for resected PASC may improve survival among these high-risk patients, though collaborative prospective investigation is needed.

Keywords: Adenosquamous carcinoma; adjuvant therapy; pancreatic cancer; platinum chemotherapy.

Figure 1

(A) Kaplan-Meier plot of survival for all patients included in the study (n=62); (B) Kaplan-Meier plot of survival stratified by whether patients received adjuvant therapy following tumor resection (blue curve) or not (red curve). Vertical tick marks represent censored patients. The P value is derived from univariate Cox regression analysis.

Figure 2

(A) Kaplan-Meier plot of survival for all patients who received adjuvant therapy following tumor resection (n=39); (B) Kaplan-Meier plot of survival stratified by whether patients received ≥2 cycles of a platinum chemotherapy agent as part of their adjuvant therapy regimen (blue curve) or not (red curve). Vertical tick marks represent censored patients. The P value is derived from univariate Cox regression analysis.