The association of adjuvant therapy with survival at the population level following pancreatic adenocarcinoma resection

Characteristics Associated With Survival in Surgically Nonresected Pancreatic Adenocarcinoma in the Military Health System

OBJECTIVES

Pancreatic cancer is often diagnosed at advanced stages with high-case fatality. Many tumors are not surgically resectable. We aimed to identify features associated with survival in patients with surgically nonresected pancreatic cancer in the Military Health System.

METHODS

We used the Military Cancer Epidemiology database to identify the Department of Defense beneficiaries aged 18 and older diagnosed with a primary pancreatic adenocarcinoma between January 1998 and December 2014 who did not receive oncologic surgery as treatment. We used Cox Proportional Hazard regression with stepwise procedures to select the sociodemographic and clinical characteristics related to 2-year overall survival, expressed as adjusted hazard ratios (aHR) and 95% CIs.

RESULTS

Among 1148 patients with surgically nonresected pancreatic cancer, sex, race-ethnicity, marital status, and socioeconomic indicators were not selected in association with survival. A higher comorbidity count (aHR 1.30, 95% CI: 1.06-1.59 for 5 vs. 0), jaundice at diagnosis (aHR 1.57, 95% CI: 1.33-1.85 vs. no), tumor grade G3 or G4 (aHR 1.32, 95% CI: 1.05-1.67 vs. G1/G2), tumor location in pancreas tail (aHR 1.49, 95% CI: 1.22-1.83 vs. head) or body (aHR 1.30, 95% CI: 1.04-1.62 vs. head), and metastases were associated with survival. Patients receiving chemotherapy (aHR 0.66, 95% CI: 0.57-0.76) had better survival compared with no treatment.

CONCLUSIONS

In a comprehensive health system, sociodemographic characteristics were not related to survival in surgically nonresected pancreatic cancer. This implicates access to care in reducing survival disparities in advanced pancreatic cancer and emphasizes the importance of treating patients based on clinical features.

Patterns of Adjuvant Chemotherapy Use and Association With Survival in Adults 80 Years and Older With Pancreatic Adenocarcinoma

IMPORTANCE

Patients 80 years and older with pancreatic ductal adenocarcinoma (PDAC) have not consistently received treatments that have established benefits in younger older adults (aged 60-79 years), yet patients 80 years and older are increasingly being offered surgery. Whether adjuvant chemotherapy (AC) provides additional benefit among patients 80 years and older with PDAC following surgery is not well understood.

OBJECTIVE

To describe patterns of AC use in patients 80 years and older following surgical resection of PDAC and to compare overall survival between patients who received AC and those who did not.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study among patients 80 years or older diagnosed with PDAC (stage I-III) between 2004 to 2016 who underwent a pancreaticoduodenectomy at hospitals across the US reporting to the National Cancer Database.

EXPOSURES

AC vs no AC 90 days following diagnosis of PDAC.

MAIN OUTCOMES AND MEASURES

The proportion of patients who received AC was assessed over the study period. Overall survival was compared between patients who received AC and those who did not using Kaplan-Meier estimates and multivariable Cox proportional hazards regression. A landmark analysis was performed to address immortal time bias. A propensity score analysis was performed to address indication bias. Subgroup analyses were conducted in node-negative, margin-negative, clinically complex, node-positive, and margin-positive cohorts.

RESULTS

Between 2004 and 2016, 2569 patients 80 years and older (median [IQR] age, 82 [81-84] years; 1427 were women [55.5%]) underwent surgery for PDAC. Of these patients, 1217 (47.4%) received AC. Findings showed an 18.6% (95% CI, 8.0%-29.0%; P = .001) absolute increase in the use of AC among older adults who underwent a pancreaticoduodenectomy comparing rates in 2004 vs 2016. Receipt of AC was associated with a longer median survival (17.2 months; 95% CI, 16.1-19.0) compared with those who did not receive AC (12.7 months; 95% CI, 11.8-13.6). This association was consistent in propensity and subgroup analyses. In multivariable analysis, receipt of AC (hazard ratio [HR], 0.72; 95% CI, 0.65-0.79; P < .001), female sex (HR, 0.88; 95% CI, 0.80-0.96; P < .001), and surgery in the more recent time period (≥2011) (HR, 0.90; 95% CI, 0.82-0.99; P = .02) were associated with a decreased hazard of death. An increased hazard of death was associated with higher pathologic stage (stage II: HR, 1.68; 95% CI, 1.43-1.97; P < .001; stage III: HR, 2.39; 95% CI, 1.88-3.04; P < .001), positive surgical margins (HR, 1.49; 95% CI, 1.34-1.65; P < .001), length of stay greater than median (10 days) (HR, 1.17; 95% CI, 1.07-1.28; P < .001), and receipt of oncologic care at a nonacademic facilities (Community Cancer Program: HR, 1.20; 95% CI, 1.07-1.35; P < .001; Integrated Network Cancer Program: HR, 1.25; 95% CI, 1.07-1.46; P < .001).

CONCLUSIONS AND RELEVANCE

In this cohort study, the use of AC among patients who underwent resection for PDAC increased over the study period, yet it still was administered to fewer than 50% of patients. Receipt of AC was associated with a longer median survival.

Economic Analysis of Adjuvant Chemoradiotherapy Compared with Chemotherapy in Resected Pancreas Cancer

BACKGROUND

Population-based survival and costs of pancreas adenocarcinoma patients receiving adjuvant chemoradiation and chemotherapy following pancreaticoduodenectomy are poorly understood.

METHODS

This retrospective cohort study used linked administrative and pathological datasets to identify all patients diagnosed with pancreas adenocarcinoma and undergoing pancreaticoduodenectomy in Ontario between April 2004 and March 2014, who received postoperative chemoradiation or chemotherapy. Stage and margin status were defined by using pathology reports. Kaplan-Meier and Cox proportional hazards regression survival analyses were used to determine associations between adjuvant treatment approach and survival, while stratifying by margin status. Median overall health system costs were calculated at 1 and 3 years for chemoradiation and chemotherapy, and differences were tested using the Kruskal-Wallis test.

RESULTS

Among 709 patients undergoing pancreaticoduodenectomy for pancreas cancer during the study period, the median survival was 21 months. Median survival was 19 months for chemoradiation and 22 months for chemotherapy. Patients receiving chemoradiation were more likely to have positive margins: 47.7% compared with 19.2% in chemotherapy. After stratifying by margin status and controlling for confounders, adjusted hazard ratio of death were not statistically different between chemotherapy and chemoradiation [margin positive, hazard ratio (HR) = 0.99, 95% confidence interval (CI) = 0.88-1.27; margin negative, HR 0.95, 95% CI 0.91-1.18]. Overall 1-year health system costs were significantly higher for chemoradiation (USD $70,047) than chemotherapy (USD $54,005) (p ≤ 0.001).

CONCLUSIONS

Chemotherapy and chemoradiation yielded similar survival, but chemoradiation resulted in higher costs. To create more sustainable healthcare systems, both the efficacy and costs of therapies should be considered.

The effect of postoperative gemcitabine on overall survival in patients with resected pancreatic cancer: A nationwide population-based Danish register study

Background: Adjuvant chemotherapy following curative resection is the standard treatment for pancreatic adenocarcinoma (PC). Randomized clinical trials using gemcitabine have shown a median overall survival (mOS) of 2 years and a 5-year survival rate of 15-20%. However, the effect of gemcitabine outside these trials is less clear. We examined the effect of postoperative gemcitabine on survival in an unselected cohort of patients receiving curative resection for PC in Denmark during a five-year period. Material and methods: From 1 May 2011 to 30 April 2016, 731 patients treated with curative resection were identified in the Danish Pancreatic Cancer Database (DPCD). Thirty patients died within 10 weeks postoperatively; 78 received other regimens or preoperative chemotherapy and were excluded. Of the remaining 623 patients, the chemotherapy (CT) group (n = 409, 66%) received gemcitabine within 10 weeks after resection, whereas the non-chemotherapy (NCT) group (n = 214, 34%) did not receive CT within 10 weeks. Results: CT patients were slightly younger than NCT patients but did not otherwise differ in baseline characteristics. The CT group showed a mOS of 24 months (95% CI; 21-27) and a 5-year survival rate of 22% (95% CI; 17-27); the NCT group had a mOS of 22 months (95% CI; 16-26, p = .27) and a 5-year survival rate of 26% (95% CI; 19-34, p = .66). Most patients (415/623) had lymph node metastases. Of these patients, those in the CT group (n = 280) had significantly longer mOS [20 months (95% CI; 18-24)] than those in the NCT group (n = 135) [14 months (95% CI; 11-17)]. Conclusions: In this national Danish cohort of PC patients undergoing resection between 2011 and 2016, the survival after postoperative gemcitabine was similar to that reported in previous clinical trials. However, the survival advantage of postoperative gemcitabine was limited to patients with lymph node metastases.

Laparoscopic distal pancreatectomy for pancreatic cancer is safe and effective

PURPOSE

To compare the short-term and oncologic outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) undergoing laparoscopic distal pancreatectomy (LDP) and open distal pancreatectomy (ODP).

METHODS

Consecutive cases of distal pancreatectomy (DP) (n = 422) were reviewed at a single high-volume institution over a 10-year period (2005-2014). Inclusion criteria consisted of any patient with PDAC by surgical pathology. Ninety-day outcomes were monitored through a prospectively maintained pancreatic resection database. The Social Security Death Index was used for 5-year survival. Two-way statistical analyses were used to compare categories; variance was reported with standard error of the mean; * indicates P value <0.05.

RESULTS

Seventy-nine patients underwent DP for PDAC. Thirty-three underwent LDP and 46 ODP. There were no statistical differences in demographics, BMI, and ASA classification. Intraoperative and surgical pathology variables were comparable for LDP versus ODP: operative time (3.9 ± 0.2 vs. 4.2 ± 0.2 h), duct size, gland texture, stump closure, tumor size (3.3 ± 0.3 vs. 4.0 ± 0.4 cm), lymph node harvest (14.5 ± 1.1 vs. 17.5 ± 1.2), tumor stage (see table), and negative surgical margins (77 vs. 87%). Patients who underwent LDP experienced lower blood loss (310 ± 68 vs. 597 ± 95 ml; P = 0.016*) and required fewer transfusions (0 vs. 13; P = 0.0008*). Patients who underwent LDP had fewer positive lymph nodes (0.8 ± 0.2 vs. 1.6 ± 0.3; P = 0.04*) and a lower incidence of type C pancreatic fistula (0 vs. 13%; P = 0.03*). Median follow-up for all patients was 11.4 months. Long-term oncologic outcomes revealed similar outcomes including distant or local recurrence (30 vs. 52%; P = 0.05) and median survival (18 vs. 15 months), as well as 1-year (73 vs. 59%), 3-year (22 vs. 21%), and 5-year (20 vs. 15%) survival for LDP and ODP, respectively.

CONCLUSIONS

The results of this series suggest that LDP is a safe surgical approach that is comparable from an oncologic standpoint to ODP for the management of pancreatic adenocarcinoma.