Trajectory of care and use of multimodality therapy in older patients with pancreatic adenocarcinoma

Abstract

Introduction: Multimodality therapy with chemotherapy and operative resection is recommended for patients with locoregional pancreatic cancer but is not received by many patients.

Objective: To evaluate patterns in the use and timing of chemotherapy and resection and factors associated with receipt of multimodality therapy in older patients with locoregional pancreatic cancer.

Methods: We used Surveillance, Epidemiology, and End Results-linked Medicare data (1992-2007) to identify patients with locoregional pancreatic adenocarcinoma. Multimodality therapy was defined as receipt of both chemotherapy and pancreatic resection. Logistic regression was used to determine factors independently associated with receipt of multimodality therapy. Log-rank tests were used to identify differences in survival for patients stratified by type and timing of treatment.

Results: We identified 10,505 patients with pancreatic adenocarcinoma. 5,358 patients (51.0%) received either chemotherapy or surgery, with 1,166 patients (11.1%) receiving both modalities. Resection alone was performed in 1,138 patients (10.8%), and chemotherapy alone was given to 3,054 (29.1%) patients. In patients undergoing resection as the initial treatment modality, 49.4% never received chemotherapy; 97.4% of patients who underwent chemotherapy as the initial treatment modality never underwent resection. The use of multimodality therapy increased from 7.4% of patients in 1992-1995 to 13.8% of patients in 2004-2007 (P < .0001). The 2-year survival was 41.0% for patients receiving multimodality therapy, 25.1% with resection alone, and 12.5% with chemotherapy alone (P < .0001). Of the patients receiving multimodality therapy, chemotherapy was delivered in the adjuvant setting in 93.1% and in the neoadjuvant setting in 6.9%, with similar 2-year survival with either approach (neoadjuvant vs adjuvant, 46.9% vs 40.6%; P = .16). Year of diagnosis, white race, less comorbidity, and no vascular invasion were independently associated with receipt of multimodality therapy.

Conclusion: Only half of older patients with locoregional pancreatic cancer receive any treatment, and fewer than one quarter of treated patients receive multimodality therapy. Nearly all patients receiving chemotherapy as the initial treatment modality did not undergo resection, whereas half of those undergoing resection first received chemotherapy. When multimodality therapy is used, the vast majority of patients had chemotherapy in the adjuvant setting with a similar survival, regardless of approach.

Figure 1

Cohort selection criteria. Only patients with histologically confirmed, locoregional pancreatic adenocarcinoma as their first primary cancer diagnosis were included. Patients without Medicare Parts A and B for 6 months before and after diagnosis, or until death, were excluded. All patients were followed for two years. N=10,505.

Figure 2

Figure 2A. Management of older patients with locoregional pancreatic cancer. Nearly half of all patients received no treatment. Only 11.1% of the overall cohort received multimodality therapy. Over 97% of patients receiving chemotherapy as the initial treatment modality did not receive surgery, while 51% of patients who received surgery as the initial treatment modality did not receive chemotherapy. The proportion of patients receiving radiation therapy for each group is also listed. Figure 2B. Management of older patients with locoregional pancreatic cancer and no vascular invasion. Of these patients with potentially treatable pancreatic cancer (N=8,253), only 51% received any treatment, and only 13.1% received multimodality therapy. Over 97% of patients receiving chemotherapy as the initial treatment modality did not receive surgery, while 51% of patients who received surgery as the initial treatment modality did not receive chemotherapy. The proportion of patients receiving radiation therapy for each group is also listed.

Figure 3

Trends in the use of multimodality therapy in older patients with locoregional pancreatic adenocarcinoma, 1992–2007. The use of multimodality therapy increased over time from 7.4% of patients in 1992–1995 compared to 13.8% of patients in 2004–2007 (p<0.0001); this increase was more pronounced for patients without vascular invasion (7.7% to 17.4%, p<0.0001). Neoadjuvant therapy use also increased over this same time period (2.5% vs. 9.4%, p=0.0095).

Figure 4

Figure 4A. Kaplan-Meier two-year survival curves in patients with locoregional pancreatic adenocarcinoma (N =10,505) by treatment group: multimodality therapy, surgery alone, chemotherapy alone, and no treatment. Survival improved with multimodality therapy compared to the other groups (41.0% vs. 29.0% vs. 12.5% vs. 5.1%, p<0.0001). Patients were censored at loss of follow-up and at two years. Figure 4B. Kaplan-Meier estimate of two-year survival for patients who received multimodality therapy (N=1,166). There were no differences in survival between a neoadjuvant and adjuvant approach to chemotherapy (46.9% vs. 40.6%, p=0.16). Patients were censored at loss of follow-up and at two years.