External radiation is associated with limited improvement in overall survival in resected margin-negative stage IIB pancreatic adenocarcinoma

The benefit of adjuvant radiotherapy on overall survival in resected stage I to II pancreatic cancer: A propensity-adjusted analysis

BACKGROUND

The survival time of patients with early pancreatic cancer (PC) is still disappointing, even after surgical resection. PC has an extremely poor prognosis. Herein, we aimed to investigate the survival effect of postoperative radiotherapy (PORT) on resected stage I to II PC.

MATERIAL AND METHODS

A large eligible sample of patients was identified from 2010 to 2015 from the Surveillance, Epidemiology, and End Results (SEER) registry. Survival analysis was conducted to evaluate the efficiency of PORT. Propensity score matching (PSM) analysis was used to reduce selection bias and to make the groups comparable.

RESULTS

A total of 3219 patients with resected stage I to II PC was included after rigid screening. The median overall survival (OS) was 26 months with PORT (n = 1055) versus 21 months with non-PORT (n = 2164) before matching (p<0.001). By multivariable analysis, PORT remained a favorable prognostic predictor for OS. In PSM analysis, receiving PORT was associated with improved OS (median, 26 months vs. 23 months; at 2 years, 51.7% vs. 46.7%; at 5 years, 23.3% vs. 17.4% (P = 0.006). After further meticulous exploration, only the stage IIB subgroup benefited from PORT (p<0.001). This result was due to the positive lymph node state (N+), whose mortality risk was cut by 23.4% (p<0.001) by PORT.

CONCLUSION

Addition of PORT to the treatment of patients with resected stage I to II PC conveys a survival benefit, particularly among those with N-positive or stage IIB disease.

Adjuvant chemotherapy versus chemoradiation in high-risk pancreatic adenocarcinoma: A propensity score-matched analysis

PURPOSE

The American Society of Clinical Oncology guidelines recommend adjuvant chemoradiation (ACR) for margin-positive (R1) and/or node-positive (N+) pancreatic cancers. Our goal was to investigate if there is evidence of superiority of adjuvant chemoradiation (ACR) over adjuvant chemotherapy (AC).

METHODS

We utilized data from the National Cancer Database (NCDB) for N+ and/or R1 pancreatic adenocarcinoma patients diagnosed from 2004 to 2012 who underwent ACR or AC. Patients who received neoadjuvant radiation, no adjuvant treatment, or adjuvant radiation alone were excluded. Propensity score nearest-neighbor 1:1 matching (PSM) was performed between ACR and AC groups based on age, sex, race, insurance, year of diagnosis, comorbidities, tumor site and size, T-stage, nodal status, margin status, grade, and treatment facility. Primary outcome was overall survival (OS).

RESULTS

A total of 8297 patients were eligible. After PSM, two well-balanced groups of 3244 patients each were analyzed. ACR resulted in superior OS compared with AC alone (Hazard ratio [HR] 0.83, 95% CI 0.79-0.87; median OS 22 vs 19 months, P < .0001). Subset analyses demonstrated OS benefit of ACR compared with AC in N+, R0 patients (HR: 0.82, 95% CI 0.77-0.88; Median OS 24 vs 20 months, P < .001) as well as N+, R1 patients (HR: 0.77, 95% CI 0.68-0.87; Median OS 17 vs 15 months, P < .001); but not in node-negative, R1 patients (HR: 1.12, 95% CI 0.84-1.48; Median OS 18 vs 22 months, P = .63).

CONCLUSION

The addition of radiation to AC was associated with a clinically small but meaningful increase in survival of patients undergoing curative-intent pancreatic resections. This association was not evident in patients with microscopically positive margins but node-negative disease and larger studies will be needed.

Clinical Impact of Neoadjuvant Chemotherapy and Chemoradiotherapy in Borderline Resectable Pancreatic Cancer: Analysis of 884 Patients at Facilities Specializing in Pancreatic Surgery

BACKGROUND

The efficacy of neoadjuvant therapy (NAT), including neoadjuvant chemotherapy (NAC) and neoadjuvant chemo-radiotherapy (NACRT), for patients with borderline resectable pancreatic cancer (BRPC) has not been elucidated. This study aimed to clarify the efficacy of NAC and NACRT for patients with BRPC.

METHODS

The study analyzed the treatment outcomes of 884 patients treated for BRPC from 2011 to 2013. Treatment results were compared between upfront surgery and NAT and between NAC and NACRT using propensity score-matching analysis. Overall survival (OS) was calculated via intention-to-treat analyses.

RESULTS

The overall resection rates for the patients who underwent NAT were significantly lower than for the patients who underwent upfront surgery (75.1% vs 93.3%; p < 0.001). However, the R0 resection rate was significantly higher for NAT than for upfront surgery (p < 0.001). Additionally, the OS for the patients who received NAT was significantly longer than for those who underwent upfront surgery (median survival time [MST], 25.7 vs 19.0 months; p = 0.015). The lymph node rate for the patients with NACRT was significantly lower than for those who underwent NAC (p < 0.001). However, the resection rate for the NACRT cases was significantly lower than for the NAC cases (p = 0.041). The local recurrence rate for the NACRT cases was significantly lower than for the NAC cases (p = 0.002). However, OS did not differ significantly between NAC and NACRT (MST, 29.2 vs 22.5 months; p = 0.130).

CONCLUSIONS

The study showed that NAT has potential benefit for patients with BRPC. Compared with NAC, NACRT decreased the rates for lymph node metastasis and local recurrence but did not improve the prognosis.