ABSTRACT
BACKGROUND: Neoadjuvant chemoradiotherapy can provide downstaging and improve margin negativity for borderline resectable and resectable pancreatic adenocarcinoma [(B)RPC]. Little is known about the relative efficacy of capecitabine (CAPE)-based vs. gemcitabine (GEM)-based 3-week chemoradiation (3WCRT) with 36 Gy in 15 fractions. This study aimed to compare the odds of achieving surgical resection, time to progression (TTP), and overall survival (OS) of patients treated with 3WCRT with concurrent CAPE versus GEM. METHODS: A retrospective cohort study was conducted, examining medical records from a single center for patients with (B)RPC treated with 3WCRT between 1/2009-12/2020. Odd ratios (OR) of achieving surgical resection were estimated using logistic regression for univariable and multivariable analyses. Median TTP (mTTP) and median OS (mOS) were estimated using the Kaplan-Meier method. Cox proportional hazards analysis was conducted to estimate hazard ratios (HR) of progression and survival in univariable and multivariable analyses. RESULTS: Thirty-one patients were included in the analysis. Twenty-two (71%) patients were treated with CAPE, while 9 (29%) were treated with GEM. All patients in the GEM group were borderline resectable, vs. 18 (82%) patients in the CAPE group, P=0.30. Nineteen (86%) patients in the CAPE group were treated with neoadjuvant FOLFIRINOX, vs. 4 (44%) patients in the GEM group, P=0.03. The CAPE group had higher odds of achieving surgical resection [OR =9.33; 95% confidence interval (CI): 1.50-58.20]. Adjusting for covariates, the odds of achieving surgical resection were still statistically higher in the CAPE group vs. the GEM group (OR =25.34; 95% CI: 1.14-563.72). The CAPE group had superior mTTP compared to the GEM group (15.4 months, 95% CI: 4.9-71.1 vs. 4.0 months, 95% CI: 0.4-14.5; P=0.01), corresponding to a hazard ratio of 0.33 (95% CI: 0.14-0.81). Adjusting for covariates this effect persisted; the adjusted hazard ratio (AHR) for progression was 0.24 (95% CI: 0.08-0.77). Cox proportional hazards analysis also demonstrated that the CAPE group had superior OS compared to the GEM group in unadjusted (HR =0.13; 95% CI: 0.04-0.40) and adjusted models (HR =0.13, 95% CI: 0.03-0.52). CONCLUSIONS: For neoadjuvant 3WCRT, this hypothesis-generating study suggests concurrent CAPE may be a more effective radiosensitizer than GEM for patients with (B)RPC.
ABSTRACT
OBJECTIVE: Cancer antigen (CA)-125 influences progression, metastasis, and outcomes in pancreatic cancer. This phase I/II trial (NCT01959672) evaluated the safety, efficacy, and immunologic correlates of chemoimmunotherapy (CIT) with oregovomab (anti-CA-125), followed by stereotactic body radiotherapy (SBRT) with the radiosensitizer nelfinavir. MATERIALS AND METHODS: Following imaging, pathologic confirmation, and staging laparoscopy, subjects received three 3-week cycles of CIT (gemcitabine/leucovorin/fluorouracil/oregovomab). Thereafter, nelfinavir was delivered (1250 mg bid) for 5 weeks, with SBRT (40 Gy/5 fractions) occurring during the third week of nelfinavir. Following another cycle of CIT, pancreaticoduodenectomy was performed if resectable. Three more cycles of CIT were then delivered (total 7 cycles). In subjects with high (≥10 U/mL) CA-125, oregovomab (2 mg) was administered for 7 total doses (3 pre-SBRT, 1 between SBRT and resection, and 3 postoperatively). The enzyme-linked immunospot assay evaluated the development of CA-125-specific CD8 T-lymphocytes. RESULTS: The trial was prematurely closed because gemcitabine/leucovorin/fluorouracil was replaced by FOLFIRINOX and gemcitabine/nab-paclitaxel as the standard of care. Median follow-up was 13 months. Of 11 enrolled patients, 10 had high CA-125; 1 patient suffered an unexpected cardiac-related death, so 9 subjects received oregovomab. Ten received SBRT and 4 underwent resection. Overall, 6/11 patients experienced any grade ≥3 event. The median survival and time to progression were 13 and 8.6 months, respectively. Five patients had samples available for immunospot testing, of whom 2 (40%) developed CA-125-specific CD8 T-lymphocytes. CONCLUSION: A combined pancreatic cancer multimodality approach using CIT and radiosensitized radiotherapy is feasible and safe; delivery of immunotherapy can lead to T-cell immunity. Re-evaluation with modern systemic paradigms is recommended.
