The addition of radiation therapy to chemotherapy improved overall survival (OS) in patients with unresected locally advanced pancreatic cancer, according to research presented at the 2017 ASCO Annual Meeting (June 2-6, 2017; Chicago, IL).
The best outcomes were seen in patients who received stereotactic body radiation therapy (SBRT), results showed.
Following the release of results from the LAP07 randomized clinical trials—which called into question the benefits of radiation therapy for patients with locally advanced pancreatic cancer—Jim Zhong, MD, radiation oncology resident at Emory University’s Winship Cancer Institute (Atlanta, GA), and colleagues sought to determine whether advances in radiation and chemotherapy delivery rendered LAP07’s findings obsolete.
The researchers accessed the National Cancer Database to observe outcomes for nonsurgical patients with locally advanced pancreatic cancer treated between 2004 and 2014. The study included data from 13,004 patients, who were stratified based on treatment type: chemotherapy alone (n = 7034) vs chemotherapy with radiation therapy (n = 5970). The radiation therapy cohort included patients who received definitive radiation therapy (defined as at least 20 fractions) or SBRT (≥ 5 Gy per fraction). OS served as the primary outcome measure.
Patients treated with radiation therapy tended to be younger (median age, 65 years vs 67 years) and less likely to be treated at an academic medical center (44% vs 51%).
The chemotherapy plus radiation therapy cohort achieved a more favorable median OS (12 months vs 10 months) and 1-year OS (50% vs 41%) than patients treated with chemotherapy alone (P < .001 for both). A multivariable analysis confirmed the favorable effects seen in the radiation cohort (hazard ratio [HR] = 0.79; 95% CI, 0.76-0.83; P < .001).
The best outcomes were seen in patients who received SBRT (HR = 0.71; 95% CI, 0.64-0.8; P < .001). The researchers further conducted a propensity-score matching analysis to reduce potential bias; the results continued to favor the chemotherapy plus radiation cohort.
“Recently we published a study using the National Cancer Data Base to suggest that the patients treated with [SBRT] had an improved overall compared to those with conventional vaccination. In this current study, the patients treated with radiation, specifically [SBRT], had the best survival of all the patients,” Dr Zhong said.—Cameron Kelsall
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