Schnall, Mitchell D.

PURPOSE In the United States, the National Cancer Institute National Cancer Clinical Trials Network (NCTN) groups have conducted publicly funded oncology research for 50 years. The combined impact of all adult network group trials has never been systematically examined. METHODS We identified randomized, phase III trials from the adult NCTN groups, reported from 1980 onward, with statistically significant findings for ≥ 1 clinical, time-dependent outcomes. In the subset of trials in which the experimental arm improved overall survival, gains in population life-years were estimated by deriving trial-specific hazard functions and hazard ratios to estimate the experimental treatment benefit and then mapping this trial-level benefit onto the US cancer population using registry and life-table data. Scientific impact was based on citation data from Google Scholar. Federal investment costs per life-year gained were estimated. The results were derived through December 31, 2020. RESULTS One hundred sixty-two trials comprised of 108,334 patients were analyzed, representing 29.8% (162/544) of trials conducted. The most common cancers included breast (34), gynecologic (28), and lung (14). The trials were cited 165,336 times (mean, 62.2 citations/trial/year); 87.7% of trials were cited in cancer care guidelines in favor of the recommended treatment. These studies were estimated to have generated 14.2 million (95% CI, 11.5 to 16.5 million) additional life-years to patients with cancer, with projected gains of 24.1 million (95% CI, 19.7 to 28.2 million) life-years by 2030. The federal investment cost per life-year gained through 2020 was $326 in US dollars. CONCLUSION NCTN randomized trials have been widely cited and are routinely included in clinical guidelines. Moreover, their conduct has predicted substantial improvements in overall survival in the United States for patients with oncologic disease, suggesting they have contributed meaningfully to this nation's health. These findings demonstrate the critical role of government-sponsored research in extending the lives of patients with cancer.

119 Background: Radiotherapy (RT) interruptions have a negative impact on outcomes in many epithelial malignancies treated with definitive RT. The purpose of this study was to analyze the impact of RT duration on outcomes in patients (pts) with esophageal cancer treated with definitive chemoradiotherapy (CRT). Methods: Pts treated with definitive CRT on RTOG trials 8501 and 9405 were included. Separate analyses were performed in pts receiving standard dose (SD-CRT; 50 Gy + 5FU + cisplatin) and high dose (HD-CRT; 64.8 Gy + 5FU + cisplatin) CRT. Local (LF) and regional (RF) failure were estimated by the cumulative incidence method. Disease-free (DFS) and overall (OS) survival were estimated by the Kaplan-Meier method. Univariate (UVA) and multivariate (MVA) Cox proportional hazards models were utilized to examine for correlation between RT duration (< vs. ≥ median) with LF, RF, DFS and OS. Results: In the SD-CRT cohort (n=235), 96 pts (41%) had ≥ 1 RT interruption for a median of 3 (IQR 1-6) days. The median RT duration was 39 (IQR 37-43) days. In UVA and MVA, RT duration was not associated with LF, RF, DFS, or OS. Estimated outcome rates are in the table. In the HD-CRT cohort (n=107), 64 pts (60%) had ≥ 1 RT interruption for a median of 3.5 (IQR 2-7.5) days. The median RT duration was 52 (IQR 50-57) days. In UVA, RT duration ≥ 52 days was associated with a 33% reduction in risk of DFS failure (HR=0.66, 95% CI [0.44-0.98], p=0.039) and a 29% reduction in risk of death (HR=0.71, 95% CI [0.48-1.06], p=0.09). When excluding the 25 pts with RT dose < 64.8 Gy, RT duration was not associated with DFS or OS. Conclusions: In pts with esophageal cancer receiving definitive SD-CRT, an association between RT duration and outcomes was not observed. In pts receiving HD-CRT, longer RT duration was associated with improved DFS, which may have been due to a significant number of deaths at RT dose < 64.8 Gy. Supported by NCI U10 grants CA21661, CA180868, CA180822, CA37422. Clinical trial information: NCT00002631. [Table: see text]