New research was presented at ASTRO 2021, the American Society for Radiation Oncology Annual Meeting, held October 24-27 in Chicago and virtually. The features below highlight some of the studies that emerged from the conference.
Closing the Racial Gap in Lung & Breast Cancer Survival
With the ACCURE system-based intervention trial shown to eliminate Black–White disparities in treatment completion and improved completion for all among patients with curable lung or breast cancer, investigators assessed how the ACCURE intervention—a real-time warning system derived from EHRs, cancer treatment feedback according to race provided to clinical teams, and a nurse navigator—influenced the survival disparity. More than 1,400 patients with stages 0, I, and II lung and breast cancer diagnosed in 2013-2015 were compared with more than 2,000 patients treated in 2007-2011. Statistically significant survival improvements were observed for Black and White patients with breast cancer and White patients with lung cancer during the study period, during which the racial gap in survival was reduced for those with lung or breast cancer. Observed 5-year survival rates for White and Black patients with breast cancer improved from 91% and 89%, respectively, to 94% for both, while the rates for those with lung cancer improved from 43% and 37%, respectively, to 56% and 54%, respectively.
SBRT for Oligoprogressive Lesions Improves Lung Cancer PFS
To test their hypothesis that an oligoprogressive state exists in metastatic cancer during which disease control can be improved with local therapy to progressive lesions only, investigators evaluated the impact of stereotactic body radiotherapy (SBRT) to sites of oligoprogression in patients with metastatic non-small-cell lung cancer (NSCLC) and breast cancer with one to five progressive lesions. Participants were randomized to SBRT to all progressive sites plus palliative standard of care (SOC) or palliative SOC only, with baseline factors balanced between the two arms. Median progression free survival (PFS) was 22 weeks in the SBRT arm, compared with 10 weeks in the palliative SOC arm, driven entirely by a PFS benefit from SBRT in patients with NSCLC (44 weeks with SBRT vs. 9 weeks with SOC); no differences in median PFS were observed between the arms for patients with breast cancer.
EBRT Underused as Bridging Therapy for Patients With HCC Awaiting Transplant
Despite prior research indicating that external-beam radiation therapy (EBRT) is safe and effective as a bridging therapy to live transplantation for patients with hepatocellular carcinoma (HCC), data are lacking on the national prevalence and clinicopathologic parameters of patients receiving EBRT as a bridging therapy while awaiting liver transplantation. To fill this knowledge gap, researchers retrospectively analyzed the United Network for Organ Sharing dataset from October 2013 to June 2020, identifying waitlisted adults with HCC who had applied for model of end-stage liver disease exceptions to receive waiting list prioritization. Among 18,447 patients with HCC, 85.4% received any liver-directed therapy (LDT) and 60.6% underwent a liver transplant at a median of 7 months, but just 3.6% received EBRT either alone or in combination with other LDTs. However, EBRT use did increased over time, with an average annual percentage increase of 14%. When comparing those who received EBRT with those who did not, the study team observed no statistical differences in tumor size, total bilirubin, portal vain thrombosis presence, or alpha-fetoprotein level.
Improved Survival With EFRT in Patients With Cervical Cancer
Due to an unestablished role of prophylactic extended-field radiation therapy (EFRT) and unclear indications for EFRT in treating patients with cervical cancer, investigators compared survival rates and toxicities of pelvic radiation therapy (PRT) with those of EFRT in patients with 2018 FIGO stage IIIC1 cervical cancer who were treated in 2011-2015. For patients treated with PRT, 5-year rates for overall survival (OS), disease-free survival (DFS), and para-aortic lymph node (PALN) control were 61.9%, 53.0%, and 89.7%, respectively, compared with rates of 85.0%, 77.9%, and 98.4%, respectively, for patients treated with EFRT. Patients deemed to be high-risk— positive common iliac lymph nodes, three or more pelvic lymph nodes, and/or T3 disease—treated with PRT and EFRT after matching had 5-year rates of 65.1% and 84.3% for OS, 54.9% and 84.4% for DFS, and 91.8% and 100.0% for PALN control, while those deemed low-risk had respective rates of 61.8% and 91.1%, 53.8% and 80.3%, and 88.4% and 100.0%. Rates of grade 3 or greater chronic toxicities were low in both groups, at 1.2% for those treated with PRT and 5.9% for those treated with EFRT.
DART Outperforms Standard of Care for Some HPV-Positive Oral Cancers
With substantial toxicity associated with standard of care (SOC) treatment for HPV-positive oropharyngeal cancers, investigators randomized patients undergoing transoral robotic surgery (TORS) or neck dissection for a margin-negative resection to SOC (60 Gy with or without cisplatin) or de-escalated adjuvant radiation therapy (DART; 30-36 Gy plus docetaxel). Patients in the DART group experienced numerically lower grade 3 or greater radiation-related adverse events at 3 months (1.6%) compared with those in the SOC group (7.1%). The DART group also had a lower rate of patients requiring a feeding tube (1.6%) compared with the SOC group (27.4%). Swallowing function change from baseline to 1 month, as measured by modified barium swallow impairment, was also greater in the DART group, with a median score of -0.3, compared with -2.6 for the SOC group. Significant improvements with DART versus SOC were also seen for quality-of-life measures and EORTC-HN pain scores (-8.6 vs 2.5). Overall, 2-year progression-free survival (PFS) rates were 86.5% in the DART group and 95.1% in the SOC group. The study authors indicate that the majority of events in PFS among those with extranodal extension (ENE) were attributed to those who were pN2, among whom 2-year PFS rates were 42.9% with DART and 100% with SOC, and thus caution against de-escalating ENE-positive patients, particularly those with pN2 disease.