ESTRO 2021 Abstract Book

S1227

ESTRO 2021

PO-1497 Stereotactic and hypofractionated radiotherapy associated with immune checkpoints inhibitors D. Anzellini 1 , V. De Sanctis 2 , M. Valeriani 3 , G. Vullo 3 , G. Facondo 3 , M. Massaro 3 , R.C. Sigillo 3 , M.F. Osti 3 1 Sapienza Università di Roma, AO Sant'Andrea Roma, UO Radioterapia Oncologica, ROMA, Italy; 2 Sapienza Università di Roma, AOU Sant'Andrea Roma, UO Radioterapia Oncologica, ROMA, Italy; 3 Sapienza Università di Roma, AOU Sant'Andrea Roma, UO Radioterapia Oncologica, ROMA, Italy Purpose or Objective Metastatic disease is the leading cause of cancer-related mortality. However, the oligometastatic hypothesis proposes that metastases may vary their aggressiveness according to their presence in one, few or many systemic sites. In this scenario, combined therapies play a crucial role in the management of these disease presentation. We evaluated local control and toxicity in patients receiving radiation therapy concomitant with immune checkpoints inhibitors and we analyzed which oligometastatic disease setting benefits the most from local ablation in terms of advantage in overall survival. Materials and Methods We retrospectively identified 60 oligoprogressive patients affected by non-small cell lung cancer (NSCLC), renal cell carcinoma (RCC), metastatic melanoma, and nasopharyngeal squamous cell carcinoma treated according to the standard treatment with a PD-1 inhibitor associated with stereotactic radiotherapy regimens or hypofractionated radiotherapy regimens on the site of progression (119 lesions). Regarding timing between systemic and local treatments, we considered only those patients on active therapy with drugs that inhibit immune check-points while receiving radiation without interrupting medical therapy. Results After a median follow-up for all patients of 11.7 months (range 1-39), nineteen of 59 irradiated brain metastasis had complete response (CR), twenty-eight/59 partial response (RP). Among extracranial metastases, a complete morphological response was observed in seventeen/60 lesions, a partial response in twenty-three/6. Among the 9 radionecrotic events, 4 (44.5%) occurred on lesions previously irradiated with the 9 Gy x 3 stereotactic technique and who received panencephalic therapy that followed the failure of intracranial over-time control. Three patients reported acute G2 dysphagia. One patient (6.66%) experienced severe treatment-related pneumonia. One patient experienced severe diarrhea Twenty-nine patients (24%) reported Grade 2 fatigue and asthenia during radiation treatment. The number of radiologically evident metastatic sites in patients who received concomitant PD-1 inhibitors and radiotherapy showed a significant increase of survival (respectively, 73% after 12 months and 47% after 24 months ) in patients with 0-3 metastases compared to patients with more than 3 organ sites involved (p <0.0001). A substantial stability of the disease was observed in the 31 patients within 6 months following the radiation treatment. This feature has been shown to indicate a significant increase in both OS and PFS. These patients had a 82% OS after 12 months and a 69% OS after 19 months. (p=0.001). Conclusion Our study confirms the efficacy and overall safety of radiotherapy associated with PD-1 inhibitors. The subgroup analysis suggests that to identify those patients eligible for the intensification of local treatments should include an amount of metastatic sites less or equal to 3 and a controlled disease of at least 6 months after RT . PO-1498 Clinical Sensitivity of PROMIS-10 Physical and Mental Quality of Life Domains to Radiation Therapy T. DeWees 1 , F. Abraha 2 , K. Corbin 3 , P. Brown 3 , C. Hallemeier 3 , B. Davis 3 , I. Petersen 3 , J. Martenson 3 , S. Ahmed 3 , K. Olivier 3 , T. Vern-Gross 4 , W. Rule 4 , W. Wong 4 , S. Vora 4 , S. Patel 4 , J. Ashman 4 , S. Schild 4 , D. Trifiletti 5 , C. Vargas 4 , D. Ma 3 1 Mayo Clinic, Quantitative Health Sciences, Radiation Oncology, Scottsdale, USA; 2 Mayo Cinic, Quantitative Health Sciences, Rochester, USA; 3 Mayo Clinic, Radiation Oncology, Rochester, USA; 4 Mayo Clinic, Radiation Oncology, Phoenix, USA; 5 Mayo Clinic, Radiation Oncology, Jacksonville, USA Purpose or Objective Patient-Reported Outcomes Measurement Information System 10 (PROMIS-10) is a commonly utilized instrument for quantifying changes in patient quality of life (QOL) before and after medical intervention. The sensitivity of the PROMIS-10 QOL instrument to radiotherapy (RT) was evaluated, with specific interest in meaningful clinically important differences (MCID) in the Global Physical and Mental domains. Materials and Methods A prospective registry to capture provider- and patient-reported clinical outcomes was instituted in a large, multi-site radiation oncology practice. Patients, regardless of cancer type, treated with RT between 2013 and 2020 were administered PROMIS-10 questionnaires at baseline, end-of-treatment, 3, 6, 12 months, then annually. A change in PROMIS scores from pre-RT to end-of-treatment (EOT) by at least 4 points was considered clinically significant. Analysis of Variance models were created to estimate the least square means in the differences between pre-RT and EOT as well as to compare differences between treatment groups. Tukey’s adjustment for multiple comparisons was utilized and 95% confidence intervals (CI) were computed for all estimates. Results 6,456 patients were eligible; 54% were males with an average age of 61.7 years old (range: 6-93 years). 2,278(35%) received protons and 3934(61%) received photons with the average dose of 54 Gy (range: 0.4-78 Gy). Hypo-fractionation (>2-4.9 Gy/fraction) was utilized in 34.4% while SBRT (>5 Gy/fraction) was utilized in 13.4% of the population. Patient disease sites were sub-grouped into 12 categories: GU(28%), Breast(26.2%), H&N(11%), CNS(8.5%), Thoracic(5.2%), Pancreas-Biliary(4.7%), Soft-Tissue/Bone(4.6%), Esophagus- Gastric(3.8%), GYN(2.6%), Heme/Lymph(2.3%), Colorectal-Anus(1.7%), and Skin/Melanoma(1.5%). Global Physical Health significantly decreased for Colorectal-Anus(5.06; 95% CI: 3.8–6.3), Esophagus- Gastric(5.05; 95% CI: 4.2–5.9), and H&N(4.72; 95% CI: 4.2–5.2) patients. All other disease sites were not significantly different with mean decreases ranging from 0.5 to 2.3 points.