Radiation Oncology

Prospective multicenter validation of deep-learning OAR auto-segmentation in thoracic and breast RT

In 500 thoracic and breast RT patients across five centers, 37 physicians generated manual, AI-generated, and AI-assisted OAR contours on CT. Across 2,483 OAR sets, AI-assisted contouring achieved higher mean vDSC (0.902 vs 0.857) and lower HD95 (5.20 vs 8.01 mm) than manual contours. AI assistance reduced median contouring time by about 82% (10 vs 55 minutes; p < 0.0001). AI-assisted workflows also reduced inter-center and inter-physician variability, suggesting potential to standardize thoracic planning quality. 1

Contemporary left-sided breast RT shows minimal excess cardiovascular risk at 15 years

This Ontario cohort included 76,586 women receiving EBRT for unilateral breast cancer between 2002 and 2017, followed a median 10.9 years. The 15-year cumulative incidence of first CVD hospitalization was similar for left vs right laterality (13.8% vs 13.5%; P = .43). CVD hospitalization rates including recurrent events were only modestly higher for left-sided disease (1.72 vs 1.63 per 100 person-years; P = .006). Among women with preexisting CVD, new heart failure and ischemic heart disease diagnoses were slightly more frequent after left-sided RT. 2

Induction serplulimab plus chemotherapy before cCRT in bulky stage III NSCLC reduces V20 and boosts responses

SUCCEED-01 enrolled 49 patients with bulky unresectable stage III NSCLC, mostly stage IIIB/IIIC, for two cycles of induction serplulimab-chemotherapy. Non-progressors underwent multidisciplinary restaging and then received cCRT with serplulimab consolidation or surgery. Induction treatment reduced lung V20 by 11.41% (p < 0.001), enabling smaller radiation fields. Post-cCRT objective response rate was 77.14%, with 12‑month PFS and OS rates of 76.15% and 90.54%, respectively. 3

Fractionated electron FLASH is feasible but shows no cutaneous sparing versus conventional RT in a porcine model

Three swine received paired five-fraction 9‑MeV electron irradiations to dorsolateral skin using either FLASH (175–246 Gy/s) or conventional dose rates. Regimens of 5 × 6 Gy and 5 × 7 Gy were well tolerated, with similar peak dermatitis, erythema indices, and histologic damage between modalities. At 5 × 8 Gy, both FLASH and conventional irradiation produced unacceptable toxicity, including moist desquamation and necrosis. No volume-dependent toxicity differences were observed across 4–10 cm fields, and dosimetry accuracy was within 3%. 4