Radiotherapy In Setting Research Articles

Toxicities after Hypofractionated Radiotherapy in Setting of Collagen Vascular Disease

Patients with collagen vascular disorders (CVD) have been regarded as contraindications for radiotherapy (RT) due to concerns of greater risks for late radiation effects. Recent reports have found toxicities between those with and without CVD to be similar using conventionally fractionated regimens. Hypofractionation is increasingly utilized for many indications, but there is hesitancy to use them for CVD patients since larger dose per fraction may compound late toxicity, despite lack of clinical evidence. We hypothesize that hypofractionation does not increase rates of toxicity in CVD patients. 249 treatments from 192 CVD patients from February 2007 to April 2019 at a single institution were retrospectively reviewed. CVD type, activity, and steroid use were evaluated. Dose per fraction, radiated site, planning target volume (PTV), and concurrent cancer therapies were also assessed. Toxicity ≤ 90 days from treatment was acute, and any after was late. Toxicity was graded by CTCAE version 5, and grade ≥ 3 was severe. Dose fractionation was defined as conventional (CF; 1.8-2Gy/fxn), moderate hypofractionated (MH; 2-5Gy/fxn), and ultra hypofractionated (UH; >5Gy/fxn). Fisher’s exact test and one-way analysis of variance (ANOVA) assessed differences in severe toxicity and PTV by fractionation groups, respectively. Uni- and multivariable logistic regression models identified prognostic variables for toxicity. Common CVDs were rheumatoid arthritis (37%), psoriasis (24%), and systemic lupus erythematosus (17%). 37%, 28%, and 35% of treatments were CF, MH, and UH, respectively. Median follow-up was 3 years. By fractionation groups, there were no significant differences in severe acute (5.4%, 7.3%, and 1.7%, p = 0.35) or late (8.3%, 0%, and 2.2%, p = 0.12) toxicities. Dose fractionation, radiated site, and multiple RT courses were significantly associated with late toxicity on multivariable analysis (Table). More specifically, MH (OR 0.32) and UH (OR 0.29) had lower odds for late toxicity compared to CF. Mean PTV was smaller with larger dose per fraction yet was not significantly different by fractionation groups (p = 0.18), nor associated with toxicity on multivariable analyses. Severe toxicity rates from MH or UH in CVD patients were not different from CF. MH and UH were associated with lower odds of developing late toxicity. Hypofractionation may be safe for CVD patients, though longer follow-up and additional patients with and without CVD are needed to further evaluate late toxicity.Abstract 2386; TableSignificant factors associated with toxicity on univariate and multivariable analysesUnivariate analysisAcute toxicityLate toxicityORp-valueORp-valueUH0.13< 0.001MH0.320.01UH0.29< 0.01Multivariable analysis--MH*0.200.02UH*0.19< 0.05Musculoskeletal radiated site0.030.01Multiple radiation courses7.360.03MH moderate hypofractionation; UH ultra-hypofractionation.*Relative to conventional fractionation. Relative to breast. Open table in a new tab

Oligorecurrent prostate cancer limited to lymph nodes: getting our ducks in a row : Nodal oligorecurrent prostate cancer.

Oligorecurrent prostate cancer with exclusive nodal involvement represents a common state of disease, amenable to local therapy. New radio-labeled tracers have enriched the possibility of cancer detection and treatment. In this review, we aim to illustrate the main nuclear medicine diagnostic options and the role of radiotherapy in this setting of patients. We performed a PubMed search referring to the PRISMA guidelines to analyze the performance of PSMA- and choline-PET in detecting oligorecurrence limited to lymph nodes, and to review the main studies supporting either ablative stereotactic body radiotherapy or regional lymph node irradiation in this clinical setting. PSMA-PET has shown higher efficacy in the diagnosis of nodal lesions if compared with choline-PET. More specifically, for PSA ≤ 2ng/ml, the median detection rate of choline-PET ranges from 19.5 to 44.5%, whereas PSMA ranges from 51.5 to 74%. SBRT achieves high local control rates positively affecting progression-free survival (PFS), with androgen deprivation therapy (ADT)-free survival ranging from 25 to 44months and with low toxicity rates (0-15%). Prophylactic nodal irradiation shows 3-year PFS rates ranging from 62 to 75%, but with a potential higher risk of toxicity. However, the chosen treatment option needs to be tailored on the single patient. Newer PET/CT radio-labeled tracers have increased disease detection in oligorecurrent prostate cancer patients. Growing evidence of their impact on metastasis-directed therapy encourages the use of the most advanced radiotherapy techniques in the clinical management of such patients.

Tu1361 Proton Radiotherapy in Setting of Esophageal Stents: Is There a Risk of Significant Dose Perturbation?

Tu1361 Proton Radiotherapy in Setting of Esophageal Stents: Is There a Risk of Significant Dose Perturbation?