The normal tissue sparing potential of an adaptive plan selection strategy for re-irradiation of recurrent rectal cancer

Background and purpose: Radiotherapy (RT) of rectal cancer is challenged by potentially large inter-fractional anatomy changes. The risk of radiation-induced morbidity is a particular concern in patients receiving re-irradiation for recurrent disease. We propose an adaptive RT plan selection strategy for these patients and report on its clinical feasibility and normal tissue sparing potential. Material and methods: Eight patients with pelvic recurrence were re-irradiated according to a hyper-fractionation protocol (ReRAD-I; 40.8 Gy) using margins around the clinical target volume (CTV) of 15 mm trimmed to anatomical barriers (Plan L). Two new library plans (S and M) were created for each patient, with the target volumes covering the CTV with isotropic margins of 5 and 10 mm. Pre-treatment cone beam CTs were assessed to determine which plan would cover the CTV following soft-tissue match. The selected plans were compared to the clinically delivered plan in terms of normal tissue volume receiving 95% of the dose (V95%) and the volume of bone receiving 30 Gy (V30 Gy). Results: Plan selections could be performed on all CBCTs for all patients. Plan S was chosen in 213 fractions (79%), plan M in 53 (20%) and plan L in 2 fractions. Normal tissue V95% was reduced by 67% (median; range 30–79%) while bone V30 Gy was reduced by 66% (median; range 40–100%). Conclusion: The CTV and/or surrogate structures were visible on all CBCTs. Margins smaller than those used clinically would have accounted for 99% of the observed target deformations, translating into a considerable normal tissue sparing potential. Keywords: Adaptive radiotherapy, Rectal recurrence, Plan selectio

Cone beam computed tomography-based monitoring and management of target and organ motion during external beam radiotherapy in cervical cancer

Background and purpose: Organ motion is a challenge during high-precision external beam radiotherapy in cervical cancer, and improved strategies for treatment adaptation and monitoring of target dose coverage are needed. This study evaluates a cone beam computed tomography (CBCT)-based approach. Materials and methods: In twenty-three patients, individualized internal target volumes (ITVs) were generated from pre-treatment MRI and CT scans with full and empty bladders. The target volumes encompassed high-risk clinical target volume (CTV-T HR) (gross tumor volume + remaining cervix) and low risk (LR) CTV-T (CTV-T HR + uterus + parametriae + upper vagina). Volumetric Modulated Arc Therapy (VMAT) was used to deliver a dose of 45 Gy in 25 fractions. CBCTs were used for setup and for radiation therapists (RTTs) to evaluate the target coverage (inside/outside the planning target volume). CBCTs were reviewed offline. Estimates of the dose delivered with minimum (point) doses across all fractions to CTV-T HR (aim 42.75 Gy) and CTV-T LR (aim 40 Gy) were assessed. In patients with insufficient dose coverage, re-plans were generated based on previous imaging. Results: Median (range) of the ITV-margins (mean of anterior-posterior margins) related to uterus and cervix was 1.2 (0.5–2.2 and 1.0–2.1) cm. RTTs were able to assess the target coverage in 90% of all CBCTs (505/563). With re-planning, one patient had considerable benefit (12.7 Gy increase of minimum dose) to CTV-T LR_vagina, four patients had improved dose to the CTV-T LR_uterus (1.2–1.8 Gy), and 3 patients did not benefit from re-planning. Conclusions: Daily CBCT-based monitoring of target coverage by the RTTs has proven safe with limited workload. It allows for reduction in the treated volumes without compromising the target dose coverage. Keywords: Image guidance, External beam radiotherapy, Adaptive radiotherapy, Cervical cancer, Cone-beam computed tomography, Interfraction motio

Temporal trends in hospitalizations and 30-day mortality in older patients during the COVID pandemic from March 2020 to July 2021.

BackgroundA reduction in mortality risk of COVID-19 throughout the first wave of the pandemic has been reported, but less is known about later waves. This study aimed to describe changes in hospitalizations and mortality of patients receiving inpatient geriatric care for COVID-19 or other causes during the pandemic.MethodsPatients 70 years and older hospitalized in geriatric hospitals in Stockholm for COVID-19 or other causes between March 2020-July 2021 were included. Data on the incidence of COVID-positive cases and 30-day mortality of the total ≥ 70-year-old population, in relation to weekly hospitalizations and mortality after hospital admissions were analyzed. Findings The total number of hospitalizations was 5,320 for COVID-19 and 32,243 for non-COVID-cases. In COVID-patients, the 30-day mortality rate was highest at the beginning of the first wave (29% in March-April 2020), reached 17% at the second wave peak (November-December) followed by 11-13% in the third wave (March-July 2021). The mortality in non-COVID geriatric patients showed a similar trend, but of lower magnitude (5-10%). During the incidence peaks, COVID-19 hospitalizations displaced non-COVID geriatric patients.InterpretationHospital admissions and 30-day mortality after hospitalizations for COVID-19 increased in periods of high community transmission, albeit with decreasing mortality rates from wave 1 to 3, with a probable vaccination effect in wave 3. Thus, the healthcare system could not compensate for the high community spread of COVID-19 during the pandemic peaks, which also led to displacing care for non-COVID geriatric patients

Decreased Mortality Over Time During the First Wave in Patients With COVID-19 in Geriatric Care : Data From the Stockholm GeroCovid Study.

OBJECTIVE: To describe temporal changes in treatment, care, and short-term mortality outcomes of geriatric patients during the first wave of the COVID-19 pandemic. DESIGN: Observational study. SETTING AND PARTICIPANTS: Altogether 1785 patients diagnosed with COVID-19 and 6744 hospitalized for non-COVID-19 causes at 7 geriatric clinics in Stockholm from March 6 to July 31, 2020, were included. METHODS: Across admission month, patient vital signs and pharmacological treatment in relationship to risk for in-hospital death were analyzed using the Poisson regression model. Incidence rates (IRs) and incidence rate ratios (IRRs) of death are presented. RESULTS: In patients with COVID-19, the IR of mortality were 27%, 17%, 10%, 8%, and 2% from March to July, respectively, after standardization for demographics and vital signs. Compared with patients admitted in March, the risk of in-hospital death decreased by 29% [IRR 0.71, 95% confidence interval (CI) 0.51-0.99] in April, 61% (0.39, 0.26-0.58) in May, 68% (0.32, 0.19-0.55) in June, and 86% (0.14, 0.03-0.58) in July. The proportion of patients admitted for geriatric care with oxygen saturation <90% decreased from 13% to 1%, which partly explains the improvement of COVID-19 patient survival. In non-COVID-19 patients during the pandemic, mortality rates remained relatively stable (IR 1.3%-2.3%). Compared with non-COVID-19 geriatric patients, the IRR of death declined from 11 times higher (IRR 11.7, 95% CI 6.11-22.3) to 1.6 times (2.61, 0.50-13.7) between March and July in patients with COVID-19. CONCLUSIONS AND IMPLICATIONS: Mortality risk in geriatric patients from the Stockholm region declined over time throughout the first pandemic wave of COVID-19. The improved survival rate over time was only partly related to improvement in saturation status at the admission of the patients hospitalized later throughout the pandemic. Lower incidence during the later months could have led to less severe hospitalized cases driving down mortality