Lessons learned after one year of COVID-19 from a urologist and radiotherapist view: A German survey on prostate cancer diagnosis and treatment.

INTRODUCTION: Since the beginning of the pandemic in 2020, COVID-19 has changed the medical landscape. International recommendations for localized prostate cancer (PCa) include deferred treatment and adjusted therapeutic routines. MATERIALS AND METHODS: To longitudinally evaluate changes in PCa treatment strategies in urological and radiotherapy departments in Germany, a link to a survey was sent to 134 institutions covering two representative baseline weeks prior to the pandemic and 13 weeks from March 2020 to February 2021. The questionnaire captured the numbers of radical prostatectomies, prostate biopsies and case numbers for conventional and hypofractionation radiotherapy. The results were evaluated using descriptive analyses. RESULTS: A total of 35% of the questionnaires were completed. PCa therapy increased by 6% in 2020 compared to 2019. At baseline, a total of 69 radiotherapy series and 164 radical prostatectomies (RPs) were documented. The decrease to 60% during the first wave of COVID-19 particularly affected low-risk PCa. The recovery throughout the summer months was followed by a renewed reduction to 58% at the end of 2020. After a gradual decline to 61% until July 2020, the number of prostate biopsies remained stable (89% to 98%) during the second wave. The use of RP fluctuated after an initial decrease without apparent prioritization of risk groups. Conventional fractionation was used in 66% of patients, followed by moderate hypofractionation (30%) and ultrahypofractionation (4%). One limitation was a potential selection bias of the selected weeks and the low response rate. CONCLUSION: While the diagnosis and therapy of PCa were affected in both waves of the pandemic, the interim increase between the peaks led to a higher total number of patients in 2020 than in 2019. Recommendations regarding prioritization and fractionation routines were implemented heterogeneously, leaving unexplored potential for future pandemic challenges.

Phase space methods for non-linear analysis of pedalling forces in cycling.

INTRODUCTION: From the perspective of dynamic systems theory, stability and variability of biological signals are both understood as a functional adaptation to variable environmental conditions. In the present study, we examined whether this theoretical perspective is applicable to the pedalling movement in cycling. Non-linear measures were applied to analyse pedalling forces with varying levels of subjective load. MATERIALS AND METHODS: Ten subjects completed a 13-sector virtual terrain profile of 15 km total length on a roller trainer with varying degrees of virtual terrain inclination (resistance). The test was repeated two times with different instructions on how to alter the bikes gearing. During the experiment, pedalling force and heart rate were measured. Force-time curves were sequenced into single cycles, linearly interpolated in the time domain, and z-score normalised. The established time series was transferred into a two-dimensional phase space with limit cycle properties given the applied 25% phase shift. Different representations of the phase space attractor were calculated within each sector and used as non-linear measures assessing pedalling forces. RESULTS AND DISCUSSION: A contrast analysis showed that changes in pedalling load were strongly associated to changes in non-linear phase space attractor variables. For the subjects investigated in this study, this association was stronger than that between heart rate and resistance level. The results indicate systematic changes of the pedalling movement as an adaptive response to an externally determined increase in workload. Future research may utilise the findings from this study to investigate possible relationships between subjective measures of exhaustion, comfort, and discomfort with biomechanic characteristics of the pedalling movement and to evaluate connections with dynamic stability measures.

Involved-field irradiation in combination with total-body irradiation (TBI) does not increase short-term toxicity compared to TBI alone in patients with advanced-stage low-grade non-Hodgkin lymphoma.

PURPOSE: High-dose therapy (HDT) is currently under investigation for patients with advanced low-grade non-Hodgkin lymphoma (NHL). We report on the toxicity of a modified HDT that combines total-body irradiation (TBI) with involved-field irradiation (IF-RT) for patients with bulky disease or residual lymphomas > 2 cm after induction chemotherapy. PATIENTS AND METHODS: 41 patients received HDT which consisted of high-dose cyclophosphamide and fractionated TBI (6 x 2 Gy) followed by autologous stem cell transplantation. Eleven patients received IF-RT prior to TBI, three patients had already received another radiotherapy treatment prior to HDT. RESULTS: After a medium follow-up of 19 months we observed an overall survival rate of 100%, and a relapse-free survival rate of 78%. Severe toxicity was observed only in one patient who developed a myelodysplastic syndrome, and another patient who showed signs of pneumonitis. About two thirds of the patients claimed minor toxicity of grade I-II according the LENT-SOMA scale, predominantly as a decrease in concentration, reduced sexual functioning, and musculo-skeletal pain. Correspondingly, laboratory tests showed grade I-II changes of blood counts, liver enzymes, hormone levels, and lung function. There was no excess toxicity in the patients who received IF-RT additional to TBI. CONCLUSIONS: HDT including TBI and prior IF-RT is feasible without excess morbidity. Careful follow-up is required to detect myelodysplastic syndrome or endocrine changes of ovarian or testicular function.

Does escalation of the apical dose change treatment outcome in beta-radiation of posterior choroidal melanomas with 106Ru plaques?

PURPOSE: To show the results of treating posterior uveal melanomas with 106Ru plaque beta-ray radiotherapy and to review and discuss the literature concerning the optimal apical dose prescription (100 vs. 160 Gy). METHODS AND MATERIALS: Forty-eight patients with uveal melanomas (median height 3.85 mm + 1 mm sclera) were treated with ruthenium plaques. The median apical dose was 120 Gy, the median scleral dose 546 Gy. RESULTS: After 5.8 years of follow-up, the overall 5-year survival rate was 90%, the disease specific 5-year survival rate was 92% (3 patients alive with metastasis). Six percent received a second ruthenium application, 10% of the eyes had to be enucleated. Local control was achieved in 90% of the patients with conservative therapy alone. Central or paracentral tumors showed 50% of the pretherapeutic vision after 4 years, and 80% of the vision was preserved in those with peripheral tumors. The main side effects were mostly an uncomplicated retinopathy (30%); macular degeneration or scarring led to poor central vision in 30% of cases. CONCLUSION: Brachytherapy with ruthenium applicators is an effective therapy for small- and medium-size posterior uveal melanomas. Our results are comparable to other series. The treatment outcome does not seem to be capable of improvement by increasing the apical dose. An internationally accepted model for defining the dosage in brachytherapy is needed.