Analysis of clinical data to determine the minimum number of sensors required for adequate skin temperature monitoring of superficial hyperthermia treatments

Purpose: Tumor response and treatment toxicity are related to minimum and maximum tissue temperatures during hyperthermia, respectively. Using a large set of clinical data, we analyzed the number of sensors required to adequately monitor skin temperature during superficial hyperthermia treatment of breast cancer patients. Methods: Hyperthermia treatments monitored with >60 stationary temperature sensors were selected from a database of patients with recurrent breast cancer treated with re-irradiation (23 7 2 Gy) and hyperthermia using single 434 MHz applicators (effective field size 351–396 cm2). Reduced temperature monitoring schemes involved randomly selected subsets of stationary skin sensors, and another subset simulating continuous thermal mapping of the skin. Temperature differences (ΔT) between subsets and complete sets of sensors were evaluated in terms of overall minimum (Tmin) and maximum (Tmax) temperature, as well as T90 and T10. Results: Eighty patients were included yielding a total of 400 hyperthermia sessions. Median ΔT was 50 sensors were used. Subsets of 50 sensors were used. Thermal profiles (8–21 probes) yielded a median ΔT < 0.01 \ub0C for T90 and Tmax, with a 95%CI of −0.2 \ub0C and 0.4 \ub0C, respectively. The detection rate of Tmax≥43 \ub0C is ≥85% while using >50 stationary sensors or thermal profiles. Conclusions: Adequate coverage of the skin temperature distribution during superficial hyperthermia treatment requires the use of >50 stationary sensors per 400 cm2applicator. Thermal mapping is a valid alternative

Interobserver variability in target definition for stereotactic arrhythmia radioablation

Background: Stereotactic arrhythmia radioablation (STAR) is a potential new therapy for patients with refractory ventricular tachycardia (VT). The arrhythmogenic substrate (target) is synthesized from clinical and electro-anatomical information. This study was designed to evaluate the baseline interobserver variability in target delineation for STAR. Methods: Delineation software designed for research purposes was used. The study was split into three phases. Firstly, electrophysiologists delineated a well-defined structure in three patients (spinal canal). Secondly, observers delineated the VT-target in three patients based on case descriptions. To evaluate baseline performance, a basic workflow approach was used, no advanced techniques were allowed. Thirdly, observers delineated three predefined segments from the 17-segment model. Interobserver variability was evaluated by assessing volumes, variation in distance to the median volume expressed by the root-mean-square of the standard deviation (RMS-SD) over the target volume, and the Dice-coefficient. Results: Ten electrophysiologists completed the study. For the first phase interobserver variability was low as indicated by low variation in distance to the median volume (RMS-SD range: 0.02–0.02 cm) and high Dice-coefficients (mean: 0.97 ± 0.01). In the second phase distance to the median volume was large (RMS-SD range: 0.52–1.02 cm) and the Dice-coefficients low (mean: 0.40 ± 0.15). In the third phase, similar results were observed (RMS-SD range: 0.51–1.55 cm, Dice-coefficient mean: 0.31 ± 0.21). Conclusions: Interobserver variability is high for manual delineation of the VT-target and ventricular segments. This evaluation of the baseline observer variation shows that there is a need for methods and tools to improve variability and allows for future comparison of interventions aiming to reduce observer variation, for STAR but possibly also for catheter ablation

Regional control of melanoma neck node metastasis after selective neck dissection with or without adjuvant radiotherapy

Objective: To examine the effect of adjuvant radiotherapy on regional control of melanoma neck node metastasis. Design: A single-institution retrospective study. Setting: Tertiary care cancer center. Patients: The study included 64 patients with melanoma neck node metastasis who were treated with neck dissection between 1989 and 2004 in The Netherlands Cancer Institute, Amsterdam. Twenty-four patients were treated with surgery only (15 modified radical neck dissections [MRNDs] and 9 selective neck dissections [SNDs]) (S group), and 40 patients underwent surgery (28 MRNDs and 12 SNDs) and adjuvant radiotherapy (S+RT group). Results: Prognostic factors, ie, number of nodes, size of nodes, and extracapsular extension, were worse in the S+RT group. With a median follow-up of 2.5 years, the 2-year ipsilateral regional recurrence (RR) rate was 18% in the S+RT group and 46% in the S group. This 28% difference in RR was not statistically significant (P=.16). However, evaluation of the effect of adjuvant RT in multivariate analysis revealed a significant reduction of the RR rate after correction for the number of involved nodes (P=.04). In the S group, SND was associated with a trend toward worse RR rate compared with MRND but was not statistically significant in univariate analysis (P=.08). The type of neck dissection did not influence the RR rate in the S+RT group (P=.60). Three of the 4 RRs occurred outside the dissected volume after SND in the S group. Conclusions: Based on our findings, we conclude that, compared with extended neck dissection, SND leads to inferior regional control in patients with melanoma neck node metastasis who are not treated with RT, even those with low-risk neck disease. Furthermore, our results suggest that adjuvant RT improves regional control in patients with 2 or more involved nodes.</p

Regional control of melanoma neck node metastasis after selective neck dissection with or without adjuvant radiotherapy

Objective: To examine the effect of adjuvant radiotherapy on regional control of melanoma neck node metastasis. Design: A single-institution retrospective study. Setting: Tertiary care cancer center. Patients: The study included 64 patients with melanoma neck node metastasis who were treated with neck dissection between 1989 and 2004 in The Netherlands Cancer Institute, Amsterdam. Twenty-four patients were treated with surgery only (15 modified radical neck dissections [MRNDs] and 9 selective neck dissections [SNDs]) (S group), and 40 patients underwent surgery (28 MRNDs and 12 SNDs) and adjuvant radiotherapy (S+RT group). Results: Prognostic factors, ie, number of nodes, size of nodes, and extracapsular extension, were worse in the S+RT group. With a median follow-up of 2.5 years, the 2-year ipsilateral regional recurrence (RR) rate was 18% in the S+RT group and 46% in the S group. This 28% difference in RR was not statistically significant (P=.16). However, evaluation of the effect of adjuvant RT in multivariate analysis revealed a significant reduction of the RR rate after correction for the number of involved nodes (P=.04). In the S group, SND was associated with a trend toward worse RR rate compared with MRND but was not statistically significant in univariate analysis (P=.08). The type of neck dissection did not influence the RR rate in the S+RT group (P=.60). Three of the 4 RRs occurred outside the dissected volume after SND in the S group. Conclusions: Based on our findings, we conclude that, compared with extended neck dissection, SND leads to inferior regional control in patients with melanoma neck node metastasis who are not treated with RT, even those with low-risk neck disease. Furthermore, our results suggest that adjuvant RT improves regional control in patients with 2 or more involved nodes.</p

Protonencentra : Ze zijn er, wat nu ?

Na een langdurige maatschappelijke discussie, is in 2018 protonentherapie beschikbaar gekomen in Nederland. Deze therapie is in Nederland op een unieke wijze geïntroduceerd. De protonencentra hebben vergunning om jaarlijks maximaal 2200 patiënten te behandelen, 4,4% van het totaal aantal patiënten dat bestraald wordt. Deze groep wordt geselecteerd met zorgvuldig uitgekozen voorspellingsmodellen om de kans op bijwerkingen in te schatten. Alleen als er voor een individuele patiënt een klinisch relevant verschil in bijwerkingen verwacht wordt ten opzichte van de huidige fotonentherapie, komt deze patiënt in aanmerking voor protonentherapie. Welke voorspellingsmodellen gebruikt dienen te worden, en welk verschil in bijwerkingen protonentherapie rechtvaardigt, is en wordt vastgelegd in landelijke indicatieprotocollen. Wij verwachten dat we op deze manier de goede internationale reputatie die Nederland heeft op het gebied van de radiotherapie, verder kunnen uitbouwen, en eendrachtig ook de protonentherapie internationaal naar een hoger niveau te tillen