Bengt Johansson

Pulsed dose rate brachytherapy as the sole adjuvant radiotherapy after breast-conserving surgery of T1-T2 breast cancer : first long time results from a clinical study

BACKGROUND AND PURPOSE To evaluate the long time outcome with regard to local tumour control, cosmetic outcome and side effects of a short (5 days) accelerated interstitial brachytherapy treatment delivered to the surroundings of the operated sector. PATIENTS AND METHODS Between 1993 and 2003 we treated 50 women with early T1 and T2 breast cancer. Radical sector resection was performed and followed later with an interstitial pulsed dose rate (PDR) brachytherapy of 50Gy in 5 days. The treatment was centred on the tumour with a margin of 30mm. One patient was treated bilaterally. The patients were followed for a median of 86 (32-126) months. RESULTS Ipsilateral breast cancer recurrence was seen in 3 patients (6%). Two of them occurred outside the treated volume. The 5- and 7-year rates of actuarial local control were 96% and 96%, respectively, overall survival 88% and 85%, disease free survival 88% and 88%, respectively. A dosimetrical analysis showed that the partial breast irradiation covered a median of 31% of the total breast volume. Fat necrosis was seen in 12% and local (moderate-strong) fibrosis in 26% of the patients. Independent cosmetic scoring showed good or excellent result in 56% of the patients. CONCLUSIONS Local outcome is favourable and very similar to other published studies of accelerated partial breast irradiation. Our long time cosmetic results are lower than other published results.

Number of patients potentially eligible for proton therapy

A group of Swedish radiation oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy in a facility where one of the principal aims is to facilitate randomized and other studies in which the advantage of protons can be shown and the magnitude of the differences compared with optimally administered conventional radiation treatment, also including intensity-modulated radiation therapy (IMRT) and brachytherapy, can be shown. The estimations have been based on current statistics of tumour incidence in Sweden, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours together with information on normal tissue complication rates. In Sweden, it is assessed that between 2200 and 2500 patients annually are eligible for proton beam therapy, and that for these patients the potential therapeutic benefit is so great as to justify the additional expense of proton therapy. This constitutes between 14–15% of all irradiated patients annually.

The potential of proton beam radiation therapy in gastrointestinal cancer

A group of Swedish oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. In gastrointestinal cancers, it is assessed that at least 345 patients, mainly non-resectable rectal cancers, oesophageal and liver cancers, are eligible. Great uncertainties do however exist both in the number of patients with gastrointestinal cancers suitable for radiation therapy, and in the proportion of those where proton beams may give sufficiently better results.

Relative biological effectiveness of high-energy photons (up to 50 MV) and electrons (50 MeV)

In vitro studies of the relative biological effectiveness (RBE) of 50-MV X rays have shown an RBE of 1.1 relative to 4-MV X rays. This will be important in clinical radiotherapy. The aim of this study was to verify these results and to investigate whether photonuclear processes might cause the difference in RBE. To do so, 50- and 20-MV X rays and 50-MeV electrons were investigated with respect to RBE. Chinese hamster V79 cells were irradiated in a specially designed system which allows for a high reproducibility of geometry and dosimetry. Fractionation experiments were also carried out to establish the RBE at the clinically relevant dose level, 2 Gy. Fricke dosimetry was used, and the results were confirmed with ionization chamber measurements. The RBE for 50-MV X rays was estimated to be 1.14 at a surviving fraction of 0.1 and 1.12 at a surviving fraction of 0.01. The RBEs for the other qualities were equal to one. The RBE calculated for the 2 Gy/fraction experiments was 1.17.

GEC-ESTRO ACROP recommendations for head & neck brachytherapy in squamous cell carcinomas: 1st update – Improvement by cross sectional imaging based treatment planning and stepping source technology

The Head and Neck Working Group of the GEC-ESTRO (Groupe Européen de Curiethérapie - European Society for Therapeutic Radiology and Oncology) published in 2009 the consensus recommendations for low-dose rate, pulsed-dose rate and high-dose rate brachytherapy in head & neck cancers. The use of brachytherapy in combination with external beam radiotherapy and/or surgery was also covered as well as the use of brachytherapy in previously irradiated patients. Given the developments in the field, these recommendations needed to be updated to reflect up-to-date knowledge. The present update does not repeat basic knowledge which was published in the first recommendation but covers in a general part developments in (1) dose and fractionation, (2) aspects of treatment selection for brachytherapy alone versus combined BT+EBRT and (3) quality assurance issues. Detailed expert committee opinion intends to help the clinical practice in lip-, oral cavity-, oropharynx-, nasopharynx-, and superficial cancers. Different aspects of adjuvant treatment techniques and their results are discussed, as well the possibilities of salvage brachytherapy applications.

The potential of proton beam radiation therapy in prostate cancer, other urological cancers and gynaecological cancers

A group of Swedish oncologists and hospital physicists have estimated the number of patients in Sweden suitable for proton beam therapy. The estimations have been based on current statistics of tumour incidence, number of patients potentially eligible for radiation treatment, scientific support from clinical trials and model dose planning studies and knowledge of the dose-response relations of different tumours and normal tissues. In prostate cancer it is estimated that annually about 300 patients and in gynaecological cancer about 50 patients, are candidates for proton beam therapy. Owing to major uncertainties, it has not been possible to give an estimate of the number of potential patients with urinary bladder cancer.

A national approach for automated collection of standardized and population-based radiation therapy data in Sweden.

PURPOSE To develop an infrastructure for structured and automated collection of interoperable radiation therapy (RT) data into a national clinical quality registry. MATERIALS AND METHODS The present study was initiated in 2012 with the participation of seven of the 15 hospital departments delivering RT in Sweden. A national RT nomenclature and a database for structured unified storage of RT data at each site (Medical Information Quality Archive, MIQA) have been developed. Aggregated data from the MIQA databases are sent to a national RT registry located on the same IT platform (INCA) as the national clinical cancer registries. RESULTS The suggested naming convention has to date been integrated into the clinical workflow at 12 of 15 sites, and MIQA is installed at six of these. Involvement of the remaining 3/15 RT departments is ongoing, and they are expected to be part of the infrastructure by 2016. RT data collection from ARIA®, Mosaiq®, Eclipse™, and Oncentra® is supported. Manual curation of RT-structure information is needed for approximately 10% of target volumes, but rarely for normal tissue structures, demonstrating a good compliance to the RT nomenclature. Aggregated dose/volume descriptors are calculated based on the information in MIQA and sent to INCA using a dedicated service (MIQA2INCA). Correct linkage of data for each patient to the clinical cancer registries on the INCA platform is assured by the unique Swedish personal identity number. CONCLUSIONS An infrastructure for structured and automated prospective collection of syntactically interoperable RT data into a national clinical quality registry for RT data is under implementation. Future developments include adapting MIQA to other treatment modalities (e.g. proton therapy and brachytherapy) and finding strategies to harmonize structure delineations. How the RT registry should comply with domain-specific ontologies such as the Radiation Oncology Ontology (ROO) is under discussion.

ENT COBRA (Consortium for Brachytherapy Data Analysis): Interdisciplinary standardized data collection system for head and neck patients treated with interventional radiotherapy (brachytherapy)

Purpose Aim of the COBRA (Consortium for Brachytherapy Data Analysis) project is to create a multicenter group (consortium) and a web-based system for standardized data collection. Material and methods GEC-ESTRO (Groupe Européen de Curiethérapie – European Society for Radiotherapy & Oncology) Head and Neck (H&N) Working Group participated in the project and in the implementation of the consortium agreement, the ontology (data-set) and the necessary COBRA software services as well as the peer reviewing of the general anatomic site-specific COBRA protocol. The ontology was defined by a multicenter task-group. Results Eleven centers from 6 countries signed an agreement and the consortium approved the ontology. We identified 3 tiers for the data set: Registry (epidemiology analysis), Procedures (prediction models and DSS), and Research (radiomics). The COBRA-Storage System (C-SS) is not time-consuming as, thanks to the use of “brokers”, data can be extracted directly from the single centers storage systems through a connection with “structured query language database” (SQL-DB), Microsoft Access®, FileMaker Pro®, or Microsoft Excel®. The system is also structured to perform automatic archiving directly from the treatment planning system or afterloading machine. The architecture is based on the concept of “on-purpose data projection”. The C-SS architecture is privacy protecting because it will never make visible data that could identify an individual patient. This C-SS can also benefit from the so called “distributed learning” approaches, in which data never leave the collecting institution, while learning algorithms and proposed predictive models are commonly shared. Conclusions Setting up a consortium is a feasible and practicable tool in the creation of an international and multi-system data sharing system. COBRA C-SS seems to be well accepted by all involved parties, primarily because it does not influence the centers own data storing technologies, procedures, and habits. Furthermore, the method preserves the privacy of all patients.

Long term results of PDR brachytherapy for lip cancer

Purpose To evaluate the long time outcome with regard to local tumour control and side effects of a pulsed dose rate (PDR) monobrachytherapy of primary or recurrent cancer of the lip. Material and methods Between 1995 and 2007 we treated 43 patients with primary or recurrent clinical T1-T3N0 lip cancers. There were 22 T1 patients (51%), 16 T2 (37%) and 5 T3 cases (12%). A median dose of 60 (55-66) Gy was given, depending on the tumour volume. The PDR treatment was delivered with 0.83 Gy/pulse every second hour for 5.5-6.5 days. The patients were followed for a median of 55 (1-158) months. Results The 2-, 5- and 10-year rates of actuarial local control were 97.6%, 94.5% and 94.5%, overall survival 88.0%, 58.9% and 39.1%, disease free survival 92.7%, 86.4% and 86.4% respectively. The regional control rate was 93%. One patient (2%) developed distant metastases. A dosimetrical analysis showed a mean treated volume of 14.9 (3.0-56.2) cm3. Long-term side effects were mild and the cosmetic outcome excellent, except for 1 case (2%) of soft tissue necrosis and 1 case (2%) of osteoradionecrosis. Conclusions Local outcome is excellent and similar to other published studies of continuous low dose rate (cLDR) brachytherapy.

Pulsed dose rate brachytherapy as the boost in combination with external beam irradiation in base of tongue cancer. Long-term results from a uniform clinical series

Purpose To evaluate long time outcome with regard to local tumour control, side effects and quality of life of combined pulsed dose rate (PDR) boost and hyperfractionated accelerated external beam radiotherapy (EBRT) for primary base of tongue (BOT) cancers. Material and methods Between 1994 and 2007, the number of 83 patients were treated with primary T1-T4 BOT cancers. Seven patients (8%) were T1-2N0 (AJCC stage I-II) and 76 (92%) patients were T1-2N+ or T3-4N0-2 (AJCC stage III-IV). The mean estimated primary tumour volume was 15.4 (1-75) cm3. EBRT was given with 1.7 Gy bid to 40.8 Gy to primary tumour and bilateral neck lymph nodes in 2.5 weeks. PDR boost of 35 Gy and a neck dissection in clinical node positive case was performed 2-3 weeks later. The patients were followed for a median of 54 (2-168) months. Results The 2-, 5- and 10-years rates of actuarial local control were 91%, 89% and 85%, overall survival 85%, 65% and 44%, disease free survival 86%, 80% and 76%, respectively. The regional control rate was 95%. Six patients (7%) developed distant metastases. A dosimetric analysis showed a mean of 100% isodose volume of 58.2 (16.7-134) cm3. In a review of late complications 11 cases of minor (13%) and 5 of major soft tissue necroses (6%), as well as 6 cases of osteoradionecroses (7%) were found. The patients median subjective SOMA/LENT scoring at last follow up was as follow: grade 0 for pain and trismus, grade 1 for dysphagia and taste alteration, and grade 2 for xerostomia. Global visual-analogue-scale (VAS) scoring of quality of life was 8. Conclusion Local and regional tumour control rate was excellent in this treatment protocol. The data shows the PDR boost as at least as effective as published continuous low dose rate (CLDR) results.