Contact Brachytherapy Research Articles

FP1.8 - Optimizing Rectal Cancer Treatment: Comprehensive response to Neoadjuvant therapy

Abstract Aims This study aimed to assess the outcomes and feasibility of a watch-and-wait strategy in patients with rectal cancer showing a complete response to neoadjuvant chemoradiotherapy (CRT). The primary objectives included evaluating the oncological results, disease-free interval, and survival rates in patients who underwent the watch-and-wait approach after a complete clinical response. Methods The study involved a retrospective analysis of last 10 years of rectal cancer patients enrolled in a complete responder surveillance program in an acute general hospital. Cohort characteristics, including age, performance status, tumor histology, distance from the anal verge, and treatment modalities, were documented. Results The median age was 74 (57-90), and the median performance status was 1, with the age at diagnosis being 69. All cohort members had a histologically confirmed rectal adenocarcinoma. The median tumor-to-anal-verge distance was 5 cm (1-10 cm). Neoadjuvant chemotherapy was administered to 55% of patients. All patients underwent long-course radiotherapy, and 35% received papillon contact brachytherapy. Total neoadjuvant therapy was received by 10%. The median follow-up involved approximately 9 colonoscopies. During follow-up, 25% of patients experienced recurrence, with a median disease-free interval of 3.5 years. Conclusion The findings of this study, in addition to ongoing prospective clinical trials and insights from databases such as EURECCA and OnCore, indicate that a watch-and-wait approach can be safe and effective for selected rectal cancer patients who have achieved a complete response to neoadjuvant CRT. This study highlights the significance of additional research to identify appropriate patients for this approach and to refine its implementation in rectal cancer management.

Contact x-ray brachytherapy for the treatment of rectal cancer: A systematic review and meta-analysis.

e15628 Background: Rectal cancer is a highly prevalent disease, particularly among the elderly and frail populations. While surgical resection has traditionally been the primary management approach, it carries inherent risks, including operative mortality, morbidity, and poor long-term functional outcomes. These risks are particularly pronounced in older, co-morbid individuals. Evidence presented in the 2023 phase III OPERA randomised trial suggests that Contact X-ray Brachytherapy (CXB) is a viable organ-preserving alternative to radical surgery. We conducted a systematic review and meta-analysis to assess the clinical effectiveness of CXB in the treatment of rectal cancer. Methods: This systematic review was prospectively registered (CRD42021284969) and reported in accordance with PRISMA guidelines. PubMed, EMBASE, SCOPUS and Cochrane CENTRAL Libraries were interrogated using the search terms “Rectal cancer”, “Contact Brachytherapy”, and synonym terms. Literature search and data extraction were conducted by two reviewers, with recourse to a senior author for resolution of conflicts. Clinical complete response (cCR) was the primary outcome. Secondary outcomes include local regrowth, regional recurrence, salvage surgery rates, long-term disease control post-salvage surgery and survival outcomes. Proportional meta-analyses were conducted and presented as forest plots with summary proportions and 95% confidence intervals. The Higgins I2 statistic was used to assess for heterogeneity. The random effects model was employed in studies reporting substantial heterogeneity (I2> 50%). Results: The literature search identified 973 studies, of which 48 studies encompassing 5,447 patients were included in the meta-analysis. Pooled estimates of outcomes were as follows: cCR rate = 80% (95% CI 76-88%), local regrowth = 15% (95% CI 12-18%), regional failure rate = 3% (95% CI 2-4%), salvage surgery rate = 14% (95% CI 11-18%), long-term disease control post-salvage surgery rate = 88% (95% CI 78-96%) and organ preservation 82% (95% CI 75-88%). A subgroup analysis was conducted and stratified by concomitant therapy (CXB alone, CXB & EBRT, CXB & EBCRT). CXB, in conjunction with EBCRT, leads to a statistically significant reduction in both local regrowth and regional failure. The local regrowth rates were 16% (95% CI 11-21%), 17% (95% CI 11-23%), and 10% (95% CI 8-13%) respectively, with a p-value of 0.05. The regional failure rates were 4% (95% CI 2-8%), 4% (95% CI 2-5%), and 1% (95% CI 0-2%), p = 0.02. Conclusions: CXB, combined with EBCRT, in the appropriately selected patient can achieve long-term disease control whilst avoiding major surgery. Salvage surgery is a viable option for patients who experience disease regrowth, with excellent long-term disease control. CXB may be considered a safe alternative to surgery in the appropriately selected patient.

2565: Clinical prediction models for contact brachytherapy in managing rectal cancers: A scoping review

2565: Clinical prediction models for contact brachytherapy in managing rectal cancers: A scoping review

Нейтроны в онкологии. Прошлое, настоящее и будущее. Обзор

For many decades, neutrons have been actively used in the treatment of various cancer diseases. In the light of recent advances in conventional photon therapy, interest in neutrons has almost faded, despite their unique biological features. At the same time, neutron-capture therapy is actively developing, the concept of which is based on the high precision of the treatment method, allowing to minimize the toxicity of the treatment. Another way of using neutrons deserves attention – as sources for contact brachytherapy. In Russia, various neutron therapy methods have been studied in depth, ranging from fundamental aspects to direct wide use in various clinical situations. Such capabilities were provided by the extensive research infrastructure of particle physics, and its accessibility to researchers and clinicians. In the modern clinical perspective, neutron therapy can be an effective treatment option for certain clinical indications. Such cases are traditionally referred to as radioresistant tumors, which are considered to be low sensitive to irradiation. This mini-review recall the history of the use of neutrons since their discovery and to the present days, as well it discusses their role in the further development of radiotherapy.

Basal Cell Carcinoma After High Dose Rate Brachytherapy: Medium-term Dermoscopic Evaluation of Cancer's Response.

Basal cell carcinoma of the facial region remains a challenge for contemporary oncology due to the presence of aesthetic regions and critical organs. Surgery is not always the optimal solution, and high dose rate (HDR) brachytherapy has emerged as an organ-sparing treatment method whose effectiveness has been proven by a growing number of publications. Dermoscopy is a diagnostic tool that bridges clinical and pathological examination of skin lesions. It is routinely used for diagnosis, monitoring of treatment, and post-treatment evaluation; however, the literature lacks data concerning changes in dermoscopic patterns of skin cancers during and after irradiation. Our team conducted a prospective non-randomized trial of 39 patients with high-risk basal cell carcinomas (BCCs), mostly localized within the high-risk zone (H-zone) of the facial region, and who qualified for HDR brachytherapy. HDR contact brachytherapy with custom-made surface molds was introduced, delivering a dose of 45Gy in 9 fractions prescribed to the tumor. Every patient was observed clinically and dermoscopically at three observational points: before treatment, at the end of treatment (3rd week), and 24weeks after the end of therapy. The evolution of clinical and dermoscopic patterns was observed by two independent dermoscopists using current diagnostic criteria. A database of 12,088 photographic observations was evaluated. Univariate logistic regression proved that brachytherapy decreases the number of clinical and dermoscopic patterns typical for basal cell carcinoma, as well as dermoscopic features not related to BCC, presumably due to the formation of scar tissue. In addition, univariate logistic regression with random effects proved a positive correlation between tumor size and presence of various dermoscopic patterns typical for BCC. Dermoscopy is proven to be easy to perform and an adequate monitoring tool for patients with BCCs undergoing HDR brachytherapy.

Planned organ preservation for elderly patients with rectal cancer using short course radiotherapy and a contact brachytherapy boost-an International multi-institution analysis.

The use of external beam radiotherapy (EBRT) and contact X-Ray brachytherapy (CXB) is emerging as an effective alternative in patients with early stage rectal cancer with the intent of organ preservation (OP). Short course radiotherapy (SCRT) is an alternative EBRT schedule for patients not fit for chemotherapy or for longer courses of EBRT. There are no multicentre studies that have reported on the outcomes of SCRT with a CXB boost, therefore we present these from patients from centres from the UK and Sweden. From the Guildford Colorectal Database or local databases, 258 patients who underwent SCRT and CXB with the intent of OP from five centres treated between 2007 and 2019 were identified. Response and survival data was analysed and presented. With a median age of 81, 226 patients were treated with radiotherapy alone (RTA) and 32 immediately after local excision (ILE). Median follow-up was 24 months. 70% and 97% of patients in the RTA and ILE groups respectively had a complete clinical response (cCR) after SCRT with CXB. Of those, local relapse was seen in 16% of the RTA and 3% of the ILE group. Median survival was 40 months after CXB in the RTA and 52 months in the ILE group. 94% of patients remained stoma-free to the point of latest follow-up. This data suggests that CXB when combined with SCRT, in a mainly elderly and comorbid population, provides good palliation with stoma-avoidance. Oncological outcomes compare with previously published work. A greater focus is required on quality of life outcomes after OP.

Brachytherapy in the Treatment of Non-Melanoma Skin Peri-Auricular Cancers-A Retrospective Analysis of a Single Institution Experience.

This paper presents the results of a retrospective analysis of 33 patients treated with contact or interstitial high-dose-rate (HDR) brachytherapy for skin cancers of the outer ear, involving the auricle and the skin of the adjacent area. Brachytherapy was used both as a definitive treatment (15 patients-43%) and adjuvant treatment after surgery (18 patients-57%). The basic criterion for adjuvant treatment was a positive or narrow (<1 mm) resection margin. Fraction doses from 3 to 7 Gy per fraction were used at intervals from six hours (interstitial brachytherapy) to a maximum of seven days (contact brachytherapy). The treatment time ranged from 1 to 42 days, and the total dose range was 7 to 49 Gy. The follow-up was 29.75 months (range 2-64). In the group of patients treated with adjuvant therapy, in the patients with post-radiation reaction, the mean time from surgery to the start of brachytherapy was 7.72 ± 3.05 weeks, the median was 8 (6-12) weeks, and in the group without post-radiation reaction, the mean time was 11.13 ± 4.41 weeks, the median time was 11 weeks (8-14). The risk of a post-radiation reaction increased significantly more often in patients with more advanced disease. In the case of contact brachytherapy, the post-radiation reaction occurred significantly more often (14/21 patients-43%) than in the case of interstitial brachytherapy (3/11 patients-9.4%). In patients with post-radiation reactions, a significantly larger volume of the skin receiving a dose of 200% was found, and the volume receiving a dose of 150% was close to statistical significance. The mean volume of the skin receiving a 200% dose in the group with post-radiation reactions was 28.05 ± 16.56 cm3, the median was 24.86 (0.5-52.3) cm3, and the mean volume in the group without post-radiation reaction was 17.98 ± 10.96 cm3, median 14.95 (3.9-44.96) cm3. The result was statistically significant (Z = 2.035, p = 0.041). Interstitial HDR (high-dose-rate) brachytherapy for non-melanoma skin cancers around the ear is highly effective, short, and has a relatively low burden on the patient. The toxicity of the treatment was low. In the case of contact brachytherapy, the toxicity profile is slightly higher but acceptable for patients. This method is preferred in patients in whom interstitial brachytherapy is impossible to perform due to anatomical and logistical reasons. The unquestionable advantage of contact brachytherapy is its ability to be performed on an outpatient basis without the need to stay in the hospital. No severe and late CTCAE ≥III and late RTOG ≥III toxicity was observed. In patients after surgery, in order to minimise the risk of radiation reaction, it is optimal to start treatment at least eight weeks after surgery. In the presence of extensive lesions, the use of interstitial brachytherapy seems to be more advantageous, especially when the expected volume of healthy skin in the dose range of 200% and 150% is above 15 cm3 and 50 cm3, respectively.

Endorectal contact radiation boosting: Making the case for dose AND volume reporting

IntroductionThe various rectal endoluminal radiation techniques all have steep, but different, dose gradients. In rectal contact brachytherapy (CXB) doses are typically prescribed and reported to the applicator surface and not to the gross tumor volume (GTV), clinical target volume (CTV) or organs at risk (OAR), which is crucial to understand tumor response and toxicity rates. To quantify the above-described problem, we performed a dose modeling study using a fixed prescription dose at the surface of the applicator and varied tumor response scenarios. MethodsEndorectal ultrasound-based 3D-volume-models of rectal tumors and the rectal wall were used to simulate the delivered dose to GTV, CTV and the rectal wall layers, assuming treatment with Maastro HDR contact applicator for rectal cancer with a fixed prescription dose to the applicator surface (equivalent to 3 × 30 Gy CXB) and various response scenarios. ResultsAn identical prescribed dose to the surface of the applicator resulted in a broad range of doses delivered to the GTV, CTV and the uninvolved intestinal wall. For example, the equieffective dose in 2 Gy per fraction (EQD2) D90% of the GTV varied between 63 and 231 Gy, whereas the EQD2 D2cc of the rectal wall varied between 97 and 165 Gy. ConclusionDoses prescribed at the surface are not representative of the dose received by the tumor and the bowel wall. This stresses the relevance of dose reporting and prescription to GTV and CTV volumes and OAR in order to gain insight between delivered dose, local control and toxicity and to optimize treatment protocols.

GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer

PurposeTo issue consensus recommendations for contact X-Ray brachytherapy (CXB) for rectal cancer covering pre-treatment evaluation, treatment, dosimetric issues and follow-up. These recommendations cover CXB in the definitive and palliative setting. MethodsMembers of GEC ESTRO with expertise in rectal CXB issued consensus-based recommendations for CXB based on literature review and clinical experience. Levels of evidence according to the Oxford Centre for Evidence based medicine guidance are presented where possible. ResultsThe GEC ESTRO ACROP consensus recommendations support the use of CXB to increase the chances of clinical complete remission and cure for patients who are elderly with high surgical risk, surgically unfit or refusing surgery. For palliative treatment, the use of CXB is recommended for symptomatic relief and disease control. The use of CXB in an organ-preservation setting in surgically fit patients is recommended within the setting of a clinical trial or registry. ConclusionsThe GEC ESTRO ACROP recommendations for CXB are provided. Recommendations towards standardisation of reporting and prescription are given. Practitioners are encouraged to follow these recommendations and to develop further clinical trials to examine this treatment modality and increase the evidence base for its use. The routine collection of outcomes both clinical and patient-reported is also encouraged.

PD-0839 Outcomes for 193 rectal cancer patients receiving contact brachytherapy for organ preservation

PD-0839 Outcomes for 193 rectal cancer patients receiving contact brachytherapy for organ preservation

Multiple endocrine neoplasia syndrome

Background. Multiple endocrine neoplasia type 1 is a rare inherited disease that combines heterogeneous autosomal inherited disorders, the pathogenesis of which is based on hyperplasia or tumor transformation of several neuro- endocrine glands. In this pathology, treatment protocols are insufficient. Surgical treatment, suppressive or replacement therapy, radiation and chemotherapy are mainly used.
 We presented a successful experience of combined radiotherapy of multiple pancreatic insulinoma as the main clinical manifestation of the syndrome of multiple endocrine neoplasia. The combination of intra-tissue brachytherapy and megavolt remote therapy in TFD, isoeffective 50 Gy, allowed to achieve reliable control of hypoglycemic attacks within 2 years of follow-up.
 Purpose – to acquaint the medical community with successful experience of combined radiation treatment of multiple pancreatic insulinoma as a main clinical manifestation of the multiple endocrine neoplasia syndrome.
 Materials and Methods. Clinical case of patient L., 30 years old, who received combined radiation therapy for clinically significant manifestations of hormonally active multiple insulinoma of the pancreas in the Department of Radiological Oncology of State Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine».
 Results. In May 2019, palliative contact brachytherapy was performed on the MULTISOURCE device. Total focal dose (TFD) for cells in the pancreas GENUS 3 Gy 5 times a week, TFD 18 Gy. At the end of brachytherapy, attacks of hypoclycemia were stopped. In March 2020, remote radiation therapy was performed on a linear accelerator CLINAC-600C (6MeV) in the mode of classical fractionation (single focal dose (SFD) 1.8 Gy 5 times a week), TFD for the entire volume of the pancreas 30.6 Gy. In May 2021, CT scan showed that the process in the pancreas was stabilized, but in connection with the resumption of hypoglycemia and the emergence of dyshormonal osteopathy, a course of remote radiation therapy for the entire pancreas, SFD 1.8 Gy, TFD 20 Gy simultaneously with the introduction of bisphosphonates.
 Conclusions. Our patient demonstrates type I syndrome of multiple neo- plasms, neuroendocrine tumor of pancreas G1 T3N0M0 IIB stage. Due to multi-stage combined radiation therapy for 2 years it is possible to achieve stabilization of the process and reliable control of hypoglycemic attacks, which indicates the effectiveness of this method as an alternative to surgery in unresectable cases.

PO-0261 Adjuvant HDR contact brachytherapy for localized penile cancer: long-term toxicities and outcomes

PO-0261 Adjuvant HDR contact brachytherapy for localized penile cancer: long-term toxicities and outcomes

Preservation of the rectum is possible in early rectal cancer with neoadjuvant radiotherapy, delay and local excision-a 12-year single-centre experience of the evolution of early rectal cancer treatment.

Treatment of early rectal cancer (ERC) is undergoing a revolution towards rectum preservation. Adjuvant and neoadjuvant therapy alongside local excision (LE) means that organ preservation is a real possibility for most patients and a viable alternative for frailer patients. This study presents our 12-year experience as a specialist regional ERC unit, evolving towards organ preservation. Data were collected prospectively between 2006 and 2018 for all patients referred to the regional ERC multidisciplinary team with suspected or confirmed ERC. Patients considered suitable for LE, or those declining radical surgery, were offered LE or neoadjuvant short-course radiotherapy (SCRT), delay and LE with subsequent rescue surgery or contact brachytherapy for unfavourable histopathology. In all, 102 patients underwent LE. Ten patients were excluded (N=92). 45 patients underwent LE directly and 47 patients received SCRT and LE. After SCRT and LE, a pathological complete response was achieved in 44.7%. This approach also resulted in a lower rate of lymphovascular invasion (22.2% vs. 6.4%), fewer distant recurrences (4.4% vs. 0%) and a better disease-specific mortality (11.1% vs. 0%) (P<0.05). Although statistically insignificant, fewer patients required rescue surgery after SCRT (15.6% vs. 4.3%). Organ preservation with a good oncological outcome is better achieved by neoadjuvant radiotherapy, delay and LE. To achieve this, careful patient selection, thorough preoperative investigation, experienced surgical technique and a deep appreciation of tumour biology managed via a dedicated ERC network is paramount.

OC-1054: MAASTRO applicator, a novel rectal applicator for contact brachytherapy with 192Ir HDR sources

OC-1054: MAASTRO applicator, a novel rectal applicator for contact brachytherapy with 192Ir HDR sources

Advanced design, simulation, and dosimetry of a novel rectal applicator for contact brachytherapy with a conventional HDR 192Ir source

PurposeDose escalation yields higher complete response to rectal tumors, which may enable the omission of surgery. Dose escalation using 50 kVp contact x-ray brachytherapy (CXB) allow the treatment of a selective volume, resulting in low toxicity and organs-at-risk preservation. However, the use of CXB devices is limited because of its high cost and lack of treatment planning tools. Hence, the MAASTRO applicator (for HDR 192Ir sources) was developed and characterized by measurements and Monte Carlo simulations to be a cost-effective alternative to CXB devices. Methods and MaterialsA cylindrical applicator with lateral shielding was designed to be used with a rectoscope using its tip as treatment surface. Both the applicator and the rectoscope have a slanted edge to potentially allow easier placement against tumors. The applicator design was achieved by Monte Carlo modeling and validated experimentally with film dosimetry, using the Papillon 50 (P50) device as reference. ResultsThe applicator delivers CXB doses in less than 9 min using a 20375 U source for a treatment area of approximately 20 × 20 mm2 at 2 mm depth. Normalized at 2 mm, the dose falloff for depths of 0 mm, 5 mm, and 10 mm are 130%, 70%, and 43% for the P50 and 140%, 67%, and 38% for the MAASTRO applicator, respectively. ConclusionsThe MAASTRO applicator was designed to use HDR 192Ir sources to deliver a dose distribution similar to those of CXB devices. The applicator may provide a cost-effective solution for endoluminal boosting with clinical treatment planning system integration.

Cutaneous T Lymphoma: Complete Therapeutic Response after Treatment with Contact Brachytherapy: About a Case and Review of Literature

Cutaneous T Lymphoma: Complete Therapeutic Response after Treatment with Contact Brachytherapy: About a Case and Review of Literature

Clinical audit of rectal cancer patient referrals for papillon contact brachytherapy

Abstract Background and purpose: Papillon treatment is a form of contact X-ray brachytherapy (CXB) which is used as an alternative to surgery for rectal cancer. This study aimed to audit patients who were referred for and treated with CXB over a 6-year period against guidelines derived from a critical review of the evidence base. Materials and methods: Patient demographics, tumour characteristics and outcome data were gathered for 31 patients referred for CXB. A critical review of the evidence identified consensus referral criteria and outcome data against which to audit patients. Results: Referral criteria were derived from six published studies. These applied to patients unfit for surgery or stoma-averse. All referred patients had a visible tumour or scar with a tumour size under 3 cm and sited less than 12 cm from the anal verge. Nodal status varied from N0 to N2, but there was no metastatic disease present. The audited cohort demonstrated demographic equivalence, while the initial clinical complete response and recurrence rates were also comparable. Conclusion: This audit confirmed the validity of referral and treatment protocols and should guide future referrals until evidence from ongoing studies becomes available. These findings should contribute to the development of robust national guidelines.

Clinical audit of rectal cancer patient referrals for Papillon contact brachytherapy

AbstractBackground and purpose:Papillon treatment is a form of contact X-ray brachytherapy (CXB) which is used as an alternative to surgery for rectal cancer. This study aimed to audit patients who were referred for and treated with CXB over a 6-year period against guidelines derived from a critical review of the evidence base.Materials and methods:Patient demographics, tumour characteristics and outcome data were gathered for 31 patients referred for CXB. A critical review of the evidence identified consensus referral criteria and outcome data against which to audit patients.Results:Referral criteria were derived from six published studies. These applied to patients unfit for surgery or stoma-averse. All referred patients had a visible tumour or scar with a tumour size under 3 cm and sited less than 12 cm from the anal verge. Nodal status varied from N0 to N2, but there was no metastatic disease present. The audited cohort demonstrated demographic equivalence, while the initial clinical complete response and recurrence rates were also comparable.Conclusion:This audit confirmed the validity of referral and treatment protocols and should guide future referrals until evidence from ongoing studies becomes available. These findings should contribute to the development of robust national guidelines.

Applicateur numérique par impression tridimensionnelle en curiethérapie de contact

Brachytherapy of skin tumours uses custom applicators that are manufactured manually. The integration of 3D printing customization of applicators during hidh dose rate brachytherapy planning could allow a better skin conformation and a better reproducibility of the positioning and treatment. We present the technical implementation of this method for our first two patients. A provisional planning scanner was carried out to create a digital applicator. The creation of the digital applicator used successively several software programs. The first, commercial, was RhinocerosR 3D used via Grasshopper, an integrated open source plug-in. The 3D applicator was then exported to the commercial software Simplify3DR. A g-code format file was generated for the printer. A second scanner was made with a 3D applicator in place to plan the final treatment. The treatment was planned by reverse optimization. The applicator could be designed within 15 days. For patient A, it was noted that 95 % of the clinical target volume received at least 35.4Gy (63Gy EQD2). For patient B, 95 % of the clinical target volume received at least 36Gy (64.8Gy EQD2). The forecast and actual planimetry met the coverage criteria of D95. Contact brachytherapy with 3D bioimpression is feasible, after software training, for complex treatment lesions. This technique could be extended to other indications.

PO-1031: High-dose-rate contact brachytherapy to treat skin carcinomas on flat surfaces

PO-1031: High-dose-rate contact brachytherapy to treat skin carcinomas on flat surfaces