Reirradiation: Standards, challenges, and patient-focused strategies across tumor types.

Reirradiation (reRT), defined as administering a course of radiation therapy to a specific area previously irradiated, is an evolving treatment strategy for locoregionally recurrent cancer that offers significant potential and poses inherent challenges. Advances in such techniques as intensity-modulated and stereotactic body radiation therapy have improved precision, making reRT a viable option for complex scenarios previously deemed high-risk. Nevertheless, reRT remains associated with substantial risks-including life-threatening side effects, functional impairments, and psychosocial effects-which must be carefully balanced against the patient's overall health and the likelihood of achieving cancer control or palliation.

Toxicity Within 6 Months of Heterogeneous Fluorodeoxyglucose-Guided Radiotherapy Dose Escalation for Locally Advanced Non-Small Cell Lung Cancer in the Scandinavian Randomized Phase III NARLAL2 Trial.

Purpose: Radiation dose escalation for locally advanced non-small cell lung cancer (LA-NSCLC) has been challenged by toxicity concerns. The Scandinavian phase III multicenter dose-escalation trial NARLAL2 (ClinicalTrials.gov identifier: NCT02354274) used a novel approach to dose escalation: heterogeneous escalation driven by the fluorodeoxyglucose positron emission tomography-avid region, with strict normal tissue dose constraints.

Evaluating primary tumor position variation for rectal cancer patients treated with long course radiotherapy.

To quantify interfraction shape and positional variations of primary tumor volumes for rectal cancer patients receiving long course radiotherapy by comparing two quantification strategies: a center-of-mass (COM) method and a surface-based metric that captures local deformations.This study utilized repeat MRI scans before and during radiotherapy (RT) for rectal cancer to investigate the positional variation of the primary gross tumor volume (GTVp). Sixteen patients underwent six MRI exams, with the initial three before the RT course and the subsequent three at one, two, and four weeks into the RT course.

Improved prognostication of overall survival after radiotherapy in lung cancer patients by an interpretable machine learning model integrating lung and tumor radiomics and clinical parameters.

Background: Accurate prognostication of overall survival (OS) for non-small cell lung cancer (NSCLC) patients receiving definitive radiotherapy (RT) is crucial for developing personalized treatment strategies. This study aims to construct an interpretable prognostic model that combines radiomic features extracted from normal lung and from primary tumor with clinical parameters. Our model aimed to clarify the complex, nonlinear interactions between these variables and enhance prognostic accuracy.

Ongoing prospective studies on reirradiation: A systematic review of a clinical trials database.

Introduction: Reirradiation has gained increasing interest, as advances in systemic therapy increase the survival of patients with cancer, and modern radiation techniques allow more precise treatments. However, high-quality prospective evidence on the safety and efficacy of reirradiation to guide clinical practice remains scarce. This systematic review evaluates ongoing prospective studies on reirradiation to identify research gaps and priorities.

Reirradiation - still navigating uncharted waters?

With the emergence of high-precision radiotherapy technologies such as stereotactic ablative radiotherapy (SABR), MR guided brachytherapy, image guided intensity modulated photon and proton radiotherapy and most recently daily adaptive radiotherapy, reirradiation is increasingly recognized as a viable treatment option for many patients. This includes those with recurrent, metastatic or new malignancies post initial radiotherapy. The primary challenge in reirradiation lies in balancing tumor control against the risk of severe toxicity from cumulative radiation doses to previously irradiated normal tissue.

Individual lymph node position variation for rectal cancer patients treated with long course chemoradiotherapy.

Background And Purpose: Delivery of high precision radiotherapy lymph node boosts requires detailed information on the interfraction positional variation of individual lymph nodes. In this study we characterized interfraction positional shifts of suspected malignant lymph nodes for rectal cancer patients receiving long course radiotherapy. Furthermore, we investigated parameters which could affect the magnitude of the position variation.

Multi-centre evaluation of variation in cumulative dose assessment in reirradiation scenarios.

Background And Purpose: Safe reirradiation relies on assessment of cumulative doses to organs at risk (OARs) across multiple treatments. Different clinical pathways can result in inconsistent estimates. Here, we quantified the consistency of cumulative dose to OARs across multi-centre clinical pathways.

Treatment planning for patients with low rectal cancer in a multicenter prospective organ preservation study.

Background: Non-surgical management of rectal cancer relies on (chemo)radiotherapy as the definitive treatment modality. This study reports and evaluates the clinical high dose radiotherapy treatment plans delivered to patients with low resectable rectal cancer in a Danish multicenter trial.

Methods: The Danish prospective multicenter phase II Watchful Waiting 2 trial (NCT02438839) investigated definitive chemoradiation for non-surgical management of low rectal cancer.

Re-irradiation in clinical practice: Results of an international patterns of care survey within the framework of the ESTRO-EORTC E-RADIatE platform.

Background: Re-irradiation is an increasingly utilized treatment for recurrent, metastatic or new malignancies after previous radiotherapy. It is unclear how re-irradiation is applied in clinical practice. We aimed to investigate the patterns of care of re-irradiation internationally.

Different benefits of adaptive radiotherapy for different histologies of NSCLC.

Background: Adenocarcinoma (AC) and squamous cell carcinoma (SCC) are the most frequent histological subtypes of non-small cell lung cancer (NSCLC). The aim of this study was to investigate how patients with AC and SCC benefit from image-guided adaptive radiotherapy (ART) with tumour match.

Material And Methods: Consecutive patients diagnosed with AC or SCC of the lung treated with definitive chemo-radiotherapy before and after the implementation of ART and tumour match were retrospectively included for analyses.

European Society for Radiotherapy and Oncology and European Organisation for Research and Treatment of Cancer consensus on re-irradiation: definition, reporting, and clinical decision making.

Re-irradiation can be considered for local recurrence or new tumours adjacent to a previously irradiated site to achieve durable local control for patients with cancer who have otherwise few therapeutic options. With the use of new radiotherapy techniques, which allow for conformal treatment plans, image guidance, and short fractionation schemes, the use of re-irradiation for different sites is increasing in clinical settings. Yet, prospective evidence on re-irradiation is scarce and our understanding of the underlying radiobiology is poor.

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

Introduction: The 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.

Development and validation of prognostic models for anal cancer outcomes using distributed learning: protocol for the international multi-centre atomCAT2 study.

Background: Anal cancer is a rare cancer with rising incidence. Despite the relatively good outcomes conferred by state-of-the-art chemoradiotherapy, further improving disease control and reducing toxicity has proven challenging. Developing and validating prognostic models using routinely collected data may provide new insights for treatment development and selection.

Prognostic factors for patients with anal cancer treated with conformal radiotherapy-a systematic review.

Aims: Anal cancer is primarily treated using concurrent chemoradiotherapy (CRT), with conformal techniques such as intensity modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) now being the standard techniques utilised across the world. Despite this, there is still very limited consensus on prognostic factors for outcome following conformal CRT. This systematic review aims to evaluate the existing literature to identify prognostic factors for a variety of oncological outcomes in anal cancer, focusing on patients treated with curative intent using contemporary conformal radiotherapy techniques.

A Phase II trial of Higher RadiOtherapy Dose In The Eradication of early rectal cancer (APHRODITE): protocol for a multicentre, open-label randomised controlled trial.

Introduction: The standard of care for patients with localised rectal cancer is radical surgery, often combined with preoperative neoadjuvant (chemo)radiotherapy. While oncologically effective, this treatment strategy is associated with operative mortality risks, significant morbidity and stoma formation. An alternative approach is chemoradiotherapy to try to achieve a sustained clinical complete response (cCR).

GEC ESTRO ACROP consensus recommendations for contact brachytherapy for rectal cancer.

Purpose: To 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.

Methods: Members of GEC ESTRO with expertise in rectal CXB issued consensus-based recommendations for CXB based on literature review and clinical experience.

Dose summation and image registration strategies for radiobiologically and anatomically corrected dose accumulation in pelvic re-irradiation.

Background: Re-irradiation (reRT) is a promising technique for patients with localized recurrence in a previously irradiated area but presents major challenges. These include how to deal with anatomical change between two courses of radiotherapy and integration of radiobiology when summating original and re-irradiation doses. The Support Tool for Re-Irradiation Decisions guided by Radiobiology (STRIDeR) project aims to develop a software tool for use in a commercial treatment planning system to facilitate more informed reRT by accounting for anatomical changes and incorporating radiobiology.

Predicting outcomes in anal cancer patients using multi-centre data and distributed learning - A proof-of-concept study.

Background And Purpose: Predicting outcomes is challenging in rare cancers. Single-institutional datasets are often small and multi-institutional data sharing is complex. Distributed learning allows machine learning models to use data from multiple institutions without exchanging individual patient-level data.

3D image-guided treatment planning for Ruthenium-106 brachytherapy of choroidal melanomas.

Background: Current standard treatment procedures for Ruthenium-106 (Ru-106) brachytherapy for choroidal melanomas do not use 3D image-guided treatment planning. We evaluated the potential impact of introducing 3D treatment planning and quantified the theoretical clinical benefits in terms of tumour control probability (TCP) and normal tissue complication probability (NTCP).

Materials And Methods: Treatment plans for thirty-two patients were optimized using 3D image-guided treatment planning and compared to the original 2D clinical plans.

Dose-Response and Normal Tissue Complication Probabilities after Proton Therapy for Choroidal Melanoma.

Purpose: Normal tissue complication probability (NTCP) models could aid the understanding of dose dependence of radiation-induced toxicities after eye-preserving radiotherapy of choroidal melanomas. We performed NTCP-modeling and established dose-response relationships for visual acuity (VA) deterioration and common late complications after treatments with proton therapy (PT).

Design: Retrospective study from single, large referral center.