ESTRO 2024 - Abstract Book

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Invited Speaker

ESTRO 2024

MARIA ANTONIETTA GAMBACORTA

FONDAZIONE UNIVERSITARIA A. GEMELLI IRCCS, DIAGNOSTIC IMAGING and RADIOTHERAPY, ROME, Italy

Abstract:

Re-irradiation: Radiotherapy in previously irradiated rectal cancer Local recurrence of locally advanced rectal cancer constitutes a rare event, with a 5-year incidence in pretreated patients of 4-8%. This is due to the adoption of multimodal treatments to eradicate primary tumors, such as preoperative radiotherapy +/- chemotherapy and TME surgery. About one-third of cases of recurrent local rectal cancer (LRRC) are completely asymptomatic, and most are diagnosed during a follow-up evaluation. Symptomatic patients suffer from rectal bleeding, altered bowel habits, pain, failure of the perineal wound healing, infection, perineal mass, and bowel obstruction, which severely compromise their quality of life. Complete eradication of local recurrence is the major factor related to survival, and a negative resection margin (R0) is the most important predictor of disease-specific survival; however, this is possible in less than half of patients because of the complexity of surgery related to changes in anatomical planes and the need for aggressive demolition to achieve an R0 resection. Irradiation of recurrence can increase the rate of optimal resection (R0) and can palliate symptoms in unresectable disease. However, it is also very challenging because of the previous irradiation, one must take into account the dose already received by the organs at risk (OAR) and at the same time be able to deliver an effective dose to the relapsing disease. Although reirradiation is recommended by current clinical guidelines, due to the paucity of solid evidence, a common modality for administering radiotherapy has not been defined with certainty. Recently multicenter groups are proposing studies with the goal of generating evidence, and ESTRO is moving to generate recommendations with the goal of homogenizing treatment approaches. The presentation will focus on the literature to provide guidance on available staging systems, radiation therapy schedules and techniques, dose and irradiation volumes, and indications of available dose constraints and ongoing studies.

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Risk-adapted and response-adapted strategies for stage 3 NSCLC

Andrea Riccardo Filippi

University of Milan and Fondazione IRCCS Istituto Nazionale dei Tumori, Radiation Oncology, Milan, Italy

Abstract:

The current standard of care for stage III unresectable NSCLC involves concurrent chemoradiotherapy (CCRT) followed by adjuvant durvalumab, but disease recurrence remains challenging. To improve survival and minimize toxicity, the focus is shifting towards predicting outcomes and anticipating tumor response to adapt treatment strategies. Although programmed death-ligand 1 (PD-L1) expression is currently the only validated biomarker, its limitations necessitate exploration of the entire tumor microenvironment (TME) to improve reliability. Additionally, the activity of various genes and molecular pathways, tumor mutational burden (TMB), and tumor-infiltrating lymphoid T-cells (TILs) are being investigated as potential predictive biomarkers. Furthermore, the association of oncogenic driver