Page 55 - SRPSKO DRUŠTVO ISTRAŽIVAČA RAKA

SDIRSACR Oncology Insights

quantitative changes in ctDNA levels, derived from droplet digital PCR and validated statistical frameworks. These
criteria allow classification of patients into distinct response categories after only one cycle of systemic therapy, with
early studies showing strong correlation with progression-free and overall survival.
This lecture will outline the rationale, methodology, and current evidence supporting ctDNA-RECIST, including
feasibility data, external validation efforts, and integration with clinical trials. The significance of ctDNA-RECIST for
improving monitoring of patient outcomes will be discussed, alongside opportunities for earlier treatment adaptation,
reduced toxicity, and optimized use of healthcare resources. Finally, the talk will highlight the ongoing international
collaboration to refine, validate, and implement ctDNA-based response evaluation as a complement—or potential
alternative—to radiological criteria in daily clinical practice

Acknowledgments and funding: This will be noted at the meeting

INVITED LECTURES

L01

Benefits of Combination Therapies in Cancer Treatment

Orcun Can 1
1 Acıbadem Maslak Hospital, Department of Medical Oncology, Istanbul, Türkiye

Keywords: immunotherapy, radiotherapy, combination therapy, biomarkers, abscopal effect, antibody-drug conjugates,
STING agonists

Background: Combination therapies have transformed oncology by overcoming resistance mechanisms seen with
monotherapies. Integrating radiotherapy, immunotherapy, targeted therapies, and biomarker-driven personalization
has expanded therapeutic options in solid tumors.
Material and Methods: The mechanistic rationale includes immunogenic cell death induced by chemotherapy
and radiotherapy, enhancing antigen presentation and T-cell priming. Modulation of the tumor microenvironment
through anti-VEGF agents and immune checkpoint inhibitors increases immune infiltration. Additional strategies
involve oncolytic viruses, antibody-drug conjugates (ADCs), and innate immune activators such as STING agonists
(e.g., MK-1454). Therapeutic pairings include chemotherapy plus immune checkpoint inhibitors (e.g., carboplatin +
atezolizumab in NSCLC), targeted therapies with PD-1 blockade (e.g., BRAF/MEK inhibitors + anti-PD-1 in melanoma),
and combinations such as ADC + ICI (e.g., enfortumab vedotin + pembrolizumab). AI-guided and multi-omic treatment-
matching platforms are increasingly utilized.
Results: Phase III trials show marked survival improvements. IMpower150 reported overall survival (OS) of 19.2 vs.
14.7 months; PACIFIC showed 5-year OS of 43% vs. 29%. CheckMate-067 and 9LA demonstrated long-term survival
advantages with combined ICI strategies. In PD-L1+ triple negative breast cancer (TNBC), IMpassion130 indicated clear
progression-free survival (PFS) benefit. A representative case involved a 60-year-old male with brain and systemic
metastases; following stereotactic radiosurgery and sequential chemo-immunotherapy (cisplatin + pemetrexed →
atezolizumab + bevacizumab), complete metabolic response was achieved. Immune-related adverse events (thyroiditis,
hepatitis, arthritis) were manageable over 47 cycles of immunotherapy.
Conclusion: Combination therapies represent a new era in oncology. Optimally sequenced and personalized multimodal
treatments enhance outcomes. Emerging tools like spatial transcriptomics, microbiome-based prediction, and AI
decision platforms will be key for future precision oncology.

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