Serbian Radiation Oncology Congress
Published November 1, 2024 | Version v1
Conference paper Open

The role of CEA and CA 19-9 Tumor Markers in Predicting Response to Neoadjuvant Radiochemotherapy in Locally Advanced Rectal Cancer

Authors/Creators

  • 1. ROR icon Institut za onkologiju i radiologiju Srbije
  • 2. ROR icon University of Belgrade – Faculty of Medicine
  • 3. ROR icon Biomedical Research Foundation of the Academy of Athens
  • 4. ROR icon Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas
  • 5. ROR icon The Netherlands Cancer Institute

Abstract (English)

Introduction: Locally advanced rectal cancer (LARC) poses significant challenges in oncology, often necessitating multimodal treatment strategies. Neoadjuvant chemoradiotherapy (nCRT) followed by surgery is the standard approach for LARC management, aimed at improving local control and facilitating sphincter preservation. Tumor markers, such as carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA 19-9), have been explored as potential predictors of treatment response and prognosis in various malignancies. This study aimed to evaluate the association between pre- and post-treatment levels of CEA and CA 19-9 and tumor response in LARC patients undergoing nCRT.
Material and Method: We conducted a prospective study including 75 patients with LARC who underwent long-course CRT between June 2020 and January 2022. Treatment involved radiotherapy using volumetric modulated arc therapy-simultaneous integrated boost, along with concomitant chemotherapy (5-fluorouracil and leucovorin) administered during the first and fifth weeks of radiotherapy. Tumor response was assessed eight weeks after the completion of nCRT. Patients were categorized as responders (complete clinical response [cCR] and TRG1-2 postoperative categories) or non-responders (TRG3-5) based on the Mandard classification. Levels of CEA and CA 19-9 were measured before treatment initiation and at the completion of therapy.
Results and Discussion: Initial elevated levels of CEA were observed in 41.3% of patients, decreasing to 9.3% post-treatment. Similarly, initial elevated CA 19-9 levels were present in 8% of patients, reducing to 1.3% post-therapy. While no significant association was found between initial CEA levels and treatment response, a significant difference was observed between patients with post-treatment CEA and CA 19-9 levels within reference values compared to those with persistently elevated levels (p < 0.05). These findings suggest that nCRT leads to a significant reduction in CEA and CA 19-9 levels, potentially indicating a favorable treatment response and improved outcomes in LARC patients.
Conclusion: Our study highlights the potential utility of CEA and CA 19-9 as predictive markers for treatment response in LARC patients undergoing neoadjuvant therapy. The significant reduction in tumor marker levels post-treatment suggests a potential role for these markers in assessing therapeutic efficacy and predicting patient outcomes. However, further validation on a larger patient cohort is warranted to confirm these findings and establish the clinical utility of tumor markers in guiding treatment decisions for LARC.

Abstract (Serbian)

Standardni tretman lokalno uznapredovalog karcinoma rektuma (LARC) je neoadjuvantna hemioradioterapija (nCRT), nakon čega sledi operacija. Cilj ove studije bio je da se proceni povezanost između hematološke toksičnosti i odgovora tumora na terapiju (TR). U periodu od juna 2020. do januara 2022. godine, u studije je prospektivno uključeno 75 pacijenata sa LARC-om koji su lečeni dugotrajnim režimom CRT-a. RT je isporučena korišćenjem volumnog rotacionog planiranja zračne terapije i simultanog integrisanog boost-a. Istovremena hemioterapija (5-FU, leukovorin) je primenjivana tokom prve i pete nedelje RT. TR je procenjen u 8. nedelji, nakon završetka nCRT. Za pacijente sa potpunim kliničkim odgovorom (cCR) nije predložena neposredna radikalna operacija. Grupa pacijenata koja je dobro odgovorila na sprovedeno lečenje (eng. responders, R) je definisana sa cCR i TRG1 i TRG2 postoperativnim kategorijama, prema Mandardovoj klasifikaciji. Grupa koja je lošije odgovorila (eng. non-responders, NR) definisana je kao TRG3-5. Akutna toksičnost je procenjivana nedeljno u skladu sa zajedničkim terminološkim kriterijumima za neželjene događaje (CTCAE) v.5.0. R su obuhvatali 46,6% pacijenata. Tokom nCRT, javili su se ukupni hematološki neželjeni efekti: anemija 40,0%, leukopenija 32,0% i neutropenija 21,3%. Anemija 3. stepena, leukopenija i neutropenija su se javile kod 6,7%, 2,7% i 4% pacijenata, respektivno. Nije prijavljena toksičnost 4. stepena. Limfopenija je primećena kod 94,7% pacijenata; 50,7% njih imalo je stepen toksičnosti 3/4. Značajna povezanost između hematološke toksičnosti i TR nije dokazana. Negativan trend je primećen kod anemije; pacijenti bez anemije tokom nCRT bolje su reagovali na lečenje (p=0,05). Ova povezanost može biti dovedena u vezu sa hipoksijom tumora i posledičnom radiorezistentnošću. Limfopenija izazvana zračenjem i njena potencijalna povezanost sa TR biće ispitana u nastavku ove studije. Dalje analize će biti usmerene na ispitivanje subpopulacija zahvaćenih limfocita korišćenjem CyTOF metodologije masene citometrije.  (Ovu studiju finansirali su: Horizon Europe Twinning projekat STEPUPIORS (br. 101079217) i Ministarstvo prosvete i nauke Republike Srbije (br. 451-03-68/2022-14/200043).

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Translated title (Serbian)
Postoji li veza između hematološke toksičnosti i odgovora na neoadjuvantnu hemoradioterapiju kod pacijenata sa lokalno uznapredovalim karcinomom rektuma?