Improved Pathologic response to chemoradiation in MGMT methylated locally advanced rectal cancer.

Autor:	Jensen GL; Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN, USA., Pourfarrokh N; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Volz M; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Morales LL; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Walker K; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Hammonds KP; Biostatistics, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., El-Ghamry M; Radiation Oncology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Wong L; Medical Oncology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Hodjat P; Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston TX, USA., Castro E; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Rao A; Departments of Pathology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA., Jhavar SG; Radiation Oncology, Baylor Scott & White Health, 2401 S. 31 St., Temple, TX 76508, USA.
Jazyk:	angličtina
Zdroj:	Clinical and translational radiation oncology [Clin Transl Radiat Oncol] 2023 Jul 24; Vol. 42, pp. 100667. Date of Electronic Publication: 2023 Jul 24 (Print Publication: 2023).
DOI:	10.1016/j.ctro.2023.100667
Abstrakt:	Background and Purpose: With the growing interest in total neoadjuvant treatment for locally advanced rectal adenocarcinoma (LARC) there is an urgent unmet need to identify predictive markers of response to long-course neoadjuvant concurrent chemoradiotherapy (LCRT). O6-Methylguanine (O6-MG)-DNA-methyltransferase (MGMT) gene methylation has been associated in some malignancies with response to concurrent chemoradiotherapy. We attempted to find if pathologic response to LCRT was associated with MGMT promoter hypermethylation (MGMTh). Materials and Methods: Patients were identified with LARC, available pre-treatment biopsy specimens, and at least 1 year of follow-up who received LCRT followed by surgical resection within 6 months. Biopsies were tested for MGMTh using a Qiagen pyrosequencing kit (Catalog number 970061). The primary outcome of LCRT responsiveness was based on tumor regression grade (TRG), with grades of 0-1 considered to have excellent response and grades of 2-3 considered to be non-responders. Secondary outcomes included overall survival (OS) and recurrence free survival (RFS). Results: Of 96 patients who met inclusion criteria, 76 had samples which produced reliable assay results. MGMTh corresponded with higher grade and age of the biopsy specimen. The percentage of responders to LCRT was higher amongst the MGMTh patients than the MGMTn patients (60.0% vs 27.5%, p value = 0.0061). MGMTh was not significantly associated with improved OS (2-year OS of 96.0% vs 98.0%, p = 0.8102) but there was a trend for improved RFS (2-year RFS of 87.6% vs 74.2%, p = 0.0903). Conclusion: Significantly greater tumor regression following LCRT was seen in MGMTh LARC. Methylation status may help identify good candidates for close observation without surgery following LCRT. Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. (© 2023 The Authors.)
Databáze:	MEDLINE
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