背景:同源重组缺陷(HRD)是癌症的重要标志之一。它与对基于铂的化疗的有利反应有关。我们探讨了具有HRD的胃癌(GC)的独特临床病理特征,以及HRD在基于铂的一线化疗治疗不可切除的转移性GC中的临床意义。
方法:我们在这项研究中招募了160例GC患者。利用靶向肿瘤测序对他们的肿瘤样品进行基因组谱分析。HRD被定义为16种HR基因中任何一种的改变(BARD1,BLM,BRCA1,BRCA2,BRIP1,MRE11A,NBN,PALB2,PARP1,POLD1,RAD50,RAD51,RAD51C,RAD51D,WRN,和XRCC2)。比较HRD组和非HRD组的临床病理特征和一线化疗对不可切除转移性GC的治疗结果。
结果:47例患者(29.4%)被归入HRD组。与非HRD组相比,该组的宏观3型或4型肿瘤比例明显较低,TMB较高。在接受铂类一线化疗的患者中,HRD组治疗后的缓解率更高,无进展生存期更长(中位8.0个月vs.3.0个月,P=0.010),调整后的风险比为0.337(95%置信区间0.151-0.753)。在未接受铂类化疗的患者中,HRD状态与治疗结果无关。
结论:宏观3型或4型肿瘤比例低,TMB高,是GC伴HRD的显著特征。HRD状态是基于铂的一线化疗中不可切除的转移性GC的潜在预测标志物。
BACKGROUND: Homologous recombination deficiency (HRD) is one of the crucial hallmarks of cancer. It is associated with a favorable response to platinum-based chemotherapy. We explored the distinctive clinicopathological features of gastric cancer (GC) with HRD and the clinical significance of HRD in platinum-based first-line chemotherapy for unresectable metastatic GC.
METHODS: We enrolled 160 patients with GC in this study. Their tumor samples were subjected to genomic profiling utilizing targeted tumor sequencing. HRD was defined as the presence of alterations in any of 16 HR genes (BARD1, BLM, BRCA1, BRCA2, BRIP1, MRE11A, NBN, PALB2, PARP1, POLD1, RAD50, RAD51, RAD51C, RAD51D, WRN, and XRCC2). The clinicopathological features and treatment outcomes of first-line chemotherapy for unresectable metastatic GC were compared between HRD and non-HRD groups.
RESULTS: Forty-seven patients (29.4%) were classified into the HRD group. This group had a significantly lower proportion of macroscopic type 3 or 4 tumors and higher TMB than the non-HRD group. Among patients who underwent platinum-based first-line chemotherapy, the HRD group had a greater response rate and longer progression-free survival after treatment (median 8.0 months vs. 3.0 months, P = 0.010), with an adjusted hazard ratio of 0.337 (95% confidence interval 0.151-0.753). HRD status was not associated with treatment outcomes in patients who did not undergo platinum-based chemotherapy.
CONCLUSIONS: Low proportion of macroscopic type 3 or 4 tumors and a high TMB are distinctive features of GC with HRD. HRD status is a potential predictive marker in platinum-based first-line chemotherapy for unresectable metastatic GC.