Although several prognostic factors in GIST have been well studied such as tumour size, mitotic rate, or localization, the influence of microscopic margins or R1 resection remains controversial. The aim of this study was to evaluate the influence of R1 resection on the prognosis of GIST in a large multicentre retrospective series of patients. From 2001 to 2013, 1413 patients who underwent surgery for any site of GIST were identified from 61 European centers. 1098 patients were included, excluding synchronous metastases, concurrent malignancies, R2 resection or GIST recurrence. Tumour rupture (TR) was reclassified according to the Oslo sarcoma classification. Cox proportional hazards ratio and Kaplan-Meier survival estimates were used to analyse 5-year recurrence-free survival (RFS). Of 1098 patients, 38 (3%) underwent R1 resection with a risk of TR of 11%. The 5-year RFS was 89.6% with a median follow-up of 81 months [range: 31.2–152 months]. On univariate analysis, lower RFS was significantly associated with R1 resection [HR = 2.13; p = 0.04], high risk score according to the modified NIH classification, administration of adjuvant therapy [HR = 2.24; p < 0.001] and intraoperative complications [HR = 2.82; p < 0.001]. Only intraoperative complications [HR = 1.79; p = 0.02] and high risk according to the modified NIH classification including the updated definition of TR [HR = 3.43; p = 0.04] remained significant on multivariate analysis. This study shows that positive microscopic margins are not an independent predictive factor for RFS in GIST when taking into account the up-dated classification of TR. R1 resection may be considered a reasonable alternative to avoid major functional sequelae and should not lead to reoperation.

中文翻译：

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阳性显微切缘（R1 切除）对 GIST（胃肠道间质瘤）患者的预后影响：一项多中心欧洲研究的结果

尽管 GIST 的几个预后因素（例如肿瘤大小、有丝分裂率或定位）已得到充分研究，但显微切缘或 R1 切除的影响仍然存在争议。本研究的目的是在大型多中心回顾性系列患者中评估 R1 切除对 GIST 预后的影响。从 2001 年到 2013 年，来自 61 个欧洲中心的 1413 名患者接受了任何部位的胃肠道间质瘤手术。纳入 1098 名患者，排除同步转移、并发恶性肿瘤、R2 切除或 GIST 复发。根据奥斯陆肉瘤分类对肿瘤破裂（TR）进行重新分类。使用 Cox 比例风险比和 Kaplan-Meier 生存估计来分析 5 年无复发生存 (RFS)。在 1098 名患者中，38 名 (3%) 接受了 R1 切除，TR 风险为 11%。 5 年 RFS 率为 89.6%，中位随访时间为 81 个月 [范围：31.2–152 个月]。在单变量分析中，较低的 RFS 与 R1 切除显着相关 [HR = 2.13； p = 0.04]，根据修改后的 NIH 分类，给予辅助治疗的高风险评分 [HR = 2.24； p < 0.001] 和术中并发症 [HR = 2.82； p < 0.001]。仅术中并发症[HR = 1.79；根据修改后的 NIH 分类（包括更新的 TR 定义），风险为高风险 [HR = 3.43；p = 0.02]。 p = 0.04] 在多变量分析中仍然显着。这项研究表明，考虑到最新的 TR 分类，镜下切缘阳性并不是 GIST RFS 的独立预测因素。 R1 切除可能被认为是避免重大功能性后遗症的合理替代方案，并且不应导致再次手术。