石 红,肖 祯
(大连医科大学附属第一医院 妇产科,辽宁 大连116011)
专家述评
子宫内膜癌手术治疗相关问题
石 红,肖 祯
(大连医科大学附属第一医院 妇产科,辽宁 大连116011)
子宫内膜癌初诊时70%为临床早期,治疗首选手术,手术原则为全子宫、双附件切除及手术分期。淋巴结切除范围和年轻患者保留卵巢的安全性问题一直是关注焦点,目前推荐根据术前评估和术中所见决定手术分期的程度。研究显示诊断时认为病变局限于子宫的患者中约10%伴有淋巴结转移,而化疗可使Ⅲ期病人获益,因此通过有经验的妇科肿瘤医生术前和术中评估识别高危因素,决定是否行淋巴结切除以及何种程度的淋巴结切除,可避免不必要的系统性淋巴结切除。盆腔淋巴结切除是手术分期的重要组成部分,但低危型病例可省略系统性淋巴结切除,而高危型子宫内膜癌的分期应包括肠系膜下动脉和肾血管水平的腹主动脉旁淋巴结的评估。对于局限于子宫的病变也可以前哨淋巴结界定淋巴结切除的范围,对于年轻的低危型子宫内膜癌患者保留卵巢是可行的。
子宫内膜癌;手术分期;淋巴结清扫
子宫内膜癌是妇科最常见恶性肿瘤之一,寿命延长和肥胖致发病率逐年增加,并呈年轻化趋势,发病率居妇科恶性肿瘤第二位。子宫内膜癌初诊时多局限于子宫,治疗首选手术,晚期则辅以放疗或化疗以及内分泌等综合治疗,其分期以手术病理分期为准,根据高危因素选择辅助治疗,对肿瘤扩散到宫颈或腹腔者,也可以考虑新辅助化疗后手术。
肿瘤局限于子宫体的子宫内膜癌的治疗原则为全子宫+双附件切除+手术分期±术后辅助治疗。手术分期包括对盆腹腔肉眼可疑处进行活检、切除可疑和增大的淋巴结、对子宫浆液性、透明细胞腺癌和癌肉瘤行大网膜切除活检、以及留取腹腔冲洗液。盆腔淋巴结(pelvic lymph node,PLN)和腹主动脉旁淋巴结(para-aortic lymph node,PAN)切除和病理评估也是手术分期的重要组成部分,但需根据个体情况区别对待,因为内膜癌高危因素及病灶部位决定转移特点和复发风险,患者高龄和合并症情况个体差异大,术式选择需要充分注意个体化。虽然任何子宫内膜癌切除淋巴结都是正确的,但越来越多的研究证明预后不良风险低的病例省略淋巴结切除是可行的,而对高危病例需要同时切除PLN和PAN,其他则仅切除PLN。术前和术中评估以选择手术分期术式为目的,即要明确有无预后不良高危因素以确定分期手术程度。
子宫内膜癌预后影响因素包括肿瘤深肌层浸润、分化程度、肿瘤组织类型,以及脉管侵袭、淋巴结转移、病灶大小和肌层浸润及宫颈侵犯等,特别是对于病灶局限于子宫者肌层浸润及宫颈侵犯的评估在决定术式上非常重要。
临床上常用超声、诊刮、CA125、MRI、宫腔镜等辅助手段进行术前评估,目前评估肌层浸润及宫颈侵犯最准确的方法是MRI或宫腔镜下活检。经阴道超声通过测定内膜厚度、了解宫腔占位性病变、肌层有无浸润、血流阻力等,对绝经后女性子宫内膜癌有筛查意义,绝经后内膜厚<5 mm时阴性预测值为96%,内膜厚≥5 mm,年龄>60岁伴流血为高危人群,检出宫腔内病变的敏感性98.7%,内膜癌符合率75.5%。诊刮是确诊或排除内膜癌的重要方法,但易漏诊(漏诊率4%~41%),其组织病理学细胞分级的准确率仅50%,术后病理报告有48%患者肿瘤分级升级,偶尔出现肿瘤类型诊断不准确。研究指出内膜癌浸润深肌层(≥1/2)时诊刮的肿瘤细胞分级符合率75%,而肿瘤局限于内膜层者符合率仅为22.2%。分段诊刮是术前诊断子宫内膜癌的传统手段,但由于假阳性率高不易准确判断宫颈是否受累,目前已不常用,美国妇科肿瘤协会建议以一次性子宫内膜取样器或宫腔镜下活检取替传统的诊刮或分段诊刮。宫腔镜被用于早期病变的镜下活检,多用于经阴道B超检查无明显增厚和病变或呈内膜息肉样变者,以及经诊刮活检阴性,仍有反复出血的患者,通过观察异常隆起性病变、异型血管、坏死组织,明确活检部位。MRI是目前评估肌层浸润最灵敏的方法,对准确显示病变范围、肌层浸润深度、和盆腔淋巴结情况等非常有帮助,常用于子宫内膜癌术前分期,Ⅰ期准确率为88.9%,Ⅱ期为75%,评估肌层浸润深度敏感性为68%~82%,对可疑Ⅱ期患者MRI有助于术前明确诊断。荟萃分析指出,MRI诊断的敏感性和特异性对深部肌层浸润诊断分别为81%和89%,对宫颈间质浸润分别为57%和95%,对淋巴结转移分别为44%和96%[1]。一项包括177病例的研究指出术前经阴道超声对内膜癌肌层浸润诊断符合率为66.9%,对肌层浸润>1/2的符合率可达86.9%,与MRI(70.3%,84.0%)无明显差异,结合术中切除子宫标本肉眼所见肌层浸润诊断准确率可达87.4%[2]。术中评估包括对肉眼可疑处活检除外子宫外病变,切除可疑和肿大的淋巴结以除外淋巴结转移,必要时可先行子宫切除,剖示标本并冰冻病理检查帮助判断和术式选择,标本剖示强调注意双侧子宫角有无病灶,并要测量病变肌层浸润深度和未受侵的肌壁厚度。血清CA125水平可在晚期内膜癌患者中升高,对判断内膜癌进展程度很有帮助,Ⅰ期子宫内膜癌患者约20%有CA125升高, CA125>35 U/mL,预测宫外扩散符合率为87.5%,将HE4与CA125联合应用能提高诊断率,并可用作术后监测指标。
Ⅰ期子宫内膜癌行全子宫双附件切除术的5年存活率可达90%以上。有研究证实筋膜外全子宫切与次广及广切预后无明显差别[3],但阴道断端是复发的高发部位(6.7%~11.5%)[4]。所以对于肿瘤局限于子宫体的Ⅰ期内膜癌全子宫双附件切除术是基本术式,强调要完整切除宫颈,闭扎输卵管伞,高位断扎子宫动脉,术中注意无瘤原则,避免肿瘤在阴道种植。
宫颈间质受侵是子宫体癌预后不良因子之一,NCCN(National Comprehensive Cancer Network)指南推荐对明确有宫颈间质浸润病例行广泛子宫切除术。但临床上Ⅱ期患者术前判断困难,术前诊断Ⅱ期与术后病理诊断一致性差,手术范围主要考虑宫旁和阴道浸润风险。宫旁浸润在Ⅲ期16.9%~52%,Ⅱ期6.3%~11.5%,在Ⅰ期也有,与宫颈受侵相比,淋巴脉管间隙浸润(LVSI)和深肌层浸润以及子宫外病变更是宫旁和阴道浸润的高危因素[5-6]。子宫峡部的内膜癌与宫颈腺癌鉴别困难,因此推荐对明确有宫颈间质浸润或与宫颈腺癌鉴别困难的病例行广泛子宫切除术。
关于盆腔及腹主动脉旁淋巴结切除对改善预后的意义一直是讨论的热点。研究表明低危组(Ⅰa期的G1或G2、肿瘤直径<2 cm的子宫内膜样腺癌)淋巴结切除与否对预后无影响[7-8],而在中高危组(肌层浸润>1/2,G3,LVSI,和任何期别的浆液性、透明细胞等特殊组织学类型,病变侵犯宫颈间质,Ⅲ、Ⅳ期子宫内膜癌)切除盆腔及腹主动脉旁淋巴结可改善预后[9-10]。由于临床Ⅰ期也有9%合并盆腔淋巴结转移,其中肌层外1/3侵犯合并PLN转移25%,G3者为18%(GOG-33研究资料),对有高危因素病例均应行系统盆腔及腹主动脉旁淋巴结切除,也可将前哨淋巴结显像应用于合适的病例。研究发现孤立的PAN转移并不多见,多伴有PLN转移,淋巴结转移病例中16%为PAN孤立转移,而PAN转移病例77%为肠系膜下动脉水平以上PAN转移[11]。所以PAN的评估需切除达肾静脉水平。
早期内膜癌卵巢转移率约为1%[12-13]。一项来自美国多中心的回顾性研究:3269例<45岁的Ⅰ期子宫内膜癌,402例保留卵巢,随访200个月,两组5年生存率相似(P=0.26),其中Ⅰa期生存率均为98%,多因素分析结果显示保留卵巢不影响长期生存率[14]。2016年NCCN指南认为对于年轻Ⅰa期G1子宫内模样腺癌患者,保留卵巢是安全的。
晚期内膜癌及子宫内膜浆液性和透明细胞腺癌、癌肉瘤的上腹部、腹主动脉旁淋巴结转移率高,其肌层浸润程度不能反应子宫外病灶的有无,强调正确诊断组织类型非常重要,手术分期如同卵巢癌,行最大限度的肿瘤减灭术,术前行CA125、MRI/PET检查评估。浆液性腺癌发生率占内膜癌10%,超过50%的病例临床分期偏低,Ⅰ期术后复发转移率达31%~50%,预后差:5年和10年生存率分别为36%和18%,50%复发,40%死亡,在混合型内膜癌中即使浆液性腺癌成分<10%时预后也劣于子宫内膜样腺癌 G3,18%上腹部见显微镜下病灶,16%~18%有腹主动脉旁淋巴结转移[15],病理组织学无肌层浸润病例也高率发现腹腔内病变(淋巴结、卵巢、大网膜转移),进行严格分期手术和肿瘤减灭术可使生存获益[10]。子宫内膜透明细胞癌5年生存率<50%,一项99例子宫内膜透明细胞癌病例分析报告结果:67%有子宫外病灶,其中术中肉眼判断病变局限于宫体内者,术后病理分期升级达52%[16]。子宫浆液性上皮内癌/微小浆液性癌(SEIC/MUSC)是子宫内膜表面或腺上皮被高级别类似于浆液性癌肿瘤细胞所取代,未侵犯间质、肌层或林巴血管系统。其89%病例合并浆液性癌,常与子宫内膜息肉分布位置相似,88%(35/40)病例合并子宫内膜息肉,53%病例病变局限于内膜息肉上,45%发生宫外播散,预后与浆液性子宫内膜癌相似。子宫癌肉瘤在发生学和病理特性上与子宫体癌相似,被分类于高度恶性的子宫体癌类中。 2016年NCCN指南推荐对于高危肿瘤,如深肌层浸润、G3、以及子宫浆液性、透明细胞腺癌和癌肉瘤等,需切除PAN达肾静脉水平,对肿瘤扩散到腹腔或宫颈者也可选择新辅助化疗后再手术。
自1993年Childers首次报道了腹腔镜子宫内膜癌的分期手术(PLN+PAN)以来,多项关于手术安全性和长期预后的RCT(randomized control trial)相继发表。一项包括3500名患者,9个随机对照实验的荟萃分析显示:腹腔镜手术时间比开腹手术长,但术后住院时间更短;腹腔镜手术术中并发症多可能是因为不熟练的操作以及较长的学习曲线相关;术中并发症如膀胱、肠管、血管损伤等腹腔镜与开腹相当;腹腔镜术中出血量更少,但术中输血率较开腹手术无减少;两种术式的淋巴结切除数无明显差异;腹腔镜手术并不能改善患者的预后及复发率,对患者的无瘤生存期及复发部位也并没有影响。腹腔镜手术与开腹手术比,患者更快恢复并获得更高的生活质量[17]。
总结已报道的6项RCT结果[18-23],手术适应证以早期内膜样腺癌为主,Ⅰ期占74%~91.7%,内膜样腺癌占73.7%~86%,腹腔镜与开腹手术相比并发症发生率无明显差异(尿管损伤方面开腹术0%~2.6%,腔镜术1%~5%;肠管损伤、血管损伤无明显差异;术后肠梗阻腹腔镜手术明显减少),见表1。术后分期Ⅱ期是6%~15%,Ⅲ期1.3%~14.2%,Ⅳ期是0%~2%,提示即使是术前诊断Ⅰ期的症例中亦有需行腹主动脉旁淋巴结切除的病例。腹腔镜与开腹术比较切除的盆腔及腹主动脉旁淋巴结数无明显差异,复发率也无明显差异(腹腔镜8.6%~20%,开腹术8.5%~18.4%),盆腔复发率也无差异(腹腔镜1.3%~5.0%,开腹术1.0%~15.8%)。6项RCT研究中腹主动脉旁淋巴结切除施行率10%~95.8%,切除腹主动脉旁淋巴结个数7~12.3个(表2)。尽管有经验的术者可达到与开腹术同等的腹主动脉旁淋巴结切除数[24],但在这6项RCT研究中的腹主动脉旁淋巴结切除多相当于取样活检程度。LAP2研究结果显示有26%症例因发现转移灶而中转开腹手术,并显示腹腔镜手术有发生重度损伤(血管损伤3%,肠管损伤2%,尿管损伤1%)。
表1 子宫内膜癌腹腔镜与开腹手术的RCT研究[18-23]Tab 1 RCT study of laparoscopic and open surgery for endometrial carcinoma[18-23]
表2子宫内膜癌腹腔镜与开腹手术比较[18-23]Tab 2 Comparison of laparoscopic and open surgery for endometrial carcinoma[18-23]
Wright最近报道的一项6304例(开腹组4139例,微创组2165例)Ⅰ-Ⅲ期子宫体癌全子宫切除手术病例的数据分析研究结果显示:微创手术总体合并症发生率低于开腹手术(22.7% vs. 39.7%,P<0.001);微创手术(腹腔镜或机器人手术)所占比例逐年增加,由2006年的9.3%增加到2011年的61.7%,其中主要是机器人手术明显增加,占微创手术的62.3%,机器人手术的合并症发生率高于腹腔镜(23.7% vs. 19.5%,P=0.03);微创手术的应用并不影响总体死亡率(OR 0.89,95%CI 0.75-1.04)或癌症特异性死亡率(HR=0.83,95%CI=0.59-1.16)。结论认为微创全子宫切除术可能不影响子宫内膜癌患者的长期生存结局[25]。
综上,早期子宫内膜样腺癌腹腔镜手术作为标准治疗正逐步得到普及,晚期和特殊型内膜癌腹腔镜手术的可行性和局限性尚待积累临床研究数据,2016年NCCN指南对高龄、大子宫和有转移的子宫内膜癌推荐行开腹手术。
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Important perspectives on the surgical treatment of endometrial cancer
SHI Hong, XIAO Zhen
(DepartmentofGynecologyandObstetrics,theFirstAffiliatedHospitalofDalianMedicalUniversity,Dalian116011,China)
As Endometrial Cancers (EMC) are mostly detected in the early stage (in about 70% of the EMC patients), surgery is generally the optimal treatment. The operation usually involves total hysterectomy, bilateral salpingo-oophorectomy and surgical staging. In this field, many studies have focused on two essential aspects: thoroughness of lymph node desection and safety of ovary preservation among young patients. It is now recommended that staging of patients should be determined from preoperative evaluation and surgical findings. Studies indicate that among patients with the tumor strictly confined to the uterus-FIGO stage I, 10% of them are found to be lymph nodes positive-actually FIGO stage III. And these patients could benefit from the post-operative chemotherapy. Thus, an experienced gynecological oncologist would identify the risk factors before and within the operation, make the decision if the patient should receive lymphadenectomy or to which extent that the lymphadenectomy should be performed. Consequently, some systemic lymph node desection could be avoided. Pelvic lymphadenectomy is an important part of surgical staging. For low-risk patients, systemic lymphadenectomy is not required. For high-risk patients, however, extended lymphadenectomy should be performed, including para-aortic lymph nodes at the level of inferior mesenteric artery and renal vessels.For patients with their lesion confined to the uterus, the thoroughness of lymphadenectomy could be based on sentinel lymph node mapping. Besides, ovary conservation is an optional choice for young patients with little risk factors.
endometrial cancer; surgical staging; lymphadenectomy
10.11724/jdmu.2017.02.01
国家自然科学基金项目(81172457)
石 红(1960-),女,教授。研究方向:妇科肿瘤。E-mail:shong60@163.com
R73
A
1671-7295(2017)02-0105-05
石红,肖祯.子宫内膜癌手术治疗相关问题[J].大连医科大学学报,2017,39(2):105-109.
2016-11-30;
2016-12-20)