吉林大学学报(医学版)  2019, Vol. 45 Issue (06): 1436-1439     DOI: 10.13481/j.1671-587x.20190641

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历程, 刘慧, 郭亮, 马云飞, 刘百龙, 董丽华
LI Cheng, LIU Hui, GUO Liang, MA Yunfei, LIU Bailong, DONG Lihua
放疗联合吉非替尼治疗EGFR敏感突变低级别肺黏液表皮样癌1例报告及文献复习
Radiotherapy combined with gefitinib in treatment of low-grade pulmonary mucoepidermoid carcinoma with EGFR sensitive mutation: A case report and literature review
吉林大学学报(医学版), 2019, 45(06): 1436-1439
Journal of Jilin University (Medicine Edition), 2019, 45(06): 1436-1439
10.13481/j.1671-587x.20190641

文章历史

收稿日期: 2019-04-01
放疗联合吉非替尼治疗EGFR敏感突变低级别肺黏液表皮样癌1例报告及文献复习
历程1 , 刘慧1 , 郭亮2 , 马云飞1 , 刘百龙1 , 董丽华1     
1. 吉林大学第一医院放疗科, 吉林 长春 130021;
2. 吉林大学第一医院病理科, 吉林 长春 130021
[摘要]: 目的 探讨局部放射疗法(放疗)联合表皮生长因子受体(EGFR)-酪氨酸激酶抑制剂(TKIs)治疗无法手术切除、EGFR敏感突变低级别肺黏液表皮样癌(PMEC)患者的疗效,分析该治疗模式的有效性和安全性,为其临床治疗提供参考。方法 收集1例明确诊断为PMEC患者的临床资料,结合相关文献,分析患者影像学和临床症状的变化与预后的关系。结果 患者,女性,22岁,因胸闷气短、干咳2个月入院。病理诊断为PMEC,基因检测示EGFR基因21号外显子L858R突变,无法手术切除。患者入院后给予吉非替尼250 mg·d-1口服,同步局部放疗2 Gy/次,25次,共50 Gy。经局部放疗联合口服吉非替尼治疗后,患者病灶较放疗前缩小,持续口服吉非替尼至今,病灶进一步缩小;患者除皮疹外无不良反应,无进展生存期(PFS)已达18个月。结论 对于EGFR敏感突变、不可手术切除的低级别PMEC,放疗联合EGFR-TKIs的治疗模式疗效较好,不良反应可以接受。
关键词: 肺黏液表皮样癌    表皮生长因子受体    突变    吉非替尼    放射治疗    酪氨酸激酶抑制剂    
Radiotherapy combined with gefitinib in treatment of low-grade pulmonary mucoepidermoid carcinoma with EGFR sensitive mutation: A case report and literature review
LI Cheng1 , LIU Hui1 , GUO Liang2 , MA Yunfei1 , LIU Bailong1 , DONG Lihua1     
1. Department of Radiation Oncology, First Hospital, Jilin University, Changchun 130021, China;
2. Department of Pathology, First Hospital, Jilin University, Changchun 130021, China
[ABSTRACT]: Objective To explore the curative effect of local radiotherapy combined with epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) in the treatment of the patient with unresectable and low-grade pulmonary mucoepidermal carcinoma (PMEC) with positive EGFR mutation, to analyze the effectiveness and safety of the treatment mode, and to provide the clinical reference for the treatment of this disease. Methods The clinical data of a patient who diagnosed as PMEC was collected. The relationships between the changes of imaging and clinical symptoms and the prognosis of the patient were analyzed and the relative literatures were reviewed. Results A 22-year-old woman was admitted to the hospital due to shortness of breath and 2 months of cough.The pathological diagnosis was PMEC, the L858R mutation in exon 21 of EGFR gene was found by gene detection and the tumor could not be resected by surgery.The patient was treated with gefitinib 250 mg·d-1 orally combined with radiotherapy, and the dose of radiotherapy was 50 Gy totally with 2 Gy per fraction(25 times). After the treatment of local radiotherapy combined with oral administration of gefitinib, the tumor size was shrunk compared with before radiotherapy. The tumor size was shrunk further after the intervention of continuous oral gefitinib; the patient had no adverse reactions except the mild skin rash, and the progression free survival (PFS) was 18 months. Conclusion For the unresectable and low-grade PMEC patient with positive EGFR mutation, the treatment mode of radiotherapy combined with EGFR-TKIs has good efficacy and the side effects could be accepted.
KEYWORDS: pulmonary mucoepidermal carcinoma    epidermal growth factor receptor    mutation    gefitinib    radiotherapy    tyrosine kinse inhibitors    

肺黏液表皮样癌(pulmonary mucoepidermoid carcinoma,PMEC)是一种罕见的肺恶性肿瘤,于1952年由Smetana首次提出,根据其组织分化程度可分为低级别与高级别两种[1]。低级别PMEC恶性度较高级别低,目前其主要的治疗方式为手术切除,大部分低级别PMEC患者可经手术切除根治。但对于不可切除的低级别PMEC,由于病例数较少,尚无标准的治疗模式。HAN等[1]报道PMEC患者表皮生长因子受体(epidermal growth factor receptor, EGFR)基因阳性突变率较高。国外已有EGFR-酪氨酸激酶抑制剂(tyrosine kinase inhibitors, TKIs)治疗PMEC患者的个案报道,但放疗与EGFR-TKIs的联合应用在国内外尚未见相关报道。本研究报道1例无法手术切除、基因检测结果显示为EGFR基因的21号外显子敏感突变的低级别PMEC患者,采用局部放疗联合吉非替尼的治疗模式,疗效较好,无进展生存期(progression free survival,PFS)至本研究截止已达18个月,本文作者结合相关文献复习探讨该治疗模式的有效性及安全性,以期为该病的治疗提供临床指导和参考。

1 临床资料 1.1 一般资料

患者,女性,22岁,2017年7月因胸闷气短、干咳2个月入院。肺部CT显示:右肺门团块状高密度影,最大层面约7.7 cm× 7.0 cm,邻近右主支气管和右肺中间段支气管变窄,局部向支气管腔内突出。支气管镜下见右肺下叶开口新生物,堵塞管腔,活检病理:考虑为低级别PMEC。免疫组织化学:CK(+)、CgA (弱+)、Syn(—)、CD56(+)、EMA(+)、TTF-1(—)、Ki67(3%+)、Vimentin (—)、P40(+)、NapsinA(—)、CD117(+)、CK5/6(+)和P63(+)(图 1,见插页七)。半个月后,于北京煤炭总医院行气管镜下肿物部分切除术,术后病理显示:低级别PMEC。术后1周,患者出现咳血,每日咳血量50 ~ 100 mL,给予止血对症治疗后症状略减轻,为进一步治疗转入本院。相关检查:头部MRI和腹部CT未见转移灶,骨扫描未见放射性核素浓聚,临床分期为cT4N0M0,ⅢA期。

A:Cells containing intracellular mucous (×400);B:Positive expression of P40 in squamous and intermediate cells (×200);C:Strongly positive expression of CD117 in mucous cells and weakly positive expression of CD117 in intermediate cells (×200);D:Low expression of Ki67 (×200). 图 1 HE染色检测PMEC患者的细胞形态表现 Fig. 1 Morphology of cells in PMEC patient detected by HE staining
1.2 治疗方法

因肿瘤较大,堵塞气道,且存在咳血,决定给予患者右肺肿瘤放射治疗。勾画右肺肺门肿物为靶区体积(gross tumor volume, GTV),各方向外扩5 mm为肿瘤计划靶区(planned gross tumor volume,PGTV)。放疗1周时,基因检测结果回报:EGFR基因21号外显子L858R突变,组织丰度为1.7%。总剂量为12 Gy/6 f,开始同步口服吉非替尼250 mg·d-1。胸部放疗靶区剂量为50 Gy/25 f,复查肺CT显示:右肺门旁见团块状高密度影,右肺下叶支气管腔明显通畅,肿物缩小(图 2),咳血消失。

A: Before radiotherapy; B: After radiotherapy; C:3 months after radiotherapy; D: 12 months after radiotherapy. 图 2 放疗前后PMEC患者胸部CT表现 Fig. 2 Thoracic CT images of PMEC patient before and after radiotherapy
1.3 随访

患者持续口服吉非替尼,250 mg·d-1,共17个月,定期复查肺CT,右肺肺门肿物缩小至3.6cm×2.8 cm(图 3),PFS已达18个月。病程中患者除轻度皮疹外,无其他不良反应,目前仍在随访中。

A: Mediastinal window; B: Lung window. 图 3 放疗后18个月PMEC患者胸部CT表现 Fig. 3 Thoracic CT images of PMEC patient 18 months after radiotherapy
2 讨论

PMEC是一种罕见的肺恶性肿瘤,于1952年由Smetana首次提出,在所有肺部肿瘤中仅占0.1% ~ 0.2%[1];PMEC起源于气管支气管树的小涎腺,通常发生在主支气管、肺叶支气管或段支气管。大多数患者表现为大气道刺激或阻塞的症状,包括咳嗽、咯血、喘息、胸痛和肺不张等。根据组织分化程度,PMEC可分为低级别和高级别两种[1-2]。PMEC的免疫组织化学检测结果中,CK7、Muc5Ac、P40和P63通常为阳性,而TTF-1、Calponin、HER2及ALK通常为阴性[3]。低级别PMEC患者较少发生淋巴结转移(低于5%),而高级别PMEC患者淋巴结转移率较高,侵袭性更强,具有更高的复发、转移风险,总生存期(overall survival,OS)与PFS明显低于低级别PMEC患者,预后较差。此外,年龄也是PMEC患者OS及PFS的影响因素[1, 4]

PMEC目前主要的治疗方式为手术。研究[3, 5-6]显示:手术切除者超过90%,单纯手术后患者5年生存率高达87%。可手术切除的低级别PMEC经根治性手术可治愈[7-9]。对于局部晚期或发生转移等不可切除的PMEC患者,通常参照非小细胞肺癌(non small cell lung cancer, NSCLC)的治疗原则来治疗[1]。目前,对于不能手术的Ⅲ期NSCLC患者,放疗同步化疗仍是标准的治疗模式,可延长患者的OS [10]。研究[11]显示:放疗用于术后切缘阳性高级别PMEC患者的辅助治疗,但对患者的生存无影响。由于PMEC发病率较低,晚期患者的数量更少,目前尚无应用放疗、化疗和靶向药物治疗不可手术切除PMEC的相关研究,其疗效尚不明确。

HAN等[1]对5例PMEC患者进行了EGFR突变基因检测,显示其突变阳性率为60%(3/5),突变位点皆为L858R,HER2突变均为阴性。该患者病理类型为低级别PMEC,基因检测结果为EGFR基因突变阳性,突变位点为L858R第21外显子,与HAN等[1]的报道相符。由于EGFR突变率较高,建议PMEC患者行基因检测,如有突变可选择EGFR-TKIs治疗。EGFR-TKIs目前仍是EGFR突变阳性的晚期NSCLC患者一线治疗的药物,其中吉非替尼或厄洛替尼的治疗有效率高达70% ~ 80% [12]

该患者肿瘤巨大,包绕肺门,无法行手术治疗,治疗前有咳血,病情凶险,且拒绝化疗,因此针对该患者的治疗,采取了局部放疗联合吉非替尼的治疗模式。研究[13-14]表明:辐射可导致EGFR表达增加,激活其下游的信号通路, 诱导细胞对放疗抵抗;而EGFR-TKIs在诱导细胞周期阻滞、细胞凋亡和DNA双链损伤修复等多个方面具有放射增敏作用。EGFR-TKIs与放疗联合应用可增加肿瘤细胞对放射治疗的敏感性。对于胸部放疗与EGFR-TKIs在NSCLC的联合应用中,国内外大部分研究纳入的患者其EGFR基因既有突变型也有野生型。XIA等[15]研究显示:联合应用治疗NSCLC的局控率可达96%,2年PFS为42%,OS为45%;而对于EGFR突变阳性患者,联合应用的疗效目前还缺乏相关Ⅱ期临床试验来证实。OKAMOT等[16]和MOSCHINI等[17]的研究表明:EGFR突变阳性的患者(2/3)局部控制较好,其PFS及OS均大于5年;WANG等[18]研究表明:对于EGFR突变阳性的Ⅲ/Ⅳ期NSCLC患者,局部放疗联合EGFR-TKIs局控率较好(约为84%),可明显延缓肿瘤的进展,提高患者的PFS及OS。在与治疗相关的不良反应中,最常见为皮疹,其余包括腹泻、厌食、疲劳和血液学毒性等。研究[17-19]表明:放疗与EGFR-TKIs联合应用可增加放射性肺炎的风险(1 ~ 2级常见,偶有3级),其具体机制还尚未明确,可能与放疗及EGFR-TKIs两者均可造成肺间质损伤有关,但总体的不良反应可以接受。

针对该患者的GIV,由于低级别PMEC患者较少发生淋巴结转移,且该患者CT检查未见阳性淋巴结,所以放射时将原发病灶勾画为GTV,外放5 mm为PGTV,不对淋巴引流区进行预防性照射。该患者肿瘤较大,同步口服吉非替尼可增加发生放射性肺炎的风险,因此选择了50 Gy/25 f的分割方式。放疗剂量为12 Gy/6 f时,患者咯血症状消失,疗效明显。经过胸部放疗同步口服吉非替尼治疗后,肿物缩小。患者持续口服吉非替尼至今,复查肺部CT显示肿物进一步缩小,无复发及远处转移,无放射性肺炎发生,疗效评价为部分缓解(partial remission, PR),PFS已达18个月,疗效满意,提高了患者的生活质量,该患者目前仍在随访中。

PMEC是一种罕见的肺恶性肿瘤,尚无标准的治疗模式。目前,尚无放疗联合EGFR-TKIs治疗不可切除、EGFR突变阳性低级别PMEC患者的相关报道。该患者经放疗联合吉非替尼治疗后取得了满意的疗效,且安全性高。对于EGFR突变阳性、不可切除的低级别PMEC患者,放疗联合EGFR-TKIs可以作为一种新的治疗模式。

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