卵巢透明细胞癌20例临床分析并文献复习
Clinical Analysis of 20 Cases of Ovarian Clear Cell Carcinoma and Literature Review
摘要: 目的:通过对20例卵巢透明细胞癌(ovarian clear cell carcinoma, OCCC)患者进行回顾性总结,结合文献,探讨卵巢透明细胞癌的临床特点,与子宫内膜异位症的关系及治疗、预后情况。方法:对西北妇女儿童医院妇科近6年(2015-1至2021-7)收治的20例OCCC患者进行回顾性总结,全部的OCCC患者均进行了手术治疗,术后经病理明确诊断为卵巢透明细胞癌。收集、整理患者的临床病历资料,对患者各项指标进行整理分析,并电话随访患者生存情况,查阅2010年至2021年国内外相关文献,进行整理分析。结果:所分析的20例OCCC患者中,I期患者15例,占75%。II期患者2例,占10%;III期患者3例,占15%。OCCC患者发病年龄在34~70岁之间,平均发病年龄(48.10 ± 10.51)岁,未绝经患者15例,占75%,绝经患者5例,占25%。有消化系统症状就诊的8人,占40%,检查提示盆腔包块的10人,占50%,包块直径大于10 cm者11人,占55%;肿瘤单侧居多占85%,双侧均有肿瘤的占15%。均进行了全面分期手术,经过全面分期手术及化疗后,I期患者预后好,II期、III期患者预后较差,较少发生铂类耐药。结论:I期OCCC患者经过全面分期手术后预后好,生存情况较好,较少发生铂类耐药;在本组病例中,I期患者占75%,患者均未复发,且生存状态好,而II期、III期患者数据过少,难以计算总生存率。未来需要更多大规模前瞻性临床研究以明确早期OCCC的生物学特性、临床特点及预后相关因素。
Abstract: Aim: To investigate the clinical features of ovarian clear cell carcinoma (OCCC), its relationship with endometriosis and its treatment and prognosis by retrospectively summarizing 20 patients with OCCC and combining them with the literature. Methods: A retrospective summary of 20 patients with OCCC admitted to the Department of Gynecology of Northwest Women’s and Children’s Hospital in the past 6 years (2015-1 to 2021-7) was conducted. All patients with OCCC underwent surgery and were clearly diagnosed as ovarian clear cell carcinoma by pathology after surgery. The patients’ clinical records were collected and collated, the patients’ indicators were collated and analysed, the patients’ survival was followed up by telephone, and relevant domestic and international literature from 2010 to 2021 was reviewed and collated for analysis. Results: Of the 20 OCCC patients ana-lysed, 15 (75%) were stage I patients, 2 (10%) were stage II patients, and 3 (15%) were stage III patients. The age of onset of OCCC patients ranged from 34 to 70 years, with an average age of onset of 48.10 ± 10.51 years. There were 15 premenopausal patients, accounting for 75%, and 5 post-menopausal patients, accounting for 25%. There were 8 patients (40%) with digestive system symptoms, 10 patients (50%) with pelvic mass, and 11 patients (55%) with mass diameter greater than 10 cm. Unilateral tumors accounted for 85%, and bilateral tumors accounted for 15%. All pa-tients underwent comprehensive staging surgery. After comprehensive staging surgery and chem-otherapy, the prognosis of stage I patients was good, and the prognosis of stage II and III patients was poor, and platinum resistance was less common. Conclusion: Patients with stage I OCCC have a good prognosis after comprehensive staging surgery, with a good survival rate and less plati-num-based resistance. In this group of cases, 75% of the patients with stage I had no recurrence and had a good survival status. However, the data of stage II and III patients were too few to calcu-late the overall survival rate. In the future, more large-scale prospective clinical studies are needed to clarify the biological characteristics, clinical characteristics and prognostic factors of early OCCC.
文章引用:康辉, 刘晨, 田燕妮, 楚光华. 卵巢透明细胞癌20例临床分析并文献复习[J]. 临床医学进展, 2022, 12(9): 8633-8639. https://doi.org/10.12677/ACM.2022.1291247

1. 背景

卵巢上皮性癌(epithelial ovarian cancer,EOC,简称卵巢癌)的病死率仍高居妇科恶性肿瘤的首位。全世界卵巢癌每年约有230,000新发病例,并有15,000例死亡 [1]。卵巢透明细胞癌(ovarian clear cell carcinoma, OCCC)是卵巢癌中公认的预后较差的一种特殊类型的卵巢上皮性肿瘤。目前临床上以发病率较低、发现时FIGO分期较早、治疗及时为其主要的特点。治疗严格按照FIGO分期进行分期手术,并在术后给予适当疗程的化学治疗、放射治疗或其他治疗方案,但患者预后仍较差。有研究认为,由于OCCC的肿瘤细胞增殖指数较低,生长较慢,所以临床OCCC的早期患者所占的比例较大,I、II期患者占59%~71%,大多数为I期患者,5年生存率约为90% [2]。晚期患者对含铂的一线化疗敏感度低,预后更差。尽管OCCC相对罕见,但最近的研究表明,对OCCC有关的分子变异和致癌的靶点研究,选择基于分子生物学的治疗,有助于患者的分层和随之的精准治疗。

通过对20例OCCC患者进行回顾性分析总结,结合文献初步探讨卵巢透明细胞癌的临床特点、治疗现状及预后。

2. 资料与方法

2.1. 患者一般情况

20例OCCC患者,其中19人目前存活,1人术后2年去世;① 发病年龄在34~70岁之间,平均年龄(48.10 ± 10.51)岁,中位年龄为47岁,30~40岁有6例,41~50岁有7例,51~60岁有5例,61岁以上有2例(表1)。20例OCCC患者中,③ 有12例BMI指数处于正常范围(18.5~23.9),1例BMI指数提示偏瘦(≤18.5),7例BMI指数提示超重(24~28)。④ 19例患者均有孕产史;1例患者未婚未育。⑤ 绝经5人,未绝经15人。

2.2. 临床特征

2.2.1. 首诊症状

发现盆腔包块10人,消化道症状8人,月经改变者1人,绝经后阴道出血1人。

2.2.2. 辅助检查

根据患者术前B超及盆腔CT检查可发现,发现单纯左侧附件包块9人,单纯右侧附件包块8人,双侧均有包块3人,肿物大小最小直径为3.4*2.8*2 cm,最大的直径可达到35*27.8*15.7,肿瘤直径 ≥ 10 cm的患者有11例,直径5~10 cm有8人,直径 < 5 cm有1人。且均提示为囊性、囊实性包块,有12例囊内有密集分隔及多个等回声区域;提示可能为多房。肿瘤系列中CA125水平以40 U/mL为分割点,≤40 U/mL (正常范围)患者有8例,占40%;>40 U/mL的患者有12例,占60%,其中>400 U/mL的患者有3例,其中1例为421 U/mL,1例为493 U/mL,1例大于1000 U/mL。结合预后,在C125 > 40 U/mL的12例患者中,除1例CA125为421 U/mL的患者死亡,其余11例患者的CA125值均在术后接受辅助治疗后稳定至低风险范围内(0~40 U/mL),之后电话随访,定期复查无明显升高。

2.2.3. 手术范围及术中特殊所见

对20例患者均进行了手术治疗,在术中探查过程中发现,有3例(15%)患者合并有腹水(表2)。有17例(85%)患者为单侧发病,仅有3例(15%)患者为双侧卵巢均受累。包块直径大于10 cm者11人,占55%;有3例(15%)发现盆腔内有紫蓝色结节,考虑可能合并有子宫内膜异位症(Endometriosis, EMs)。术中发现肿瘤囊内有淡黄色稀薄液体或稠厚液体。18例进行了全子宫 + 双侧附件切除术 + 大网膜 + 盆腔、腹主动脉旁淋巴结 + 阑尾切除术,其中2例术中进行了腹壁多点活检。

2.2.4. 术后病理结果

根据术后病理结果,发现肿物有13例呈囊实性,7例为囊性包块(表2)。12例肿物呈多房性,囊壁较硬,且囊内壁分布有乳头状实性结节,表面有细小乳头,质稍脆。镜下可见肿瘤具有OCCC的特殊病病理表现,有8例主要表现为圆形的透明细胞,有5例主要表现为圆形的透明细胞和靴钉样细胞并存。镜下支持合并有EMs的患者有3例,占15%;通过手术及术后病理分析,其中I期患者15例,占总例数75%,II期患者仅2例,占10%,III期患者3例占15%。

2.2.5. 术后辅助治疗

20例患者均在术后2周给予化疗方案治疗,其中14例接受了6个疗程化疗,1例接受了8个疗程化疗;1例接受了14个疗程化疗,并于2年后去世;1例接受了16个疗程化疗。未接受足疗程的有3人,其中有2例接受了3个疗程的化疗,有1例接受了2个疗程的化疗。未接受足疗程的患者中有2例为自身身体原因,无法耐受足疗程的化疗而放弃,有1例患者因家庭经济条件放弃进行足疗程化疗。

2.2.6. 电话随访

对20例OCCC患者术后进行电话随访,随访率为100%,随访时间为8个月~48个月,有1例FIGO III期患者于术后1年死亡;余19例患者目前均存活。

3. 结果

所分析的20例OCCC患者中,I期患者15例,占75%。II期患者2例,占10%;III期患者3例,占15%。OCCC患者发病年龄在34~70岁之间,平均发病年龄(48.10 ± 10.51)岁,未绝经患者15例,占75%,绝经患者5例,占25%。有消化系统症状就诊的8人,占40%,检查提示盆腔包块的10人,占50%,包块直径大于10 cm者11人,占55%;肿瘤单侧居多占85%,双侧均有肿瘤的占15%。均进行了全面分期手术,经过全面分期手术及足疗程化疗后,I期患者预后好,II期III期患者预后较差,较少发生铂类耐药。

Table 1. Clinical data of 20 cases of ovarian clear cell carcinoma

表1. 20例卵巢透明细胞癌临床资料

Table 2. The condition of ovarian mass

表2. 卵巢肿块的情况

4. 讨论

4.1. 卵巢透明细胞癌的特征

卵巢透明细胞癌(ovarian clear cell carcinoma, OCCC)是卵巢上皮性癌的一种,约占卵巢上皮性癌的5%~11%。OCCC最初被Schiller于1939年命名为“中肾细胞瘤”,因为认为其起源于中肾结构,类似于肾癌。OCCC患者常表现为盆腔或腹部肿块。OCCC通常较大,直径可达30厘米,平均大小为13~15厘米,90%以上的病例为单侧 [3]。这些肿块也可以在常规超声检查中偶然发现,尤其是绝经前妇女。有几种生殖和激素风险因素与发生OCCC的风险增加有关,如初潮早、绝经晚、口服避孕药使用率低和妊娠率低 [4]。OCCC患者往往在年轻和早期诊断,偶尔发现有血栓栓塞并发症 [5]。目前,OCCC没有特定的生物标志物,OCCC患者通常出现血清CA125轻度升高 [6]。在本研究中 [7],19.77%的患者的CA125水平正常,38.37%的患者的CA125水平 < 100 U/mL。因此,需要识别新的诊断标志物以提高OCCC的早期诊断。含有深静脉血栓形成(DVT)和肺栓塞(PE)的VTE在OCCC患者中很常见,其风险比其他EOC亚型高2.5~4倍 [8] [9]。

4.2. 卵巢透明细胞癌与子宫内膜异位症的关系

OCCC其发病机制与子宫内膜异位症高度相关 [10]。Tay等 [11] 对新加坡1968~2006年卵巢癌的流行病学调查显示,OCCCs发病的独立危险因素是未生育(OR = 1.36)和子宫内膜异位症(OR = 4.87) [11]。多项研究均表明,子宫内膜异位症为OCCCs发病的重要危险因素 [6] [7]。重视OCCCs发病危险因素及癌前病变,采取针对性措施降低其发病,有助于改善OCCCs的临床结局。子宫内膜异位症为独立危险因素 [12]。卵巢非典型子宫内膜异位症与非典型腺纤维瘤为OCCCs的癌前病变,子宫内膜异位症的恶变发生于围绝经期 [13]。大量研究提示,年龄与内异症相关性卵巢癌的发生风险之间有一定的相关性。首先,相较于非内异症相关性卵巢癌,内异症相关性卵巢癌患者更为年轻,其平均年龄在40~55岁 [14] [15]。Kobayashi等 [16] 对6398例卵巢型内异症患者的队列研究发现,绝经状态是内异症相关性卵巢癌的独立危险因素,绝经妇女内异症恶变的风险是未绝经者的3倍。

子宫内膜异位症通过慢性炎症、局部高雌激素和氧化应激促进上皮性卵巢癌的发生。一些炎症介质,如TNF-α、IL-6和TGF-β,已被证明参与子宫内膜异位症相关卵巢癌的发生和发展 [17]。子宫内膜异位病变中雌二醇的大量存在是由于芳香化酶和类固醇生成急性调节蛋白的局部表达增加,同时17β羟基类固醇脱氢酶2的表达降低 [18]。这些激素途径被认为与激素受体阳性的卵巢子宫内膜样癌更密切相关。另一方面,由于经常检测到与氧化应激反应和活性氧(ROS)代谢相关的基因异常 [19],氧化应激被认为是子宫内膜异位症癌变为OCCC的主要因素。子宫内膜异位症通常导致巧克力(子宫内膜异位症)囊肿形成,卵巢中含有含过量铁的旧血。铁及其代谢物通过芬顿反应促进活性氧的生成,作为DNA损伤和糖、脂质和蛋白质修饰的诱导物,导致致癌 [20] [21]。清除氧化应激可抑制子宫内膜异位症中OCCC的发展。强抗氧化剂,如维生素A、类胡萝卜素或类黄酮,可能有助于预防OCCC的致癌。

4.3. 卵巢透明细胞癌治疗方法及预后

根据国内外文献报道,影响预后的主要因素有肿瘤分期FIGO分期、术前CA125值、肿瘤细胞减灭术满意程度、化疗方案的疗程是否足够。FIGO分期越早,患者预后越好,这与疾病的特征性临床表现之间的关系密不可分。早期未发生转移时OCCC的患者预后结果较好,然而晚期患者对现有的化学药物治疗不敏感 [22]。根据日本研究所的回顾性试验,OCCC被归类为高级别癌,即使在早期IC,其复发率也为33.3% [23]。根据这项研究,保留对侧卵巢和子宫的保留生育能力手术明显增加了复发率。NCCN [24] 和ESMO [25] 目前的治疗指南推荐采用3~6个疗程的铂类方案辅助化疗。目前,根据许多临床试验,在初次手术去瘤或分期后,上皮性卵巢癌的标准铂类化疗选择是紫杉醇和卡铂 [26]。卵巢透明细胞癌(OCCC)对常规抗癌药物具有耐药性;此外,晚期或复发患者的预后极差。为了提高OCCC患者的生存率,需要在肿瘤发生和化疗耐药机制方面开展更多更深入的研究,寻找新的治疗策略 [27]。OCCC是异质性很强的肿瘤,与卵巢高级别浆液性癌不同,OCCC通常是p53野生型,识别其驱动突变是实现其个性化治疗关键的第一步。基于OCCC基因表达谱与肾透明细胞癌之间的相似性,多个酪氨酸激酶抑制剂已在OCCC治疗中开展研究。初步数据显示,PI3K/Akt/mTOR途径抑制剂和抗血管生成药物与CPT-11和紫杉醇以及抗程序性细胞死亡1抗体(PD-1抑制剂)联合使用对转移性肾细胞癌有效,从而改善了透明细胞癌预后 [28]。应该考虑在治疗OCCC方案中联合靶向药物治疗,以期改善OCCC患者的预后 [3]。另一种可能改善OCCC患者预后的治疗策略是使用免疫检查点抑制剂 [29] [30]。根据最近的报道,虽然研究的患者例数非常有限,但nivolumab或avelumab在OCCC患者中显示出较好的抗肿瘤效果。因此,在今后,免疫治疗对OCCC患者的疗效也有待进一步深入研究。

NOTES

*通讯作者。

参考文献

[1] Machida, H., Matsuo, K., Yamagami, W., et al. (2019) Trends and Characteristics of Epithelial Ovarian Cancer in Japan between 2002 and 2015: A JSGO-JSOG Joint Study. Gynecologic Oncology, 153, 589-596.
https://doi.org/10.1016/j.ygyno.2019.03.243
[2] Takahashi, K., Takenaka, M., Kawabata, A., et al. (2020) Re-thinking of Treatment Strategies and Clinical Management in Ovarian Clear Cell Carcinoma. International Journal of Clinical Oncology, 25, 425-431.
https://doi.org/10.1007/s10147-020-01625-w
[3] Pozzati, F., Moro, F., Pasciuto, T., et al. (2018) Imaging in Gy-necological Disease (14): Clinical and Ultrasound Characteristics of Ovarian Clear Cell Carcinoma Multicenter Study. Ultrasound in Obstetrics & Gynecology, 52, 792-800.
https://doi.org/10.1002/uog.19171
[4] Yamamoto, A., Johnstone, E.B., Bloom, M.S., Huddleston, H.G. and Fu-jimoto, V.Y. (2017) A Higher Prevalence of Endometriosis among Asian Women does Not Contribute to Poorer IVF Outcomes. Journal of Assisted Reproduction and Genetics, 34, 765-774.
https://doi.org/10.1007/s10815-017-0919-1
[5] Machida, H., Matsuo, K., Yamagami, W., Ebina, Y., Kobayashi, Y., Tabata, T., et al. (2019) Trends and Characteristics of Epithelial Ovarian Cancer in Japan between 2002 and 2015: A JSGO-JSOG Joint Study. Gynecologic Oncology, 153, 589-596.
https://doi.org/10.1016/j.ygyno.2019.03.243
[6] Liu, H., Xu, Y., Ji, J., Dong, R., Qiu, H. and Dai, X. (2020) Prognosis of Ovarian Clear Cell Cancer Compared with Other Epithelial Cancer Types: A Population-Based Analysis. Oncology Letters, 19, 1947-1957.
https://doi.org/10.3892/ol.2020.11252
[7] Zhu, C., Zhu, J., Qian, L., et al. (2021) Clinical Characteristics and Prognosis of Ovarian Clear Cell Carcinoma: A 10-Year Retrospective Study. BMC Cancer, 21, Article No. 322.
https://doi.org/10.1186/s12885-021-08061-7
[8] Ye, S., Yang, J., Cao, D., Bai, H., Huang, H., Wu, M., et al. (2015) Characteristic and Prognostic Implication of Venous Thromboembolism in Ovarian Clear Cell Carcinoma: A 12-Year Retrospective Study. PLOS ONE, 10, e0121818.
https://doi.org/10.1371/journal.pone.0121818
[9] Swier, N. and Versteeg, H.H. (2017) Reciprocal Links between Venous Thromboembolism, Coagulation Factors and Ovarian Cancer Progression. Thrombosis Research, 150, 8-18.
https://doi.org/10.1016/j.thromres.2016.12.002
[10] Brilhante, A.V., Augusto, K.L., Portela, M.C., Sucupira, L.C., Oliveira, L.A., Pouchaim, A.J., Nóbrega, L.R., Magalhães, T.F. and Sobreira, L.R. (2017) Endometriosis and Ovarian Cancer: An Integrative Review (Endometriosis and Ovarian Cancer). Asian Pacific Journal of Cancer Prevention, 18, 11-16.
[11] Tay, S.K. and Cheong, M.A. (2014) Evidence for Ethnic and Environmental Contributions to Frequency of Ovarian Clear Cell Carcinoma. The Australian and New Zealand Journal of Obstetrics and Gynaecology, 54, 225-230.
https://doi.org/10.1111/ajo.12188
[12] Prat, J. (2012) New Insights into Ovarian Cancer Pathology. Annals of On-cology, 23, x111-x117.
https://doi.org/10.1093/annonc/mds300
[13] Kobayashi, H., Sumimoto, K., Moniwa, N., et al. (2007) Risk of De-veloping Ovarian Cancer among Women with Ovarian Endometrioma: A Cohort Study in Shizuoka, Japan. International Journal of Gynecological Cancer, 17, 37-43.
https://doi.org/10.1111/j.1525-1438.2006.00754.x
[14] Varma, R., Rollason, T., Gupta, J.K., et al. (2004) Endo-metriosis and the Neoplastic Process. Reproduction, 127, 293-304.
https://doi.org/10.1530/rep.1.00020
[15] Van Gorp, T., Amant, F., Neven, P., et al. (2004) Endometriosis and the Development of Malignant Tumours of the Pelvis. A Review of Literature. Best Practice & Research Clinical Obstetrics & Gynaecology, 18, 349-371.
https://doi.org/10.1016/j.bpobgyn.2003.03.001
[16] Kobayashi, H., Sumimoto, K., Kitanaka, T., et al. (2008) Ovarian Endometrioma: Risks Factors of Ovarian Cancer Development. The European Journal of Obstetrics & Gyne-cology and Reproductive Biology, 138, 187-193.
https://doi.org/10.1016/j.ejogrb.2007.06.017
[17] Worley, J.M.J., Welch, W.R., Berkowitz, R.S. and Ng, S.-W. (2013) Endometriosis-Associated Ovarian Cancer: A Review of Pathogenesis. International Journal of Molecular Sci-ences, 14, 5367-5379.
https://doi.org/10.3390/ijms14035367
[18] Bulun, S.E. (2009) Endometriosis. The New England Journal of Medi-cine, 360, 268-279.
https://doi.org/10.1056/NEJMra0804690
[19] Yamaguchi, K., Mandai, M., Oura, T., Matsumura, N., Hamanishi, J., Baba, T., Matsui, S., Murphy, S.K. and Konishi, I. (2010) Identification of an Ovarian Clear Cell Carcinoma Gene Signature that Reflects Inherent Disease Biology and the Carcinogenic Processes. Oncogene, 29, 1741-1752.
https://doi.org/10.1038/onc.2009.470
[20] Toyokuni, S. (2009) Role of Iron in Carcinogenesis: Cancer as a Ferro-toxic Disease. Cancer Science, 100, 9-16.
https://doi.org/10.1111/j.1349-7006.2008.01001.x
[21] Yamaguchi, K., Mandai, M., Toyokuni, S., Hamanishi, J., Higuchi, T., Takakura, K. and Fujii, S. (2008) Contents of Endometriotic Cysts, Especially the High Concentration of Free Iron, Are a Possible Cause of Carcinogenesis in the Cysts through the Iron-Induced Persistent Oxidative Stress. Clinical Cancer Research, 14, 32-40.
https://doi.org/10.1158/1078-0432.CCR-07-1614
[22] 杜媛媛, 王安生, 杨阳. 卵巢透明细胞癌从耐药机制到靶向药物选择的新进展[J]. 国际生殖健康/计划生育杂志, 2021, 40(4): 348-352.
[23] Satoh, T., Hatae, M., Watanabe, Y., Yaegashi, N., Ishiko, O., Kodama, S., Yamaguchi, S., Ochiai, K., Takano, M., Yokota, H., et al. (2010) Outcomes of Fertility-Sparing Surgery for Stage I Epithelial Ovarian Cancer: A Proposal for Patients Election. Journal of Clinical Oncology, 28, 1727-1732.
https://doi.org/10.1200/JCO.2009.24.8617
[24] Website of National Comprehen-sive Cancer Network, USA (2019).
https://www.nccn.org/login?ReturnURL=
https://www.nccn.org/professionals/physician
[25] Website of Oxford Academic Journals (2019).
https://academic.oup.com/annonc/article-pdf/30/5/672/29189474/mdz062
[26] Ozols, R.F., Bundy, B.N., Greer, B.E., Fowler, J.M., Clarke-Pearson, D., Burger, R.A., Mannel, R.S., DeGeest, K., Hartenbach, E.M., Baergen, R., et al. (2003) Phase III Trial of Carboplatin and Paclitaxel Compared with Cisplatin and Paclitaxel in Patients with Optimally Resected Stage III Ovarian Cancer: A Gynecologic Oncology Group Study. Journal of Clinical Oncology, 21, 3194-3200.
https://doi.org/10.1200/JCO.2003.02.153
[27] Mabuchi, S., Sugiyama, T., Kimura, T., et al. (2016) Clear Cell Carcinoma of the Ovary: Molecular Insights and Future Therapeutic Perspectives. Journal of Gynecologic Oncology, 27, e31.
https://doi.org/10.3802/jgo.2016.27.e31
[28] 张国楠. 巢透卵明细胞癌的治疗策略与展望[J]. 中国实用妇科与产科杂志, 2021, 37(2): 193-197.
[29] Hamanishi, J., Mandai, M., Ikeda, T., et al. (2015) Safety and Antitumor Activity of Anti-PD-1 Antibody, Nivolumab, in Patients with Platinum-Resistant Ovarian Cancer. Journal of Clinical Oncology, 33, 4015-4022.
https://doi.org/10.1200/JCO.2015.62.3397
[30] Disis, M.L., Patel, M.R., Pant, S., et al. (2015) Avelumab (MSB0010718C), an Anti-PD-L1 Antibody, in Patients with Previously Treated, Recurrent or Refractory Ovarian Can-cer: A Phase Ib, Open-Label Expansion Trial. Journal of Clinical Oncology, 33, 5509.
https://doi.org/10.1200/jco.2015.33.15_suppl.5509