BCAT1 expression associates with ovarian cancer progression: possible implications in altered disease metabolism

Previously, we have identified the branched chain amino-acid transaminase 1 (BCAT1) gene as notably hypomethylated in low-malignant potential (LMP) and high-grade (HG) serous epithelial ovarian tumors, compared to normal ovarian tissues. Here we show that BCAT1 is strongly overexpressed in both LMP and HG serous epithelial ovarian tumors, which probably correlates with its hypomethylated status. Knockdown of the BCAT1 expression in epithelial ovarian cancer (EOC) cells led to sharp decrease of cell proliferation, migration and invasion and inhibited cell cycle progression. BCAT1 silencing was associated with the suppression of numerous genes and pathways known previously to be implicated in ovarian tumorigenesis, and the induction of some tumor suppressor genes (TSGs). Moreover, BCAT1 suppression resulted in downregulation of numerous genes implicated in lipid production and protein synthesis, suggesting its important role in controlling EOC metabolism. Further metabolomic analyses were indicative for significant depletion of most amino acids and different phospho- and sphingolipids following BCAT1 knockdown. Finally, BCAT1 suppression led to significantly prolonged survival time in xenograft model of advanced peritoneal EOC. Taken together, our findings provide new insights about the functional role of BCAT1 in ovarian carcinogenesis and identify this transaminase as a novel EOC biomarker and putative EOC therapeutic target.     

Obesity and survival among women with ovarian cancer: results from the Ovarian Cancer Association Consortium

Background:

Observational studies have reported a modest association between obesity and risk of ovarian cancer; however, whether it is also associated with survival and whether this association varies for the different histologic subtypes are not clear. We undertook an international collaborative analysis to assess the association between body mass index (BMI), assessed shortly before diagnosis, progression-free survival (PFS), ovarian cancer-specific survival and overall survival (OS) among women with invasive ovarian cancer.

Methods:

We used original data from 21 studies, which included 12 390 women with ovarian carcinoma. We combined study-specific adjusted hazard ratios (HRs) using random-effects models to estimate pooled HRs (pHR). We further explored associations by histologic subtype.

Results:

Overall, 6715 (54%) deaths occurred during follow-up. A significant OS disadvantage was observed for women who were obese (BMI: 30–34.9, pHR: 1.10 (95% confidence intervals (CIs): 0.99–1.23); BMI: ⩾35, pHR: 1.12 (95% CI: 1.01–1.25)). Results were similar for PFS and ovarian cancer-specific survival. In analyses stratified by histologic subtype, associations were strongest for women with low-grade serous (pHR: 1.12 per 5 kg m⁻²) and endometrioid subtypes (pHR: 1.08 per 5 kg m⁻²), and more modest for the high-grade serous (pHR: 1.04 per 5 kg m⁻²) subtype, but only the association with high-grade serous cancers was significant.

Conclusions:

Higher BMI is associated with adverse survival among the majority of women with ovarian cancer.     

Characterization of DOK1, a candidate tumor suppressor gene, in epithelial ovarian cancer

In attempt to discover novel aberrantly hypermethylated genes with putative tumor suppressor function in epithelial ovarian cancer (EOC), we applied expression profiling following pharmacologic inhibition of DNA methylation in EOC cell lines. Among the genes identified, one of particular interest wаs DOK1, or downstream of tyrosine kinase 1, previously recognized as a candidate tumor suppressor gene (TSG) for leukemia and other human malignancies. Using bisulfite sequencing, we determined that a 5′-non-coding DNA region (located at nt −1158 to −850, upstream of the DOK1 translation start codon) was extensively hypermethylated in primary serous EOC tumors compared with normal ovarian specimens; however, this hypermethylation was not associated with DOK1 suppression. On the contrary, DOK1 was found to be strongly overexpressed in serous EOC tumors as compared to normal tissue and importantly, DOK1 overexpression significantly correlated with improved progression-free survival (PFS) values of serous EOC patients. Ectopic modulation of DOK1 expression in EOC cells and consecutive functional analyses pointed toward association of DOK1 expression with increased EOC cell migration and proliferation, and better sensitivity to cisplatin treatment. Gene expression profiling and consecutive network and pathway analyses were also confirmative for DOK1 association with EOC cell migration and proliferation. These analyses were also indicative for DOK1 protective role in EOC tumorigenesis, linked to DOK1-mediated induction of some tumor suppressor factors and its suppression of pro-metastasis genes. Taken together, our findings are suggestive for a possible tumor suppressor role of DOK1 in EOC; however its implication in enhanced EOC cell migration and proliferation restrain us to conclude that DOK1 represents a true TSG in EOC. Further studies are needed to more completely elucidate the functional implications of DOK1 and other members of the DOK gene family in ovarian tumorigenesis.     

Predictors of ovarian cancer survival: a population-based prospective study in Sweden

Ovarian cancer is the leading cause of death from gynecologic malignancies among women worldwide. Little is known about reproductive factors or lifestyle determinants and ovarian cancer prognosis. The objective of this study was to examine whether ovarian cancer survival is influenced by reproductive history, anthropometric characteristics, prediagnostic life-style factors and family history of breast or ovarian cancer. The study population consisted of 635 epithelial ovarian cancer (EOC) cases derived from a nationwide population-based case-control study conducted in Sweden between 1993 and 1995. Exposure data on prediagnostic factors of interest were collected through questionnaires at the beginning of the parent study. Clinical data were abstracted from medical records. Cases were followed-up by means of record linkage to nationwide registers until December 31, 2002. Cox proportional hazard regression model was used to estimate the prognostic effect of each factor in terms of hazard ratios (HR) and 95% confidence intervals (CI), following adjustment for age at diagnosis, FIGO tumor stage and WHO grade of tumor differentiation. Tumor characteristics significantly influenced the risk of death from EOC. After adjustment for these, no clear associations were detected between reproductive history (parity, age at first or last birth, oral contraceptive use, age at menarche or menopause), anthropometric characteristics (body size and shape in different periods of life), lifestyle factors before diagnosis (alcohol consumption, smoking and physical activity over lifetime), nor family history of breast cancer or ovarian cancer and EOC survival. Our findings indicate that these prediagnostic factors do not influence the EOC survival. Nevertheless, among women with early stage disease (FIGO stage I and II), there was some indication that overweight in young adulthood or recent years increased the risk of death, while physical activity in young adult life appeared to reduce the risk of death due to EOC.     

卵巢上皮癌DNA含量和细胞增殖水平测定的临床意义

目的探讨DNA含量及细胞增殖水平对判断卵巢上皮癌预后的价值.方法应用流式细胞技术对43例卵巢上皮癌的术后新鲜组织进行DNA含量及细胞增殖水平测定.结果卵巢上皮癌的异倍体率为72.1%.Ⅰ期、Ⅱ期与Ⅲ期、Ⅳ期异倍体比较(P<0.01)有非常显著意义,DNA异倍体与低分化肿瘤及术后残余肿瘤的大小有密切关系(P<0.05),而与病理类型及有无腹水无相关性.在2年以上的随访过程中,18例死亡者皆为异倍体,死亡组DI值2.01±0.20高于存活组1.21±0.18,SPF值18.1±3.9高于存活组13.2±3.3.结论DNA倍体、SPF值与卵巢上皮癌的恶性生物学行为有关,可作为卵巢上皮癌的一个重要的预后指标.     

287例盆腔及腹主动脉旁淋巴结清扫术与卵巢上皮性癌生存预后的临床分析

Objective: To evaluate the relationship between the pelvic and para-aortic lymphadenectomy and the prognosis of epithelial ovarian cancer. Methods: 287 patients suffering from primary epithelial ovarian cancer from 1995 to 2005 were analyzed retrospectively. Results: The 3-, 5-, 10-year survival with systematic lymphadenectomy (SL) were slightly higher than those without SL, but there were no statistically significance (P ＞ 0.05). The 3-, 5-, 10-year survival of clinical stages without SL were lower than those with SL, but there were no significant difference either (P ＞ 0.05). The 3-,5-, and 10-year survival rates with SL were higher than those without SL with no statistically differences (P ＞ 0.05) among the subgroups such as absent, ≤ 2 cm and ＞ 2 cm residual tumor. The survival rates of the groups without residual tumor and the group with ≤ 2cm residual tumor were significantly higher than that of ＞ 2 cm (P ＜ 0.005). On multivariate analysis, patient staging (P = 0.01)and size of residual disease after primary cytoreductive surgery (P ＜ 0.001 and = 0.002, respectively) retained prognostic significance. SL was not proved to be an independent prognostic factor (P = 0.69). Conclusion: Systematic pelvic and paraaortic lymphadenectomy can not improve and prolong the survival time significantly.     

保留生育功能手术在上皮性卵巢癌治疗中的系统评价

目的:采用循证医学Meta分析的方法评价保留生育功能手术与根治性手术对治疗上皮性卵巢癌患者生存率的影响,并且系统评价保留生育功能手术治疗上皮性卵巢癌的生存率、复发率和术后妊娠情况.方法:计算机检索Cochrane Library、Pubmed、Embase、MEDLINE、CBMdise、维普等数据库,检索年限从建库至2013年7月,并追查了所有纳入文献的参考文献.手工检索相关杂志、会议论文集、学位论文汇编等.采用STATA 10.0软件进行Meta分析.并对非临床对照研究资料进行分析.结果:共纳入8个保留生育功能手术和根治性手术治疗上皮性卵巢癌生存率比较的临床对照实验和11个无对照的临床研究.Meta分析结果表明,保留生育功能手术和根治性手术治疗上皮性卵巢癌的生存率差异无统计学意义(OR:0.88,95％ CI=0.52～1.51,P=0.64).根据11篇分析保留生育功能手术的临床研究文献计算出的生存率为97％,复发率为11％,其中9篇临床病例研究详细记录和分析了有生育要求并尝试怀孕和实际成功受孕的例数并计算出总的妊娠率为67％.结论:保留生育手术不会降低年轻的早期上皮性卵巢癌患者的生存期且能维持正常的妊娠和生育功能,提高了患者生存质量.     

Sprouty 1 predicts prognosis in human epithelial ovarian cancer

Sprouty proteins are evolutionary-conserved modulators of receptor tyrosine kinase (RTK) signaling. We have previously reported inverse correlation of the Sprouty 1 (Spry1) protein expression with ovarian cancer cell proliferation, migration, invasion and survival. In the present study, the expression status of Spry1 protein and its clinical relevance in patients with epithelial ovarian cancer were explored. Matched tumor and normal tissue samples from 100 patients with epithelial ovarian cancer were immunohistochemically stained for Spry1. Expression of ERK, p-ERK, Ki67, FGF-2, VEGF and IL-6 and their correlation with Spry1 were also evaluated. In addition, correlation between Spry1 and clinicopathological characteristics and predictive significance of Spry1 for overall survival (OS) and disease-free survival (DFS) were analysed. Our data indicated that Spry1 was significantly downregulated in tumor tissues (p=0.004). Spry1 showed significant inverse correlation with p-ERK/ERK (p=0.045), Ki67 (p=0.010), disease stage (p=0.029), tumor grade (p=0.037), recurrence (p=0.001) and lymphovascular invasion (p=0.042). It was revealed that Spry1 low-expressing patients had significantly poorer OS (p=0.010) and DFS (p=0.012) than those with high expression of Spry1. Multivariate analysis showed that high Spry1 (p=0.030), low stage (p=0.048) and no residual tumor (p=0.007) were independent prognostic factors for a better OS, among which high Spry1 (p=0.035) and low stage (p=0.035) remained as independent predictors of DFS, too. We also found that the expression of Spry1 significantly correlates with the expression of Spry2 (p<0.001), but not that of Spry4. In conclusion, we report for the first time to our knowledge that Spry1 protein is downregulated in human epithelial ovarian cancer. Spry1 expression significantly impacts tumor behavior and shows predictive value as an independent prognostic factor for survival and recurrence.     

上皮性卵巢癌预后因素的研究进展

卵巢癌是女性生殖系统中最常见的肿瘤之一,其中上皮性卵巢癌是卵巢癌最常见的病理类型。约70%的上皮性卵巢癌患者被诊断时已经是晚期,因此早发现、早诊断、早治疗是提高上皮性卵巢癌患者生存率的重要方法之一。上皮性卵巢癌的标准治疗方式为细胞瘤减灭术及铂类为主的化疗,但是随着肿瘤细胞对化疗产生耐药性大多数患者在医治后容易复发,患者存活率一般都很低并且疾病很难控制。近年来,对上皮性卵巢癌发病的分子机制的研究不断进展,发现了更多影响上皮性卵巢癌预后的因素,并且可作为潜在的治疗靶点提高患者生存率。     

RUNX3 and CAMK2N1 hypermethylation as prognostic marker for epithelial ovarian cancer

Treatment of epithelial ovarian cancer consists of surgery plus platinum‐taxane based chemotherapy. Neither prognostic nor predictive serum or tissue markers except BRCA1/2 mutations are available thus precluding individualized treatment. Aim of this study is the identification and validation of DNA‐methylation markers with prognostic value. Genome‐wide array analyses were used to determine methylation patterns in groups of serous EOC with different outcome (PFS < vs. > 3 years, each n = 6) but comparable clinical parameters. Two hundred and twenty differentially methylated regions in tumor tissue of patients with short vs. long PFS (106 hypo‐ and 114 hypermethylated regions) were identified. Thirty‐five of 37 selected CpG islands were validated by MSP using the same samples as for microarray analyses. Six of these regions were analyzed by targeted next‐generation bisulfite‐sequencing confirming array and MSP results. Validation experiments with an enlarged patient group of Type II EOC samples (PFS <3 years n = 30; >3 years n = 18) revealed the CpG island of RUNX3 as significantly more often methylated in patients with short PFS (10/30 vs. 0/18; p < 0.01). Marker combinations with significantly different methylation frequencies in patient groups reached an increased sensitivity with equal specificity (RUNX3+CAMK2N1; sens 40%; spec 100%; p < 0.01). RUNX3/CAMK2N1 methylation‐positive patients of the array‐independent subset (n = 36) showed a significantly lower PFS (p < 0.01) but no other difference in clinical parameters compared to methylation‐negative patients. Genome‐wide methylation analyses reliably identified markers of potentially prognostic value. Hypermethylation of RUNX3/CAMK2N1 is associated with poor clinical outcome in Type II EOC, also after macroscopic complete resection.     

Rac GTPase activating protein 1 promotes oncogenic progression of epithelial ovarian cancer

Rac GTPase activating protein 1 (RacGAP1) can regulate cytokinesis and cell differentiation. The oncogenic role of RacGAP1 has been partially studied in gastric cancer, colorectal cancer, and breast cancer. In the present study, we endeavor to evaluate its expression and functions in epithelial ovarian cancer (EOC). We retrospectively collected the clinicopathological information of 117 patients who underwent curative surgery for EOC. Expression of RacGAP1 protein in primary tumor tissues was evaluated by immunohistochemistry, which was significantly associated with tumor pathological grade, tumor stage, and lymph node metastasis. Patients with lower RacGAP1 level had a longer survival time and lower recurrence risk. Multivariate results identified the independent prognostic role of RacGAP1 for both recurrence and survival in EOC patients. Cellular studies showed that RacGAP1 can positively regulate the activation of RhoA and Erk proteins. In addition, wound healing assay and Transwell assay found that RacGAP1 can up‐regulate the migration and invasion process of EOC cells, respectively. In all, our results not only confirmed the prognostic role of RacGAP1 for recurrence and survival in EOC patients, but also highlighted its possible potency for drug development.     

晚期卵巢癌患者外周血循环肿瘤细胞的检测及其临床意义

目的:探讨晚期卵巢癌患者外周血中循环肿瘤细胞(CTC)的检测及其临床意义.方法:选择2014年6月至2016年6月永州市中心医院收治的60例晚期卵巢癌患者作为观察组,收集同期本院的30例健康志愿者作为对照组.分别抽取外周血7.5 ml,采用流式细胞仪检测卵巢癌患者一线方案化疗2周期前后及对照组外周血中EpCAM、CK19同时(+)且CD45(-)的CTC的变化情况,同时分析其与临床特征及化学疗效的关系以及比较化疗前后CTC数目评价与RECIST疗效评价标准之间的关系,并随访患者的无进展生存期(PFS),分析患者治疗过程中CTC数目的变化与患者PFS的关系.结果:观察组中42例检测到CTC,阳性率70%,对照组未检测到CTC,两组比较,差异具有统计学意义(P<0.05).CTC阳性表达情况与卵巢癌患者的分化程度及CA125表达相关(P<0.05),与患者的年龄、肿瘤直径、腹水情况均无相关性(P>0.05).观察组中化疗前CTC阳性表达42例,阳性率为70%,化疗2周期后卵巢癌患者CTC阳性表达18例,阳性率为30%,两组差异具有统计学意义(P<0.05).化疗2周期后,CTC数目评价与RECIST疗效评价标准之间差异无统计学意义(P>0.05),且两种方法的吻合度较高(k=0.479).运用相关分析显示,CTC表达与化学疗效呈负相关(r=-0.223,P=0.009).化疗2周期后外周血中循环肿瘤细胞数目<5,其无进展生存期为13.2(11.0~15.1)个月,外周血中循环肿瘤细胞数目≥5,其无进展生存期为6.4(3.8~9.2)个月,两组差异具有统计学意义(P<0.05).结论:CTC阳性表达与卵巢癌患者的分化程度及CA125表达相关,与化疗疗效呈负相关,CTC的表达情况可以预测卵巢癌患者的化疗疗效及预后.     

Role of cytoreductive surgery in recurrent ovarian cancer

Cytoreductive surgery is well established in patients with primary ovarian cancer. The benefit of surgery in patients with recurrent ovarian cancer remains a controversial matter. There is a large heterogeneity in surgical results published in the literature, possibly caused by infrastructure, surgeons’ philosophy and belief in adding various surgical skills. This might also be a result of different preoperative selection procedures. Further questions to be addressed are the definition of surgical end points and whether there are predictive factors for a successful surgery. The surgical end point in recurrent ovarian cancer should be complete resection. Predictive factors could help identify patients in whom complete resection is possible.     

Reproductive factors and epithelial ovarian cancer survival in the EPIC cohort study

Background:

Reproductive factors influence the risk of developing epithelial ovarian cancer (EOC), but little is known about their association with survival. We tested whether prediagnostic reproductive factors influenced EOC-specific survival among 1025 invasive EOC cases identified in the European Prospective Investigation into Cancer and Nutrition (EPIC) study, which included 521 330 total participants (approximately 370 000 women) aged 25–70 years at recruitment from 1992 to 2000.

Methods:

Information on reproductive characteristics was collected at recruitment. Cox proportional hazards regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs), and multivariable models were adjusted for age and year of diagnosis, body mass index, tumour stage, smoking status and stratified by study centre.

Results:

After a mean follow-up of 3.6 years (±3.2 s.d.) following EOC diagnosis, 511 (49.9%) of the 1025 women died from EOC. We observed a suggestive survival advantage in menopausal hormone therapy (MHT) users (ever vs never use, HR=0.80, 95% CI=0.62–1.03) and a significant survival benefit in long-term MHT users (⩾5 years use vs never use, HR=0.70, 95% CI=0.50–0.99, P_trend=0.04). We observed similar results for MHT use when restricting to serous cases. Other reproductive factors, including parity, breastfeeding, oral contraceptive use and age at menarche or menopause, were not associated with EOC-specific mortality risk.

Conclusions:

Further studies are warranted to investigate the possible improvement in EOC survival in MHT users.     

妊娠及围产期卵巢上皮性癌3例分析及文献回顾

妊娠及围产期上皮性卵巢癌（EOC）是威胁母婴健康的恶性疾病之一，发生率低，早期诊断困难，且对生命及家庭生活会产生巨大的影响。本文通过详尽分析3例妊娠及围产期上皮性卵巢癌病例的诊断、治疗经过及结局，并回顾相关文献报道，以提出对该病的治疗建议。通过病例分析及文献回顾发现妊娠合并EOC早期诊断困难，肿瘤标志物及B超诊断价值有限。一旦诊断，是否继续妊娠以及手术化疗的治疗方案要根据患者及其家庭情况多方面考量，充分沟通，每个患者均应获得个体化治疗方案。目前预后尚存在不确定性。     

Shifting incidence and survival of epithelial ovarian cancer (1995-2014): A SurvMark-2 study

The aim of the study is to provide a comprehensive assessment of incidence and survival trends of epithelial ovarian cancer (EOC) by histological subtype across seven high income countries (Australia, Canada, Denmark, Ireland, New Zealand, Norway and the United Kingdom). Data on invasive EOC diagnosed in women aged 15 to 99 years during 1995 to 2014 were obtained from 20 cancer registries. Age standardized incidence rates and average annual percentage change were calculated by subtype for all ages and age groups (15-64 and 65-99 years). Net survival (NS) was estimated by subtype, age group and 5-year period using Pohar-Perme estimator. Our findings showed marked increase in serous carcinoma incidence was observed between 1995 and 2014 among women aged 65 to 99 years with average annual increase ranging between 2.2% and 5.8%. We documented a marked decrease in the incidence of adenocarcinoma “not otherwise specified” with estimates ranging between 4.4% and 7.4% in women aged 15 to 64 years and between 2.0% and 3.7% among the older age group. Improved survival, combining all EOC subtypes, was observed for all ages combined over the 20-year study period in all countries with 5-year NS absolute percent change ranging between 5.0 in Canada and 12.6 in Denmark. Several factors such as changes in guidelines and advancement in diagnostic tools may potentially influence the observed shift in histological subtypes and temporal trends. Progress in clinical management and treatment over the past decades potentially plays a role in the observed improvements in EOC survival.     

A Phase II study of trabectedin single agent in patients with recurrent ovarian cancer previously treated with platinum-based regimens

The objective of this study was to determine the objective response rate in patients with platinum-sensitive and platinum-resistant recurrent ovarian cancer to treatment with trabectedin (Yondelis) administered as a 3-h infusion weekly for 3 weeks of a 4-week cycle. We carried out a multicentre Phase II trial of trabectedin in patients with advanced recurrent ovarian cancer. Trabectedin (0.58 mg m(-2)) was administered via a central line, after premedication with dexamethasone, to 147 patients as a 3-h infusion weekly for 3 weeks followed by 1-week rest. Major eligibility criteria included measurable relapsed advanced ovarian cancer and not more than two prior platinum-containing regimens. Patients were stratified according to the treatment-free interval (TFI) between having either platinum-sensitive (>/=6 months TFI) or platinum-resistant disease (<6 months TFI)/platinum-refractory disease (progression during first line therapy). In the platinum-sensitive cohort, 62 evaluable patients with measurable disease had an overall response rate (ORR) of 29.0% (95% CI: 18.2-41.9%) and median progression-free survival (PFS) was 5.1 months (95% CI: 2.8-6.2). Four patients with measurable disease per Response Evaluation Criteria in Solid Tumours (RECIST) criteria had no follow-up scans at the end of treatment. In the platinum-resistant/refractory cohort, 79 patients were evaluable with an ORR of 6.3% (95% CI: 2.1-14.2%). Median PFS was 2.0 months (95% CI: 1.7-3.5 months). Two patients with measurable disease per RECIST criteria had no follow-up scans at the end of treatment. The most frequent (>/=2% of patients) drug-related treatment-emergent grade 3/4 adverse events were reversible liver alanine transferase elevation (10%), neutropaenia (8%), nausea, vomiting, and fatigue (5% each). Trabectedin is an active treatment, with documented responses in patients with platinum sensitive advanced relapsed ovarian cancer, and has a manageable toxicity profile.     

Long-term survival of young women receiving fertility-sparing surgery for ovarian cancer in comparison with those undergoing radical surgery

Objectives:

To compare the clinical outcome of patients with stage I epithelial ovarian cancer (EOC) who received with fertility-sparing surgery (FSS) with those who underwent radical surgery (RS).

Methods:

After a central pathological review and search of the medical records from multiple institutions, a total of 572 patients were retrospectively evaluated. All patients were divided into three groups: group A {FSS (n=74); age, ⩽40} groups B and C [RS; age, 40⩾{(B), n=52} 40<{(C), n=446}].

Results:

Five-year overall survival (OS) and disease-free survival (DFS) rates of patients in the groups were as follows: group A, 90.8% (OS)/87.9% (DFS); group B, 88.3% (OS)/84.4% (DFS); group C, 90.6% (OS)/85.3% (DFS), respectively (OS, P=0.802; DFS, P=0.765). Additionally, there was no significant difference in OS and DFS among the three groups stratified to stage IA or IC (OS (IA), P=0.387; DFS (IA), P=0.314; OS (IC), P=0.993; DFS (IC), P=0.990, respectively). Furthermore, patients with a grade 1–2 or 3 tumours in the FSS group did not have a poorer prognosis than those in the RS group.

Conclusions:

Stage I EOC patients treated with FSS showed an acceptable prognosis compared with those who underwent RS.