基于调强放疗的鼻咽癌分期探讨

目的 验证鼻咽癌第7版UICC或AJCC分期,并为其进一步修订提供依据。方法 收集2005—2011年间本院收治的经病理确诊、无远处转移并接受根治性IMRT的初治鼻咽癌患者 323例。根据鼻咽癌第7版UICC或AJCC分期标准进行分期。Kaplan-Meier计算生存率,Logrank法检验差异,Cox模型多因素预后分析。结果 5年样本数为 45例。T₁与T₂期、T₂与T₃期 5年LRFS率相近(P=0.055、P=0.746)。将T₂、T₃和T₄期翼内肌组合并为T₂期,T₄期其他的降期为T₃期,新T分期中T₁、T₂、T₃期LRFS曲线明显分开。N₂与N_3a期、N₂与N_3b期、N_3a与N_3b期 5年DMFS率相近(P=0.272、P=0.063、P=0.810)。多因素分析结果显示颈淋巴结部位是DMFS的唯一影响因素(P=0.037)。将N_3a期中颈淋巴为单侧的降期为N₁期,N_3a期中颈淋巴结为双侧的降期为N₂期,则新N分期中N₀、N₁、N₂、N₃期DMFS曲线分开。Ⅰ与Ⅱ期、Ⅲ与 Ⅳ_a期 5年OS相近(P=0.434、P=0.951)。将T₁N_0-1期作为 Ⅰ_{a期、T2N0-1期作为 Ⅰb期、T1-3N2期和(或) T3N0-1期作为Ⅱ期、T1-3N3期作为Ⅲ期,各期 5年OS曲线明显分开。结论 第7版UICC或AJCC分期仍存在不足,推荐新分期能更好预测预后,但需要更大样本量数据验证。}     

第7版UICC或AJCC鼻咽癌分期的IMRT验证研究

目的 验证第7版 UICC或AJCC 鼻咽癌分期系统在以MR为分期手段、IMRT为基础综合治疗策略下的合理性及适用性。方法 回顾分析2007—2011年间在本院经MRI分期和IMRT治疗的 720例初诊M₀期鼻咽癌患者的生存及失败情况,评价T、N分期对预测患者生存及失败的可靠性。Kaplan-Meier计算生存率,Logrank法检验差异,Cox模型多因素预后分析。结果 第7版 UICC或AJCC 鼻咽癌T分期是OS、CSS、DFS和DMFS的影响因素(P=0.013、0.025、0.001、0.002),但T₁、T₂、T₃期间相近(P=0.054~0.626)。从局部复发和远转风险来看,T₃与T₂期非常接近(P=0.796)。N分期是DFS、DMFS的影响因素(P=0.005,0.000)。但N₀和N₁期间相近(P=0.549、0.707)。在N₀—N₁期中也未发现单纯咽后淋巴结转移对OS、DFS和DMFS有影响(P=0.360、0.083、0.062)。结论 第7版UICC或AJCC鼻咽癌分期系统对经MRI分期和IMRT的鼻咽癌患者预后仍有较好预测价值,但有进一步优化的空间。     

鼻咽癌前瞻性多中心临床分期研究的初步结果

目的 通过比较鼻咽癌2008分期和第7版UICC或AJCC分期标准的病例分布和预后价值,探讨两种分期合理性。方法 分析2009—2010年全国9个肿瘤中心收治的 1508例无远处转移鼻咽癌首诊患者的临床资料,分别根据鼻咽癌2008分期与第7版UICC或AJCC分期进行分期,分析和评价两种分期病例分布的一致性及 3年LRFS、DMFS、OS率。采用Kaplan-Meier法计算LRFS、DMFS和OS率,Logrank检验差异。结果 两种分期的T期、N期、临床分期病例分布相似(Kappa=0.80、0.60、0.60),临床分期OS曲线和T分期LRFS曲线也较一致,但Ⅰ、Ⅱ期OS曲线相似,T₁—T₃期LRFS曲线出现靠拢或重叠。2008分期N₀与N₁期曲线相似,而UICC或AJCC分期N₁与N₂期曲线相似。结论 两种分期病例分布、临床分期及T分期预后相似,但N分期预后不同。两种分期中临床分期、T分期、N分期的预后需进一步完善。     

改良食管癌UICC第七版分期预测术前放疗预后价值分析

目的 评价食管癌术前放疗后病理T、N分期以及国际抗癌联盟(UICC) TNM分期是否能准确预测预后。方法 回顾分析1980—2007年本院接受术前放疗并有详细临床、病理、放疗和手术记录的 311例食管鳞状细胞癌患者资料。Kaplan-Meier法生存分析并Logrank检验和单因素分析。结果 随访率96.5%,随访时间满5、10年者分别为89、43例。全组单因素分析发现放疗后原发部位有无肿瘤残存(T-pCR,χ²=11.53,P=0.001)和淋巴结转移个数(0、1~3、≥4个,χ²=42.13,P=0.000)是影响预后因素。UICC第7版分期可用于区分上述患者预后。而根据转移淋巴结数改良第7版N分期为N₀(0个)、N₁(1~3个)、N₂(≥4个)期并结合残存癌T分期,则ypⅠ期(T_1~2N₀M₀期)与ypⅡ期(T_0-3N₁M₀期+T₃N₀M₀期)、ypⅡ期与ypⅢ期(T₄N_0~1M₀期或T_0-3N₂M₀期)间预后差异均有统计学意义(χ²=11.15、23.39,P=0.001、0.000)。结论 食管鳞状细胞癌术前放疗后病理的T分期和阳性淋巴结个数是影响预后因素。UICC 第7版分期能较准确评价预后,改良第7版N分期后与T分期结合更方便、准确预测预后。     

食管癌非手术治疗临床分期新标准的对比研究

目的 比较不同食管癌临床分期对同一组病例的预测价值,并完善T分期标准,为更准确进行临床分期提供参考。方法 回顾分析我院701例根治性放疗食管癌患者,分别按AJCC标准、2004年标准、2009年草案标准并结合GTV-T体积标准进行预后判断。结果 按3种标准进行T分类后,发现AJCC分期偏早,T₁期达23.1%,且T₃与T₄期的生存曲线接近。2004年标准下各期生存曲线分离度均较好,但T₁和T₄期者偏少,分布不均。2009年草案标准中T₃和T₄期生存曲线交叉且T₄期较多达43.2%。根据GTV大小及病变对周围组织器官侵及程度行新T分期,各期生存曲线未见交叉,所占比例较均衡。N分期仍采用N₀、N₁、N₂期分类法,将N分期与新T分期结合进行TNM分期,所得各期生存曲线分离度均很好(P=0.000)。结论 将食管癌局部肿瘤体积大小结合外侵程度确定的T分期与区域内外淋巴结转移确定的N分期联合,能比较准确地预测非手术治疗患者的生存预后。     

基于MRI和IMRT的鼻咽癌鼻窦侵犯的预后研究

目的探讨基于MRI和IMRT的鼻咽癌鼻窦侵犯在鼻咽癌分期中的意义。方法 回顾分析2005—2010年基于MRI诊断的接受IMRT的1197例初诊鼻咽癌患者资料。根据AJCC第7版分期重新分期。鼻窦侵犯分为伴有鼻窦侵犯T₃、T₄期。Kaplan-Meier法计算LRFS、DMFS、OS率并Logrank法检验。Cox模型多因素预后分析及T分期各亚组局部复发风险比。结果 鼻窦侵犯率为14.2%。鼻窦侵犯不是影响鼻咽癌OS、LRFS、DMFS的因素(P=0.677、0.485、0.211)。T₂期、伴鼻窦侵犯T₃期及不伴鼻窦侵犯T₃期局部复发风险比接近(HR=1.927、2.030、2.283)。LRFS、OS曲线在T₂期、伴鼻窦侵犯T₃期及不伴鼻窦侵犯T₃期接近(P>0.05),与伴鼻窦侵犯T₄期及不伴鼻窦侵犯T₄期明显分开(P<0.05)。结论 鼻窦侵犯不是IMRT鼻咽癌OS、LRFS和DMFS的预后因素,但伴鼻窦侵犯的T₃期OS、LRFS与T₂、T₃期相似,预后较T₄期好。     

基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌N分期研究

目的 建立一个基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌新N分期。 方法 回顾分析广西医科大学第一附属医院2010—2011年经病理学证实、无DM并接受IMRT的初治鼻咽癌患者324例,根据鼻咽癌UICC/AJCC分期标准(第7版)进行重新分期。Kaplan-Meier法计算生存率,Logrank法单因素预后分析,Cox模型多因素预后分析。 结果 324例患者中269例(83.0%)出现转移淋巴结,中位随访58个月(6~77个月),全组5年OS率为84.8%,DFS率为77.1%,RFS率为92.7%,DMFS率为80.5%。对其中颈部淋巴结阳性患者预后因素分析显示咽后淋巴结、颈部淋巴结水平、侧数是影响鼻咽癌患者预后因素(P值均<0.05)。根据风险比差异确定鼻咽癌新N分期: N₀期为无淋巴结转移;N₁期为Ⅶ_a区或/和单侧上颈(Ⅰ、Ⅱ、Ⅲ、V_a区)淋巴结转移;N₂期为双侧上颈(Ⅰ、Ⅱ、Ⅲ、Ⅴ_aa区)淋巴结转移;N₃期为Ⅳ _a、Ⅴ_b区及以下区域淋巴结转移。 结论 基于IMRT和RTOG颈部淋巴结分区标准的鼻咽癌新N分期更符合现状,并能更客观预测预后、指导治疗。     

基于MRI及IMRT下的鼻咽癌新T分期研究

目的 建立一个基于MRI并与IMRT相适应的鼻咽癌新T分期系统。方法 回顾分析2008—2010年我院基于MRI并接受IMRT的608例初治无转移鼻咽癌患者资料,按鼻咽癌第7版UICC/AJCC分期系统进行分期。Kaplan-Meier法计算相关生存率及Logrank检验,Cox法多因素分析。现行UICC/AJCC分期系统存在不足,在此基础上建立新鼻咽癌T分期系统,并对新T分期系统合理性进行评价。结果 5年随访率为94.5%,5年OS、DFS、LRFS、DMFS分别为81.5%、80.1%、86.0%、81.1%。单因素及多因素分析结果显示鼻咽、咽旁间隙、颅底解剖结构均为影响患者OS率因素(P=0.000—0.045)。根据风险差异性及生存曲线分布提出新T分期标准:T₁期:侵袭鼻咽、咽旁间隙、口咽、鼻腔、颅底、翼内肌;T₂期:侵袭翼外肌、鼻窦、眼眶、颅内、颞下窝、颅神经。推荐新T分期系统LRFS曲线及OS曲线均能很好地拉开。结论 推荐新T分期系统能较客观地预测鼻咽癌患者预后,可作为鼻咽癌临床新分期探索性的尝试。     

IMRT时代鼻咽癌临床分期的降期新建议研究

目的 在不改变目前T、N、M分期定义基础上,提出适用于IMRT时代鼻咽癌临床分期的降期新建议。方法 回顾分析中山大学附属肿瘤医院2002—2006年536例鼻咽癌病例,采用Kaplan-Meier计算DSS率并Logrank检验,Cox法计算各亚组DSS风险比。结果 依据第7版UICC/AJCC分期系统,Ⅰ—Ⅲ期非T₃N₂M₀期患者5年DSS均在85%以上,Ⅳ_A、Ⅳ_B期的分别为71.8%、46.2%(P=0.171),而Ⅳ_C期的仅为24.0%。Ⅲ期患者中非T₃N₂M₀期患者5年DSS (91.5%)高于T₃N₂M₀期患者(78.6%)(P=0.042)。T₃N₂M₀期患者DSS经临床综合评估与Ⅳ_A—Ⅳ_B期患者相似。新Ⅰ期包括T_1-3N_0-1M₀和T_1-2N₂M₀,新Ⅱ期包括T₃N₂M₀、T₄N_0-2M₀和 TxN₃M₀期,新Ⅲ期包括TxNxM₁期,新Ⅰ、Ⅱ、Ⅲ期的5年DSS分别为93.3%、72.7%、24.0%(P=0.000),相比于新Ⅰ期,新Ⅱ、Ⅲ期的5年DSS风险比分别为4.01、16.76。结论 IMRT时代把鼻咽癌临床分期降为3个组可以更好地区分预后及指导临床治疗。     

基于调强放疗N0期鼻咽癌颈部预防照射的选择

目的 探讨基于调强放疗(IMRT) N₀期鼻咽癌患者颈部预防照射的方式。方法 回顾分析2003—2008年本中心IMRT的 270例N₀期(第6版AJCC/UICC分期)初治鼻咽癌患者的临床资料,其中 171例接受上半颈预防照射,99例接受全颈预防照射。所有患者均接受鼻咽原发灶、上颈部淋巴引流区(包括双颈Ⅱ、Ⅲ、Ⅴ_A区)6 MV X线IMRT,鼻咽原发灶剂量为68 Gy分30次,上颈剂量为54 Gy分30次,疗程6周。全颈预防照射者下颈部及锁骨上采用颈前半野常规技术,剂量为50 Gy分25次。结果 中位随访65.1个月,随访率为93%。上颈、全颈预防照射的 5年肿瘤相关生存率分别为95.3%、91.9%(χ²=0.76,P=0.384),颈部无复发生存率分别为99.4%、99.0%(χ²=1.18,P=0.278),无远处转移生存率分别为98.8%、94.9%(χ²=2.31,P=0.128)。咽后淋巴结阴、阳性患者 5年无远处转移生存率分别为99.4%、93.7%(χ²=8.96,P=0.003)。急性不良反应主要为1、2级黏膜炎和咽喉炎,无3+4级张口困难和口干等晚期不良反应。结论 N₀期鼻咽癌患者IMRT时行上半颈预防照射也许是可行的,第7版AJCC/UICC将颈淋巴结阴性而咽后淋巴结阳性鼻咽癌上调为N₁是合理的。     

In-depth evaluation of the AJCC/UICC 1997 staging system of nasopharyngeal carcinoma: prognostic homogeneity and proposed refinements

PURPOSE: To critically evaluate the American Joint Commission on Cancer (AJCC)/International Union Against Cancer (UICC) 1997 staging system and look back on its achievements by comparing it with the AJCC/UICC 1992 and Ho 1978 staging systems. To identify areas for additional refinement, we analyzed the prognostic heterogeneity within each stage in depth, which provided important clues for the addition or better categorization of the different defining criteria. METHODS AND MATERIALS: We performed a retrospective review of the data from 1294 consecutive biopsy-proven nonmetastatic nasopharyngeal carcinoma patients and staged the extent of disease according to the defining criteria of the three staging systems. All patients had undergone detailed pretreatment assessment by fiberoptic endoscopy and CT. Radical-intent radiotherapy was given using the Ho technique according to our standard protocol. RESULTS: The AJCC/UICC 1997 staging system was superior to the other two staging systems, because it assigned patients to more uniform-size stage groupings and correlated better with prognosis. Parapharyngeal space involvement was not an independent predictor for survival, local control, or metastasis. On the other hand, carotid space involvement correlated with a greater likelihood of metastasis. Prognostic heterogeneity was found. Those with orbit, cranial nerve, or intracranial involvement fared worse within Stage T4; those with a maximal lymph node size >3 cm fared worse within Stage N2; and those with bilateral lymph node metastasis fared worse within Stage N3. CONCLUSION: The prognostic accuracy of the AJCC/UICC 1997 staging system can be improved further by recategorization of the T, N, and group stage criteria.     

333例鼻咽癌咽后淋巴结转移特点的MRI分析

目的了解鼻咽癌咽后淋巴结的发生率及特征,探讨其与受累部位、颈部淋巴结转移的关系。方法回顾性分析333例经病理证实、无远处转移的初诊鼻咽癌患者MRI资料。根据2008临床分期标准进行分期。采用率的比较分析咽后淋巴结转移与临床分期、肿瘤侵犯部位及颈部淋巴结转移的关系。结果（1）咽后淋巴结阳性率为66.3%,其中单侧41.4%,双侧24.9%;不同T、N分期（T1、T2、T3、T4;N1b、N2、N3）的咽后淋巴结转移率均不同,其中T1期均低于T2、T3以及T4期（P＜0.05）,N1b期均较N2、N3期低（P＜0.05）;（2）茎突前间隙、颈动脉鞘区、口咽、椎前肌、翼内肌等结构侵犯者的咽后淋巴结转移发生率均明显高于其未侵犯者（P＜0.05）;（3）全组病例颈淋巴结转移率为82.0%,其中咽后淋巴结阳性者高于阴性者（87.8% vs.70.5%,P＜0.05）;双侧咽后淋巴结转移者高于单侧转移者（94.0% vs. 84.1%,P＜0.05）;（4）咽后淋巴结最大直径≤20 mm与最大直径＞20 mm患者的颈淋巴结各区转移率差异无统计学意义（P＞0.05）。结论（1）鼻咽癌咽后淋巴结转移率高与茎突前间隙、颈动脉鞘区、椎前肌、翼内肌及口咽侵犯相关;（2）鼻咽癌咽后淋巴结转移影响颈淋巴结的转移;（3）咽后淋巴结的直径大小与颈淋巴结各区转移无相关性。     

Determining of metastatic lymph node ratio in patients who underwent D2 dissection for gastric cancer

The purpose of this study was to determine outcome of the ratio of metastatic lymph nodes to the total number of dissected lymph nodes (MLR) in patients with gastric cancer. We retrospectively analyzed 111 patients who underwent D₂ lymph node dissection. The prognostic factors including UICC/AJCC TNM classification and MLR were evaluated by univariate and multivariate analysis. The MLR was significantly higher in patients with a larger tumor, lymphatic vessel invasion, blood vessel invasion and perineural invasion, and advanced stage. Moreover, the MLR was significantly associated with the depth of invasion and the number of lymph node metastasis. The univariate analysis revealed for overall survival (OS) that stage of disease, lymphatic vessel invasion, blood vessel invasion, perineural invasion, lymph node metastasis (UICC/AJCC pN stage) and MLR were relevant prognostic indicators. Furthermore, both UICC/AJCC pN stage and MLR were detected as prognostic factor by multivariate analysis, as was perineural invasion. Our results indicated that MLR and UICC/AJCC pN staging system were important prognostic factors for OS of patients with D₂ lymph node dissection in gastric cancer in a multivariate analysis. MLR may be useful for evaluating the status of lymph node metastasis in gastric cancer.     

A novel lymph node staging system for gastric cancer including modified Union for cancer Control/American Joint Committee on cancer and Japanese Gastric Cancer Association criteria

BackgroundThe TNM system of the International Union for Cancer Control/American Joint Committee on Cancer (UICC/AJCC) and the Japanese Gastric Cancer Association (JGCA) systems are the most used lymph node (LN) staging systems in gastric cancer. This study estimated the influence of anatomic location-based node stations on survival and proposed a new staging method based on both the number and anatomical distribution of metastatic LNs (mLNs).MethodsStage I–III gastric cancer patients with radical gastrectomy were retrospectively evaluated. Overall survival (OS) was estimated in 1786 patients with UICC/AJCC stage N1–N3b disease and compared with estimates obtained using JGCA group 1–3 mLN staging.ResultsThe OS of UICC/AJCC stage N1–N3b patients with group 2 JGCA mLNs was significantly worse than that of patients with only group 1 mLNs. The OS of the patients with group 2 mLNs was similar to that of patients with group 1 mLNs but in the next more advanced UICC/AJCC-N stage. The OS of patients with group 3 mLNs was worse than that of patients with any UICC/AJCC-N stage and was similar to that of N3b patients with group 2 mLNs. A new pathological node (pN) staging classification was developed that advanced the N-staging of patients with group 2 mLNs. It was a better indicator of prognosis than the eighth UICC/AJCC-N and the thirteenth JGCA group staging systems.ConclusionsA simple, accurate pN staging system including both the number and location of mLNs had improved homogeneity, discriminatory ability, and gradient monotonicity.     

三种淋巴结分期方法对结直肠癌患者预后准确性的研究进展

淋巴结转移是结直肠癌（colorectal cancer，CRC）的主要转移方式之一，也是影响患者预后的重要因素。为了对结直肠癌患者的预后进行准确评估以及制定最佳的治疗方案，需要对患者进行准确的分期。目前主要存在三种淋巴结分期方法即AJCC/UICC的N分期、阳性淋巴结比率（positive lymph node ratio,LNR）和阳性淋巴结对数比率（log odds of positive lymph nodes,LODDS）分期。现对三种淋巴结分期方法的研究进展进行综述。     

The effectiveness of the new (7th) UICC N classification in the prognosis evaluation of gastric cancer patients: a comparative study between the 5th/6th and 7th UICC N classification

Background

The most important prognostic factor after curative surgery for gastric carcinoma is the presence of lymph node metastases. According to the 7th edition of the UICC TNM staging system for gastric cancer, N classification was categorized as N0 (no regional lymph node metastasis), N1 (1?C2 regional lymph node metastases), N2 (3?C6 regional lymph node metastases), and N3 (7 or more regional lymph node metastases). The purpose of this study was to evaluate the rationality of the new UICC/AJCC N classification in comparison with the 6th UICC classification.

Methods

From August 2002 to July 2006, 295 patients with gastric cancer underwent curative resection with D2 lymph node dissection by a single surgeon. We analyzed retrospectively the significant prognostic factors and identified the suitability of the 7th UICC N staging system.

Results

According to the 7th UICC N classification, the 5-year cumulative survival rates (5-YSR) of N0, N1, N2, N3a, and N3b were 89.7, 73.6, 54.9, 23.1, and 5.4%, respectively (P?<?0.0001). Using univariate analysis, the N classification of the 7th and 6th UICC/AJCC TNM staging system, T classification of the 7th UICC TNM staging system, size and location of tumor, and histology were associated with the overall survival of gastric cancer after curative surgery. However, Cox regression multivariate analysis showed the 7th UICC N classification was an independent prognostic factor instead of the 6th UICC N classification (P?<?0.0001).

Conclusion

The 7th UICC classification for lymph node metastasis is thought to be a more reliable prognostic factor for gastric cancer than the 6th classification.     

Cancer of the supraglottic larynx with neck node metastasis treated by radiation therapy only. The revised 1987 UICC classification system as prognostic indicator

In 1987, a thoroughly renewed TNM classification was published; the revision was a conjunct effort of the International Union Against Cancer (UICC) and American Joint Committee on Cancer (AJCC). With respect to the former UICC classification, a major change was introduced regarding the regional lymph node subcategories in head and neck cancer; that is compared to the 1978 edition the subjective subcategory of fixation was eliminated and size of the lymph node has become of paramount importance. To see whether the 1987 UICC classification system is indeed more predictive and discriminatory than the 1978 edition, we have analysed patients with supraglottic cancer with clinically detectable lymph node metastasis (T1-4, N+). All patients treated between 1965 and 1980 by radiation therapy only were staged according to both editions of the UICC classification system. From these data we conclude that the prognosis of patients with lymph nodal involvement indeed worsens from N1 to N3 when classified according to the 1987 edition; in contrast, no difference is seen between the N1, N2 or N3 subcategories when staged according to the 1978 classification rules.     

MRI在鼻咽癌分期中的作用

背景与目的:随着磁共振成像(magnetic resonance imaging,MRI)的广泛应用,MRI对于鼻咽癌的诊断价值已被证实明显优于CT.本研究旨在分析MRI与CT检查对鼻咽癌'92分期及6th UICC/AJCC分期的影响.方法:收集2003年1月至2004年6月收治的、经病理证实的初诊鼻咽癌250例,所有病例同时具有治疗前鼻咽和颈部的增强CT及MRI资料.结合临床资料如颅神经受损及颈淋巴结大小,分别采用CT和MRI检查进行'92分期及6th UICC/AJCC分期,评价两者之间的差异.结果:MRI在诊断鼻咽癌软组织超腔侵犯(口咽、鼻腔、咽旁间隙)、咽后淋巴结转移以及颅底骨质、副鼻窦、海绵窦/颅内、颞下窝及颈椎侵犯等方面均明显优于CT,而对于颈部巴结转移的检出两者无显著性差异.对于'92分期,MRI使32.0%的T分期发生改变(26.0%升级,6.0%降级);11.6%的N分期发生改变(6.4%升级,5.2%降级);30.4%的临床分期发生改变(24.0%升级,6.4%降级).对于6th UICC/AJCC分期,MRI使39.6%的T分期发生改变(36.0%升级,3.6%降级);9.2%的N分期发生改变(5.6%升级,3.6%降级);37.6%的临床分期发生改变(33.6%升级,4.0%降级).结论:MRI检测鼻咽癌局部病灶的侵犯范围要明显优于CT,而在颈部淋巴结转移的检出方面与CT结果相似.建立新的、以MRI为主要手段的鼻咽癌临床分期系统的研究具有临床必要性及可行性.