Controversy about treatment of colorectal cancer in view of surgeon--lymph node dissection for colorectal surgery (lateral lymph node dissection and TME)

Lateral lymph node dissection is technique for reducing local recurrence rate after resection of rectal cancer. In this study, we will report a decade experience for lateral lymph node dissection of rectal cancer in 491 cases. Lateral lymph node metastases occurred in 15.4% of rectal cancer which was below peritoneal reflection and through muscularis propria into non-peritoneal. It is a problem that it has never been well designed study of lateral lymph node dissection for rectal cancer. On the other hand, TME has also contributed reducing local recurrence rate. But, distant margin for resection of rectal cancer is controversial.     

直肠不同部位进展期癌的手术原则和方法

目的:探讨直肠不同部位进展期癌患者的手术原则、手术方法及其临床意义.方法:回顾性分析96例进展期直肠癌患者的临床资料.结果:肿瘤位于腹膜返折以下者41例行全直肠系膜切除术(TME),位于腹膜返折以上者55例行宽直肠系膜切除术(WME),两组疗效相仿.行前切除术(AR)75例,腹会阴联合切除术(APR)21例,AR组与APR组术后2、3年局部复发率和3、5年生存率均无显著差别.96例行肠系膜下动脉根部结扎并清扫该动脉根部及腹主动脉前区域淋巴结(D3),肠系膜下动脉根部淋巴结(N3)转移率11.5%,N3转移阳性组和阴性组术后疗效无显著差别.行闭孔及髂内淋巴结清扫11例,2例转移.结论:上中段直肠癌只须行WME,下段直肠癌应行TME;保肛手术要以根治为前提,不可盲目追求保肛率的高低;各部位进展期直肠癌患者均应行D3式扩大淋巴结清扫,部分下段直肠癌患者应同时行侧方淋巴结清扫.     

对Ⅲ期低位直肠癌行择区扩大淋巴结清扫的临床意义

背景与目的：目前对于Ⅲ期低位直肠癌的淋巴结清扫范围存在争议：日本学者多主张行择区扩大清扫双侧髂总、髂内、髂外和闭孔淋巴结脂肪组织;欧美学者则多主张行全直肠系膜切除术,辅以新辅助治疗。本研究旨在探讨对Ⅲ期低位直肠癌行择区扩大淋巴结清扫的临床意义。方法：对31例Ⅲ期低位直肠癌的病例(术前影像学分期,术后经病理证实)行择区扩大淋巴结清扫,即顺序清扫双侧髂总、髂内、髂外和闭孔淋巴结脂肪组织,尽量保留盆腔自主神经,除非神经受到肿瘤浸润,并与35例行传统根治术的低位直肠癌的病例进行比较。结果：行择区扩大淋巴结清扫组内有5例侧方淋巴结阳性(低分化腺癌4例、黏液细胞癌1例,较高、中分化腺癌有明显差异)。行择区扩大淋巴结清扫组在性功能障碍、排尿困难发生率及手术时间上与行传统根治术组差异有统计学意义(P＜0.05),行择区扩大淋巴结清扫组在吻合口瘘和手术失血量上与行传统根治术组差异无统计学意义(P＞0.05),但择区扩大淋巴结清扫组在盆腔复发率及5年生存率上优于传统根治术组。结论：对Ⅲ期低位直肠癌行择区扩大淋巴结清扫对降低盆腔复发、提高生存率有临床意义。     

直肠癌侧方淋巴结清扫的研究进展与相关争议

盆腔侧方淋巴结（lateral pelvic lymph node,LPLN）是中低位直肠癌常见的淋巴回流通路,有14%～30%的局部中晚期直肠癌患者同时合并LPLN转移。然而,术前诊断的遗漏和不规范的治疗是导致术后LPLN复发的常见原因,同时也是诊疗中的难点之一。目前,侧方淋巴结清扫术（lateral pelvic lymph node dissection,LPLND）的价值与意义,在国际上尚存争议。近些年来,新辅助放化疗（neoadjuvant chemoradiotherapy,nCRT）与LPLND相互替代的治疗模式趋于融合,逐渐形成了一套精确化、个体化的治疗策略。同时,随着外科器械设备的更新与淋巴结示踪剂技术的不断发展,使得以往制约LPLND的因素逐渐消失,可逐渐在临床推广开展。但针对直肠癌LPLN转移的治疗策略、nCRT后LPLND的适应证、预后价值、有效清扫范围、安全性仍存在诸多问题,需深入研究。      

Definition and delineation of the clinical target volume for rectal cancer

PURPOSE: Optimization of radiation techniques to maximize local tumor control and to minimize small bowel toxicity in locally advanced rectal cancer requires proper definition and delineation guidelines for the clinical target volume (CTV). The purpose of this investigation was to analyze reported data on the predominant locations and frequency of local recurrences and lymph node involvement in rectal cancer, to propose a definition of the CTV for rectal cancer and guidelines for its delineation. METHODS AND MATERIALS: Seven reports were analyzed to assess the incidence and predominant location of local recurrences in rectal cancer. The distribution of lymphatic spread was analyzed in another 10 reports to record the relative frequency and location of metastatic lymph nodes in rectal cancer, according to the stage and level of the primary tumor. RESULTS: The mesorectal, posterior, and inferior pelvic subsites are most at risk for local recurrences, whereas lymphatic tumor spread occurs mainly in three directions: upward into the inferior mesenteric nodes; lateral into the internal iliac lymph nodes; and, in a few cases, downward into the external iliac and inguinal lymph nodes. The risk for recurrence or lymph node involvement is related to the stage and the level of the primary lesion. CONCLUSION: Based on a review of articles reporting on the incidence and predominant location of local recurrences and the distribution of lymphatic spread in rectal cancer, we defined guidelines for CTV delineation including the pelvic subsites and lymph node groups at risk for microscopic involvement. We propose to include the primary tumor, the mesorectal subsite, and the posterior pelvic subsite in the CTV in all patients. Moreover, the lateral lymph nodes are at high risk for microscopic involvement and should also be added in the CTV.     

Prognostic significance of the size of cancer nests in metastatic lymph nodes in human esophageal cancers

BACKGROUND: Postoperative survival of patients with esophageal cancers after curative surgery is strongly affected by the presence of lymph node metastasis. The number and location of lymph node metastases have been evaluated and graded, but the clinical significance of their size has not been well investigated. METHODS: Of 322 esophageal cancer patients who underwent curative operations with radical lymph node dissection, 170 (53%) had lymph node metastasis. A total of 784 metastatic lymph nodes were obtained, and the area of the cancer nests was measured microscopically in the cross section. The data from each patient included the area of the largest cancer nest in the positive nodes (Nmax), classified as Na (<4 mm2), Nb (4-25 mm2), Nc (25-100 mm2), or Nd (>100 mm2). RESULTS: The 170 patients were classified according to the Nmax value: Na, 31 (18.2%); Nb, 35 (20.5%); Nc, 49 (28.8%); and Nd, 55 (32.4%). The 5-year survival rate was 77.7% in patients without lymph node metastasis and 35.4% in those with lymph node metastasis. When classified by Nmax, the 5-year survival rate was 77.8% for Na, 63.9% for Nb, 18.8% for Nc, and 12.8% for Nd. There was no significant difference in the survival rate between Na patients and those without lymph node metastasis. Nmax showed significant correlation with the primary tumor size, depth of tumor invasion, and number and location of metastatic lymph nodes, but not with histologic type or primary tumor location. In multivariate analysis, the Nmax value, the number of lymph node metastases and depth of tumor invasion were independent prognostic factors, while the location of the lymph node metastases was not statistically significant. CONCLUSIONS: The area of the largest cancer nest in the lymph nodes was one of the most significant prognostic factors for esophageal cancers. This estimation is objective and reproducible and may be of great importance when deciding the therapeutic modality for patients with esophageal cancers.     

Review of sentinel lymph node research from the viewpoint of clinical significance

We report on the clinical significance of sentinel lymph node (SLN) biopsy in the 3 major visceral cancers for which these biopsies are performed. In cases of gastric cancer, the SLN concept was established from the viewpoint that QOL was clearly improved by a reduction in lymph node dissections or the extent of gastric resection. In such cases, it would be of great clinical significance if it was possible to determine the appropriateness of lymph node dissection. For colon cancer, SLNs are expected to become an indicator for lateral lymph node dissection in cases of rectal cancer, and to contribute to a more efficient diagnosis of micrometastasis. In cases of breast cancer, where SLN biopsies are already being used to determine axillary nodal status to obviate axillary lymph node dissection, SLNs also help to more accurately classify the stage of the disease. This helps in determining appropriate multidisciplinary treatment. Thus, SLNs help to promote the streamlining of cancer treatments, albeit the significance varies depending on the affected viscera. We therefore believe SLN research to be very important.     

直肠癌外科治疗及其疗效

总结我院１９７５年６月～１９９１年１２月手术治疗直肠癌１００２例，其中单纯造瘘术１０５例，姑息性手术１０４例，一般根治术４９１例，扩大根治术３０２例。分析结果如下：直肠癌淋巴转移率为４５．３％，转移度８．９％。上方途径第三站转移率为１０％，而侧方转移仅发生于腹膜返折以下的癌，侧方第三站转移率为１０％。因此我们主张按此淋巴转移规律进行扩大淋巴清除术，其中５年生存率达６８％，１０年生存率达４７％，生存率明显高于其他术式（Ｐ＜０．０１）。通过直肠癌壁内逆向浸润研究，指出逆向浸润的平均距离为２．４ｃｍ，并以此规律指导直肠癌的保肛手术。对直肠癌术后局部复发、肝转移、早期癌及功能性直肠癌手术提出了外科治疗原则，得到良好效果。     

Lymphoscintigraphic and intraoperative detection of the sentinel lymph node in breast cancer patients: the nuclear medicine perspective

The concept of sentinel lymph node biopsy in breast cancer surgery relates to the fact that the tumor drains in a logical way via the lymphatic system, from the first to upper levels. Therefore, (1) the first lymph node met (the sentinel node) will most likely be the first one affected by metastasis, and (2) a negative sentinel node makes it highly unlikely that other nodes are affected. Sentinel lymph node biopsy would represent a significant advantage as a mini-invasive procedure, considering that, after operation, about 70% of patients are found to be free from metastatic disease, yet axillary node dissection can lead to significant morbidity. Although the pattern of lymphatic drainage from a breast cancer can be very variable, the mammary gland and the overlying skin can be considered as a biologic unit in which lymphatics tend to follow the vasculature. Considering that tumor lymphatics are disorganized and relatively ineffective, subdermal, and peritumoral injection of small aliquots of radiotracer is preferred to intratumoral administration. (99m)Tc-labeled colloids with most of the particles in the 100-200 nm size range would be ideal for radioguided sentinel node biopsy in breast cancer. Lymphoscintigraphy is an essential part of radioguided sentinel lymph node biopsy, as images are used to direct the surgeon to the site of the node. The sentinel lymph node should have a significantly higher count than background. After removal of the sentinel node, the axilla must be re-examined to ensure all radioactive sites are identified and removed for analysis. The success rate of radioguidance in localizing the sentinel lymph node in breast cancer surgery is about 94-97% in Institutions where a high number of procedures are performed, approaching 99% when combined with the vital blue dye technique. At present, there is no definite evidence that a negative sentinel lymph node biopsy is invariably correlated with a negative axillary status, except perhaps for T(1a-b) breast cancers, with size < or =1 cm. Randomized clinical trials should elucidate the impact of avoiding axillary node dissection in patients with a negative sentinel lymph node on the long-term clinical outcome of patients.     

甲状腺癌颈部淋巴结转移区域的超声特点研究

目的：探究甲状腺癌颈部淋巴结转移区域的超声特点。方法回顾性分析58例甲状腺癌患者的临床资料。将患者术前颈部淋巴结转移区域的超声诊断与患者的病理诊断进行比较,分析其超声表现的特点。结果58例患者中经术前超声诊断显示,有36例（62．07％）颈部淋巴结转移,其中3例单纯中央区淋巴结转移、18例单纯颈侧区淋巴结转移、15例颈侧区合并中央区淋巴结转移;中央区淋巴结转移率为31．03％,显著低于颈侧区淋巴结转移率56．89％。病理诊断结果显示,58例患者中有33例（56．89％）颈部淋巴结转移,其中21例单纯中央区淋巴结转移,2例单纯颈侧区淋巴结转移,10例颈侧区合并中央区淋巴结转移;中央区淋巴结转移率为53．44％,显著高于颈侧区淋巴结转移率20．68％。超声诊断颈部转移性淋巴结的特异性为80．0％（12／15）,敏感性为100．0％（33／33）。超声检查对中央区转移性淋巴结的检出率为58．06％（18／31）,显著低于颈侧区转移性淋巴结的检出率100．0％（12／12）。超声诊断颈侧区淋巴结转移与病理结果的符合率为36．36％（12／33）,显著低于中央区淋巴结转移与病理结果的符合率58．06％（18／31）,差异具有统计学意义（P＜0．05）。颈侧区和中央区中淋巴门回声消失和低回声占较高的比例,且颈侧区和中央区颈侧区转移性淋巴结中L／T＜2所占的比例差异具有统计学意义（P＜0．05）。结论甲状腺癌多转移至颈部中央区淋巴结,采用超声检查具有较高的特异性,对中央区淋巴结的诊断有十分重要的意义。     

Patterns of lymphatic spread in rectal cancer. A topographical analysis on lymph node metastases

The presence of lymph node (LN) metastases is the most important prognostic factor in rectal cancer. The exact LN status can only be known when an extended lymph node dissection (LND) has been performed, a process not routinely performed. If the likelihood of LN metastases can be more accurately assessed preoperatively, then an optimal multimodality treatment plan can be established. 605 patients with primary rectal cancer operated upon with wide LND (D3 level) were analysed for LN metastases combining topographical localisation and morphological features of the tumour. More distal rectal tumours tend to more LN metastases and more lateral lymphatic spread. Tumours >or=3 cm show more LN metastases compared with those smaller than 3 cm. Depth of bowel wall invasion is strongly related to the presence of LN metastases. The peritoneal reflection has no discriminating role in the mode of spread. Intra-operative assessment by the surgeon for presence of LN metastases is not reliable. When localisation, depth of bowel wall invasion and diameter of a rectal tumour are known, a likelihood of LN metastases can be assessed pre-operatively, not intra-operatively.     

乳腺癌淋巴结转移规律对术后放射治疗设野的影响

目的 探讨乳腺癌淋巴结转移规律和乳腺癌根治术后放射治疗的适应证及照射范围。方法 行选择性胸膜外式乳腺癌扩大根治术78例,分析其中资料完整的61例,探讨内乳淋巴结的转移情况。非选择性乳腺癌根治术 锁骨上淋巴结清扫术46例,术前检查锁骨上淋巴结均为阴性,将锁骨上淋巴结及腑窝淋巴结分别标记为S及L1、L2、L3送检。行乳腺癌根治术412例,标记出L1、L2、L3淋巴结分别送检,用以分析腋窝淋巴结跳跃式转移的规律。结果 内乳淋巴结总的转移率为24.6%,其中腋窝淋巴结转移者,内乳淋巴结转移率为36.7%,而腋窝淋巴结无转移者,内乳淋巴结转移率为12.9%,转移部位仅限于1、2、3肋间。锁骨上淋巴结跳跃式转移率为3.8%;腋窝淋巴结的跳跃式转移率为8.1%。结论 乳腺癌淋巴结转移有其内在规律,乳腺癌根治术后照射野可以依据其区域淋巴结的转移规律进行修改,照射内乳区淋巴结时可以不必常规包括4、5肋间。当腋窝淋巴结仅有L1、L2组转移而无L3组转移时,锁骨上淋巴结区也可以不予照射。     

Time trends of surgical treatment and the prognosis for Japanese patients with gastric cancer

The incidence of gastric cancer is much higher in Japan than in other countries even though diagnostics and treatments of such patients have improved. The objective of this study was to present an overview of the past, present and future of surgical treatment for our patients with gastric cancer. We analysed data on 2152 Japanese men and women with gastric cancer who underwent surgical resection from 1965 to 1995 at Kyushu University in Fukuoka, Japan, based on a univariate and the multivariate analysis. We focused on time trends of surgical treatment and the postoperative outcome. Over the years, there have been favourable changes in the numbers of patients with early gastric cancer. In all cases of gastric cancer, the rate of 18% in the first six year period (group 1) was 57% in the last 5 year period (group 6). Size of the tumour was smaller, well-differentiated tumour tissue was more common, and lymphatic involvement was less frequent. Lymph node metastasis, liver metastasis and peritoneal dissemination all decreased. Extensive lymph node dissection was more frequently done and the rate of curative resection (curability A and B) increased. With increases in identifying the early stage of cancer and better perioperative care, mortality rates 30 days after the surgery greatly decreased. Multivariate analysis revealed that the 10 factors of depth of invasion, lymph node metastasis, lymph node dissection, tumour size, liver metastasis, peritoneal dissemination, lymphatic invasion, vascular invasion, lesion in the whole stomach and lesion in the middle stomach were independent factors for determining the prognosis. Detection of the tumour in an early stage, standardized surgical treatment, including routine lymph node dissection, close follow-up schedules and better perioperative management are expected to increase survival time for patients with this malignancy.     

155例肺癌患者淋巴结转移的临床研究

背景与目的胸内淋巴结(包括肺门和纵隔)转移是影响肺癌预后的重要因素之一。本研究旨在探讨原发性非小细胞肺癌胸内淋巴结转移特点及转移方式,为确定肺癌术中淋巴结清扫方式提供依据。方法按Naruke肺癌淋巴结分布图作为淋巴结清扫依据,对155例非小细胞肺癌行完全性切除及系统性淋巴结清扫术。结果155例非小细胞肺癌共清除淋巴结1553枚。总转移率为58.7%(91/155),N1占20.0%(31/155),N2占38.7%(60/155),跳跃性N2共9.7%(15/155)。肺原发肿瘤T分期与淋巴结转移之间呈线性关系。淋巴结转移率在各类型非小细胞肺癌间无差异。肺癌淋巴结可呈跳跃式纵隔转移,且区域性转移与非区域性转移均多见。结论肺癌淋巴结转移具有多组别、多区域及跳跃性特点。除临床分期为T1者外,系统性胸内淋巴结清扫在肺癌术中应常规应用。     

肺癌淋巴结转移特点的临床分析

目的探讨原发性肺癌胸内淋巴结转移特点及转移方式，为确定肺癌术中淋巴结廓清范围提供依据。方法按Naruke肺癌淋巴结分布图作为淋巴结廓清标志，对105例肺癌行完全性切除及系统性淋巴结廓清术。结果105例肺癌，共清除淋巴结801枚。N1占15．9％(59／371枚)，N2占14．9％(64／430枚)。跳跃性N2共12例，分布在纵隔第2、4、5、6、7组淋巴结。肺原发肿瘤大小与淋巴结转移之间无明显关系。小细胞肺癌淋巴结转移率最高，腺癌淋巴结转移率亦高于鳞癌。肺癌淋巴结可呈跳跃式纵隔转移，且肺下叶癌较肺上叶癌多见。结论肺癌淋巴结转移具有多组别、多区域及跳跃性特点，系统性胸内淋巴结廓清在肺癌术中应常规应用。     

Predictive factors of pathological lateral pelvic lymph node metastasis in patients without clinical lateral pelvic lymph node metastasis (clinical stage II/III): The analysis of data from the clinical trial (JCOG0212)

BackgroundMesorectal excision (ME) is the standard surgical procedure for lower rectal cancer. However, in Japan, total or tumor-specific ME with lateral pelvic lymph node dissection (LLND) is the standard surgical procedure for patients with clinical stages II or III lower rectal cancer, because lateral pelvic lymph node metastasis occasionally occurs in these patients. The aim of study was to elucidate the predictive factors of pathological lateral pelvic lymph node metastasis in patients without clinical lateral pelvic lymph node metastasis.MethodsData form the clinical trial (JCOG0212) was analyzed. The JCOG0212 was a randomized controlled trial to confirm the non-inferiority of mesorectal excision alone to mesorectal excision with lateral lymph node dissection for clinical stage II/III patients who don't have clinical lateral pelvic lymph node metastasis in terms of relapse free survival. This study was conducted at a multitude of institution33 major hospitals in Japan. Among the 351 patients who underwent lateral lymph node dissection in the JCOG0212 study, 328 patients were included in this study. Associations between pathological lateral pelvic lymph node metastasis and preoperative and postoperative factors were investigated. The preoperative factors were age, sex, clinical stage, tumor location, distance from anal verge, tumor size, and short-axis diameter of lateral pelvic lymph node on computed tomography and the postoperative factors were pathological T, pathological N, and histological grade.ResultsAmong the 328 patients, 24 (7.3%) had pathological lateral pelvic lymph node metastasis. In multivariable analysis of the preoperative factors, patient age (p = 0.067), tumor location (p = 0.025), and short-axis diameter of lateral pelvic lymph node (p = 0.002) were significantly associated with pathological lateral pelvic lymph node metastasis.ConclusionsPatient age, tumor location, and short-axis diameter of lateral pelvic lymph node were predictive factors of pathological lateral pelvic lymph node metastasis.     

Urinary dysfunction after rectal cancer surgery: Results from a randomized trial comparing mesorectal excision with and without lateral lymph node dissection for clinical stage II or III lower rectal cancer (Japan Clinical Oncology Group Study,JCOG0212)

Background

Postoperative urinary dysfunction is a major complication of rectal cancer surgery. A randomized controlled trial (JCOG0212) concluded that the noninferiority of mesorectal excision alone to mesorectal excision with lateral lymph node dissection was not confirmed in terms of relapse-free survival.

What Is the Role of Lateral Lymph Node Excision in Patients with Locally Advanced Rectal Cancer Who Received Preoperative Chemoradiotherapy?

In the era of preoperative chemoradiotherapy (CRT) for rectal cancer, the role of lateral pelvic lymph node dissection (LPLND) has become much more complicated because preoperative CRT affects both the lateral pelvic lymph nodes (LPLN) and the main tumor. Most previous studies do not demonstrate the benefits of LPLND following preoperative CRT in comparison with total mesorectal excision, although some authors have argued that selective LPLND is beneficial. LPLN treatment strategies differ depending on whether the disease was considered systemic metastatic disease or local disease which can be treated using surgical resection. The role of LPLND in rectal cancer is better evaluated on the basis of its oncologic impact rather than technical feasibility. Here, we review LPLN metastasis status in rectal cancer, whether LPLN metastasis is systemic or local disease, and studies on the use of LPLND to treat rectal cancer.     

直肠癌扩大根治术的临床病理学研究

目的：通过临床病理学研究,证实直肠癌扩大根治术的合理性,从而指导直肠癌的治疗。方法：通过对进展期直肠癌进行三方向淋巴结清扫获得的标本,以常规病理学方法研究淋巴结转移规律,并以此规律指导临床进行扩大根治手术,统计其治疗效果,结果：国人进展期直肠癌淋巴转移率为47％,上方1,2,3站轩移率分别为4％,14％及10％,侧方第3站转移率为9％,直肠癌淋巴转移与肿瘤浸润周径,深度及病理学类型有关,扩大根治术后的5年及10年生存率为68％及47％,高于一般根治术的45％及39．8％,结论：直肠癌扩大根治术清除了可能发生转移的所有淋巴结,减少了转移淋巴结残留,可明显提高生存率。     

cN0声门上型喉癌的颈部复发相关因素分析

背景与目的：声门上型喉癌的隐性淋巴结转移率高,是此类喉癌诊治的重点之一。本研究旨在探讨声门上型喉癌的隐性淋巴结转移的相关因素、预后及治疗情况。方法：回顾分析1992-1999年我科收治的oNO声门上型喉癌104例。对其隐性淋巴结转移率、转移淋巴结的分布、影响隐性淋巴结转移的因素及颈部处理等进行研究。结果：本组cNO声门上型喉癌隐性淋巴结转移率为23．1％（24／104）,其中T2期23．9％（11／46）,T3期30．8％（8／26）,T4期18．5％（5／17）。隐性转移淋巴结主要位于病变侧Ⅱ、Ⅲ区（22／24）。出现隐性转移组预后差（log-rank=10．66．P=0．001）。切缘阳性影响隐性淋巴结转移率（χ^2=10．015,P=-0．002）。病理分化程度（χ^2=3．349,P=0．175）、T分期（χ^2=2．701,P=0．440）、原发灶处理方式（χ^2=1．093,P=0．296）等对隐性淋巴结转移率影响差异无统计学意义。颈部选择性清扫能降低cNO声门上型喉癌隐性淋巴结转移率（χ^2=4．070,P=0．044）。结论：cNO声门上型喉癌的隐性淋巴结转移主要位于病变侧Ⅱ、Ⅲ区;出现隐性淋巴结转移影响预后：切缘阳性影响隐性淋巴结转移率;对T1N0期喉癌颈部可观察,T2-4N0期喉癌行侧颈清扫（Ⅱ-Ⅳ区）是合理有效的。