Akasu T, Sugihara K, Moriya Y, Fujita S
Department of Surgery, National Cancer Center Hospital, Tokyo, Japan.
Dis Colon Rectum. 1997 Oct;40(10 Suppl):S10-5. doi: 10.1007/BF02062014.
This study was designed to evaluate the accuracy of preoperative staging by transrectal ultrasonography (TRUS) and to clarify the limitations and pitfalls of TRUS by clinicopathologic analysis for staging errors.
Results of TRUS for 164 consecutive patients with rectal cancer were compared prospectively with histopathologic findings according to the newest TNM classification. Clinicopathologic factors that may influence staging errors were analyzed by reviewing both resected specimens and hard copies of TRUS.
There were 13 patients histopathologically staged as pTis, 21 as pT1, 34 as pT2, 84 as pT3, 12 as pT4, 73 as pN0, and 91 as pN1-3. Of these, 85, 86, 56, 93, 75, 74, and 77 percent, respectively, were correctly staged by TRUS. Excluding 12 cases with incomplete examinations because of annular constricting tumors, overstaging of tumor invasion depth was mostly caused by tumor invasion close to the deeper uninvolved layer, inflammatory cell aggregation, desmoplastic change, and hypervascularity around the tumor, mimicking tumor invasion on TRUS. The understaging was mostly the result of microscopic invasion beyond the estimated layers and difficulties in examination because of the tumor location being close to the anal canal or on the Houston's valves or the tumor shapes being polypoid or bulky and fungating. Overstaging in lymph node status was caused by reactive lymph node swelling and understaging by the presence of only small involved node and metastasis in the extramesorectal nodes.
An awareness of the limitations and pitfalls of TRUS, as demonstrated by the present study, should improve staging accuracy and contribute to optimum clinical decision-making.
本研究旨在评估经直肠超声检查（TRUS）术前分期的准确性，并通过对分期错误的临床病理分析阐明TRUS的局限性和陷阱。
根据最新的TNM分类，将164例连续直肠癌患者的TRUS结果与组织病理学结果进行前瞻性比较。通过回顾切除标本和TRUS硬拷贝分析可能影响分期错误的临床病理因素。
组织病理学分期为pTis的患者有13例，pT1的21例，pT2的34例，pT3的84例，pT4的12例，pN0的73例，pN1 - 3的91例。其中，TRUS正确分期的比例分别为85%、86%、56%、93%、75%、74%和77%。排除因环形狭窄肿瘤导致检查不完整的12例病例后，肿瘤浸润深度的过度分期主要是由于肿瘤浸润接近较深的未受累层、炎症细胞聚集、促纤维增生性改变以及肿瘤周围血管增多，在TRUS上模拟肿瘤浸润。分期不足主要是由于显微镜下浸润超出估计层面以及由于肿瘤位置靠近肛管或位于Houston瓣上或肿瘤形态为息肉样或巨大且呈蕈状而导致检查困难。淋巴结状态的过度分期是由反应性淋巴结肿大引起的，而分期不足是由仅存在小的受累淋巴结和直肠系膜外淋巴结转移所致。
如本研究所示，认识到TRUS的局限性和陷阱应能提高分期准确性，并有助于做出最佳临床决策。
