藪中 幸一¹, 福井 寛也², 玉手 信治², 梶山 雄司², 上道 武², 中谷 元太郎², 藤岡 正幸¹, 福富 經昌²

Koichi YABUNAKA¹, Hiroya FUKUI², Shinji TAMATE², Yuji KAJIYAMA², Takeshi UEMICHI², Gentarou NAKATANI², Masayuki FUJIOKA¹, Tsunemasa FUKUTOMI²

¹大東中央病院超音波室, ²大東中央病院外科

¹Department of Ultrasonography, Daito Central Hospital, ²Department of Surgery, Daito Central Hospital

キーワード : advanced colorectal cancer, ultrasonography

当院で過去5年間に行われた体外式超音波検査(以下US)のうち, 大腸癌の検索が行われたのは1,579 例であった. このうち, US施行前に大腸癌と診断されていた15例を除く1,564 を対象として, USによる進行大腸癌の描出能について検討した. 結果は, US陽性例51例, US偽陽性例9例, US偽陰性例28例, US陰性例1,476例となり, 感度は64.6%, 特異度は99.6％ であった. US偽陰性例28例のうち, 直腸癌は16例で最も多く, 次いで横行結腸6例, S状結腸3例, 上行結腸2例, 下行結腸1例あった. これらのうち, 大腸の狭窄から大腸癌を疑ったが, 腫瘍像を認めずUS陰性とした症例が3例あった. 部位別の感度は, 直腸が(30.4％)と最も低く, 直腸を除いた大腸の感度は, 78.6%であった. 大腸癌を疑わせる臨床症状, 臨床検査を前情報としたところ, 前情報の有無によるUS感度において有意差は認めなかった. スクリーニングのUSにおいても実質臓器だけでなく大腸も検査することにより, 進行大腸癌の約65%を発見することができ, USは進行大腸癌の発見に有効な検査と考えられる.

We investigated the efficacy of transabdominal ultrasonography for the diagnosis of advanced colorectal cancer. Colonic examination by colonoscopy, barium study, or surgery was carried out in our institution on 1579 patients during the past 5 years. This study focused on 1564 of these patients, 15 who had been diagnosed with colorectal cancer before ultrasound examination having been excluded. The results included 51 ultrasound-positive cases, 9 ultrasound-false-positive cases, 1476 ultrasound-negative cases, and 28 ultrasound-false-negative cases. Sensitivity was 64.6 percent and specificity was 99.6 percent. Of the 28 ultrasound-false-negative cases, the lesion was detected in the ascending colon in 2, in the transverse colon in 6, in the descending colon in 1, in the sigmoid colon in 3, and in the rectum in 16. Obstruction and dilatation suggested colorectal cancer in 3 cases, which were thus classified as ultrasound-negative when no tumors were detected. Sensitivity was investigated by site. Sensitivity was lowest at 30.4 percent in rectal cancer, but was 78.6 percent in colon cancer, exclusive of rectal cancer. Laboratory findings and clinical symptoms which were suggestive of colorectal cancer were used as information before ultrasound examination was performed. Sensitivity of examinations carried out on examinees on whom prior information was available and on those on whom there was no information did not differ significantly. Furthermore, ultrasound was thought to detect approximately 65 percent of advanced colorectal cancers when it was used aggressively to investigate the large intestine. Ultrasound was thus considered effective for detecting advanced colorectal cancer.