Predicting rectal cancer T stage using circumferential tumor extent determined by computed tomography colonography.
OBJECTIVE
Patients with stage T3 or T4 rectal cancer are candidates for neoadjuvant chemoradiation therapy. The aim of this study is to clarify the usefulness of circumferential tumor extent determined by computed tomography (CT) colonography in differentiating T3 or T4 from T1 or T2 rectal cancer.


METHODS
Seventy consecutive rectal cancer patients who underwent curative-intent surgery were enrolled in this study. All patients underwent colonoscopy and CT colonography on the same day. The circumferential tumor extent was estimated in 10% increments. The pathological T stage was used as the reference.


RESULTS
The median circumferential tumor extent evaluated by colonoscopy for T1 (n = 6), T2 (n = 21), and T3/T4 (n = 43) were 10%, 30%, and 80%, respectively (T1/T2 vs. T3/T4, p < 0.0001). The median circumferential tumor extent evaluated by CT colonography for T1, T2, and T3/T4 is 10%, 30%, and 70%, respectively (T1/T2 vs. T3/T4, p < 0.0001). The correlation coefficient between colonoscopy and CT colonography was very high (0.94). By defining a circumferential tumor extent ≥ 50% by CT colonography as the criterion for stage T3 or T4, the sensitivity, specificity, positive predictive value and accuracy were 72%, 88%, 91%, and 79%, respectively.


CONCLUSIONS
Circumferential tumor extent ≥ 50% determined by CT colonography is a simple and potentially useful marker to identify candidates for neoadjuvant chemoradiation therapy.
Department of Surgery, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan. Electronic address: hisahorie@jichi.ac.jp.
Hisanaga
H
Horie
Department of Surgery, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Kazutomo
K
Togashi
Department of Radiology, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Kenichi
K
Utano
Department of Surgery, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Yasuyuki
Y
Miyakura
Department of Surgery, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Alan T
AT
Lefor
Department of Surgery, School of Medicine, Jichi Medical University, Yakushiji 3311-1, Shimotsuke, Tochigi 329-0498, Japan.
Yoshikazu
Y
Yasuda
D003113:Colonoscopy; D006801:Humans; D000072662:Margins of Excision; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D012004:Rectal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000601:surgery; D014057:Tomography, X-Ray Computed
CT colonography; T stage; circumferential tumor extent; rectal cancer