Clinical characteristics of rectal cancer involving the anal canal.
BACKGROUND
This study evaluates the clinical characteristics of rectal cancer involving the anal canal.


METHODS
A total of 346 consecutive patients with primary low rectal cancer located below the peritoneal reflection were reviewed in this study. Patients were divided into two groups according to whether the lower edge of the tumor came in contact with the anal canal (P group, n = 78) or not (Rb group, n = 268). Clinical and pathological parameters, recurrence rates, and survival rates were compared between the two groups.


RESULTS
The occurrence of uncommon histological types of tumor was significantly higher in the P group than in the Rb group. P group patients also had a significantly higher lateral pelvic node metastasis rate (p < 0.001), lower 5-year overall survival rate (p = 0.0491), and higher 5-year local recurrence rate (p = 0.0171) than Rb group patients. Multivariate analysis revealed that tumor location was a significant risk factor for local recurrence. In the P group, multivariate analysis showed that uncommon histological tumor types were a significant prognostic factor.


CONCLUSIONS
Rectal cancer involving the anal canal should be treated with special care, considering the particularly high lateral pelvic lymph node metastasis rate and high local recurrence rate.
Department of Gastroenterological Surgery, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan. m_ota@yokohama-cu.ac.jp
Mitsuyoshi
M
Ota
Shoichi
S
Fujii
Yasushi
Y
Ichikawa
Hirokazu
H
Suwa
Kenji
K
Tatsumi
Kazuteru
K
Watanabe
Kuniya
K
Tanaka
Hirotoshi
H
Akiyama
Itaru
I
Endo
D001003:Anal Canal / Q000473:pathology*; D002277:Carcinoma / Q000401:mortality* / Q000473:pathology* / Q000556:secondary / Q000601:surgery; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009367:Neoplasm Staging; D011379:Prognosis; D016016:Proportional Hazards Models; D012004:Rectal Neoplasms / Q000401:mortality* / Q000473:pathology* / Q000601:surgery; D015996:Survival Rate