Cigarette smoking, genetic polymorphisms and colorectal cancer risk: the Fukuoka Colorectal Cancer Study

Background: It is uncertain whether smoking is related to colorectal cancer risk. Cytochrome P-450 CYP1A1, glutathione-S-transferase (GST) and NAD(P)H:quinone oxidoreductase 1 (NQO1) are important enzymes in the metabolism of tobacco carcinogens, and functional genetic polymorphisms are known for these enzymes. We investigated the relation of cigarette smoking and related genetic polymorphisms to colorectal cancer risk, with special reference to the interaction between smoking and genetic polymorphism. Methods: We used data from the Fukuoka Colorectal Cancer Study, a population-based case-control study, including 685 cases and 778 controls who gave informed consent to genetic analysis. Interview was conducted to assess lifestyle factors, and DNA was extracted from buffy coat. Results: In comparison with lifelong nonsmokers, the odds ratios (OR) of colorectal cancer for <400, 400-799 and ≥800 cigarette-years were 0.65 (95 % confidence interval [CI], 0.45-0.89), 1.16 (0.83-1.62) and 1.14 (0.73-1.77), respectively. A decreased risk associated with light smoking was observed only for colon cancer, and rectal cancer showed an increased risk among those with ≥400 cigarette-years (OR 1.60, 95 % CI 1.04-2.45). None of the polymorphisms under study was singly associated with colorectal cancer risk. Of the gene-gene interactions studied, the composite genotype of CYP1A1*2A or CYP1A1*2C and GSTT1 polymorphisms was associated with a decreased risk of colorecta

Endoanal Ultrasonography of Mucinous Adenocarcinoma Arising from Chronic Fistula-in-ano: Three Case Reports

Mucinous adenocarcinoma arising in chronic fistula-in-ano is rare, and diagnosing it at an early stage is difficult. The role of endoanal ultrasonography in diagnosing the condition has not been discussed in the study. Herein, we report three cases of mucinous adenocarcinoma arising from anal fistulas in which endosonography played an important role in diagnosing malignant change. Three male patients with a 5- to 20-year history of anal fistula were referred to our hospital due to perianal induration, progressive anal pain, or mucopurulent secretion. In all three patients, endosonography revealed a multiloculated complex echoic mass with isoechoic solid components communicating with a trans-sphincteric fistula and sonography-guided biopsy under anesthesia revealed mucinous adenocarcinoma. All patients underwent abdominoperineal resection with lymph node dissection. One patient with a local recurrence died 3 years after surgery and two have remained disease-free for >6 years. These observations suggest that endosonography may be a reliable technique for the diagnosis of mucinous adenocarcinoma arising from chronic fistula-in-ano. Sonography-guided biopsy is useful for the definitive diagnosis of malignancy. Therefore, periodic endosonography assessment should be recommended for patients with persistent anal fistula, especially those with progressive clinical symptoms. Once malignancy is suspected, aggressive sonography-guided biopsy under anesthesia should be performed, which may enable an early diagnosis, curative treatment, and favorable long-term results