Diameter of Superior Rectal Vein – CT Predictor of KRAS mutation in Rectal Carcinoma

Abstract

Background The purpose of this study was to investigate the feasibility of CT parameters to predict the presence of KRAS mutation in rectal cancer patients. The relationship between KRAS mutation and pathological findings was evaluated simultaneously.Methods 89 patients (29 females, 60 males, age 27–90, mean 59.7 ± 12 years) with pathologically proven rectal cancer were enrolled. KRAS mutation test was completed following surgery. Parameters evaluated on CT included the diameter of superior rectal vein (SRV) and inferior mesenteric vein (IMV), the presence of calcification, ulceration, lymph node enlargement (LNE), distant metastasis, tumor growth pattern (single nodule or annular thickening), enhanced pattern (homogeneous or heterogeneous), CT ratio and the length of tumor (LOT). Pathological findings included lymphovascular emboli, signet ring cell, peripheral fat interval infiltration, focal ulcer, lymph node metastasis, tumor pathological type and differentiation extent. The correlations between KRAS status and CT parameters, KRAS status and pathological findings were investigated. The accuracy of CT characteristics for predicting KRAS mutation was evaluated.Results KRAS mutation was detected in 42 cases. On CT image, the diameter of SRV was significantly increased in KRAS mutation group than in KRAS wild-type group (4.6 ± 0.9 mm vs. 4.2 ± 0.9 mm, p = 0.02). And LNE was more likely to occur in KRAS mutation group (73.3% vs. 26.7%, p = 0.03). There was no significant difference between KRAS mutation group and KRAS wild-type group on the other CT parameters (IMV, calcification, ulcer, distant metastasis, tumor growth pattern, enhanced pattern, CT ratio and LOT). In pathological findings, KRAS mutation was more likely to occur in middle differentiation group (p = 0.03). No significant difference was found between KRAS mutation group and KRAS wild-type group in the presence of lymphovascular emboli, signet ring cell, peripheral fat interval infiltration, focal ulcer, lymph node metastasis, tumor pathological type. The AUC of SRV to predict KRAS mutation was 0.63.Conclusion It was feasible to use the diameter of SRV to predict KRAS mutation in rectal cancer patients, and LNE also can be regarded as an important clue on preoperative CT images.

Prognostic Significance of The Diameter of Superior Rectal Vein For Locally Advanced Rectal Cancer

“…( 6) Some studies have found that the dSRV can not only be used as a predictor of lymphatic vascular invasion and lymph node metastasis of rectal cancer (6, 7) but is also valuable in determining whether liver lesions are metastatic lesions and predicting KRAS mutations in rectal cancer. (8,9) Although it has been reported that the dSRV in patients with metastasis is wider than that in patients without metastasis, (6) some studies have reported different results, and there is no signi cant difference in the dSRV between patients with metastasis and those without metastasis. (7) At present, research on the role of the superior rectal vein in rectal cancer is still controversial, and the related studies are few.…”