Extent of Mesorectal Tumor Invasion as a Prognostic Factor After Curative Surgery for T3 Rectal Cancer Patients

Abstract

Objective: To determine the significance of the extent of mesorectal tumor invasion as a prognostic factor for T3 rectal cancer patients. Summary Background Data: There is controversy as to which primary lesion characteristics, other than regional lymph node involvement, in T3 rectal cancer are reliable prognostic factors. Patients and Methods:The extent of mesorectal tumor invasion was evaluated using 2 data sets comprising 196 and 247 patients undergoing curative surgery at separate institutes. When the outer aspect of the muscular layer was not identifiable, an estimate was obtained by drawing a straight line between the 2 break points of the muscular layer. Results: We selected 6 mm as the optimal value for subclassification of T3 rectal patients into 2 groups, based on the extent of mesorectal invasion, using the first data set. The overall 5-year survival rate was significantly higher in patients with Ͻ6 mm than in those with Ն6 mm of mesorectal invasion (72% versus 50%; P Ͻ 0.01). Similarly, in the second data set, the overall 5-year survival rates of patients with mesorectal invasion Ͻ6 mm and Ն6 mm were 59% and 37%, respectively (P Ͻ 0.01). In both data sets, multivariate analyses verified the extent of mesorectal invasion to be an independent prognostic factor, together with nodal involvement. Regarding positive nodal involvement and mesorectal invasion Ն6 mm as risk factors, the overall 5-year survival rates with none, one, and both of these factors were 84%, 61%, and 38%, respectively, in the first data set (P Ͻ 0.01). Prognostic results were similar for the second data set. Conclusion: Extent of mesorectal invasion, based on a 6-mm cutoff value, is useful for subclassification of T3 rectal cancer patients. (Ann Surg 2006;243: 492-498)

High-risk features in potentially resectable colon cancer: a prospective MDCT-pathology agreement study

“…Our tailored endoluminal distension (air or CO 2 for right colon cancers and water for left colon cancers) may have increased observers' confidence for the exclusion of extramural tumor extension, translating into higher specificity. Various studies have identified the degree of extramural invasion as one of the most important prognostic features in colorectal cancer [13][14][15][16][17][18], patients with £5 mm extramural extension, irrespective of nodal status, having an 85% cancer-specific survival compared to only 54% when >5 mm extramural invasion is present [19]; our low minimum sensitivity values (42.9-76.2%) with respect to this parameter indicate that, if CT measurements were to be viewed as pathology surrogates, in a CT-based decision setting, too many highrisk patients might miss preoperative chemotherapy. Norgaard et al also evaluated the accuracy of CT for the differentiation between locally advanced and nonlocally advanced colon cancers in a retrospective single observer study, achieving diagnostic accuracy values that were slightly inferior (0.73 vs. 0.76-0.86); sensitivity and specificity values in the range of those obtained in our study (70 and 78 vs. 42.9-76.2 and 75.5-90.6%, respectively) [10].…”

Prognostic Heterogeneity of Endosonographic T3 Rectal Cancer

“…Similar limitations have been found in anatomopathologic studies which state that the muscular layer is unidentifiable in 65 percent of T3 tumors. 7 To avoid this important bias, we decided to measure the more objective ultrasonographic maximum tumor thickness. The ERUS technique involves filling the endoluminal balloon with distilled water, which may be a potential source of bias when the uMTT is measured.…”

“…Preoperative ERUS subdivision of uT3 is feasible and simple and supports the argument that T3 tumors with slight penetration do not need adjuvant therapy. 3,4,6,7 In addition, more complex imaging tools such as high-resolution MRI would be unnecessary because the probability of CRM involvement is minimal. MRI is a currently expanding method for local rectal cancer staging, but it is limited by the expense and availability.…”

“…1Y8 Mesorectal tumor penetration is an independent prognostic factor. 2,3,6,7 However, the prognostic cutoff point for subdividing T3 tumors into slight or extensive mesorectal spread varies according to different authors (microscopic invasion, 6 more or less than 2 mm, 3 4 mm, 2 5 mm, 5 or 6mm, 7 respectively). The local recurrence rates reflect the prognostic implications of these two subgroups ( in many parts of the world, some patients with early T3 tumors are overtreated by this approach, and a method for risk stratifying T3 tumors to avoid unnecessary treatment for low-risk T3 patients is needed. At present, preoperative staging of rectal cancer is considered essential for selecting patients for surgery and neoadjuvant therapy.…”

Depth of tumor invasion in locally advanced rectal cancer correlates with patients’ prognosis: The usefulness of elastic stain for its measurement

“…8,9 Furthermore, the measured extent of perirectal fat invasion has been shown to be an independent predictor of outcome in patients with T3 and T4 CRC. [10][11][12][13][14][15] The possibility of a correlation between prognosis and the measured extent of tumor invasion has also been assumed in T3 and T4 CRC, in a similar way to CRC and SM depth. In addition, JSCCR published a standard method for the measurement of tumor invasion beyond the outer border of the MP in CRC on their online website in 2005, and proposed that the relationship between the depth of locally advanced CRC and clinicopathological factors be examined at each institution.…”