Objective The 7th edition of AJCC staging manual implicitly states that only T1 and T2 lesions that lack regional lymph node metastasis but have tumor deposit(s) will be classified in addition as N1c, though it is not consistent in that pN1c is also an option for pT3/T4a tumors in the staging table. Nevertheless, in this TNM classification, how to classify tumor deposits (TDs) in colorectal cancer patients with lymph node metastasis (LNM) and TDs simultaneously is still not clear. The aim of this study is to investigate the possibility of counting TDs as metastatic lymph nodes in TNM classification and to indentify its prognostic value for colorectal cancer patients. Methods and Results In this retrospective study, 513 cases of colorectal cancer with LNM were reviewed. We proposed a novel pN (npN) category in which TDs were counted as metastatic lymph nodes in the TNM classification. Cancer-specific survival according to the npN or pN category was analyzed using Kaplan-Meier survival curves. Univariate and multivariate analyses were performed to indentify significant prognostic factors. Harrell's C statistic was used to test the predictive capacity of the prognostic models. The results revealed that the TD was a significant prognostic factor in colorectal cancer. Univariate and multivariate analyses uniformly indicated that the npN category was significantly correlated with prognosis. The results of Harrell's C statistical analysis demonstrated that the npN category exhibited a superior predictive capacity compared to the pN category of the 7th edition TNM classification. Moreover, we also found no significant prognostic differences in patients with or without TD in the same npN categories. Conclusions The counting of TDs as metastatic lymph nodes in the TNM classification system is potentially superior to the classification in the 7th edition of the TNM staging system to assess prognosis and survival for colorectal cancer patients.
References
[1]
Landis SH, Murray T, Bolden S, Wingo PA (1999) Cancer statistics,1999. CA Cancer J Clin 49: 8–31.
[2]
Levin B, Brooks D, Smith RA, Stone A (2003) Emerging technologies in screening for colorectal cancer: CT colonography, immunochemical fecal occult blood tests, and stool screening using molecular markers. CA Cancer J Clin 53: 44–55.
[3]
Compton CC (2006) Key issues in reporting common cancer specimens: problems in pathologic staging of colon cancer. Arch Pathol Lab Med 130: 318–324.
[4]
Sobin LH, Wittekind C (1997) UICC TNM classification of malignant tumours, 5th edition.
[5]
Sobin LH, Wittekind C (2002) TNM classification of malignant tumours, 6th edition.
[6]
Sobin LH, Gospodarowicz MK, Wittekind C (2010) TNM classification of malignant tumours, 7th edition.
[7]
Belt EJ, van Stijn MF, Bril H, de Lange-de Klerk ES, Meijer GA, et al. (2010) Lymph node negative colorectal cancers with isolated tumor deposits should be classified and treated as stage III. Ann Surg Oncol 17: 3203–3211.
[8]
Nagtegaal ID, Quirke P (2007) Colorectal tumour deposits in the mesorectum and pericolon: a critical review. Histopathology 51: 141–149.
[9]
Tateishi S, Arima S, Futami K, Kawahara K, Tachikawa D, et al. (2005) A clinicopathological investigation of “tumor nodules” in colorectal cancer. Surg Today 35: 377–384.
[10]
Prabhudesai A, Arif S, Finlayson CJ, Kumar D (2003) Impact of microscopic extranodal tumor deposits on the outcome of patients with rectal cancer. Dis Colon Rectum 46: 1531–1537.
[11]
Goldstein NS, Turner JR (2000) Pericolonic tumour deposits in patients with T3N+M0 colon adenocarcinomas: markers of reduced disease free survival and intra-abdominal metastases and their implications for TNM classification. Cancer 88: 2228–2238.
[12]
Edge SB, Byrd DR, Compton CC, Fritz AG, Greene FL, et al. (2010) AJCC cancer staging handbook, 7th edition. New York: Springer. 149 p.
[13]
Chok KS, Law WL (2007) Prognostic factors affecting survival and recurrence of patients with pT1 and pT2 colorectal cancer. World J Surg 31: 1485–1490.
[14]
Sun Z, Zhu GL, Lu C, Guo PT, Huang BJ, et al. (2009) A novel subclassification of pT2 gastric cancers according to the depth of muscularis propria invasion: superficial muscularis propria versus deep muscularis propria/subserosa. Ann Surg 249: 768–775.
[15]
Harrell FE Jr, Lee KL, Mark DB (1996) Multivariable prognostic models: issues in developing models, evaluating assumptions and adequacy, and measuring and reducing errors. Stat Med 15: 361–387.
[16]
Harrell FE Jr, Lee KL, Califf RM, Pryor DB, Rosati RA (1984) Regression modelling strategies for improved prognostic prediction. Stat Med 3: 143–152.
[17]
Gabriel WB, Dukes CE, Bussey HJR (1935) Lymphatic spread in cancer of the rectum. Br J Surg 23: 395–413.
[18]
Ueno H, Mochizuki H (1997) Clinical significance of extrabowel skipped cancer infiltration in rectal cancer. Surg Today 27: 617–622.
[19]
Ueno H, Mochizuki H, Hashiguchi Y, Ishiguro M, Miyoshi M, et al. (2007) Extramural cancer deposits without nodal structure in colorectal cancer: optimal categorization for prognostic staging. Am J Clin Pathol 127: 287–294.
[20]
Han HQ, Liu T, Zhao LZ, Qi F, Wang PZ (2006) Clinical value of the sixth edition TNM stages analysing prognosis of colorectal cancer. Zhonghua Yi Xue Za Zhi 86: 819–821.
[21]
Tong LL, Gao P, Wang ZN, Song YX, Xu YY, et al. (2012) Is the 7th edition of the UICC/AJCC TNM staging system reasonable for patients with tumor deposits in colorectal cancer? Ann Surg 255: 208–213.
[22]
Wang W, Li Y, Zhang Y, Yuan X, Xu D, et al. (2011) Incorporation of extranodal metastasis of gastric carcinoma into the 7th edition UICC TNM staging system. PLoS One 6: e19557.
[23]
Kanehara &Co., LTD Tokyo (1997) Japanese Society for Cancer of the Colon and Rectum: Japanese classification of Colorectal Carcinoma, First English Edition.
[24]
Ueno H, Mochizuki H, Shirouzu K, Kusumi T, Yamada K, et al. (2011) Actual status of distribution and prognostic impact of extramural discontinuous cancer spread in colorectal cancer. J Clin Oncol 29: 2550–2556.
