TABLE 3.
Scientific literature reporting the value of new staging based on the “counting” principle for categorizing tumor deposits (TDs) in colorectal cancer
| Authors (publication year) | Study design | Patients examined | Summary of the results |
|---|---|---|---|
| Ueno et al. (2007) 15 | Retrospective, single‐center study | 1027 patients with T2–T4 CRC (1980–1999) | pNnew was superior to pNTNM5/TNM6 in AIC for CSS, when TDs other than intravascular TD were added to the LNM count. |
| Ueno et al. (2012) 26 | Retrospective, multicenter study | 1716 (1994–1998: first cohort) and 2242 (1999–2003: second cohort) patients with stage I–III CRC | pNnew and pTNMnew were superior to pNTNM5/TNM6/TNM7 and pTNNTNM7, respectively, in AIC and C‐index for DSS, when nodular TDs were added to the LNM count. |
| Song et al. (2012) 38 | Retrospective, single‐center study | 513 patients with stage III CRC (1994–2007) | pNnew and pTNMnew were superior to pNTNM7 and pTNMTNM7, respectively, in C‐index for CSS, when TDs were added to the LNM count. |
| Li et al. (2016) 39 | Retrospective, multicenter study | 4121 patients with stage II and III CRC (2004–2011) | pNnew was superior to pNTNM7 in C‐index for DFS and OS, when TDs were added to the LNM count. |
| Nagtegaal et al. (2017) 9 | Systematic review and meta‐analysis | 17 studies comprised 10 106 patients with CRC (1964–2013) | An increasing number of TD was associated with poor outcomes. The combination of TD and LNM was associated with a significantly higher risk of liver metastasis than LNM alone. |
| Delattre et al. (2020) 42 | Post hoc analysis of a clinical trial | 1942 patients with stage III colon cancer (2009–2014) in the IDEA France study | Patients upstaged from pN1 to pN2new by the addition of TD to LNM count had a significantly worse DFS than those with pN1new, and it was comparable to pN2. |
| Pei et al. (2020) 40 | Retrospective database analysis | 21 290 patients with stage III CRC from the SEER database (1975 to 2016) | pNnew and pTNMnew were superior to pNTNM8 and pTNMTNM8, respectively, in AUC and AIC for OS, when TDs were added to the LNM count. |
| Pei et al. (2020) 41 | Retrospective database analysis | 9198 patients with stage III CRC from the SEER database (2010–2016) | pNnew was superior to pN in AUC and AIC for OS, when TDs were added to the LNM count. |
| Cohen et al. (2021) 43 | Post hoc analysis of a clinical trial | 2028 patients with stage III CRC (2010–2015) included in the CALGB/SWOG 80702 study | Patients upstaged from pN1 to pN2new by the addition of TD to LNM count had significantly worse DFS and OS than those with pN1new, and they were comparable to pN2. |
| Pyo et al. (2021) 44 | Retrospective, single‐center study | 2446 patients with stage III CRC (2010–2019) | Among patients who completed 6 months of adjuvant chemotherapy, those upstaged from pN1 to pN2new by the addition of TD to LNM count had a significantly worse DFS than those pN1new, and it was comparable to pN2. |
Abbreviations: AIC, Akaike's information criterion; AUC, area under the receiver‐operating characteristic curve; C‐index, Harrell's concordance index; CRC, colorectal cancer; CSS, cancer‐specific survival; DFS, disease‐free survival; DSS, disease‐specific survival; OS, overall survival; pNnew and pTNMnew, revised pN and pTNM based on the “counting” principle, respectively, i.e., a new method of categorization with adding the number of tumor deposits (TDs) to the number of LNMs to derive a final N stage; pNTNM5/TNM6/TNM7, pN according to the definition of TNM5, TNM6, or TNM7; pTNMTNM7, pTNM according to the definition of TNM7; SEER, Surveillance, Epidemiology, and End Results.