Prognostic value of N1c in colorectal cancer: a large population-based study using propensity score matching

Tumor deposits in colorectal cancer: Refining their definition in the TNM system

Tumor deposits (TDs) are discontinuous tumor spread in the mesocolon/mesorectum which is found in approximately 20% of colorectal cancer (CRC) and negatively affects survival. We have a history of repeated revisions on TD definition and categorization in the tumor-node-metastasis (TNM) system leading to stage migration. Since 1997, TDs have been categorized as T or N factors depending on their size (TNM5) or contour (TNM6). In 2009, TNM7 provided the category of N1c for TDs in a case without positive lymph nodes (LNs), which is also used in TNM8. However, increasing evidence suggests that these revisions are suboptimal and only "partially" successful. Specifically, the N1c rule is certainly useful for oncologists who are having difficulty with TDs in a case with no positive LNs. However, it has failed to maximize the value of the TNM system because of the underused prognostic information of individual TDs. Recently, the potential value of an alternative staging method has been highlighted in several studies using the "counting method." For this method, all nodular type TDs are individually counted together with positive LNs to derive the final pN, yielding a prognostic and diagnostic value that is superior to existing TNM systems. The TNM system has long stuck to the origin of TDs in providing its categorization, but it is time to make way for alternative options and initiate an international discussion on optimal treatment of TDs in tumor staging; otherwise, a proportion of patients end up missing an opportunity to receive the optimal adjuvant treatment.

Beyond N staging in colorectal cancer: Current approaches and future perspectives

Traditionally, lymph node metastases (LNM) evaluation is essential to the staging of colon cancer patients according to the TNM (tumor–node–metastasis) system. However, in recent years evidence has accumulated regarding the role of emerging pathological features, which could significantly impact the prognosis of colorectal cancer patients. Lymph Node Ratio (LNR) and Log Odds of Positive Lymph Nodes (LODDS) have been shown to predict patients’ prognosis more accurately than traditional nodal staging and it has been suggested that their implementation in existing classification could help stratify further patients with overlapping TNM stage. Tumor deposits (TD) are currently factored within the N1c category of the TNM classification in the absence of lymph node metastases. However, studies have shown that presence of TDs can affect patients’ survival regardless of LNM. Moreover, evidence suggest that presence of TDs should not be evaluated as dichotomic but rather as a quantitative variable. Extranodal extension (ENE) has been shown to correlate with presence of other adverse prognostic features and to impact survival of colorectal cancer patients. In this review we will describe current staging systems and prognostic/predictive factors in colorectal cancer and elaborate on available evidence supporting the implementation of LNR/LODDS, TDs and ENE evaluation in existing classification to improve prognosis estimation and patient selection for adjuvant treatment.

Postoperative radioiodine therapy impact on survival in poorly differentiated thyroid carcinoma: a population-based study

PURPOSE

The true impact of postoperative radioiodine therapy on survival has been controversial for patients with poorly differentiated thyroid carcinoma (PDTC). We aimed to determine the impact of postoperative radioiodine on survival in PDTC through a population-based study.

METHODS

Data on patients with PDTC were collected from the US SEER database (2004 to 2015). Patients were divided into the radioiodine group and nonradioiodine group. Survival comparison between groups was evaluated by Kaplan-Meier curves, log-rank test and multivariate Cox regression analysis. Akaike information criterion was used to select variables in the nomogram. The performance of the nomogram was assessed by discrimination (C-index) and calibration plots.

RESULTS

The radioiodine group had more aggressive features, such as advanced tumor node metastasis stage and radical surgery, compared to the nonradioiodine group. PDTC patients receiving radioiodine therapy had a significant survival advantage in terms of overall survival (OS) (P = 0.001) but not in terms of cancer-specific survival (P = 0.083). Multivariate analysis revealed radioiodine therapy was an independent favorable factor for OS in PDTC patients (hazard ratio = 0.57; 95% CI, 0.44-0.75, P < 0.001). Subgroup analysis identified patients' characteristics favoring radioiodine therapy. The nomogram (age, tumor size, extension, neck lymph nodes metastasis and radioiodine therapy) of OS for predicting 3-, 5- and 10-year OS probability showed good discrimination (C-index, 0.797) and calibration power.

CONCLUSION

Postoperative radioiodine therapy can prolong the long-term OS in patients with PDTC, and is an independent favorable prognostic factor for those patients. Further prospective studies are warranted.

Prognostic Value of the N1c in Stage III and IV Colorectal Cancer: A Propensity Score Matching Study Based on the Surveillance, Epidemiology, and End Results (SEER) Database

The prognostic role of the N1c remains unclear in colorectal cancer (CRC). Our study aimed to determine the prognostic value of N1c.

Patients diagnosed in 2010-2015 were accessed from the Surveillance, Epidemiology, and End Results (SEER) database. COX univariate and multivariate regression analysis and the Kaplan-Meier method were used to assess the impact of the N1c stage on the cause-specific (CSS) and overall survival (OS). Propensity score matching (PSM) was used to construct a matched group with similar propensity scores.

Kaplan-Meier analysis showed that the CSS and OS rates in N1a were significantly better than N1c in stage III and IV CRCs after reducing selection bias (CSS: P < 0.001 in stage III, P = 0.041 in stage IV; OS: P < 0.001 in stage III, P = 0.0079 in stage IV). There were no statistical differences in CSS and OS between N1b and N1c (CSS: P = 0.500 in stage III, P = 0.270 in stage IV; OS: P = 0.390 in stage III, P = 0.600 in stage IV). Further, the prognostic value of N1c with only one tumor deposit (TD) is equivalent to N1a based on the comparison of CSS and OS rates (CSS: P = 0.420; OS: P = 0.310). Whereas N1c with only one TD had significantly better CSS and OS than N1b (CSS: P = 0.039; OS: P = 0.037).

The CSS and OS rates of N1c do not achieve a statistical difference with N1b in both stage III and IV CRCs. Significantly, higher CSS and OS rates were found in N1c with only one TD versus N1b stage in stage III CRC.

Prognostic value of tumor deposits in locally advanced rectal cancer: a retrospective study with propensity score matching

BACKGROUND

The actual risks posed by tumor deposits (TDs) in colorectal cancer are still incompletely assessed. We explored the prognostic value of TDs in locally advanced rectal cancer (LARC) patients using propensity score matching (PSM) method.

METHODS

Consecutive LARC patients in Peking University First Hospital between 2011 and 2015 were retrospectively analyzed. Kaplan-Meier methods and Cox proportional hazard regression analysis were conducted to explore prognostic values of TDs. PSM method was conducted to minimize selection bias. The correlation between TDs number and prognosis was explored.

RESULTS

Four hundred and fifty-one LARC patients were recruited, and 78 (17.3%) patients were with TDs. Multivariate Cox analysis identified that the presence of TDs was an independent prognostic risk factor for overall survival (OS) (P = 0.044). PSM identified 76 matched pairs of LARC patients, and Kaplan-Meier curves revealed that patients with TDs experienced worse  OS (log-rank P = 0.0220) and relapse-free survival (RFS) (log-rank P = 0.0117). Subgroup analysis of 50 pairs extracted by PSM from 246 LARC patients with lymph node metastasis (LNM) further proved that TDs were significantly associated with worse OS (log-rank P = 0.0415), and the association was barely significant for RFS (log-rank P = 0.0527). There were non-significant tendencies towards higher mortality in TDs ≥ 2 than TD = 1 group (log-rank P = 0.348 for OS, log-rank P = 0.087 for RFS).

CONCLUSION

Our study manifested that the presence of TDs was an independent risk factor for LARC patients. The prognostic value of TDs for LARC patients with LNM should not be ignored.

The Role of Tumor Deposits in Predicting the Efficacy of Chemotherapy in Stage III Colon Cancer

Purpose

To evaluate the role of tumor deposits (TDs) in predicting the efficacy of chemotherapy in stage III colon cancer.

Methods

Using the SEER^∗Stat software Version 8.3.6, we started with a national cohort of colon cancer cases diagnosed between 2004 and 2016. We used the χ² (Chi-square) test to compare differences between different categorical variables according to the number of TDs. The Cox proportional hazards regression model was used to determine the independent association of different clinical and pathological variables with CSS, which were adjusted for other significant prognostic factors.

Results

We have identified 29,017 patients diagnosed with stage III colon cancer from the SEER database. The results of multivariate analyses showed that patients with the receipt of chemotherapy had 54.7% decreased risk of cancer-specific mortality compared with those not (HR = 0.453, 95% CI = 0.425-0.483, P < 0.0001) in the no-TD group; In the 1-2-TD group, patients with the receipt of chemotherapy had 56.8% decreased risk of cancer-specific mortality compared with those not (HR = 0.432, 95% CI = 0.364-0.512, P < 0.0001); In the ≥3-TD group, patients with the receipt of chemotherapy had 51.8% decreased risk of cancer-specific mortality compared with those not (HR = 0.482, 95% CI = 0.389-0.597, P < 0.0001).

Conclusions

Our study demonstrated that the presence of TDs was associated with a dismal prognosis and high number of TDs would also contribute to the worse survival of colon cancer. High number of TDs did not affect the survival benefit of chemotherapy in stage III colon cancer.

The Prognostic Significance of Tumor Deposit Count for Colorectal Cancer Patients after Radical Surgery

Background

The prognostic value of tumor deposit (TD) count in colorectal cancer (CRC) patients has been rarely evaluated. This study is aimed at exploring the prognostic value of TD count and finding out the optimal cutoff point of TD count to differentiate the prognoses of TD-positive CRC patients.

Method

Patients diagnosed with CRC from Surveillance, Epidemiology, and End Results (SEER) database from January 1, 2010, to December 31, 2012, were analyzed. X-tile program was used to identify the optimal cutoff point of TD count in training cohort, and a validation cohort was used to test this cutoff point after propensity score matching (PSM). Univariate and multivariate Cox proportional hazard models were used to assess the risk factors of survival.

Results

X-tile plots identified 3 (P < 0.001) as the optimal cutoff point of TD count to divide the patients of training cohort into high and low risk subsets in terms of disease-specific survival (DSS). This cutoff point was validated in validation cohort before and after PSM (P < 0.001, P = 0.002). More TD count, which was defined as more than 3, was validated as an independent risk prognostic factor in univariate and multivariate analysis (P < 0.001).

Conclusion

More TD count (TD count ≥ 4) was significantly associated with poor disease-specific survival in CRC patients.

Tumor deposit serves as a prognostic marker in gastric cancer: A propensity score-matched analysis comparing survival outcomes

BACKGROUND

Gastric cancer (GC) treatment is determined by accurate tumor staging. The value of tumor deposit (TD) in prognostic prediction staging system is not yet determined.

METHODS

We retrospectively analyzed clinical information on GC patients who underwent gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital from July 2014 to June 2016. Propensity score matching (PSM) was performed to reduce the possibility of selection bias according to the presence of TD.

RESULTS

Of the 1034 GC patients, 240 (23.21%) presented with TD, which was associated with younger age and larger tumor size (all P < .05). TD-positive patients had a worse survival than TD-negative patients before (P < .001) and after (P = .017) matching. Multivariable analysis showed that mortality risk of patients with TD increased by 58%, 62%, 37%, and 40% in the crude (HR = 1.58, 95% CI 1.32-1.89, P < .001), adjusted I (HR = 1.62, 95% CI 1.35-1.94, P < .001), adjusted II (HR = 1.37, 95% CI 1.13-1.66, P = .001), and adjusted III (HR = 1.40, 95% CI 1.16-1.68, P < .001) models before matching. Similarly, in the PSM cohort patients with TD had worse prognosis in the crude (HR = 1.32, 95% CI 1.07-1.63, P = .011), adjusted I (HR = 1.35, 95% CI 1.09-1.67, P = .005), adjusted II (HR = 1.26, 95% CI 1.00-1.58, P = .049), and adjusted III (HR = 1.33, 95% CI 1.07-1.65, P = .010) models. TD had a similar value range between N1 and N2 stages among different models.

CONCLUSIONS

Among GC patients, TD is associated with survival and may have a role in the staging of patients.