Impact of Mucinous Histology on the Prognosis of Stage I-III Adenocarcinomas of the Appendix: a Population-Based, Propensity Score-Matched Analysis

Extent of Resection and Long-Term Outcomes for Appendiceal Adenocarcinoma: a SEER Database Analysis of Mucinous and non-Mucinous Histologies

BACKGROUND

Mucinous appendiceal adenocarcinomas (MAA) and non-mucinous appendiceal adenocarcinomas (NMAA) demonstrate differences in rates and patterns of recurrence, which may inform the appropriate extent of surgical resection (i.e., appendectomy versus colectomy). The impact of extent of resection on disease-specific survival (DSS) for each histologic subtype was assessed.

PATIENTS AND METHODS

Patients with resected, non-metastatic MAA and NMAA were identified in the Surveillance, Epidemiology, and End Results database (2000-2020). Multivariable models were created to examine predictors of colectomy for each histologic subtype. DSS was calculated using Kaplan-Meier estimates and examined using Cox proportional hazards modeling.

RESULTS

Among 4674 patients (MAA: n = 1990, 42.6%; NMAA: n = 2684, 57.4%), the majority (67.8%) underwent colectomy. Among colectomy patients, the rate of nodal positivity increased with higher T-stage (MAA: T1: 4.6%, T2: 4.0%, T3: 17.1%, T4: 21.6%, p < 0.001; NMAA: T1: 6.8%, T2: 11.4%, T3: 25.6%, T4: 43.8%, p < 0.001) and higher tumor grade (MAA: well differentiated: 7.7%, moderately differentiated: 19.2%, and poorly differentiated: 31.3%; NMAA: well differentiated: 9.0%, moderately differentiated: 20.5%, and 44.4%; p < 0.001). Nodal positivity was more frequently observed in NMAA (27.6% versus 16.4%, p < 0.001). Utilization of colectomy was associated with improved DSS for NMAA patients with T2 (log rank p = 0.095) and T3 (log rank p = 0.018) tumors as well as moderately differentiated histology (log rank p = 0.006). Utilization of colectomy was not associated with improved DSS for MAA patients, which was confirmed in a multivariable model for T-stage, grade, and use of adjuvant chemotherapy [hazard ratio (HR) 1.00, 95% confidence interval (CI) 0.81-1.22].

CONCLUSIONS

Colectomy was associated with improved DSS for patients with NMAA but not MAA. Colectomy for MAA may not be required.

Comparative analysis of tumor biology and prognosis in mucinous and signet-ring cell colon cancers versus classical adenocarcinoma

Background: Limited information is currently available on the natural history and prognosis of two distinct histological subtypes of adenocarcinoma (AC) in the colon: mucinous adenocarcinoma (MAC) and signet-ring cell carcinoma (SRCC). Therefore, the aim of this study is to examine the clinicopathological characteristics of colon MAC and SRCC, comparing them to classical AC, using a large cohort of cases from the United States. Methods: Patients diagnosed with colon AC, MAC, or SRCC from the SEER database between 2000 and 2018 were included in our study. Incidence trends, patient demographics, tumor characteristics, treatment, and survival were analyzed. Results: In our study, we analyzed a total of 310,813 patients with colon cancers, including 271,382 cases of classical AC, 34,750 cases of MAC, and 4,681 cases of SRCC. Over the study period, we observed a decline in the age-adjusted incidence rates of colon AC, MAC, and SRCC. Notably, the MAC and SRCC cohorts differed significantly from AC in terms of patient characteristics, tumor locations, and treatment patterns. Patients with MAC and SRCC had poorer survival outcomes compared to those with AC. Factors associated with worse survival included older age, male sex, poorly differentiated tumors, advanced stage, and the presence of MAC or SRCC histology. On the other hand, surgical intervention was associated with improved survival. Conclusion: Our study underscores the significance of recognizing the distinct features and outcomes associated with different histological subtypes of colon cancer. Further research is warranted to delve into the underlying biological traits that contribute to these differences and to develop more tailored treatment strategies.

Lymph node positivity and association with long-term survival for different histologies of appendiceal cancer

BACKGROUND

Appendiceal cancers represent a diverse group of malignancies with varying biological behavior. The significance of lymph node metastases in relation to long-term survival and chemotherapy response is poorly defined.

METHODS

The National Cancer Database was queried to find patients diagnosed with appendiceal cancer from 1998 to 2012. Kaplan-Meier curves and multivariable Cox regression analyses were used to study the association between lymph node status and overall survival. Stage IV patients were excluded.

RESULTS

The rate of nodal positivity of the 9841 patients with known node status was: signet ring 47.4%, carcinoid 42.3%, nonmucinous adenocarcinoma 28.8%, goblet cell 21.9%, and mucinous adenocarcinoma 20.4%. Node-positive patients had worse long-term survival for all subtypes with the exception of carcinoid tumors (p < 0.001). The strongest association was for signet cell and goblet cell. Adjuvant chemotherapy in node-positive patients improved survival for mucinous, nonmucinous, and signet ring cell histology (p < 0.01), but not for goblet cell.

CONCLUSIONS

Nodal involvement in patients with appendiceal cancer varies in incidence, association with adverse survival, and response to systemic therapy. Individualized treatment algorithms for the management of the subtypes of appendiceal cancer are needed.

Predictors of lymph node metastases in patients with mucinous appendiceal adenocarcinoma

BACKGROUND

Lymph node metastasis (LN+) is a prognostic factor in appendiceal cancers, but predictors and outcomes for LN+  in mucinous appendiceal adenocarcinoma (MAC) remain poorly defined.

METHODS

Patients were identified from the 2010 to 2016 NCDB who underwent surgical resection as first-line management for Stage I-III mucinous appendiceal cancer. A LN+ risk-score model was developed using multivariable regression on a training data set and internally validated using a testing data set. Three-year overall survival (OS) was analyzed by Cox proportional hazards regression.

RESULTS

Of 1158 patients, LN+ (N = 244, 21.1%) patients were more likely to have higher pT group and grade of disease, lymphovascular invasion (LVI), and positive margins on univariate analyses. Predictive factors associated with LN+ on multivariable analysis included positive surgical margins (odds ratio [OR] 3.00, P <.0001), higher grade (moderately differentiated: OR, 2.16, P < .0001; poorly or undifferentiated: OR, 3.07, P < .0001), and LVI (OR, 7.28, P < .0001). A validated risk-score model using these factors was developed with good performance (AUC 0.749). LN+ patients had a worse 3-year OS compared with LN- patients (17.4% vs 82.6%, hazard ratio 1.96, P = .001).

CONCLUSIONS

LN+ is associated with worse survival in patients with MAC. A risk-score model using margin status, LVI, and grade can accurately risk stratify patients for LN+.

The prognostic relevance of histologic subtype in appendiceal adenocarcinoma

BACKGROUND

The aim of this population-based study was to determine the prognostic value of the histologic subtypes mucinous (MAC), non-mucinous (AC) and signet ring cell (SRCC) adenocarcinoma among patients with appendiceal cancer.

METHODS AND MATERIALS

Data from the Netherlands Cancer Registry (NCR) of patients with primary appendiceal adenocarcinomas with MAC, AC and SRCC histologic subtype, diagnosed between 2001 and 2015 were used (n = 675). To categorize patients according to the recent histopathological classification, the NCR was linked with the Dutch Pathology Registry (PALGA). Log-rank tests and Kaplan-Meier analyses were performed to estimate overall survival (OS), and the cox proportional hazards model was run to identify prognostic factors.

RESULTS

AC was the most frequently encountered histologic subtype (50.9%), followed by MAC (35.8%) and SRCC (13.3%). In locoregional disease, histologic subtype was not a prognostic factor for OS with 5-year survival rates for patients with AC, MAC and SRCC of 60.0%, 60.5% and 69.6% respectively (p = 0.68). Metastatic disease was more common in SRCC (53.8%) than in MAC (38.8%) and AC (23.4%) (p < 0.0001). Median OS for patients with metastatic disease was 12.6, 27.7 and 18.2 months in AC, MAC and SRCC respectively (p < 0.005). MAC was associated with higher survival compared to AC (HR 0.48, 95%CI 0.34-0.69). In subanalyses, MAC was only a positive prognostic factor compared to AC in patients with peritoneal metastases (HR 0.42, 95%CI 0.28-0.62).

CONCLUSION

Histologic subtype had no prognostic relevance in locoregional or systemic metastatic disease in appendiceal adenocarcinoma. In peritoneal metastases, mucinous histologic subtype was a favorable prognostic factor, compared to non-mucinous and signet ring cell subtype.

Trends of incidence and survival in patients with gastrointestinal mucinous adenocarcinoma

The epidemiology and clinical outcome of gastrointestinal mucinous adenocarcinoma (MA) are not well illustrated. The present study aimed to explore the evolving epidemiology and prognostic factors that affect the survival of patients with MA in the gastrointestinal tract. A retrospective and population-based study was conducted to determine the annual age-adjusted incidence, overall survival (OS) and survival trend of gastrointestinal mucinous MA using nationally representative data from the Surveillance, Epidemiology, and End Results (SEER) program between 2000 and 2014. A Kaplan-Meier curve and a Cox proportional regression model were used to evaluate prognostic factors for this disease. Of the 51632 cases, females accounted for 50.5% (26058). The annual incidence of MA steadily decreased from 2000 to 2014. This trend occurred across all stages, grades and sites, apart from the appendix. In the SEER 18 registry grouping (2000-2014), the highest incidence was 3.333 per 100,000 persons for the colon. The median OS varied significantly between different primary sites, stages, grades, and age of clinical diagnosis, and the time period of diagnosis, according to a multivariable analysis. The five-year OS of gastrointestinal MA improved gradually between 2000 and 2014. The improvement in survival over the same interval was more pronounced in the subgroup of distant gastrointestinal MA. All sites along the alimentary tract, with the exception of the appendix, showed a decrease in the incidence of MA. Improved survival rates were observed for most of the gastrointestinal tract, especially for patients with advanced stage disease. MA in the upper gastrointestinal tract was less frequent but had poorer survival than colorectal MA. Clinicians should consider the primary tumour site when making therapeutic guidelines and treatment decisions for gastrointestinal MA.

Survival after resection of appendiceal carcinoma by hemicolectomy and less radical than hemicolectomy: a population-based propensity score matched analysis

AIM

The operative treatment for non-metastatic appendiceal carcinoma is controversial despite the recommendation of right hemicolectomy (RH) by many researchers. The aim of this population-based study was to compare outcomes after RH and less radical resection than right hemicolectomy (LRH).

METHOD

A total of 1144 patients who underwent resection with additional lymphadenectomy of Stages I-III appendiceal carcinoma from 2004 to 2012 were identified in the Surveillance, Epidemiology and End Results database. Overall survival (OS) and cancer-specific survival (CSS) after RH and LRH were assessed by unadjusted and risk-adjusted Cox regression analysis and by propensity score matched analysis.

RESULTS

A total of 855 (74.7%) patients underwent RH and 289 (25.3%) underwent LRH. In an unadjusted analysis, survival after LRH and RH did not differ in OS [hazard ratio (HR) 0.95, 95% CI 0.71-1.26, P = 0.707] and CSS (HR 0.95, 95% CI 0.69-1.32, P = 0.762). The 5-year OS and CSS in patients who underwent RH were 71.6% (95% CI 67.8-75.6%) and 76.4% (95% CI 72.8-80.3) compared with 73.8% (95% CI 67.9-80.2) and 78.7% (95% CI 73.2-84.7) in patients with LRH, respectively. No relevant difference in survival between LRH and RH could be observed in a multivariable analysis (OS, HR 0.90, 95% CI 0.65-1.25, P = 0.493; CSS, HR 0.87, 95% CI 0.60-1.26, P = 0.420) and after propensity score adjusted analysis (OS, HR 0.87, 95% CI 0.62-1.22, P = 0.442; CSS, HR 0.97, 95% CI 0.67-1.40, P = 0.883).

CONCLUSIONS

In this retrospective analysis, survival after RH for non-metastatic appendiceal carcinoma was not statistically significantly superior to LRH. Hence, LRH with lymphadenectomy might be sufficient for treatment of non-metastatic appendiceal carcinoma.