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

Mortality risk prediction for primary appendiceal cancer

BACKGROUND

Accurately predicting survival in patients with cancer is crucial for both clinical decision-making and patient counseling. The primary aim of this study was to generate the first machine-learning algorithm to predict the risk of mortality following the diagnosis of an appendiceal neoplasm.

METHODS

Patients with primary appendiceal cancer in the Surveillance, Epidemiology, and End Results database from 2000 to 2019 were included. Patient demographics, tumor characteristics, and survival data were extracted from the Surveillance, Epidemiology, and End Results database. Extreme gradient boost, random forest, neural network, and logistic regression machine learning models were employed to predict 1-, 5-, and 10-year mortality. After algorithm validation, the best-performance model was used to develop a patient-specific web-based risk prediction model.

RESULTS

A total of 16,579 patients were included in the study, with 13,262 in the training group (80%) and 3,317 in the validation group (20%). Extreme gradient boost exhibited the highest prediction accuracy for 1-, 5-, and 10-year mortality, with the 10-year model exhibiting the maximum area under the curve (0.909 [±0.006]) after 10-fold cross-validation. Variables that significantly influenced the predictive ability of the model were disease grade, malignant carcinoid histology, incidence of positive regional lymph nodes, number of nodes harvested, and presence of distant disease.

CONCLUSION

Here, we report the development and validation of a novel prognostic prediction model for patients with appendiceal neoplasms of numerous histologic subtypes that incorporate a vast array of patient, surgical, and pathologic variables. By using machine learning, we achieved an excellent predictive accuracy that was superior to that of previous nomograms.

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.

Case report: A rare case of synchronous mucinous neoplasms of the renal pelvis and the appendix

Background

Mucinous neoplasms are tumors arising in the epithelial tissue, characterized by excessive mucin secretion. They mainly emerge in the digestive system and rarely in the urinary system. They also seldom develop in the renal pelvis and the appendix asynchronously or simultaneously. The concurrence of this disease in these two regions has not yet been reported. In this case report, we discuss the diagnosis and treatment of synchronous mucinous neoplasms of the right renal pelvis and the appendix. The mucinous neoplasm of the renal pelvis was preoperatively misdiagnosed as pyonephrosis caused by renal stones, and the patient underwent laparoscopic nephrectomy. Herein, we summarize our experience with this rare case in combination with related literature.

Case presentation

In this case, A 64-year-old female was admitted to our hospital with persistent pain in the right lower back for over a year. Computer tomography urography (CTU) showed that the patient was confirmed as right kidney stone with large hydronephrosis or pyonephrosis, and appendiceal mucinous neoplasm (AMN). Subsequently, the patient was transferred to the gastrointestinal surgery department. Simultaneously, electronic colonoscopy with biopsy suggested AMN. Open appendectomy plus abdominal exploration was performed after obtaining informed consent. Postoperative pathology indicated low-grade AMN (LAMN) and the incisal margin of the appendix was negative. The patient was re-admitted to the urology department, and underwent laparoscopic right nephrectomy because she was misdiagnosed with calculi and pyonephrosis of the right kidney according to the indistinctive clinical symptoms, standard examination of the gelatinous material, and imaging findings. Postoperative pathology suggested a high-grade mucinous neoplasm of the renal pelvis and mucin residing partly in the interstitium of the cyst walls. Good follow-up results were obtained for 14 months.

Conclusion

Synchronous mucinous neoplasms of the renal pelvis and the appendix are indeed uncommon and have not yet been reported. Primary renal mucinous adenocarcinoma is very rare, metastasis from other organs should be first considered, especially in patients with long-term chronic inflammation, hydronephrosis, pyonephrosis, and renal stones, otherwise, misdiagnosis and treatment delay may occur. Hence, for patients with rare diseases, strict adherence to treatment principles and close follow-up are necessary to achieve favorable outcomes.

A Nomogram for Predicting Lymph Nodal Metastases in Patients with Appendiceal Cancers: An Analysis of SEER Database

BACKGROUNDS

Appendiceal cancers are usually diagnosed after appendectomy accidentally. The need for subsequent right hemicolectomy in these patients was determined by the potential risk of regional lymph node (LN) metastasis. Establishing a nomogram to forecast the potential risk of lymph node metastasis of appendiceal cancer could help in the next step of treatment.

METHODS

Patients with appendiceal cancer undergoing surgery was queried in the American cancer database of Surveillance, Epidemiology and End Results database from 2004 to 2016. A nomogram was established based on Logistic regression model.

RESULTS

Finally, 3,075 patients were diagnosed with appendectomy cancer from 2004 to 2016. Among them, there were 2028 (65.9%) cases with negative lymph nodes, 1047 (34.1%) cases with positive lymph nodes. Risk factors associated with lymph node metastasis include age, histological type, tissue grade, T stage, distant metastasis, and tumor size. We drew the ROC curves of the training group（0.754, P < 0.001） and the validation group （0.775, P < 0.001） respectively. C-index values of predictions were 0.772 (95%CI, 0.750-0.793) and 0.776 (95%CI, 0.746-0.807), and Brier score were 0.178 and 0.172 in training and validation group respectively. All of them showed excellent performance of the nomogram in our study.

CONCLUSION

A new nomogram was created to assess the potential risk of LN metastasis in patients of appendiceal cancer by utilizing age, tumor histology, tumor pathologic grade, tumor size, T-stage, and M-stage. The nomogram could provide a strong reference for the right hemicolectomy and facilitate clinic decision.

Nationwide overview of survival and management of appendiceal tumors in children

INTRODUCTION

There remains a paucity of literature on survival related to pediatric appendiceal tumors. The purpose of this study was to determine the incidence, surgical management, and survival outcomes of appendiceal tumors in pediatric patients.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) Registry was analyzed for pediatric appendiceal tumors from 1973 to 2011. Parameters analyzed were: tumor type, surgical management (appendectomy vs. extensive resection), tumor size, and lymph node sampling. Chi-square analysis for categorical and Student's t test for continuous data were used.

RESULTS

Overall, 209 patients had an appendiceal tumor, including carcinoid (72%), appendiceal adenocarcinoma (16%), and lymphoma (12%). Patients undergoing appendectomy vs. extensive resection had similar 15-year survival rates (98% vs. 97%; p=0.875). Appendectomy vs. extensive resection conferred no 15-year survival advantage when patients were stratified by tumor type, including adenocarcinoma (87% vs. 89%; p=0.791), carcinoid (100% vs. 100%; p=0.863), and lymphoma (94% vs. 100%; p=0.639). There was no significant difference in 15-year survival between tumor size groups ≥2 and <2cm (both 100%) and presence or absence of lymph node sampling (96% and 97%; p=0.833) for all patients with a carcinoid tumor.

CONCLUSION

Appendectomy may be adequate for pediatric appendiceal tumors. Extensive resection may be of limited utility for optimizing patient survival, placing patient at greater operative risk.

TYPE OF STUDY

Retrospective Prognostic Study.

LEVEL OF EVIDENCE

III.