Application of propensity score model to examine the prognostic significance of lymph node number as a care quality indicator. Surg Oncol. 2012;21:e75-e85. [PMID: 22221938 DOI: 10.1016/j.suronc.2011.12.003]

Prognostic factors in patients with intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second commonly-seen liver malignancy and one of the most fatal cancers in Taiwan. Survival after diagnosis of ICC remains poor. This study aimed to investigate the survival and prognostic factors in patients with ICC. All patients with newly diagnosed ICC during 2004 to 2018 were identified from a national cancer database and followed until December 2020. Estimates of overall survival (OS) were conducted using the Kaplan-Meier method and Cox proportional hazards model. Hazard ratios with 95% confidence intervals were calculated. Initially, 7940 patients with ICC disease (stage IV: 55.6%, 4418/7940) were eligible for this study. Only 32.3% (2563/7940) patients with ICC underwent liver resection. After Propensity score matching, 969 pairs (N = 1938) of patients were matched and selected (mean age 62.8 ± 11.0 years, 53.1% were male, 29.7% had cirrhosis). The median follow-up time was 80.0 months (range 25-201 months). The 3-, 5-year OS rates were 44.0%, 36.4% in the surgical group and 26.0%, 23.7% in the non-surgical group, respectively. Surgery, young patients (≤ 54 years), small tumor size, no vascular invasion and chemotherapy were associated with better OS in patients with stages I-III disease. Surgery benefit was maximum in stage I disease followed by stage II. In patients with stage IV disease, factors such as surgery, young patients (≤ 64 years), single tumor, and no vascular invasion were associated with better OS. Chemotherapy was insignificantly associated with better OS. Long-term survival in patients with ICC is very poor. Compared to non-surgical patients, surgery conveys approximately 18% and 12% better OS rates at 3-year and 5-year, respectively. Early detection and surgical intervention may improve OS substantially in patients with ICC.

Measurement that matters: A systematic review and modified Delphi of multidisciplinary colorectal cancer quality indicators

AIM

To develop a priority set of quality indicators (QIs) for use by colorectal cancer (CRC) multidisciplinary teams (MDTs).

METHODS

The review search strategy was executed in four databases from 2009-August 2019. Two reviewers screened abstracts/manuscripts. Candidate QIs and characteristics were extracted using a tailored abstraction tool and assessed for scientific soundness. To prioritize candidate indicators, a modified Delphi consensus process was conducted. Consensus was sought over two rounds; (1) multidisciplinary expert workshops to identify relevance to Australian CRC MDTs, and (2) an online survey to prioritize QIs by clinical importance.

RESULTS

A total of 93 unique QIs were extracted from 118 studies and categorized into domains of care within the CRC patient pathway. Approximately half the QIs involved more than one discipline (52.7%). One-third of QIs related to surgery of primary CRC (31.2%). QIs on supportive care (6%) and neoadjuvant therapy (6%) were limited. In the Delphi Round 1, workshop participants (n = 12) assessed 93 QIs and produced consensus on retaining 49 QIs including six new QIs. In Round 2, survey participants (n = 44) rated QIs and prioritized a final 26 QIs across all domains of care and disciplines with a concordance level > 80%. Participants represented all MDT disciplines, predominantly surgical (32%), radiation (23%) and medical (20%) oncology, and nursing (18%), across six Australian states, with an even spread of experience level.

CONCLUSION

This study identified a large number of existing CRC QIs and prioritized the most clinically relevant QIs for use by Australian MDTs to measure and monitor their performance.

Tumor sidedness influences prognostic impact of lymph node metastasis in colon cancer patients undergoing curative surgery

This study aimed to evaluate prognostic impacts of the number of lymph nodes (LNs) examined and LN ratio on cancer-specific mortality after surgery in patients with right-sided colon cancer (RCC) or left-sided colon cancer (LCC) using the Surveillance, Epidemiology, and End Results database. Number of LNs examined and LN ratio were treated as categorical and/or continuous. Competing risks proportional hazards regressions adjusted by propensity score were performed. All included patients had stage I, II, or III disease, and 45.1% of them had RCC. RCC and LCC patients with high level of LNs examined had better prognosis after segmental resection or hemicolectomy. RCC and LCC patients with higher LN ratio had worse prognosis regardless of surgery. Survival benefit of having high level of LNs examined was observed in RCC patients with stage I, II, or III disease, but only in LCC patients with stage II disease. Both higher LN ratio and high level of LN were negative prognostic factors for cancer-specific mortality in stage III patients regardless of tumor sidedness. In conclusion, RCC patients in various conditions had worse or comparable prognosis compared to their LCC counterparts, which reflected the severity of LN metastasis.

Recursive partitioning analysis of lymph node ratio in breast cancer patients

Lymph node ratio (LNR) is a powerful prognostic factor for breast cancer. We conducted a recursive partitioning analysis (RPA) of the LNR to identify the prognostic risk groups in breast cancer patients. Records of newly diagnosed breast cancer patients between 2002 and 2006 were searched in the Taiwan Cancer Database. The end of follow-up was December 31, 2009. We excluded patients with distant metastases, inflammatory breast cancer, survival <1 month, no mastectomy, or missing lymph node status. Primary outcome was 5-year overall survival (OS). For univariate significant predictors, RPA were used to determine the risk groups. Among the 11,349 eligible patients, we identified 4 prognostic factors (including LNR) for survival, resulting in 8 terminal nodes. The LNR cutoffs were 0.038, 0.259, and 0.738, which divided LNR into 4 categories: very low (LNR ≤ 0.038), low (0.038 < LNR ≤ 0.259), moderate (0.259 < LNR ≤ 0.738), and high (0.738 < LNR). Then, 4 risk groups were determined as follows: Class 1 (very low risk, 8,265 patients), Class 2 (low risk, 1,901 patients), Class 3 (moderate risk, 274 patients), and Class 4 (high risk, 900 patients). The 5-year OS for Class 1, 2, 3, and 4 were 93.2%, 83.1%, 72.3%, and 56.9%, respectively (P< 0.001). The hazard ratio of death was 2.70, 4.52, and 8.59 (95% confidence interval 2.32-3.13, 3.49-5.86, and 7.48-9.88, respectively) times for Class 2, 3, and 4 compared with Class 1 (P < 0.001). In conclusion, we identified the optimal cutoff LNR values based on RPA and determined the related risk groups, which successfully predict 5-year OS in breast cancer patients.

Can composite performance measures predict survival of patients with colorectal cancer?

AIM: To assess the relationship between long-term colorectal patient survival and methods of calculating composite performance scores.

METHODS: The Taiwan Cancer Database was used to identify patients who underwent bowel resection for colorectal adenocarcinoma between 2003 and 2004. Patients were assigned to one of three cohorts based on tumor staging: cohort 1, colon cancer stage < III; cohort 2, colon cancer stage III; cohort 3, rectal cancer. A composite performance score (CPS) was calculated for each patient using five different aggregating methods, including all-or-none, 70% standard, equal weight, analytic hierarchy process (AHP), and principal component analysis (PCA) algorithms. The relationships between CPS and five-year overall, disease-free, and disease-specific survivals were evaluated by a Cox proportional hazards model. A goodness-of-fit analysis for all five methods was performed using Akaike’s information criterion.

RESULTS: A total of 3272 colorectal cancer patients (cohort 1, 1164; cohort 2, 790; cohort 3, 1318 patients) with a mean age of 65 years were enrolled in the study. Bivariate correlation analysis showed that CPS values from the equal weight method were highly correlated with those from the AHP method in all cohorts (all P < 0.05). Multivariate Cox hazards analysis showed that CPS values derived from equal weight and AHP methods were significantly associated with five-year survivals of patients in cohorts 1 and 2 (all P < 0.05). In these cohorts, higher CPS values suggested a higher probability of five-year survival. However, CPS values derived from the all-or-none method did not show any significant process-outcome relationship in any cohort. Goodness-of-fit analyses showed that CPS values derived from the PCA method were the best fit to the Cox proportional hazards model, whereas the values from the all-or-none model showed the poorest fit.

CONCLUSION: CPS values may highlight process-outcome relationships for patients with colorectal cancer in addition to evaluating quality of care performance.

Clinical and pathologic factors affecting lymph node yields in colorectal cancer

OBJECTIVE

Lymph node yield is recommended as a benchmark of quality care in colorectal cancer. The objective of this study was to evaluate the impact of various factors upon lymph node yield and to identify independent factors associated with lymph node harvest.

MATERIALS AND METHODS

The records of 162 patients with Stage I to Stage III colorectal cancers seen in one institution were reviewed. These patients underwent radical surgery as definitive therapy; high-risk patients then received adjuvant treatment. Pathologic and demographic data were recorded and analyzed. The subgroup analysis of lymph node yields was determined using a t-test and analysis of variants. Linear regression model and multivariable analysis were used to perform potential confounding and predicting variables.

RESULTS

Five variables had significant association with lymph node yield after adjustment for other factors in a multiple linear regression model. These variables were: tumor size, surgical method, specimen length, and individual surgeon and pathologist. The model with these five significant variables interpreted 44.4% of the variation.

CONCLUSIONS

Patients, tumor characteristics and surgical variables all influence the number of lymph nodes retrieved. Physicians are the main gatekeepers. Adequate training and optimized guidelines could greatly improve the quality of lymph node yields.

Estimating the treatment effect from non-randomized studies: The example of reduced intensity conditioning allogeneic stem cell transplantation in hematological diseases

Background

In some clinical situations, for which RCT are rare or impossible, the majority of the evidence comes from observational studies, but standard estimations could be biased because they ignore covariates that confound treatment decisions and outcomes.

Methods

Three observational studies were conducted to assess the benefit of Allo-SCT in hematological malignancies of multiple myeloma, follicular lymphoma and Hodgkin’s disease. Two statistical analyses were performed: the propensity score (PS) matching approach and the inverse probability weighting (IPW) approach.

Results

Based on PS-matched samples, a survival benefit in MM patients treated by Allo-SCT, as compared to similar non-allo treated patients, was observed with an HR of death at 0.35 (95%CI: 0.14-0.88). Similar results were observed in HD, 0.23 (0.07-0.80) but not in FL, 1.28 (0.43-3.77). Estimated benefits of Allo-SCT for the original population using IPW were erased in HR for death at 0.72 (0.37-1.39) for MM patients, 0.60 (0.19-1.89) for HD patients, and 2.02 (0.88-4.66) for FL patients.

Conclusion

Differences in estimated benefits rely on whether the underlying population to which they apply is an ideal randomized experimental population (PS) or the original population (IPW). These useful methods should be employed when assessing the effects of innovative treatment in non-randomized experiments.

Risk groups defined by Recursive Partitioning Analysis of patients with colorectal adenocarcinoma treated with colorectal resection

BACKGROUND

To define different prognostic groups of surgical colorectal adenocarcinoma patients derived from recursive partitioning analysis (RPA).

METHODS

Ten thousand four hundred ninety four patients with colorectal adenocarcinoma underwent colorectal resection from Taiwan Cancer Database during 2003 to 2005 were included in this study. Exclusion criteria included those patients with stage IV disease or without number information of lymph nodes. For the definition of risk groups, the method of classification and regression tree was performed. Main primary outcome was 5-year cancer-specific survival.

RESULTS

We identified six prognostic factors for cancer-specific survival, resulting in seven terminal nodes. Four risk groups were defined as following: Group 1 (mild risk, 1,698 patients), Group 2 (moderate risk, 3,129 patients), Group 3 (high risk, 4,605 patients) and Group 4 (very high risk, 1,062 patients). The 5-year cancer-specific survival for Group 1, 2, 3, and 4 was 86.6%, 62.7%, 55.9%, and 36.6%, respectively (p < 0.001). Hazard ratio of death was 2.13, 5.52 and 10.56 (95% confidence interval 1.74-2.60, 4.58-6.66 and 8.66-12.9, respectively) times for Group 2, 3, and 4 as compared to Group 1. The predictive capability of these grouping was also similar in terms of overall and progression-free survival.

CONCLUSION

The use of RPA offered an alternative grouping method that could predict the survival of patients who underwent surgery for colorectal adenocarcinoma.