SOURCE: A Registry-Based Prediction Model for Overall Survival in Patients with Metastatic Oesophageal or Gastric Cancer

External validation of a nomogram predicting conditional survival after tri-modality treatment of esophageal cancer

BACKGROUND

A conditional survival nomogram was developed at a single high-volume center to predict 5-year overall survival for esophageal cancer patients after neoadjuvant chemoradiation and esophagectomy. The aim of this study was to externally validate the nomogram in a cohort of patients with esophageal adeno- or squamous cell carcinoma from another high-volume center.

METHODS

Consecutive patients with an esophageal adeno- or squamous cell carcinoma who had undergone esophagectomy after being treated with preoperative chemoradiation between 2004 and 2016 were selected from a prospectively maintained institutional database. The level of discrimination for prediction of 5-year overall survival was quantified by Harrell's C statistic. Calibration of the conditional survival nomogram was visualized by plotting predicted 5-year survival and observed 5-year survival for comparison.

RESULTS

Of the 296 patients examined, the probability of 5-year overall survival directly after surgery was 45% and increased to 51%, 68%, 78%, and 89% for each additional year survived. The predicted 5-year overall survival differed from the observed survival, with a calibration slope of 0.54, 0.55, 0.59, 0.73, and 1.09 directly after surgery and 1, 2, 3, and 4 years of survival after surgery, respectively. The nomogram's discrimination level for 5-year survival was moderate, with a C statistic of 0.65 compared to the 0.70 reported in the original study.

CONCLUSION

The nomogram model has moderate predictive discrimination and accuracy, supporting its applicability to external cohorts to predict conditional survival. Further validation studies should empirically assess the model for predictive performance.

Effect of a prediction tool and communication skills training on communication of treatment outcomes: a multicenter stepped wedge clinical trial (the SOURCE trial)

Background

For cancer patients to effectively engage in decision making, they require comprehensive and understandable information regarding treatment options and their associated outcomes. We developed an online prediction tool and supporting communication skills training to assist healthcare providers (HCPs) in this complex task. This study aims to assess the impact of this combined intervention (prediction tool and training) on the communication practices of HCPs when discussing treatment options.

Methods

We conducted a multicenter intervention trial using a pragmatic stepped wedge design (NCT04232735). Standardized Patient Assessments (simulated consultations) using cases of esophageal and gastric cancer patients, were performed before and after the combined intervention (March 2020 to July 2022). Audio recordings were analyzed using an observational coding scale, rating all utterances of treatment outcome information on the primary outcome-precision of provided outcome information-and on secondary outcomes-such as: personalization, tailoring and use of visualizations. Pre vs. post measurements were compared in order to assess the effect of the intervention.

Findings

31 HCPs of 11 different centers in the Netherlands participated. The tool and training significantly affected the precision of the overall communicated treatment outcome information (p = 0.001, median difference 6.93, IQR (-0.32 to 12.44)). In the curative setting, survival information was significantly more precise after the intervention (p = 0.029). In the palliative setting, information about side effects was more precise (p < 0.001).

Interpretation

A prediction tool and communication skills training for HCPs improves the precision of treatment information on outcomes in simulated consultations. The next step is to examine the effect of such interventions on communication in clinical practice and on patient-reported outcomes.

Funding

Financial support for this study was provided entirely by a grant from the Dutch Cancer Society (UVA 2014-7000).

A nomogram for individually predicting the overall survival in colonic adenocarcinoma patients presenting with perineural invasion: a population study based on SEER database

Background

Colonic adenocarcinoma, representing the predominant histological subtype of neoplasms in the colon, is commonly denoted as colon cancer. This study endeavors to develop and validate a nomogram model designed for predicting overall survival (OS) in patients with colon cancer, specifically those presenting with perineural invasion (PNI).

Methods

The Surveillance, Epidemiology, and End Results (SEER) database supplied pertinent data spanning from 2010 to 2015, which facilitated the randomization of patients into distinct training and validation cohorts at a 7:3 ratio. Both univariate and multivariate analyses were employed to construct a prognostic nomogram based on the training cohort. Subsequently, the nomogram's accuracy and efficacy were rigorously evaluated through the application of a concordance index (C-index), calibration plots, decision curve analysis (DCA), and receiver operating characteristic (ROC) curves.

Results

In the training cohorts, multivariable analysis identified age, grade, T-stage, N-stage, M-stage, chemotherapy, tumor size, carcinoembryonic antigen (CEA), marital status, and insurance as independent risk factors for OS, all with P-values less than 0.05. Subsequently, a new nomogram was constructed. The C-index of this nomogram was 0.765 (95% CI: 0.755-0.775), outperforming the American Joint Committee on Cancer (AJCC) TNM staging system's C-index of 0.686 (95% CI: 0.674-0.698). Calibration plots for 3- and 5-year OS demonstrated good consistency, while DCA for 3- and 5-year OS revealed excellent clinical utility in the training cohorts. Comparable outcomes were observed in the validation cohorts. Furthermore, we developed a risk stratification system, which facilitated better differentiation among three risk groups (low, intermediate, and high) in terms of OS for all patients.

Conclusion

In this study, we have devised a robust nomogram and risk stratification system to accurately predict OS in colon cancer patients exhibiting PNI. This innovative tool offers valuable guidance for informed clinical decision-making, thereby enhancing patient care and management in oncology practice.

Treatment decision-making during outpatient clinic visit of patients with esophagogastric cancer. The perspectives of clinicians and patients, a mixed method, multiple case study

BACKGROUND

The probability of undergoing treatment with curative intent according to the hospital of diagnosis varies for esophagogastric cancer in the Netherlands. Little is known about the factors contributing to this variation. This study aimed to improve the understanding of the differences between the multidisciplinary team meeting treatment proposal and the treatment that was actually carried out and to qualitatively investigate the differences in treatment decision-making after the multidisciplinary team meeting treatment proposal between hospitals.

METHODS

To gain an in-depth understanding of treatment decision-making, quantitative data (i.e., multidisciplinary team meeting proposal and treatment that was carried out) were collected from the Netherlands Cancer Registry. Changes in the multidisciplinary team meeting proposal and applied treatment comprised changes in the type of treatment option (i.e., curative or palliative, or no change) and were calculated according to the multivariable multilevel probability of undergoing treatment with curative intent (low, middle, and high). Qualitative data were collected from eight hospitals, including observations of 26 outpatient clinic consultations, 30 in-depth interviews with clinicians, seven focus groups with clinicians, and three focus groups with patients. Clinicians and patients' perspectives were assessed using thematic content analysis.

RESULTS

The multidisciplinary team meeting proposal and applied treatment were concordant in 97% of the cases. Clinicians' implementation of treatment decision-making in clinical practice varied, which was mentioned by the clinicians to be due to the clinician's personality and values. Differences between clinicians consisted of discussing all treatment options versus only the best fitting treatment option and the extent of discussing the benefits and harms. Most patients aimed to undergo curative treatment regardless of the consequences, since they believed this could prolong their life.

CONCLUSION

Since changes in the multidisciplinary team meeting-proposed treatment and actual treatment were rarely observed, this study emphasizes the importance of an adequately formulated multidisciplinary team meeting proposal.

Study Protocol of a Prospective Multicenter Study on Patient Participation for the Clinical Trial: Surgery as Needed Versus Surgery on Principle in Post-Neoadjuvant Complete Tumor Response of Esophageal Cancer (ESORES)

Ideally, patient-centered trial information material encourages the discussion with the treating physician, and helps patients making trade-offs regarding treatment decisions In a situation of possible equivalent treatment options in terms of overall survival (OS), it can make it easier to weigh up advantages and disadvantages. Preferences for choice of treatment in esophageal cancer (EC) are complex, and no standardized assessment tools are available. We will explore patient’s factors for treatment choice and develop a comprehensive patient information leaflet for the inclusion into randomized controlled trials (RCT) on EC. We conduct a cross-sectional, observational study based on a mixed-methods design with patients suffering from non-metastatic EC with post-neoadjuvant complete response after neoadjuvant chemotherapy (nCT) or neoadjuvant chemoradiation (nCRT), to develop patient-centered trial information material. This pilot study is performed in a concept development phase and a subsequent pilot phase. We start with patient interviews (n = 10–15) in the concept development phase to evaluate patients’ needs, and develop a Preference and Decision Aid Questionnaire (PDAQ). We pre-test the PDAQ with another n = 10 patients with EC after nCT or nCRT, former patients from a self-help organization, and n = 10 medical experts for their comments on the questionnaire. In the pilot phase, a multicenter trial using the PDAQ and additional measures is carried out (n = 120). Based on evidence of a possible equivalence in terms of OS of the treatment options “surgery as needed” and “surgery on principle” in patients with post-neoadjuvant complete response of EC, this pilot study on patient participation is conducted to assess patient’s needs and preferences, and optimize patients’ inclusion in a planned RCT. The aim is to develop patient-centered trial information material for the RCT to increase patients’ consent and compliance with the randomized treatment. The trial is registered at the German Clinical Trials Register (DRKS00022050, October 15, 2020).

Novel approaches in cancer treatment: preclinical and clinical development of small non-coding RNA therapeutics

Short or small interfering RNAs (siRNAs) and microRNA (miRNAs) are molecules similar in size and function able to inhibit gene expression based on their complementarity with mRNA sequences, inducing the degradation of the transcript or the inhibition of their translation.

siRNAs bind specifically to a single gene location by sequence complementarity and regulate gene expression by specifically targeting transcription units via posttranscriptional gene silencing. miRNAs can regulate the expression of different gene targets through their imperfect base pairing.

This process - known as RNA interference (RNAi) - modulates transcription in order to maintain a correct physiological environment, playing a role in almost the totality of the cellular pathways.

siRNAs have been evolutionary evolved for the protection of genome integrity in response to exogenous and invasive nucleic acids such as transgenes or transposons. Artificial siRNAs are widely used in molecular biology for transient silencing of genes of interest. This strategy allows to inhibit the expression of any target protein of known sequence and is currently used for the treatment of different human diseases including cancer.

Modifications and rearrangements in gene regions encoding for miRNAs have been found in cancer cells, and specific miRNA expression profiles characterize the developmental lineage and the differentiation state of the tumor. miRNAs with different expression patterns in tumors have been reported as oncogenes (oncomirs) or tumor-suppressors (anti-oncomirs). RNA modulation has become important in cancer research not only for development of early and easy diagnosis tools but also as a promising novel therapeutic approach.

Despite the emerging discoveries supporting the role of miRNAs in carcinogenesis and their and siRNAs possible use in therapy, a series of concerns regarding their development, delivery and side effects have arisen.

In this review we report the biology of miRNAs and siRNAs in relation to cancer summarizing the recent methods described to use them as novel therapeutic drugs and methods to specifically deliver them to cancer cells and overcome the limitations in the use of these molecules.

Informing Patients With Esophagogastric Cancer About Treatment Outcomes by Using a Web-Based Tool and Training: Development and Evaluation Study

Background

Due to the increasing use of shared decision-making, patients with esophagogastric cancer play an increasingly important role in the decision-making process. To be able to make well-informed decisions, patients need to be adequately informed about treatment options and their outcomes, namely survival, side effects or complications, and health-related quality of life. Web-based tools and training programs can aid physicians in this complex task. However, to date, none of these instruments are available for use in informing patients with esophagogastric cancer about treatment outcomes.

Objective

This study aims to develop and evaluate the feasibility of using a web-based prediction tool and supporting communication skills training to improve how physicians inform patients with esophagogastric cancer about treatment outcomes. By improving the provision of treatment outcome information, we aim to stimulate the use of information that is evidence-based, precise, and personalized to patient and tumor characteristics and is communicated in a way that is tailored to individual information needs.

Methods

We designed a web-based, physician-assisted prediction tool—Source—to be used during consultations by using an iterative, user-centered approach. The accompanying communication skills training was developed based on specific learning objectives, literature, and expert opinions. The Source tool was tested in several rounds—a face-to-face focus group with 6 patients and survivors, semistructured interviews with 5 patients, think-aloud sessions with 3 medical oncologists, and interviews with 6 field experts. In a final pilot study, the Source tool and training were tested as a combined intervention by 5 medical oncology fellows and 3 esophagogastric outpatients.

Results

The Source tool contains personalized prediction models and data from meta-analyses regarding survival, treatment side effects and complications, and health-related quality of life. The treatment outcomes were visualized in a patient-friendly manner by using pictographs and bar and line graphs. The communication skills training consisted of blended learning for clinicians comprising e-learning and 2 face-to-face sessions. Adjustments to improve both training and the Source tool were made according to feedback from all testing rounds.

Conclusions

The Source tool and training could play an important role in informing patients with esophagogastric cancer about treatment outcomes in an evidence-based, precise, personalized, and tailored manner. The preliminary evaluation results are promising and provide valuable input for the further development and testing of both elements. However, the remaining uncertainty about treatment outcomes in patients and established habits in doctors, in addition to the varying trust in the prediction models, might influence the effectiveness of the tool and training in daily practice. We are currently conducting a multicenter clinical trial to investigate the impact that the combined tool and training have on the provision of information in the context of treatment decision-making.

The association between effectiveness of first-line treatment and second-line treatment in gastro-oesophageal cancer

BACKGROUND

Population-based predictive factors for the effectiveness of second-line palliative systemic therapy in gastro-oesophageal cancer are not available. This study investigates the predictive value of effectiveness of first-line treatment for second-line treatment outcomes in gastro-oesophageal cancer in a real-world setting.

METHODS

Patients with metastatic gastro-oesophageal cancer diagnosed in 2010-2017 who were treated with second-line therapy after disease progression on first-line therapy were identified from the Netherlands Cancer Registry. Patients were divided into four groups as per duration of time to treatment failure (TTF) of the first line (0-3, 3-6, 6-9 and >9 months), and the association with overall survival (OS) and second-line TTF was assessed using Kaplan-Meier curves and two-sided multivariable regression models.

RESULTS

Median OS since the start of the second line of patients (n = 611) with first-line TTF of 0-3, 3-6, 6-9 and >9 months was 4.0, 4.1, 5.5 and 7.1 months, respectively (P < 0.001). Median second-line TTF of patients with first-line TTF of 0-3, 3-6, 6-9 and >9 months was 2.8, 2.4, 3.0 and 4.5 months, respectively (P < 0.001). Patients with first-line TTF of >9 months showed a longer OS than patients with first-line TTF of 0-3 months (adjusted hazard ratio (HR) 1.90; 95% confidence interval (CI) 1.46-2.47), 3-6 months (adjusted HR 1.88; 95% CI 1.47-2.39) and 6-9 months (adjusted HR 1.31; 95% CI 1.04-1.65). Results for second-line TTF were similar.

CONCLUSIONS

This study shows a positive correlation between effectiveness of first-line therapy and outcomes of second-line therapy in gastro-oesophageal cancer. Physicians should take duration of the first line into account when considering second-line palliative systemic therapy.

SOURCE-PANC: A Prediction Model for Patients With Metastatic Pancreatic Ductal Adenocarcinoma Based on Nationwide Population-Based Data

BACKGROUND

A prediction model for overall survival (OS) in metastatic pancreatic ductal adenocarcinoma (PDAC) including patient and treatment characteristics is currently not available, but it could be valuable for supporting clinicians in patient communication about expectations and prognosis. We aimed to develop a prediction model for OS in metastatic PDAC, called SOURCE-PANC, based on nationwide population-based data.

MATERIALS AND METHODS

Data on patients diagnosed with synchronous metastatic PDAC in 2015 through 2018 were retrieved from the Netherlands Cancer Registry. A multivariate Cox regression model was created to predict OS for various treatment strategies. Available patient, tumor, and treatment characteristics were used to compose the model. Treatment strategies were categorized as systemic treatment (subdivided into FOLFIRINOX, gemcitabine/nab-paclitaxel, and gemcitabine monotherapy), biliary drainage, and best supportive care only. Validation was performed according to a temporal internal-external cross-validation scheme. The predictive quality was assessed with the C-index and calibration.

RESULTS

Data for 4,739 patients were included in the model. Sixteen predictors were included: age, sex, performance status, laboratory values (albumin, bilirubin, CA19-9, lactate dehydrogenase), clinical tumor and nodal stage, tumor sublocation, presence of distant lymph node metastases, liver or peritoneal metastases, number of metastatic sites, and treatment strategy. The model demonstrated a C-index of 0.72 in the internal-external cross-validation and showed good calibration, with the intercept and slope 95% confidence intervals including the ideal values of 0 and 1, respectively.

CONCLUSIONS

A population-based prediction model for OS was developed for patients with metastatic PDAC and showed good performance. The predictors that were included in the model comprised both baseline patient and tumor characteristics and type of treatment. SOURCE-PANC will be incorporated in an electronic decision support tool to support shared decision-making in clinical practice.

Long-Term Quality of Life Following Transthoracic and Transhiatal Esophagectomy for Esophageal Cancer

BACKGROUND

The impact of transthoracic (TTE) and transhiatal esophagectomy (THE) on long-term health-related quality of life (HR-QoL) in patients with distal esophageal or gastro-esophageal junction (GEJ) cancer has been studied with variable results. This study investigates long-term HR-QoL in patients having undergone TTE or THE.

METHODS

Disease-free patients after TTE or THE for distal esophageal or GEJ cancer with a follow-up > 2 years were included. Patients who visited the outpatient clinic of a tertiary referral center between 2014 and 2018 were asked to complete EORTC-QLQ-C30 and EORTC-QLQ-OG25 questionnaires. Uni- and multivariable linear regression analysis of HR-QoL was performed in all patients and in subgroups of minimally invasive esophagectomy and neoadjuvant therapy.

RESULTS

A total of 132 patients after TTE and 56 after THE were included. When compared with the general population, all patients reported worse HR-QoL in 'role functioning' and 'social functioning' and in a range of disease- and/or treatment-specific symptoms. The only significant difference between TTE and THE was a better HR-QoL score for "hair loss" following TTE (ß = 29.4,95%CI = -49.108 - -9.671, p = 0.016). Subgroup analysis of minimally invasively operated patients showed better scores in "physical functioning" following TTE (ß = 13.8,95%CI = 2.755-24.933, p = 0.030). No significant differences in HR-QoL were found between TTE and THE after neoadjuvant therapy.

CONCLUSION

Long-term HR-QoL is largely comparable in disease-free patients following TTE or THE for distal esophageal or GEJ cancer. If there were differences between the surgical groups, they were in favor of TTE. These findings may aid in preoperative counseling of patients with esophageal or GEJ cancer.

Low-Dose Versus High-Dose Radiation Therapy for the Palliation of Dysphagia From Esophageal Cancer: A Multicenter Retrospective Cohort Study

PURPOSE

Clinical evidence regarding optimal radiation dose for palliation of dysphagia from esophageal cancer is generally lacking. In an effort to investigate optimal radiation dose, we assessed 2 different radiation schedules for palliation of dysphagia.

METHODS AND MATERIALS

We performed a multicenter, retrospective study comparing low-dose radiation therapy (LR: 5 x 4 Gy external beam radiation therapy [EBRT]) with high-dose radiation therapy (HR: 10 x 3 Gy EBRT and 12-Gy single-dose intraluminal brachytherapy) for palliation of dysphagia in patients with inoperable or metastasized esophageal cancer. Primary outcome was improvement of dysphagia at 6 weeks after start of radiation therapy. Additional outcomes were persistent and recurrent dysphagia during patients' remaining life, severe adverse events, and survival.

RESULTS

In total, 292 patients (LR, n = 117; HR, n = 175) were included in this study. After matching, 144 patients (72 in each group) were compared. Improvement of dysphagia at 6 weeks was achieved in 50% of patients after LR and in 66% after HR (P = .071). Persistent or recurrent dysphagia occurred in 64% of patients after LR and in 42% after HR (P = .012). No difference in the rate of severe adverse events was found (P = .889). Median survival was 88 days (95% confidence interval, 64-112) after LR and 177 days (95% confidence interval, 131-223) after HR (P < .001).

CONCLUSIONS

This study shows that both LR and HR were well tolerated and effective in short-term relief of dysphagia in patients with inoperable or metastasized esophageal cancer. HR was associated with better long-term relief of dysphagia compared with LR. Our findings suggest that HR could be considered for patients with a longer life expectancy, but prospective studies are required.

Nomogram-based prediction of survival in unresectable or metastatic gastric cancer patients with good performance status who received first-line chemotherapy

Background

Good performance status (PS) is widely acknowledged to have a high prognostic ability, although the prognostic parameters of cancer patients with good PS are still uncertain. This study was conducted to establish and validate a point-based nomogram to assist with predicting prognosis in unresectable or metastatic gastric cancer (GC) patients who had good PS and underwent first-line chemotherapy.

Methods

At random, a total of 309 patients with GC were split into 2 cohorts: a training cohort (n=259) and an internal validation cohort (n=50). An independent external validation cohort comprising 147 patients was also recruited. Both univariate and multivariate Cox regression analyses were used to evaluate patients based on the overall survival (OS) to develop the nomogram, which was subsequently validated using the concordance index (c-index), calibration curve, and decision curve analysis (DCA).

Results

The nomogram contained 3 independent prognostic variables in the training cohort: the number of distant metastatic sites (P<0.001), carbohydrate antigen 199 (CA199) level (P=0.002), and fibrinogen (P=0.020). The nomogram predicted an OS with a c-index of 0.623 (95% CI, 0.58–0.67) in the training cohort. The internal validation showed that the nomogram had a c-index of 0.614 (95% CI, 0.51–0.72). For external validation, the c-index was 0.638 (95% CI, 0.58–0.70).

Conclusions

A reliable point-based nomogram for predicting the prognosis of patients who had unresectable or metastatic GC and good PS who underwent first-line chemotherapy was developed and validated.

Keywords

Nomogram-based prediction; overall survival; unresectable gastric cancer; metastatic gastric cancer; good performance status; first-line chemotherapy

Impact of multidisciplinary tumor board discussion on palliation of patients with esophageal or gastro-esophageal junction cancer: a population-based study

Background: The Dutch guidelines for esophageal and gastro-esophageal junction (GEJ) cancer recommend discussion of patients by a multidisciplinary tumor board (MDT). Despite this recommendation, one previous study in the Netherlands suggested that therapeutic guidance was missing for palliative care of patients with esophageal cancer. The aim of the current study was therefore to assess the impact of an MDT discussion on initial palliative treatment and outcome of patients with esophageal or GEJ cancer.Material and methods: The population-based Netherlands Cancer Registry was used to identify patients treated for esophageal or GEJ cancer with palliative intent between 2010 and 2017 in 7 hospitals. We compared patients discussed by the MDT with patients not discussed by the MDT in a multivariate analysis. Primary outcome was type of initial palliative treatment. Secondary outcome was overall survival.Results: A total of 389/948 (41%) patients with esophageal or GEJ cancer were discussed by the MDT before initial palliative treatment. MDT discussion compared to non-MDT discussion was associated with more patients treated with palliative intent external beam radiotherapy (38% vs. 21%, OR 2.7 [95% CI 1.8-3.9]) and systemic therapy (30% vs. 23%, OR 1.6 [95% CI 1.0-2.5]), and fewer patients treated with stent placement (4% vs. 12%, OR 0.3 [95% CI 0.1-0.6]) and best supportive care alone (12% vs. 33%, OR 0.2 [95% CI 0.1-0.3]). MDT discussion was also associated with improved survival (169 days vs. 107 days, HR 1.3 [95% CI 1.1-1.6]).Conclusion: Our study shows that MDT discussion of patients with esophageal or GEJ cancer resulted in more patients treated with initial palliative radiotherapy and chemotherapy compared with patients not discussed by the MDT. Moreover, MDT discussion may have a positive effect on survival, highlighting the importance of MDT meetings at all stages of treatment.

External Validation of the Dutch SOURCE Survival Prediction Model in Belgian Metastatic Oesophageal and Gastric Cancer Patients

The SOURCE prediction model predicts individualised survival conditional on various treatments for patients with metastatic oesophageal or gastric cancer. The aim of this study was to validate SOURCE in an external cohort from the Belgian Cancer Registry. Data of Belgian patients diagnosed with metastatic disease between 2004 and 2014 were extracted (n = 4097). Model calibration and discrimination (c-indices) were determined. A total of 2514 patients with oesophageal cancer and 1583 patients with gastric cancer with a median survival of 7.7 and 5.4 months, respectively, were included. The oesophageal cancer model showed poor calibration (intercept: 0.30, slope: 0.42) with an absolute mean prediction error of 14.6%. The mean difference between predicted and observed survival was −2.6%. The concordance index (c-index) of the oesophageal model was 0.64. The gastric cancer model showed good calibration (intercept: 0.02, slope: 0.91) with an absolute mean prediction error of 2.5%. The mean difference between predicted and observed survival was 2.0%. The c-index of the gastric cancer model was 0.66. The SOURCE gastric cancer model was well calibrated and had a similar performance in the Belgian cohort compared with the Dutch internal validation. However, the oesophageal cancer model had not. Our findings underscore the importance of evaluating the performance of prediction models in other populations.

Conditional survival after neoadjuvant chemoradiotherapy and surgery for oesophageal cancer

Background

Conditional survival accounts for the time already survived after surgery and may be of additional informative value. The aim was to assess conditional survival in patients with oesophageal cancer and to create a nomogram predicting the conditional probability of survival after oesophagectomy.

Methods

This retrospective study included consecutive patients with oesophageal cancer who received neoadjuvant chemoradiation followed by oesophagectomy between January 2004 and 2019. Conditional survival was defined as the probability of surviving y years after already surviving for x years. The formula used for conditional survival (CS) was: CS_(x|y) = S_(x + y)/S_(x), where S_(x) represents overall survival at x years. Cox proportional hazards models were used to evaluate predictors of overall survival. A nomogram was constructed to predict 5‐year survival directly after surgery and given survival for 1, 2, 3 and 4 years after surgery.

Results

Some 660 patients were included. Median overall survival was 44·4 (95 per cent c.i. 37·0 to 51·8) months. The probability of achieving 5‐year overall survival after resection increased from 45 per cent directly after surgery to 54, 65, 79 and 88 per cent given 1, 2, 3 and 4 years already survived respectively. Cardiac co‐morbidity, cN category, ypT category, ypN category, chyle leakage and pulmonary complications were independent predictors of survival. The nomogram predicted 5‐year survival using these predictors and number of years already survived.

Conclusion

The probability of achieving 5‐year overall survival after oesophagectomy for cancer increases with each additional year survived. The proposed nomogram predicts survival in patients after oesophagectomy, taking the years already survived into account.

Treatment strategies for metastatic gastric cancer: chemotherapy, palliative surgery or radiotherapy?

Aim: This study explored whether chemotherapy combined with palliative surgery and/or radiotherapy is a possible treatment for metastatic gastric cancer. Materials & methods: Patients were divided into groups according to treatments. COX models were used to explore prognostic factors. Kaplan-Meier models and log-rank tests were used to analyze outcomes. Outcomes were analyzed before and after propensity score matching. Results: Chemotherapy combined with gastrectomy or metastasectomy prolongs the survival time compared with chemotherapy alone (p < 0.05). Chemotherapy combined with gastrectomy plus metastasectomy and/or radiation therapy also prolongs the survival time (p < 0.05). Conclusion: Chemotherapy combined with gastrectomy could be a more effective treatment for metastatic gastric cancer. Chemotherapy combined with gastrectomy plus metastasectomy and/or radiation therapy could also be a promising treatment.

The Use of (Network) Meta-Analysis in Clinical Oncology

Meta-analysis is important in oncological research to provide a more reliable answer to a clinical research question that was assessed in multiple studies but with inconsistent results. Pair-wise meta-analysis can be applied when comparing two treatments at once, whereas it is possible to compare multiple treatments at once with network meta-analysis (NMA). After careful systematic review of the literature and quality assessment of the identified studies, there are several assumptions in the use of meta-analysis. First, the added value of meta-analysis should be evaluated by examining the comparability of study populations. Second, the appropriate comparator in meta-analysis should be chosen according to the types of comparisons made in individual studies: (1) Experimental and comparator arms are different treatments (A vs. B); (2) Substitution of a conventional treatment by an experimental treatment (A+B vs. A+C); or (3) Addition of an experimental treatment (A+B vs. B). Ideally there is one common comparator treatment, but when there are multiple common comparators, the most efficacious comparator is preferable. Third, treatments can only be adequately pooled in meta-analysis or merged into one treatment node in NMA when considering likewise mechanism of action and similar setting in which treatment is indicated. Fourth, for both pair-wise meta-analysis and NMA, adequate assessment of heterogeneity should be performed and sub-analysis and sensitivity analysis can be applied to objectify a possible confounding factor. Network inconsistency, as statistical manifestation of violating the transitivity assumption, can best be evaluated by node-split modeling. NMA has advantages over pair-wise meta-analysis, such as clarification of inconsistent outcomes from multiple studies including multiple common comparators and indirect effect calculation of missing direct comparisons between important treatments. Also, NMA can provide increased statistical power and cross-validation of the observed treatment effect of weak connections with reasonable network connectivity and sufficient sample-sizes. However, inappropriate use of NMA can cause misleading results, and may emerge when there is low network connectivity, and therefore low statistical power. Furthermore, indirect evidence is still observational and should be interpreted with caution. NMA should therefore preferably be conducted and interpreted by both expert clinicians in the field and an experienced statistician. Finally, the use of meta-analysis can be extended to other areas, for example the identification of prognostic and predictive factors. Also, the integration of evidence from both meta-analysis and expert opinion can improve the construction of prognostic models in real-world databases.