ORIGINAL PAPERS

 

Management and outcomes in digestive cancer surgery: design and initial results of a multicenter cohort study

Proceso asistencial y resultados en la cirugía de cáncer digestivo: diseño y resultados iniciales de un estudio de cohortes multicéntrico

 

 

M. Espallargues^1,2, C. Almazán^1,2, C. Tebé^1,2, R. Pla³, J. M. V. Pons^1,2, E. Sánchez^1,2, M. Mias^1,2, S. Alomar¹ and J. M. Borràs⁴, on behalf of the ONCOrisc* Study Group

¹Catalan Agency for Health Technology Assessment and Research (CAHTA). Barcelona.
²CIBER Epidemiología y Salud Pública (CIBERESP). Spain.
³Bellvitge University Hospital. Hospitalet de Llobregat, Barcelona. Spain.
⁴Master Plan in Oncology. Catalan Institute of Oncology. Barcelona, Spain

This study has been partially funded by the Carlos III Health Institute by means of the Programme for Promotion of Biomedical and Health Sciences Research, which offers funding for research projects (03/1641) and for the performance of research studies on health technology assessment (05/90185). We would also like to thank the Cooperative Cancer Research Network (RD06/0020/0089). The Generalitat of Catalonia has recognized the Agency for Health Technology Assessment and Research as a research group in Assessment of Health services and Outcomes (2009SGR 1317).

*At the end of the article the members of the ONCOrisc study group (Assessment of the therapeutic procedure and its outcomes in digestive oncology) are listed.

Correspondence

 

 

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ABSTRACT

Background: most studies that analyze the influence of structure factors on clinical outcomes are retrospective, based on clinical-administrative databases, and mainly focusing on surgical volume.
Objective: to study variations in the process and outcomes of oncologic surgery for esophagus, stomach, pancreas, liver metastases and rectum cancers in Catalonia, as well as the factors associated with these variations.
Patients and method: a retrospective (2002) and prospective (2003-05) multicenter cohort study. Data forms were designed to collect patient, process, and care outcome characteristics before surgery, at hospital discharge, and at 3 and 6 months after discharge. Main outcome measures were hospital and follow-up mortality, complications, re-interventions, and relapse rates.
Results: 49 hospitals (80%) participated in the retrospective phase, 44 of which (90%) also participated in the prospective phase: 3,038 patients (98%) were included. No differences were observed in the profile of operated patients according to hospital level of complexity, but clinical-pathological staging and other functional status variables could not be assessed because of over 20% of missing values. There was significant variability in the volume of interventions as well as in certain aspects of the healthcare process depending on type of cancer and center complexity. High rates of esophageal cancer mortality (18.2% at discharge, 27.3% at 6 months) and of complications and re-interventions for all cancers assessed, especially rectal cancer (18.4% re-interventions at 6 months), were identified.
Conclusions: the study of the variability identified will require adequate risk-adjustment and should take into account different structure factors. It is necessary that information included in medical records be improved.

Key words: Digestive cancer. Surgery. Medical practice variations. Structure, process, and outcomes of care.

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RESUMEN

Antecedentes: la mayoría de estudios que analizan la influencia de factores de estructura sobre los resultados son retrospectivos, realizados con bases de datos clínico-administrativas y basados principalmente en el volumen de intervenciones.
Objetivo: estudiar la variabilidad en el proceso y los resultados de la cirugía oncológica de esófago, estómago, páncreas, metástasis hepáticas y recto en Cataluña, así como los factores asociados a esta.
Pacientes y método: estudio de cohortes multicéntrico retrospectivo (2002) y prospectivo (2003-05). Se recogió información sobre el paciente, el proceso y los resultados de la atención previamente a la cirugía, al alta, y a los 3 y 6 meses.
Resultados: participaron 49 (80%) hospitales en la etapa retrospectiva, de los cuales 44 (90%) prosiguieron en la prospectiva. Se incluyeron 3.038 pacientes (98%). No se observaron diferencias en el perfil de pacientes operados según el nivel de complejidad del hospital pero no se pudo analizar el estadiaje clínico-patológico y otras variables de estado funcional por presentar más del 20% de valores ausentes. Existió una variabilidad importante en el volumen de intervenciones por centro así como en algunos aspectos del proceso asistencial según el tipo de cáncer y la complejidad del centro. Se identificaron elevadas tasas de mortalidad en esófago (18,2% al alta, 27,3% a los 6 meses) y de complicaciones y reintervenciones en todos los cánceres evaluados, especialmente en cáncer de recto (18,4% de reintervenciones a los 6 meses).
Conclusiones: el estudio de la variabilidad identificada requerirá un adecuado ajuste del riesgo y debería tener en cuenta diferentes factores de estructura. Es necesario mejorar la información recogida en la historia clínica.

Palabras clave: Cáncer digestivo. Cirugía. Variaciones de la práctica médica. Estructura, proceso y resultados de la atención.

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Introduction

One of the aspects that is most debated in oncologic surgery and other fields (both surgical and medical procedures) is the relationship between the volume of patients having undergone surgery and clinical outcomes. It has been 30 years since the relationship between increased volume and improved outcomes was described (1). However, this relationship is not always observed, and the reasons why it occurs remain unknown. Several hypotheses, especially relating to surgeon-related technical factors (2-6), have been considered. However, if better outcomes are obtained in several different procedures or pathologies, healthcare organization and coordination factors should also be sought. This may be especially useful in the case of oncology, where it is necessary for professionals from different specialties to work together in tackling with diagnosis and treatment: surgery, oncology, as well as the site's central and general services.

Most studies that have analyzed the influence of these physician-/center-related factors, particularly volume, on the variability of the process and outcome of cancer surgery are retrospective (7) and based on clinical-administrative databases (8). This explains why the most frequently examined outcome is hospital mortality, why there is no adjustment for significant clinical variables (such as severity and length of disease, comorbidities and their treatment, or functional status), and why very short-term follow-ups are performed. This fact could explain the differences observed in some prospective studies with primary data (which enable the inclusion of a greater number of variables and have follow-ups which extend beyond the hospital period), in which the relationship between volume and outcomes is less consistent (8,9).

Studies do not usually take into account other center-related factors that may influence outcomes, such as structure-related characteristics and process-related factors, as was suggested by A. Donabedian's approach for the assessment of health care quality (10,11) (Fig. 1).

A multicenter cohort study, based on the "structure, process and outcomes" paradigm described, and overcoming the previous limitation, was presented with the aim of studying variations in the process and outcomes of oncologic digestive surgery in Catalonia. This manuscript describes the methodology employed, and the main results obtained are described.

 

Material and methods

An observational study with retrospective and prospective follow-up of a cohort of patients who had undergone oncologic surgery for esophageal, pancreatic, rectal cancers, and liver metastases. All general surgery services at both public (n = 51) and private (n = 10) hospitals in Catalonia performing this type of procedure were invited to participate. The retrospective phase included all patients operated in 2002 who had undergone one of the surgical procedures described in the Annex (in any of the 4 procedure variables of the Hospital Discharge Minimum Basic Data Set -HDMBD).

In the prospective phase, patients who had undergone cancer surgery with the previous procedures were consecutively included for a period of 6 months (between November 2003 and July 2005). In both phases, patients who underwent re-intervention or procedures in two stages (with the first intervention taking place prior to the study period) were excluded. It was estimated that the inclusion of 2,500 patients with an expected overall mortality of about 15% at 6 months after surgery (8) would enable to establish the potential prognostic or predictive role of approximately 30 independent variables in a step-by-step logistic regression analysis, hence creating a risk adjustment model (12) for mortality (primary outcome variable).

In the retrospective phase the main source of information was the medical record. In the prospective phase, data were obtained directly from the surgeon as much as possible, and also from the medical record. Assessments were performed in the pre-operative period, at discharge, and at 3 and 6 months. These assessments were carried out by healthcare professionals (mainly specialized surgeons or surgeons in training) specifically trained to this end.

Specific data collection forms were designed for each assessment period, and were accompanied by an instructional manual and operative definitions to standardize data collection. The pre-operative data collection form included data on administrative and demographic information, staging, diagnostic tests, complementary tests, blood tests, pathological medical history and treatment, neoadjuvant radiation therapy and chemotherapy (primary), functional status - using Karnofsky's Performance Score (13) and the Glasgow Coma (14-15) scales - and surgical-anesthetic risk - ASA scale - American Society of Anesthesiology (16). The data collection form at hospital discharge gathered data on surgical procedure (prophylaxis, tumor location, surgical technique - access route, resection, lymphadenectomy, reconstruction, anastomosis -, residual tumor, red blood cell and plasma bags, and length of surgery), intra- and postoperative complications (general, local, pertaining to the surgical technique, re-intervention and death), and administrative data. In the data collection forms at 3 and 6 months follow-up information was obtained on complications, relapses, re-admittances, pathology, adjuvant radiation therapy and chemotherapy (postoperative), and functional status (Karnofsky scale only at 6 months). Pilot tests were performed in each study phase to test data collection forms and to identify problems in communication circuits, data collection, and coordination tasks between centers and research team.

An internal validation of the quality and consistency of the information introduced into the database was performed using the Cardiff™TeleForm^® system.

 

Analysis

An analysis of participation was carried out. The main demographic, clinical and process and outcome characteristics of the patients included were described and compared by type of cancer and by level of center complexity (regional, reference, high technology, and private). In order to study the association between risk, process, and outcome variables, a Chi² test was applied for categorical variables and Student's t-test or Mann-Whitney's U (taking into account variable distribution) for continuous variables. A survival analysis was also conducted using the time elapsed from admission until 6 months on follow-up, loss to follow-up, or patient death. Results were stratified by type of cancer, and arbitrarily used a 5% level of significance. Data management and statistical analyses were carried out using the SPSS v.13 and STATA v.9.

The identity of participants (patients, surgeons, and centers) was kept strictly confidential. The study protocol was assessed and approved by one of the Ethics Committees of Clinical Research of the participating centers.

 

Results

Participation

Out of the 61 centers that in 2002 had performed a surgical procedure of interest to this study, 49 (80%) agreed to participate (45 public centers and 4 private ones). Out of these, the vast majority (90%) continued to participate in the prospective phase of the study. Overall, participating hospitals managed 94% of patients of interest throughout Catalonia, and the participation of private hospitals was significantly lesser than that of public hospitals (40 versus 88%). Figure 2 shows the diagram for individual participation by phases.

Patient characteristics

The most frequent procedures were for rectal cancer (55.6%), followed by stomach (26.6%), liver metastases (7.5%), pancreatic (7.0%), and esophageal (3.3%) cancer. The volume of procedures in each center by type of cancer and level of complexity (Fig. 3) showed high variability. Centralization for esophageal, pancreatic, and liver metastases was observed, as procedures for these types of cancer were performed almost exclusively in reference and high-technology hospitals. Larger volume was also associated with higher center complexity, mainly for stomach and rectum cancers.

Table I shows the main demographic and clinical characteristics of patients included in this study. Even though no differences were observed in the profile of patients by level of center complexity, for rectal cancer it was detected that higher complexity (in public hospitals) was associated with a higher surgical risk for patients (p < 0.001).

In 65.1% of cases an assessment of clinical TNM staging could not be found in the medical record. pT and pN were not identified either for 20.6% of cases (alive at discharge). Other variables that were also excluded from the analysis due to a high percentage (> 20%) of missing values were functional status assessment, height, urea, and classification of residual tumor.

Characteristics of the healthcare process

The diagnostic tests applied, as well as the use of neoadjuvant and adjuvant radiation therapy and/or chemotherapy, depended mainly on the type of cancer (Table II), and variations resulting from center complexity were observed in only some of them. In rectal cancer, the use of diagnostic tests was different in regional hospitals (decreased use of computerized tomography and increased use of abdominal ultrasounds (p < 0.001) and in private hospitals (decreased use of colonoscopy, p < 0.001), in comparison with the rest. Similarly, in stomach cancer regional hospitals made more use of abdominal ultrasounds (p < 0.001) and private hospitals used less computerized tomography and esophagogastroscopy (p < 0.001). In rectal cancer and liver metastases variability was observed in primary treatments, the application of which was more frequent in centers with a higher level of complexity and less frequent in private hospitals (p < 0.001).

In terms of surgical technique, private centers primarily applied anterior resection with anastomosis in rectal cancer (73%, p = 0.001), and partial gastrectomies in stomach cancer (88%, p < 0.05). The latter technique was also more frequent in less complex public hospitals (p = 0.07). For esophageal cancer, thoracoabdominal esophagectomy was more frequent in high-technology centers and cervicoabdominal esophagectomy was more frequent in reference centers (p < 0.001). Mean hospital stay ranged from 10 to 23 days, length being shorter for stomach and rectal cancer as well as for liver metastases (p < 0.001).

Outcomes of care

The most frequent complications during hospital stay were systemic or general complications given that they presented in over 40% of cases - especially renal complications (16.5%), except for esophageal cancer, in which most frequent complications were pulmonary complications (45.5%)-. Complications until discharge resulting from surgical technique and surgical wounds (local) developed in 24.0% and 18.1% of patients, respectively (Fig. 4A). Differences were observed depending on hospital complexity level, with the % of general complications (p < 0.0001) and wound-related complications (p = 0.001) being lower in high-technology centers (in private hospitals, only in the case of general complications) when compared to others.

Relapses at 3 (5.6%) and 6 months (11.2%) varied depending on type of cancer (Fig. 4B). The frequency of re-interventions until discharge (9.9%) and at 6 months (17.8%) also varied in terms of type of cancer (Fig. 4C). Repeat procedures in rectal cancer were more frequent in centers with higher complexity, and reached the highest rate in private hospitals, both at 3 and 6 months (20.7% and 30.2%, respectively, p < 0.01).

Gross (non-adjusted) intrahospital surgical mortality ranged from 2.6% for liver metastases to 18.2% for esophageal cancer, approximately doubling that of almost all types of cancer at 6 months (Fig. 4D). Only in the case of stomach cancer did the center's complexity level appear to be associated with mortality at 6 months after adjusting for patient age and ASA (p < 0.01), with high-technology hospitals exhibiting the best results.

 

Discussion

This study has attempted to describe the profile of patients who have undergone surgery for digestive cancer, their healthcare process and short-mid-term outcomes, in many hospitals that perform this type of surgery in Catalonia. Only procedures with a significant impact on quality of life and which are considered tertiary (presenting high technological complexity and a large number of requirements relating to structural resources or level of expertise in professionals) have been included. Overall, no differences were observed in terms of the characteristics of operated patients by center complexity level, but clinical-pathological staging and other functional status variables could not be analyzed due to a high percentage of missing values. Healthcare process characteristics and outcomes were, generally speaking, as expected, except for the high mortality at discharge and at 6 months' follow-up in esophageal cancer, and for the frequency of complications and re-interventions in the different types of surgery assessed.

These results differ from other published results - both in Spain and in other developed countries (8,17-29) - and can be explained, only in part, by the inclusion of palliative and emergency procedures (also by the sealing of colostomy in patients who have undergone a procedure using the Hartmann technique in rectal cancer), even though the differences in characteristics of the series included should also be taken into account (30). The high relapse rate at 6 months' follow-up occurred especially in palliative surgery cases, and the possibility that they could really be a progression of the disease could not be ruled out. However, some of these results do not reach the standards proposed in our setting (31).

The variability identified in some aspects of the process did not translate into different outcomes according to hospital complexity, except in the case of rectal cancer, for re-interventions, and in stomach cancer, for mortality. However, clear practice patterns or styles during the healthcare process that explain this phenomenon have not been identified. In both types of cancer the performance of diagnostic tests showed a similar pattern, with a tendency to performing fewer tests in private hospitals and using less complex tests (abdominal ultrasounds) in regional hospitals. A similar behavior was also observed in these types of cancer in terms of the radicality of the surgical technique and center complexity: fewer total gastrectomies and fewer resections with colostomy in private centers when compared to public hospitals, and, within these, in those presenting lesser complexity (only for stomach cancer).

Furthermore, in rectal cancer, as the number of procedures per center increased, the variability in the percentage of sphincter preserving surgery (without colostomy) decreased, as was expected, and leaned towards 70% of cases (except in one center) (17,21-23). However, this pattern was not observed for stomach cancer, where variability in radicality was significant for any volume of procedures, even in centers with a larger volume (25 to 68% of total gastrectomies). In other less frequent types of cancer, despite the existence of variability in the process and outcomes by level of center complexity, no statistically significant differences were observed, probably due to the limited statistical power of the analyses.

However, there was high variability in the volume of procedures performed in each center for all types of cancer, especially in reference hospitals. Given that a large volume of procedures does not always guarantee good results (8,32), and that there may be determining process and structure factors, it seems the most reasonable option before recommending any change in care would be to develop risk adjustment models that adequately include patient severity (33) and take into account different structure factors for the study of identified variations in process and outcomes. This study would enable the definition of these models, but a series of possible limitations should be taken into account.

The first limitation identified is the lack of standardization and absence of relevant information (staging, functional status, some aspects of the surgical technique) in the medical record, the main source of information. This entails a lesser capacity to adequately adjust patient severity or risk and the healthcare process but highlights the importance of obtaining and including these data in the medical record (or in other information tools/systems) in order to assess the effectiveness of clinical practice.

Additionally, the aforementioned limitation and the possible variability in this process due to the collaboration of several professionals (practically a different person in each center) may have decreased the validity and reliability of the information. However, when comparing common variables pertaining to our study and hospital discharge MBDS no differences were reported (data not shown).

Finally, the follow-up of outcomes was limited to 6 months after surgery. For some of the types of cancer studied this 6-month follow-up may be a fairly short period for the assessment of outcomes, but it represents a significant advancement over the majority of studies that limit their analyses to the in-hospital period, especially those based on hospital discharge MBDS.

 

Acknowledgements

The authors would like to thank Júlia López and Mercè Salvat for their collaboration during the study's field work, and all professionals who participated in collecting data from the hospitals that took part in the study.

*ONCOrisc Study Group:

Advisory Committee

Antoni Anglada (H. de Vic, Barcelona); Manuel Armengol, Josep Tabernero (H. General Vall d'Hebron, Barcelona); Pedro Barrios (H. General de l'Hospitalet, Barcelona); Jordi Boix (CatSalut); Marc Antoni Broggi, Jaume Fernández-Llamazares (H. Universitari Germans Trias i Pujol, Badalona, Barcelona); José A. Carceller, Joan Viñas (H. Univ. Arnau de Vilanova, Lleida); Ferran Caballero (H. Comarcal Alt Penedès, Vilafranca del Penedès, Barcelona); Juan José Calvo (H. Comarcal Móra d'Ebre, Tarragona); Antoni Castells, Laureano Fernández-Cruz, Pere Gascon (H. Clínic i Provincial, Barcelona), Luis Grande, Rafael Manzanera, Antoni Sitges, Jordi Varela (H. del Mar, Barcelona); Xavier Castells, Francesc Macià (IMAS, Barcelona), Jaume Estany (Consorci Sanitari de Barcelona); Antonio Codina, Joan Figueras (H. Universitari Dr. Josep Trueta, Girona); Joan Martí Ragué (Ciutat Sanitària i Universitària de Bellvitge, Hospitalet, Barcelona); Constancio Marco (H. Mútua de Terrassa, Barcelona); Santiago Nofuentes (Consorci Integral de l'Hospitalet, Barcelona); Eugeni Saigí (Corporació Sanitària Parc Taulí, Sabadell, Barcelona); Josepa Ribes (H. Duran i Reynals, Hospitalet, Barcelona); Rosa Solà (Universitat Rovira i Virgili, Tarragona); Manuel Trias (H. de la Santa Creu i Sant Pau, Barcelona).

Cooperative Group

Roser Cid (H. de Barcelona); Federico Madrid (Centro Médico Teknon, Barcelona); Josep Domingo (H. de Figueres, Girona), Lluis Pérez Ruiz (H. Universitari Arnau de Vilanova, Lleida); Francisco García Borobia (Ciutat Sanitària Univ. de Bellvitge, Hospitalet, Barcelona); Josep Maria Badia (H. General Granollers, Barcelona); Felip Pi (H. de Viladecans, Barcelona); Jordi Pié (H. Municipal de Badalona, Barcelona); Josep Maria Pueyo (Consorci Sanitari Integral - H. Dos de Maig, Barcelona); Pere Puig (H. Sant Jaume, Calella, Barcelona); Enric Quintanilla (Serveis Integral del Baix Empordà, H. de Palamos, Girona); Xavier Rodamilans (H. Provincial Santa María, Lleida); Joan Sala (Consorci Sanitari de Terrassa, Barcelona); Baltasar Sanmartí (H. Comarcal de la Selva, Girona); José Segura (H. General de Mollet, Barcelona); Constantí Serra (H. General de Vic, Barcelona); Rosa María Servent (H. Comarcal de Sant Bernabé, Berga, Barcelona); Xavier Sunyol (Consorci Sanitari Mataró, Barcelona); Jordi Serra (H. Comarcal del Pallars, Lleida); Manel Trias (H. de la Santa Creu i Sant Pau, Barcelona); Joan Urgellès (H. de Sant Boi, Barcelona); Josep Verge (H. Residència Sant Camil, Sant Pere de Ribes, Barcelona); Joan Aixàs (Fundació Sant Hospital, La Seu d'Urgell, Lleida); Pedro Barrios (Consorci Sanitari Integral - Hospital General de l'Hospitalet, Barcelona); Marc Antoni Broggi (H. Univ. Germans Trias i Pujol, Badalona, Barcelona); Jordi Caballé (Centre Hospitalari de Manresa, Barcelona); Ferran Caballero (H. Comarcal de l'Alt Penedès, Vilafranca del Penedès, Barcelona); Juan José Calvo (H. Comarcal Móra d'Ebre, Tarragona); Enric Caubet (H. Sant Pau i Santa Tecla, Tarragona); Antoni Codina (H. Universitari Dr. Josep Trueta, Girona); Daniel del Castillo (H. Universitari Sant Joan de Reus, Tarragona); Fernando Doncel (Hospital General de Catalunya, Sant Cugat del Vallès, Barcelona); Juan Carlos Garcia-Valdecasas (H. Clínic i Provincial, Barcelona); Miquel Fernández Layos (H. General de Manresa, Barcelona); Enrique Fernández Sallent (Fundació Sanitària Igualada-H. General d'Igualada, Barcelona); Javier Foncillas (H. Quinta de Salut l'Aliança - Sagrat Cor, Barcelona); Rosa Fradera (Pius H. de Valls, Tarragona); Salvador Navarro (Consorci Hospitalari Parc Taulí, Sabadell, Barcelona); Antoni Gil (H. Sant Joan de Déu de Martorell, Barcelona); Luis Grande (H. del Mar, Barcelona); Manuel Martínez Brey (H. de Tortosa Verge de la Cinta, Tarragona); Josep Maria Greoles (Clínica de Ponent, Lleida); Marta Lahuerta (H. de Sant Rafael, Barcelona); Ferran López Lanao (H. Provincial Santa Caterina, Girona); Luis Luengo (H. Universitari Joan XXIII, Tarragona); Constancio Marco (H. Mútua de Terrassa, Barcelona); Joaquim Martínez Puig (H. Sant Jaume d'Olot, Girona); Lluis Masferrer (Consorci Sanitari Integral l' Hospitalet, Barcelona); Didac Miró (H. de Sant Celoni Fundació Privada, Barcelona); Joan Valverde (H. de l'Esperit Sant, Santa Coloma, Barcelona); Manel Armengol (H. Universitari Vall d 'Hebron, Barcelona); Joan Torralba (Institut Universitari Dexeus, Barcelona); Xavier Piulachs (Clínica Plató Fundació Privada, Barcelona); Francesc Tuca (Clínica Girona, S.L., Girona).

 

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Correspondence:
Mireia Espallargues.
Agency for Health Technology Assessment and Research.
Carrer de Roc Boronat, 81-95, 2ª. 08005 Barcelona, Spain.
e-mail: mespallargues@aatrm.catsalut.net

Received: 05-02-09.
Accepted: 26-05-09.