Assessment of quality of life of patients with gastric cancer after surgery : a systematic review

Introduction: Stomach cancer is the second leading cause of deaths worldwide owed to cancer. In less advanced stages of the disease, surgery tends to be the most usual treatment. Due to the social, scientific and medical development, rate of surviving is increasing making quality of life (QoL) particularly important in what health care concerns. Aim: To assess validity of the instruments used to measure QoL of patients submitted to surgery for gastric cancer across published articles and to summarize it among those using validated questionnaires. Methods: A systematic review of published articles in MEDLINE and Scopus Databases, until 2005. All papers that evaluate QoL in patients submitted to surgery for gastric cancer were included and data extracted from 5 of them after applying exclusion criteria. Results: Validity: A multiplicity of questionnaires (n=40) for QoL assessment was found, being the most applied the Spitzer Index (n=6) and Visick Score (n=5), but only 7 were validated. In fact, most (41 %) articles, among those that obeyed the inclusion criteria, did not approach QoL in a global definition of QoL or only assessed symptoms, performance status or physician-reported outcomes. Summarize: Among the 5 articles, with validated questionnaires (EORTC QLQ-C30 and Gastrointestinal QoL Index), total gastrectomy with a pouch trended to be considered a better option than total gastrectomy without one in terms of QoL, both in 6 month (EORTC QLQ-C30: 52 vs. 50; Gastrointestinal QoL Index: 106 vs 96) and 12 month (EORTC QLQ-C30: 65 vs. 49) follow-up. Although no summary estimated was obtained, similar results were found when the same questionnaires were used. Discussion: In future studies, QoL in patients submitted to surgery for gastric cancer should use previously validated questionnaires, such as EORTC-QLQ C30, enabling future systematic reviews. Unstandardized questionnaires, if validated and disseminated, may improve QoL measurements in this setting in the future. Key-words: Gastrectomy, Stomach neoplasm, Quality of life (MeSH terms) Introduction Gastric cancer develops when cells of the innermost lining, mucosa, undergo a malignant growth, invading the surrounding healthy cells. Being the second leading cause of cancer deaths worldwide after lung cancer , it is important to study the disease itself as well as the therapy involved, the consequent rate of surviving, (the 5year survival rate of gastric carcinoma is low ) but also quality of life (QoL) for the patient, since in the last 50 years, due to the social, scientific and medical development, gastric cancer occurrence as well as mortality rate have decreased . Currently, surgery is the only therapeutic option offering a chance of cure . The specific type of surgery depends on what part of the stomach is involved and how much damaged is the surrounding tissue. There are two possible main types of surgery: subtotal gastrectomy (only part of the stomach is removed) and total gastrectomy (total stomach is removed). Subtotal gastrectomy can be performed with or without pylorus preservation and total gastrectomy with or without a pouch. QoL, although difficult to define, has been considered as “the functional effect of an illness and its consequent therapy upon a patient, as perceived by the patient” [6] or “the degree to which a person enjoys the important possibilities of his or her life” . Understanding QoL is today particularly important in health care. In order to improve surgical treatment and post-operative quality of life, patients have been invited to participate in scientific studies where QoL is measured via questionnaires and interviews. Scores of those measures allow us to interpret and compare different surgical techniques used in several groups of patients with an identical disease. Our aim is to assess validity of the instruments used to evaluate QoL of patients submitted to surgery for gastric cancer across published articles and to summarize it among those using validated questionnaires. Participants and Methods Study design Our study consists in a systematic review where a strategy was defined (see inclusion and exclusion criteria) in order to accomplish our aims. Data source (Fig.1) We conducted literature searches in MEDLINE using as query “("Quality of Life"[MeSH] OR quality of life) AND ("Stomach Neoplasms"[MeSH] OR stomach neoplasm OR gastric cancer OR stomach carcinoma) NOT intestinal cancer AND ("Gastrectomy"[MeSH] OR gastrectomy OR gastric surgery) NOT chemotherapy NOT radiotherapy”, from 1950 to September 2005. As terms MeSH are relatively recent, it was necessary to look for non-MeSH terms. It seemed also imperative to use different synonyms. Only papers in English with abstracts and referring to humans were selected. Scopus Database was also used for literature searches until 2006 with the same query (exception for the MeSH terms). The search was limited to the "health" and "life sciences" areas and to "review" and "article" document type. Inclusion criteria Included studies were both those regarding a target population with gastric cancer that has been submitted to gastrectomy and those that refer to QoL assessment after surgery for gastric cancer. Only papers with abstracts were included. Exclusion criteria In a first phase, studies referring exclusively to treatments as radiotherapy or chemotherapy were excluded. Those where QoL is not assessed or approached in a global view, i.e., that only refer to a specific physician or psychologist parameter, that didn’t use an instrument to measure QoL or had only one case in study were also excluded. In a second phase, articles that do not describe the patients in the study and those where the time interval since surgery until QoL measurement was not defined were excluded too. It was also determined that articles without a validated questionnaire, with quantified data that couldn’t be retrieved or that we couldn’t access to, would not be used our study. Review and data extracted (Fig.1) Selected papers (260) were distributed into four groups of two reviewers each, and subsequent disagreement was resolved by consensus. From the 76 included articles in the first phase we extracted data referring to: the instrument used, time interval since surgery until QoL measurement, number and description of patients in study and type of surgery to which the population was submitted. The different types of specific techniques of surgery were grouped into six categories as indicated in Table 1 . Later, we verified the validation of the found questionnaires. Literature references [9-19] were searched in MEDLINE in order to validate each of the used instruments in the articles (Table 2). From each of the 5 included articles it was extracted the value (mean) of QoL (when available), year of publication, number of patients in the study according to the type of surgery and the affiliation/department where the study took place. Data analysis Data from each included paper (Table 3) was plotted according to the following variables: used instrument, surgical technique (Table 1) and different questionnaire evaluation (preoperative, up to 6 months or over 6 months after surgery). Quantifying data from each article, regarding QoL value, was expressed using mean. Collected data was assembled using the statistic program “SPSS 14.0 for Windows”. The frequencies (expressed in percentage) of nominal variables, namely inclusion/exclusion criteria, main criteria for papers exclusion (Fig.1) and final result (included/excluded) were measured. The frequency of the scale variable “year of publication” was also studied. Results Search results The literature search in MEDLINE and in Scopus Database identified 173 and 189 studies, respectively (total of 260 studies), having 102 of them been identified in both databases (Fig. 1). Of 260 studies only 104 obeyed the inclusion criteria. Of these 104 papers, most of them (41%) did not use a post-operative questionnaire or studied QoL in a global way, not even according to QoL definition itself, since many of the times it was only assessed the physician-reported rather than patient-reported outcomes. Usually only gastro-esophageal reflux and weight changes were measured. Once applied exclusion criteria, only 76 articles were selected. We read 45 of these articles and only 5 of them were included in our study. We couldn’t have access to the remaining 31 papers (no full text in English available or accessible).