The selection of appropriate outcomes is crucial when designing clinical trials in order to compare the effects of different interventions directly. For the findings to influence policy and practice, the outcomes need to be relevant and important to key stakeholders including patients and the public, health care professionals and others making decisions about health care. It is now widely acknowledged that insufficient attention has been paid to the choice of outcomes measured in clinical trials. Researchers are increasingly addressing this issue through the development and use of a core outcome set, an agreed standardised collection of outcomes which should be measured and reported, as a minimum, in all trials for a specific clinical area. Accumulating work in this area has identified the need for guidance on the development, implementation, evaluation and updating of core outcome sets. This Handbook, developed by the COMET Initiative, brings together current thinking and methodological research regarding those issues. We recommend a four-step process to develop a core outcome set. The aim is to update the contents of the Handbook as further research is identified.

This review summarizes reporting of complications of esophageal cancer surgery. Accurate assessment of morbidity and mortality after surgery for cancer is essential to compare centers, allow data synthesis, and inform clinical decision-making. A lack of defined standards may distort clinically relevant treatment effects. Systematic literature searches identified articles published between 2005 and 2009 reporting morbidity and mortality after esophagectomy for cancer. Data were analyzed for frequency of complication reporting and to check whether outcomes were defined and classified for severity and whether a validated system for grading complications was used. Information about reporting outcomes adjusting for baseline risk factors was collated, and a descriptive summary of the results of included outcomes was undertaken. Of 3458 abstracts, 224 full papers were reviewed and 122 were included (17 randomized trials and 105 observational studies), reporting outcomes of 57,299 esophagectomies. No single complication was reported in all papers, and 60 (60.6%) did not define any of the measured complications. Anastomotic leak was the most commonly reported morbidity, assessed in 80 (80.1%) articles, defined in 28 (28.3%), but 22 different descriptions were used. Five papers (5.1%) categorized morbidity with a validated grading system. One hundred fifteen papers reported postoperative mortality rates, 25 defining the term using 10 different definitions. In-hospital mortality was the most commonly used term for postoperative death, with 6 different interpretations of this phrase. Eighteen papers adjusted outcomes for baseline risk factors and 60 presented baseline measures of comorbidity. Outcome reporting after esophageal cancer surgery is heterogeneous and inconsistent, and it lacks methodological rigor. A consensus approach to reporting clinical outcomes should be considered, and at the minimum it is recommended that a "core outcome set" is defined and used in all studies reporting outcomes of esophageal cancer surgery. This will allow meaningful cross study comparisons and analyses to evaluate surgery.

Colorectal cancer (CRC) is a major cause of worldwide morbidity and mortality. Surgical treatment is common, and there is a great need to improve the delivery of such care. The gold standard for evaluating surgery is within well-designed randomized controlled trials (RCTs); however, the impact of RCTs is diminished by a lack of coordinated outcome measurement and reporting. A solution to these issues is to develop an agreed standard “core” set of outcomes to be measured in all trials to facilitate cross-study comparisons, meta-analysis, and minimize outcome reporting bias. This study defines a core outcome set for CRC surgery. The scope of this COS includes clinical effectiveness trials of surgical interventions for colorectal cancer. Excluded were nonsurgical oncological interventions. Potential outcomes of importance to patients and professionals were identified through systematic literature reviews and patient interviews. All outcomes were transcribed verbatim and categorized into domains by two independent researchers. This informed a questionnaire survey that asked stakeholders (patients and professionals) from United Kingdom CRC centers to rate the importance of each domain. Respondents were resurveyed following group feedback (Delphi methods). Outcomes rated as less important were discarded after each survey round according to predefined criteria, and remaining outcomes were considered at three consensus meetings; two involving international professionals and a separate one with patients. A modified nominal group technique was used to gain the final consensus. Data sources identified 1,216 outcomes of CRC surgery that informed a 91 domain questionnaire. First round questionnaires were returned from 63 out of 81 (78%) centers, including 90 professionals, and 97 out of 267 (35%) patients. Second round response rates were high for all stakeholders (>80%). Analysis of responses lead to 45 and 23 outcome domains being retained after the first and second surveys, respectively. Consensus meetings generated agreement on a 12 domain COS. This constituted five perioperative outcome domains (including anastomotic leak), four quality of life outcome domains (including fecal urgency and incontinence), and three oncological outcome domains (including long-term survival). This study used robust consensus methodology to develop a core outcome set for use in colorectal cancer surgical trials. It is now necessary to validate the use of this set in research practice.

Methods for developing a core outcome or information set require involvement of key stakeholders to prioritise many items and achieve agreement as to the core set. The Delphi technique requires participants to rate the importance of items in sequential questionnaires (or rounds) with feedback provided in each subsequent round such that participants are able to consider the views of others. This study examines the impact of receiving feedback from different stakeholder groups, on the subsequent rating of items and the level of agreement between stakeholders. Randomized controlled trials were nested within the development of three core sets each including a Delphi process with two rounds of questionnaires, completed by patients and health professionals. Participants rated items from 1 (not essential) to 9 (absolutely essential). For round 2, participants were randomized to receive feedback from their peer stakeholder group only (peer) or both stakeholder groups separately (multiple). Decisions as to which items to retain following each round were determined by pre-specified criteria. Whilst type of feedback did not impact on the percentage of items for which a participant subsequently changed their rating, or the magnitude of change, it did impact on items retained at the end of round 2. Each core set contained discordant items retained by one feedback group but not the other (3–22 % discordant items). Consensus between patients and professionals in items to retain was greater amongst those receiving multiple group feedback in each core set (65–82 % agreement for peer-only feedback versus 74–94 % for multiple feedback). In addition, differences in round 2 scores were smaller between stakeholder groups receiving multiple feedback than between those receiving peer group feedback only. Variability in item scores across stakeholders was reduced following any feedback but this reduction was consistently greater amongst the multiple feedback group. In the development of a core outcome or information set, providing feedback within Delphi questionnaires from all stakeholder groups separately may influence the final core set and improve consensus between the groups. Further work is needed to better understand how participants rate and re-rate items within a Delphi process. The three randomized controlled trials reported here were each nested within the development of a core information or outcome set to investigate processes in core outcome and information set development. Outcomes were not health-related and therefore trial registration was not applicable.

The information surgeons impart to patients and information patients want about surgery for cancer is important but rarely examined. This study explored information provided by surgeons and patient preferences for information in consultations in which surgery for oesophageal cancer surgery was discussed. Pre-operation consultations in which oesophagectomy was discussed were studied in three United Kingdom hospitals and patients were subsequently interviewed. Consultations and interviews were audio-recorded, transcribed in full and anonymized. Interviews elicited views about the information provided by surgeons and patients’ preferences for information. Thematic analysis of consultation-interview pairs was used to investigate similarities and differences in the information provided by surgeons and desired by patients. Fifty two audio-recordings from 31 patients and 7 surgeons were obtained (25 consultations and 27 patient interviews). Six consultations were not recorded because of equipment failure and four patients declined an interview. Surgeons all provided consistent, extensive information on technical operative details and in-hospital surgical risks. Consultations rarely included discussion of the longer-term outcomes of surgery. Whilst patients accepted that information about surgery and risks was necessary, they really wanted details about long-term issues including recovery, impact on quality of life and survival. This study demonstrated a need for surgeons to provide information of importance to patients concerning the longer term outcomes of surgery. It is proposed that “core information sets” are developed, based on surgeons’ and patients’ views, to use as a minimum in consultations to initiate discussion and meet information needs prior to cancer surgery.