The principal outcome of this study was the development of a novel photographic assessment tool for SQA of gastrectomy. The tool was evaluated using data from the ADDICT Trial and is, therefore, well placed to support SQA in future clinical trials.

The development of the current tool was able to benefit from existing widely accepted descriptors for D1, D1+ and D2 gastrectomy as well as previous work relating to SQA in the context for oesophagectomy and colorectal surgery [9,10,11,12]. Use of photographic images for the purpose of SQA was noted to simplify the assessment process, albeit with some limitations that are commented on below. Furthermore, it was found that it was easier to capture, transfer and store still images compared to video files which have been utilized in previous SQA tools. Another strength of the proposed tool is its ability to allow the rater to determine not only the quality but also the extent of the lymphadenectomy (e.g., D1, D1+, D2) based on the remaining anatomy rather than the excised specimen. This has advantages in surgical RCTs, such as the ADDICT trial, where the differences between operative interventions must be clearly apparent to avoid a Type I or II error.

In this study, a photographic surgical quality assurance tool is used to reliably determine the extent of the lymphadenectomy performed during gastrectomy. Gastric lymph node stations have been comprehensively described and are universally accepted. While there may be variability in the volume of tissue and number of lymph nodes within individual lymph node stations, the anatomical structures that remain after their removal are clearly defined. The completeness of lymphadenectomy can, therefore, only be truly evaluated by reviewing the tissue and structures that remain and not by what is removed. The longstanding practice of using lymph node count as a surrogate of the completeness of lymphadenectomy, should not be considered a valid method of surgical quality assurance in this context.

This study nevertheless has several acknowledged limitations. While the importance of SQA as a concept is not in doubt, the template for its use is based on low-level evidence. Despite this, it has been replicated and published in upper and lower gastrointestinal surgical oncology trials with widespread surgeon acceptance and support for the framework described herein.

Including all three assessors and coding missing data as absent rather than a mean value [11], the G-coefficient and inter-rater reliability of the gastrectomy assessment tool fell below that attained previously with the esophagectomy tool in the ROMIO study [9]. However, the values obtained suggest that the tool can still be considered both valid and reliable.

The current study did highlight the importance of assessor selection and training with SQA tools. In this case, one assessor, despite being a consultant gastric cancer surgeon and demonstrating intra-rater reliability for the 19-item and single-item global rating scale, was the outlier in the group. It was noted that this assessor was the least experienced with SQA and had the longest lag time between the training session and their data submission. At present, seniority and familiarization with the operative intervention have been the major drivers in assessor selection. In future work, it may be necessary to demonstrate the same rigor in approving assessors for trial operative monitoring as there currently is for credentialing of surgeons for entry into a trial. In this research study, the three assessors guided the content of the tool and duration of training prior to using the tool, whereas a more formal approach and training strategy may be required to ensure objectivity and standardization of ratings. This improved approach is already being implemented in ongoing trials including the TIGER Study [23].

Beyond the SQA of gastrectomy as a fixed entity, being able to reliably assess the quality and extent of lymphadenectomy in gastric cancer resection offers the potential to definitively determine the relationship between radicality of lymphadenectomy and patient outcome. This could impact tailoring of individualized patient operations, reducing peri-operative morbidity from unnecessary dissection, improved survival, and prediction of disease recurrence patterns in those with lymph node involvement. The current study was not, however, designed or adequately powered to examine the link between SQA score and histopathological and clinical correlates. This has been identified as an important piece of further work that will be embedded within the ADDICT trial, to establish both the oncological and clinical validity of the tool.

Feedback received from all assessors was that short video clips of the operative field, at the end of the lymphadenectomy and post reconstruction, would potentially be more informative than still photographs (and longer unedited videos). It was felt that a dynamic view of the surgical field would help provide a more complete assessment of the resection through its ability to see structures from different angles. Furthermore, this could help to reduce missing data particularly that which is considered under the category of insufficient evidence which accounted for over 11% of data entry point in this study.

Future work will include examining the oncological clinical validity by correlating lymphadenectomy and tumor recurrence after completion of ADDICT. Adoption of artificial intelligence may also support real-time intra-operative guidance as well as automation of SQA processes. If achievable this could reduce assessors’ workload and improve reliability.

In conclusion, a novel photographic SQA tool is presented herein that may be used to assess the extent and quality of gastrectomy in the context of gastric cancer. The tool was determined to be objective and reliable, and allowed the assessor to evaluate not only the quality but also the extent of the lymphadenectomy. Assessor selection and training, however, remain central to ensuring the best performance of the tool.