Colorectal cancer (CRC) is the third most common malignancy worldwide, with more than 1.9 million new cases reported annually. Survival among patients with CRC depends on several factors, including disease stage at diagnosis, the patient's clinical condition, tumour characteristics, and treatment modalities. Despite advances in surgical techniques, active involvement in clinical, translational, and basic research, and improvements in perioperative care, substantial disparities in short- and long-term outcomes persist across healthcare providers and countries.

To reduce these variations and improve the quality of cancer care, several metrics have been used to evaluate hospitals, therapeutic approaches, and surgical outcomes.

In response to these needs, a composite measure known as "Textbook Outcome" (TO) was developed. It encompasses multiple favourable outcomes and requires patients to meet all essential quality-of-care criteria for a given procedure. TO serves as an effective predictor of survival and is recognised as an indicator of the quality of hospital care.

This study aims to investigate the value of TO as an indicator of clinical outcomes and quality of care in the surgical treatment of colorectal cancer.

The primary objective is to assess the achievement of Textbook Outcome criteria in colorectal cancer surgery performed by Italian surgeons. Textbook Outcome is defined by the fulfilment of six key parameters: in-hospital survival, defined as the absence of death during hospitalisation or within 30 days after surgery; radical resection, defined as an R0 resection with at least 12 lymph nodes examined; absence of reoperation; absence of an unplanned stoma; absence of major adverse events, classified according to the Clavien-Dindo criteria as grade III or higher, within 30 days after surgery; and a hospital length of stay of 14 days or less without unplanned readmission. The simultaneous achievement of all six parameters constitutes the optimal outcome, defined as Textbook Outcome.

The secondary objective is to assess the consistency with which surgeons meet TO criteria during colorectal surgery and to identify patient- and procedure-related factors associated with failure to achieve TO. Through a detailed analysis of these factors, the study aims to identify the variables influencing TO failure and to determine which aspects of clinical practice or patient characteristics represent the main barriers to meeting these quality standards. The usefulness of TO as a quality indicator in the surgical management of colorectal cancer will also be evaluated by examining which individual unmet components are most frequently associated with unfavourable clinical outcomes, with particular attention to the different clinical presentations of the disease.

The study will include all adult patients admitted to the participating surgical departments with a diagnosis of colorectal cancer between 1 January 2022 and 31 December 2024.

Patient data will be analysed retrospectively. Demographic characteristics, comorbidity status, clinical and radiological findings, treatment strategies, and 30-day morbidity and mortality will be evaluated. Data will be entered into an online database between 1 January 2025 and 31 May 2025.

The study will last 12 months: the first five months will be dedicated to data collection and the subsequent seven months to data analysis.

The study is scheduled to begin in January 2025 with the commencement of data collection.

The sample size required to achieve 80% statistical power, with a margin of error of ±5% at a 95% confidence level, is 324 patients.

Continuous variables not following a normal distribution will be expressed as medians with interquartile ranges (IQRs), whereas normally distributed continuous variables will be reported as means with standard deviations (SDs). The Mann-Whitney U test will be used to compare non-normally distributed continuous variables between groups. Normally distributed continuous variables will be compared using the independent-samples t-test or one-way analysis of variance (ANOVA), as appropriate. Categorical variables will be reported as frequencies, and proportions will be compared between groups using the χ² test. Survival curves will be estimated using the Kaplan-Meier method and compared using the log-rank test. Prognostic factors for survival will be assessed using multivariable Cox proportional hazards regression. Statistical significance will be set at a two-sided P value of < .05.