ProLARS Trial: Prospective Longitudinal Follow-up of Low Anterior Resection Syndrome (LARS) and COREFO Score After Rectum Surgery in Patients Undergoing Upfront Surgery or Different Neo-adjuvant Treatment Regimens

Evolution of LARS-score (low anterior resection syndrome) at 2 years after rectal surgery compared to baseline (absolute difference)

0-20 = no LARS 21-29 = minor LARS 30-42 = major LARS

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the LARS-score (low anterior resection syndrome) at 2 years after rectal surgery compared to baseline (relative difference) will be examined.

0-20 = no LARS 21-29 = minor LARS 30-42 = major LARS

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) at 2 years after rectal surgery compared to baseline (relative difference) will be examined

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100)

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the LARS-score (low anterior resection syndrome) in the absence of baseline data will be examined as well (absolute difference), comparing 2-year outcome to earliest results.

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42)

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the LARS-score (low anterior resection syndrome) in the absence of baseline data will be examined as well (relative difference), comparing 2-year outcome to earliest results.

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42)

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) in the absence of baseline data will be examined as well (absolute difference), comparing 2-year outcome to earliest results.

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100)

Time frame: 2 years from when rectal resection or stoma reversal was performed

The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) in the absence of baseline data will be examined as well (relative difference), comparing 2-year outcome to earliest results.

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100)

Time frame: 2 years from when rectal resection or stoma reversal was performed

LARS-score (low anterior resection syndrome) score at diagnosis

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42) LARS = low anterior resection syndrome Using a questionnaire Unit = mean score (0-42)

Time frame: At diagnosis = baseline

COREFO-score at diagnosis (Colorectal Functional Outcome questionnaire)

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100) COREFO = Colorectal Functional Outcome questionnaire Using a questionnaire Unit = mean score (0-100)

Time frame: At diagnosis = baseline

LARS-score (low anterior resection syndrome) after neo-adjuvant therapy

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42) LARS = low anterior resection syndrome Using a questionnaire Unit = mean score (0-42)

Time frame: After neo-adjuvant therapy (up to 6 months from baseline)

COREFO-score after neo-adjuvant therapy (Colorectal Functional Outcome questionnaire)

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100) COREFO = Colorectal Functional Outcome questionnaire Using a questionnaire Unit = mean score (0-100)

Time frame: After neo-adjuvant therapy (up to 6 months from baseline)

LARS-score (low anterior resection syndrome) shortly prior to surgery when there is a delay of 4 or more weeks after finishing neoadjuvant therapy

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42) LARS = low anterior resection syndrome Using a questionnaire Unit = mean score (0-42)

Time frame: 2 days prior to surgery

COREFO-score (Colorectal Functional Outcome questionnaire) shortly prior to surgery when there is a delay of 4 or more weeks after finishing neoadjuvant therapy

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100) COREFO = Colorectal Functional Outcome questionnaire Using a questionnaire Unit = mean score (0-100)

Time frame: 2 days prior to surgery

LARS-scores (low anterior resection syndrome) postoperatively after 1 month, 3 months, 6 months, 1 year and 2 years

0-20 no LARS 21-29 minor LARS 30-42 major LARS (min 0 - max 42) LARS = low anterior resection syndrome Using a questionnaire Unit = mean score (0-42)

Time frame: Postoperatively after 1 month, 3 months, 6 months, 1 year and 2 years

COREFO-scores (Colorectal Functional Outcome questionnaire) postoperatively after 1 month, 3 months, 6 months, 1 year and 2 years

27 questions on 5-point Likert scale Higher score = worse bowel function (min 0 - max 100) COREFO = Colorectal Functional Outcome questionnaire Using a questionnaire Unit = mean score (0-100)

Time frame: Postoperatively after 1 month, 3 months, 6 months, 1 year and 2 years

Evolution of quality of defecation process

Visual analogue scale 0-10 0 = worst defecation ever 10 = best defecation ever

Time frame: 2 years after rectal resection or stoma reversal

Incapacity for work

Time (days) between date of start work incapacity and date back to work (if not yet retired)

Time frame: At diagnose (baseline), 2 days after radiotherapy, 1 week after chemotherapy and 1 month after rectal resection

Initiation of treatment for potential LARS (low anterior resection syndrome) during follow-up

Yes/no: * Dietary measures * Medication (probiotics, antidiarrheals, ...) * Pelvic floor physiotherapy * Transanal irrigation, rectal irrigation, enema * Neuromodulation (neurostimulator) * Other Calculating proportion of patients who received treatment for LARS

Time frame: Up to 2 years after rectal resection