Rectal AdenocarcinomaProLARSNCT07339904
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
A study testing Questionnaire in people with Rectal Adenocarcinoma and LARS - Low Anterior Resection Syndrome, run by University Hospital, Antwerp at 1 site in Belgium.
Trial summary
OBJECTIVE Low anterior resection syndrome (LARS) is a term for functional bowel complaints occurring after low anterior resection. Symptoms can range from faecal incontinence and frequent loose stools to urgency and incomplete emptying with great impact on quality of life. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Rectal Adenocarcinoma, LARS - Low Anterior Resection Syndrome, Rectal Resection
- What is being tested?
- Questionnaire
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteBelgium
- Study dates
- 26 Aug 2024to Aug 2029
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 18 years or older.
- Diagnosis of rectal cancer, discussed at the multidisciplinary consultation, with the intention to perform a sphincter preserving total mesorectal excision (TME) or partial mesorectal excision (PME), regardless of the need of neoadjuvant treatment.
Who cannot join
- History of inflammatory bowel disease (Crohn's disease, ulcerative colitis) due to often persistent bowel complaints and therefore distorted baseline and follow-up data.
- Dementia or intellectual disability.
- Patients who are obstructive and in need a decompressive stoma or rectal stenting due to the lack of baseline data as they are often admitted to the hospital in an urgent setting
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Belgium1 site, 1 recruiting
- Recruiting
University Hospital Antwerp
Edegem, Antwerp, 2650
Lieselotte Iket, +32 3 821 30 00, studies.abdominaleheelkunde@uza.be
About this study
OBJECTIVE Low anterior resection syndrome (LARS) is a term for functional bowel complaints occurring after low anterior resection. Symptoms can range from faecal incontinence and frequent loose stools to urgency and incomplete emptying with great impact on quality of life. Little is known about the longitudinal evolution of LARS and the impact of different schedules of neoadjuvant chemoradiotherapy combined with surgery.
The investigators aim to investigate the incidence and evolution of functional bowel complaints in function of different neoadjuvant treatment regimens, type of surgery and adjuvant therapy in patients who undergo surgery for rectal cancer. The investigators focus on following objectives: evolution of LARS- and COREFO-scores per treatment regimen and their impact on work incapacity; identification of possible risk factors potentially related to functional outcome; monitoring and treatment of LARS.
Read more
METHODS This will be a multicentre prospective interventional study. The study population will consist of adult patients with rectal cancer, regardless of any neo-adjuvant therapy. Patients will be included for 5 years with a 2 year postoperative follow-up. Interim analysis will be made after 2 years of inclusion. Patients with intellectual disability or clinical colon obstruction are excluded. Automated online questionnaires including LARS and COREFO scores, incapacity for work and defecation quality will be sent at different time points (figure 1) using REDCap.
RESULTS and CONCLUSIONS Longitudinal change of LARS- and COREFO-scores will be visually summarized. Patient, disease or procedure specific risk factors will be assessed as well.
LARS is proven to be the principal postoperative problem after rectal surgery. If the investigators can predict the severity of LARS (minor or major LARS), this can be extremely helpful in deciding whether to perform a sphincter-sparing resection or a rectal amputation instead. Furthermore, the investigators want to offer perspective to patients who are susceptible to a disturbed postoperative bowel function.
- Conditions
- Rectal Adenocarcinoma, LARS - Low Anterior Resection Syndrome, Rectal Resection, Low Anterior Resection, Total Mesorectal Excision
- Being tested
- Questionnaire
- Keywords
- LARS, Rectal resection, Total mesorectal excision, Low anterior resection, Rectal carcinoma
- Medical subject headings
- Rectal Neoplasms, Low Anterior Resection Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
QuestionnaireOther
Online questionnaire regarding LARS- and COREFO-scores, quality of defecation process, incapacity for work and initiation of treatment for potential LARS at different moments in time
| Study group | Role | What they receive |
|---|---|---|
| Upfront surgery | Other | Patients who undergo rectal resection without neo-adjuvant therapy Receives: Other: Questionnaire |
| Neo-adjuvant therapy | Other | Patients who receive neo-adjuvant therapy before undergoing rectal surgery Receives: Other: Questionnaire |
What is being measured
The primary outcome is the main question the study is designed to answer.
The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) at 2 years after rectal surgery compared to baseline (absolute difference) will be examined
27 questions on 5-point Likert scale Higher score = worse bowel function
Measured: 2 years from when rectal resection or stoma reversal was performed
Secondary outcomes (18)
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
Measured: 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
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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)
Measured: 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
Measured: 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)
Measured: 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
Measured: Up to 2 years after rectal resection
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted14 Jan 2026
- Study start26 Aug 2024
- Primary completionAug 2029 (estimated)
- Study completionAug 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Rectal AdenocarcinomaStudies of the same condition, open and under way.
- More trials run by University Hospital, AntwerpThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Model description
- Patients receive online questionnaires regarding LARS- and COREFO-scores
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University Hospital, Antwerp
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Niels Komen, University Hospital, Antwerp
- Investigators
- Niels Komen, MD PhD, Principal investigator, University Hospital, Antwerp
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07339904
- Sponsor's protocol ID
- 6510
- Acronym
- ProLARS
- Status last verified
- Dec 2025
- First submitted
- 12 Apr 2025
- Last updated
- 14 Jan 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided
Study at a glance
From the registry record, last updated by the sponsor on 14 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- 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
- ClinicalTrials.gov ID
- NCT07339904
- Acronym / sponsor ID
- ProLARS / 6510
- Conditions
- Rectal Adenocarcinoma, LARS - Low Anterior Resection Syndrome, Rectal Resection, Low Anterior Resection, Total Mesorectal Excision
- Keywords
- LARS, Rectal resection, Total mesorectal excision, Low anterior resection, Rectal carcinoma
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- University Hospital, AntwerpUniversity, hospital or other
- Study start
- 26 Aug 2024 (actual)
- Primary completion
- Aug 2029 (estimated)
- Study completion
- Aug 2029 (estimated)
- First posted
- 14 Jan 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
OBJECTIVE Low anterior resection syndrome (LARS) is a term for functional bowel complaints occurring after low anterior resection. Symptoms can range from faecal incontinence and frequent loose stools to urgency and incomplete emptying with great impact on quality of life. Little is known about the longitudinal evolution of LARS and the impact of different schedules of neoadjuvant chemoradiotherapy combined with surgery.
The investigators aim to investigate the incidence and evolution of functional bowel complaints in function of different neoadjuvant treatment regimens, type of surgery and adjuvant therapy in patients who undergo surgery for rectal cancer. The investigators focus on following objectives: evolution of LARS- and COREFO-scores per treatment regimen and their impact on work incapacity; identification of possible risk factors potentially related to functional outcome; monitoring and treatment of LARS.
METHODS This will be a multicentre prospective interventional study. The study population will consist of adult patients with rectal cancer, regardless of any neo-adjuvant therapy. Patients will be included for 5 years with a 2 year postoperative follow-up. Interim analysis will be made after 2 years of inclusion. Patients with intellectual disability or clinical colon obstruction are excluded. Automated online questionnaires including LARS and COREFO scores, incapacity for work and defecation quality will be sent at different time points (figure 1) using REDCap.
RESULTS and CONCLUSIONS Longitudinal change of LARS- and COREFO-scores will be visually summarized. Patient, disease or procedure specific risk factors will be assessed as well.
LARS is proven to be the principal postoperative problem after rectal surgery. If the investigators can predict the severity of LARS (minor or major LARS), this can be extremely helpful in deciding whether to perform a sphincter-sparing resection or a rectal amputation instead. Furthermore, the investigators want to offer perspective to patients who are susceptible to a disturbed postoperative bowel function.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Non-randomised
- Intervention model
- Sequential
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Patients receive online questionnaires regarding LARS- and COREFO-scores
| Arm | Type | Receives |
|---|---|---|
| Upfront surgery | Other | Other: QuestionnairePatients who undergo rectal resection without neo-adjuvant therapy |
| Neo-adjuvant therapy | Other | Other: QuestionnairePatients who receive neo-adjuvant therapy before undergoing rectal surgery |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- 18 years or older.
- Diagnosis of rectal cancer, discussed at the multidisciplinary consultation, with the intention to perform a sphincter preserving total mesorectal excision (TME) or partial mesorectal excision (PME), regardless of the need of neoadjuvant treatment.
Key exclusion criteria (3 listed)
- History of inflammatory bowel disease (Crohn's disease, ulcerative colitis) due to often persistent bowel complaints and therefore distorted baseline and follow-up data.
- Dementia or intellectual disability.
- Patients who are obstructive and in need a decompressive stoma or rectal stenting due to the lack of baseline data as they are often admitted to the hospital in an urgent setting
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| QuestionnaireOnline questionnaire regarding LARS- and COREFO-scores, quality of defecation process, incapacity for work and initiation of treatment for potential LARS at different moments in time | Other | Neo-adjuvant therapy, Upfront surgery |
Primary outcome
The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) at 2 years after rectal surgery compared to baseline (absolute difference) will be examined
Time frame: 2 years from when rectal resection or stoma reversal was performed
27 questions on 5-point Likert scale Higher score = worse bowel function
18 secondary outcomes
Evolution of LARS-score (low anterior resection syndrome) at 2 years after rectal surgery compared to baseline (absolute difference)
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.
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
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.
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.
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.
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.
Time frame: 2 years from when rectal resection or stoma reversal was performed
LARS-score (low anterior resection syndrome) score at diagnosis
Time frame: At diagnosis = baseline
COREFO-score at diagnosis (Colorectal Functional Outcome questionnaire)
Time frame: At diagnosis = baseline
LARS-score (low anterior resection syndrome) after neo-adjuvant therapy
Time frame: After neo-adjuvant therapy (up to 6 months from baseline)
COREFO-score after neo-adjuvant therapy (Colorectal Functional Outcome questionnaire)
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
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
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
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
Time frame: Postoperatively after 1 month, 3 months, 6 months, 1 year and 2 years
Evolution of quality of defecation process
Time frame: 2 years after rectal resection or stoma reversal
Incapacity for work
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
Time frame: Up to 2 years after rectal resection
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Jan 2026.
- Individual participant dataSharing planned: Undecided
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Niels Komen, MD PhD principal investigator
University Hospital, Antwerp
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Questionnaire in people with Rectal Adenocarcinoma and LARS - Low Anterior Resection Syndrome, run by University Hospital, Antwerp at 1 site in Belgium.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 3 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 14 Jan 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Belgium. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Niels Komen, MD PhD (+32 3 821 30 00, niels.komen@uza.be), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
The evolution of the COREFO-score (Colorectal Functional Outcome questionnaire) at 2 years after rectal surgery compared to baseline (absolute difference) will be examined (time frame: 2 years from when rectal resection or stoma reversal was performed). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Jan 2026.