Organ-preserving Management in Patients With Complete or Near-complete Tumour Response After Preoperative Radio(Chemo)Therapy for Rectal Cancer

Study Overview
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Brief Summary
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Watch-and-wait strategy in rectal cancer is gaining momentum. There is a large variability in reporting the proportion of patients achieving clinical complete response (cCR) after routinely delivered preoperative radio(chemo)therapy, likely because of patients' selection. This proportion in population-based level is poorly defined. In addition, predictive factors for cCR are also poorly defined. It is known that cCR response is observed often in small tumours. However, cCR proportion in large cancers has not been sufficiently evaluated. For example, even though pathological complete response (pCR) does occur in large fixed cancer, it is unknown whether cCR does also occur because persistent fibrous stroma may mimic residual cancer in all of such cases. This is a prospective observational population-based cohort study on low rectal cancer to answer the question of how often clinical or near-clinical tumour response occur after routinely delivered preoperative radiotherapy in relation to the pre-treatment tumour characteristics. The additional question was how often pCR occur in relation to the pre-treatment tumour characteristics in the patients managed by total mesorectal excision because of persistent tumour after radiotherapy. The additional aim was the implementation of watch-and-wait strategy or full-thickness local excision (as an option instead of total mesorectal excision in the patients with sustained near-cCR) within a frame of a prospective study. In the patients managed by organ preservation, the secondary outcome measures were: i) local regrowth rate, ii) effectiveness of salvage surgery, iii) disease-free survival at 3 years and overall survival at 5 years, iv) anorectal function.

Official Title
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Organ-preserving Management in Patients With Complete or Near-complete Tumour Response After Preoperative Radio(Chemo)Therapy for Rectal Cancer

Conditions
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Rectal Neoplasms, Rectal Cancer

Intervention / Treatment
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* Radiation: Preoperative Radio(Chemo)Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Primary rectal cancer Low tumour (accessible by digital rectal examination) Routine preoperative radio(chemo)therapy according to the institutional policy; short-course radiation and immediate surgery is not allowed. Informed consent for watch-and-wait strategy or local excision in patients with cCR and near-cCR Exclusion Criteria: Recurrent cancer Cancers situated in the upper rectum Distant metastases

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Resectable rectal cancer<br> | Radiation: Preoperative Radio(Chemo)Therapy<br>* Preoperative radiotherapy +/- chemotherapy, then surgery (total mesorectal excision) or watch-and-wait<br>|
| Rectal cancer with threatened mesorectal fascia<br> | Radiation: Preoperative Radio(Chemo)Therapy<br>* Preoperative radiotherapy +/- chemotherapy, then surgery (total mesorectal excision) or watch-and-wait<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentages of cCR and near-cCR in the patients with resectable cancer |  | 11 weeks from the start of radiotherapy | 
| Percentages of cCR and near-cCR in the patients with threatened mesorectal fascia. |  | 11 weeks from the start of radiotherapy | 
| Percentages of cCR and near-cCR in relation to the selected tumour characteristics. | The selected tumour characteristics: TN categories, tumour length, degree of circumferential involvement, tumour mobility on digital rectal examination (mobile, tethered, fixed) and status of mesorectal fascia (threatened or not). | 11 weeks from the start of radiotherapy | 
| Percentages of pCR in the patients after total mesorectal excision performed because of tumour persistence. |  | 12 weeks from the start of radiotherapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Local regrowth rate |  | 5 years | 
| Disease-free survival |  | 3 years | 
| Overall survival |  | 5 years | 
| Anorectal function assessed by low anterior resection syndrome (LARS) score | The questionnaire will be completed by patients. It includes 5 items related to anorectal function. The range of the score (0-42) is divided into 0 to 20 (no LARS), 21 to 29 (minor LARS) and 30 to 42 (major LARS). | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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rectal cancer, preoperative radiotherapy, organ preservation, watch-and-wait