An interventional study of Additional surgery in Colorectal Cancer, sponsored by Tampere University Hospital. Not yet recruiting at 14 sites in Finland. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-10-28.
Sponsored by Tampere University Hospital · Not applicable, Interventional, and Treatment
The goal of this two-arm clinical trial is to compare additional surgery with active surveillance in patients with high-risk pT1 colorectal cancer after local excision. The main questions it aims to answer are Does additional surgery result in lower rates of distant or extraluminal recurrence compared with active surveillance? How do the two treatment strategies differ in survival, complications, quality of life, and treatment-related costs?
Participants will be randomly assigned to either additional surgery or active surveillance.
Patients assigned to the surgery group will undergo standard preoperative assessment followed by additional surgery. Following surgery, patients will undergo surveillance according to the predefined follow-up protocol.
Patients assigned to the active surveillance group will not receive any additional treatment. They will undergo surveillance according to a more intensive predefined follow-up protocol.
Finnish and European guidelines recommend additional surgery after local excision of high-risk pT1 colorectal cancer (CRC) because of the risk of lymph node metastases. However, most patients do not have lymph node involvement. As a result, many patients may undergo radical surgery without direct oncological benefit while being exposed to treatment-related morbidity and mortality.
Prospective randomized evidence demonstrating the benefit of additional surgery over active surveillance remains limited.
T1LDA-trial is a national, multicenter, open-label, two-arm randomized superiority trial designed to evaluate treatment of high-risk pT1 colorectal cancer following local excision. The study is coordinated by Tampere University Hospital.
Inclusion criteria: Age ≥18 years, histologically confirmed pT1 colorectal cancer treated by local excision, and the presence of one to three histopathological high-risk factors for lymph node metastasis or recurrence.
Exclusion criteria: Patient is not eligible for either surgery or surveillance, have suspected lymph node involvement or metastatic disease.
Participants are randomly assigned in a 1:1 ratio to either additional surgery or active surveillance. Both groups will follow a predefined follow-up schedule. Eligible patients who do not consent to randomization may participate in a parallel prospective observational cohort. Treatment allocation in the observational cohort is based on patient and physician choice, and participants will be followed according to the study protocol.
The primary endpoint is 3-year distant or extraluminal recurrence within 3 years of study enrollment.
Secondary outcomes include survival outcomes (recurrence-free, disease-specific, and overall survival), recurrence patterns, lymph node metastases, complications, salvage surgery, health-related quality of life, and treatment-related costs.
Eligible patients will be followed up for 5 years according to predefined follow-up protocol. For surveillance group the follow-up protocol is designed to be more intense, according to clinical practice.
Both treatment strategies are based on standard clinical practice, although the majority of patients currently undergo additional surgery. Participants assigned to active surveillance may avoid the risks associated with CRC surgery but may be at higher risk for disease recurrence. Safety will be evaluated throughout the study by recording adverse events, disease recurrence, complications, salvage surgeries, and mortality.
Study data will be collected and recorded in pseudonymized form in an electronic Case Report Form (eCRF) derived from hospital electronic health records. The eCRF is implemented in REDCap and hosted and maintained by Tampere University Hospital.
The target effect size was defined using the smallest worthwhile effect (SWE) framework, based on patient input from the Association of Cancer Patients in Finland and the Finnish Colorectal Cancer Association. The final sample size for the randomized cohort was determined to be 340 participants.
6,541 studies on the registry are indexed under Colorectal Neoplasms; 1,667 are open to participants now.
This study's planned enrollment of 500 is above the median of 76 across 4,800 interventional studies indexed under Colorectal Neoplasms.
Browse Colorectal Neoplasms studies →Tampere University Hospital is the lead sponsor of 212 studies on the registry; 56 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Clearly pathologic nodes or suspicious nodes with additional risk factors, i.e. suspicious if: ≥9 mm or mucinous signal Smaller nodes 5-9 mm: Require 2 additional malignant features for cN+ classification. Nodes \<5 mm, unless mucinous, are considered benign.
Additional malignant features: indistinct LN border or heterogeneous MRI signal
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
ECOG performance status
A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.
Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants undergo additional oncologic bowel resection.
Procedure: Additional surgery
Patients undergo follow-up alone without additional treatment.
Patients assigned to the intervention group undergo standard preoperative assessment and preparation, followed by additional oncologic resection of the bowel segment containing the tumor, including the mesentery and regional lymph nodes. The appropriate surgical technique is selected at the discretion of the treating surgeon, based on standard clinical practice and individual patient characteristics. Open, laparoscopic and robotic approaches are all permitted.
Distant or extraluminal recurrence rate
The primary endpoint is 3-year distant or extraluminal recurrence, defined as the occurrence of any distant recurrence or extraluminal local recurrence within 3 years of study enrollment.
Time frame: 3 years
Recurrence-free survival (RFS)
Time from study enrollment to the first occurrence of confirmed recurrence or colorectal cancer-related death.
Time frame: 3 and 5 years
Disease-specific survival (DSS)
Time from study enrollment to confirmed colorectal cancer-specific death. Deaths due to other causes will be treated as censoring events.
Time frame: 3 and 5 years
Overall survival (OS)
Time from study enrollment to death from any cause.
Time frame: 3 and 5 years
Local, distant and overall recurrence
The proportion of participants with confirmed local (intraluminal or extraluminal) recurrence, distant recurrence or overall recurrence during follow-up. Overall recurrence includes both local and distant recurrences.
Time frame: 3 and 5 years
Rate of lymph node metastases
The proportion of participants with histologically confirmed lymph node metastases identified in surgical specimens.
Time frame: 3 and 5 years
Predictive value of predefined histopathological high-risk factors for histologically confirmed lymph node metastases.
The predictive value of predefined histopathological high-risk features, including lymphovascular invasion, tumor budding, poor differentiation, and deep submucosal invasion, for histologically confirmed lymph node metastases will be evaluated.
Time frame: 5 years
Complication and mortality rates (surgical- and non-surgical)
The proportion of participants experiencing complications or death within 30 and 90 days after treatment allocation. Complications will be graded according to the Clavien-Dindo classification
Time frame: 30 and 90 days
Long-term complication rates (surgical- and non-surgical)
The proportion of participants experiencing treatment-related complications occurring more than 90 days after treatment allocation.
Time frame: 5 years
Number and characteristics of salvage surgeries
Number of salvage surgical procedures performed during follow-up, including indications and type of surgery.
Time frame: 5 years
Re-operation rate
The proportion of participants requiring one or more additional surgical procedures following the initial treatment strategy.
Time frame: 3 and 5 years
Costs of treatment
Direct healthcare costs associated with the assigned treatment strategy, including treatment procedures, hospitalizations, follow-up examinations and management of complications.
Time frame: 5 years
Health-related quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30)
Health-related quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). Scores range from 0 to 100. Higher scores indicate better functioning and quality of life for functional and Global Health Status scales, and greater symptom burden for symptom scales.
Time frame: 1, 3 and 5 years
Health-related quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal Cancer Module (EORTC QLQ-CR29)
Health-related quality of life assessed using the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Colorectal Cancer Module (EORTC QLQ-CR29). Scores range from 0 to 100. Higher scores indicate better functioning for functional scales and worse symptoms for symptom scales.
Time frame: 1, 3 and 5 years
Health-related quality of life assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L)
Health-related quality of life assessed using the EuroQol 5-Dimension 5-Level questionnaire (EQ-5D-5L). EQ-5D-5L index values range from below 0 to 1.0, where 1.0 indicates full health and 0.0 indicates a health state equivalent to death. Higher values indicate better health status.
Time frame: 1, 3 and 5 years
Plan to share: No — Data sharing is not planned due to restrictions related to the European General Data Protection Regulation (GDPR) regarding patient-level data.
No publications or documents are linked to this record.
Start is estimated for Nov 2026; primary completion for Nov 2032, 72 months later.
Of 898 non-industry interventional studies with no phase under Colorectal Neoplasms, half reached primary completion within 32 months of starting (the median), counting those still running; a quarter within 15 and three quarters within 62. This study's planned 72 months is above that.
Counting every sponsor, half of 955 studies reached it within 32 months; a quarter within 14 and three quarters within 60.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Oct 2026. You cannot join it, but the record below documents what was studied.
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