Short summary

The standard treatment of rectal cancer is surgery. International and Danish research shows that a high proportion of patients can be cured with radiotherapy and chemotherapy and thus avoid surgery.

In this trial, the most effective level of radiotherapy will be established.

Rationale

The main curative treatment modality for rectal cancer is surgery, potentially combined with chemotherapy and radiotherapy to lower the risk of local recurrence. In recent years, an increasing number of retrospective and prospective observational studies have indicated that a subset of patients may avoid surgery altogether if they can achieve a complete response to chemoradiotherapy. These studies have mainly focused on locally advanced tumors with a high risk of local recurrence. Smaller, less advanced tumors appear to respond better to chemoradiotherapy, but the optimal treatment for non-surgical management has not been established. Prospective trials, including the previous Danish Watchful Waiting trials (NCT00952926, NCT02438839) in rectal cancer have demonstrated high levels of organ preservation with dose-escalation, but it is unclear whether this was primarily due to tumor stage or dose level. High-level evidence is currently absent for the question of radiotherapy dose, especially in early stage cancers.

The aim of the present study is to investigate if a higher dose of radiotherapy is superior compared to a standard dose in patients with rectal cancer undergoing chemoradiotherapy with curative intent.

Description of the cohort

Patients with rectal cancer. Both sexes. Age of at least 18 years.

Data and biological material

Data about the cancer, demographics, treatment and outcome.

Biopsy from the tumor before treatment. Serial blood samples.

Collaborating researchers and departments

Department of Oncology 5073, Rigshospitalet

• MD Christiane Ehlers Mortensen

Department of Oncology, Aalborg University Hospital

• MD, PhD, Laurids Østergaard Poulsen

Department of Surgery, Copenhagen University Hospital, Bispebjerg Hospital

• MD, Med ScD, Tommie Mynster