Clinical trial NCT05336643: Radioisotope and Fluorescence Guidance in Rectal Cancer
Official title: Pelvic Side Wall Lymph Node Detection in Rectal Cancer Using Dual Radioisotope and Fluorescence Guidance
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Rectal Cancer
Lymph Node Metastasis
Lead sponsor: University College, London
Sponsor class: OTHER
First posted: 2022-04-20
Enrollment: 10
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Intervention model description: Open label, single arm, feasibility study for a medical device
Primary purpose: DEVICE_FEASIBILITY

Brief summary: A study to investigate if pelvic side wall lymph nodes that remain after neo-adjuvant chemoradiotherapy can be identified intraoperatively using dual radioisotope and fluorescence guidance.

Detailed description: Background Total mesorectal excision (TME) revolutionised the management of rectal cancer by improving outcomes and standardising surgical technique. When excising mesorectal lymph nodes, most involved nodes are removed. However, a proportion of lower rectal lymphatic drainage is through the pelvic sidewall (PSW) system, all PSW nodes are left behind in TME. Up to 15% patients with rectal cancer have PSW involvement at presentation, this is associated with increased local recurrence.

Problem There are two main approaches in the management of PSW nodes. In the Western hemisphere, patients are typically staged with pre-operative MRI. Those with nodes undergo neo-adjuvant chemoradiotherapy to downstage the tumour, followed by surgical resection, PSW lymph nodes are left in place. In the East patients undergo PSW lymph node dissection at the time of rectal resection. There is evidence that lymphadenectomy at initial surgery or after chemoradiotherapy improves oncological outcome, though this is at the cost of increased morbidity, worsening urinary and sexual function.

Objective The aim is to make PSW lymph node dissection safer and more targeted. This initial feasibility study, is investigating if PSW lymph nodes can be individually identified using dual modalities, fluorescence, and a radioisotope tracer. The fluorophore indocyanine green (ICG) has been used successfully for lymph node mapping in rectal cancer. ICG and Technetium-99m nanocolloid (Tc99m), a radioisotope, have been used as dual tracers for lymph nodes in gynaecological, esophagogastric and oral surgery, but never in rectal surgery.

Method The investigators have designed an open label, single-centre, feasibility study to investigate if PSW lymph nodes can be identified intra-operatively using a radioisotope and fluorescence. Ten post neo-adjuvant chemotherapy rectal cancer patients will be scheduled for resection. Pre-operatively patients will receive an injection of Tc99m and ICG to the submucosa around the tumour. Patients will undergo single-photon emission computed tomography (SPECT) scanning to identify lymphatic drainage. Intra-operatively, after bowel resection, the surgical team will examine the PSW for lymph nodes using a minimally invasive gamma probe (SENSEI, Lightpoint Medical) to detect Tc99m, and a near infrared camera system (Firefly, Intuitive) to visualise ICG. The primary outcome is intraoperative detection of PSW lymph nodes.

Significance The aim from this feasibility study is to demonstrate that individual PSW nodes can be detected intra-operatively. By proving this technique, the investigators will design a larger study to investigate the oncological outcome of excising individual involved nodes, with the aim of reducing PSW recurrence and surgical morbidity.

Eligibility criteria: Inclusion Criteria:

* 18 years of age or older
* Primary diagnosis of biopsy-proven rectal cancer
* Scheduled for curative robotic surgery of primary tumour
* Have signed an approved informed consent form for the study
* Be willing and able to comply with the study protocol

Exclusion Criteria:

* Known allergy or history of adverse reaction to Technetium-99m nanocolloid or indocyanine green
* Pregnant or lactating subjects
* Subjects who, in the Investigator's and/or designee's opinion, have any medical condition that makes the subject a poor candidate for the investigational procedure, or interferes with the interpretation of study results

Primary outcomes:
measure: Lymph node detection with indocyanine green and near-infrared light source
timeFrame: 12 months
measure: Lymph node detection with technetium 99m colloid and SENSEI gamma probe
timeFrame: 12 months
Secondary outcomes:
measure: Radioactive count of identified lymph nodes (MBq)
timeFrame: 12 months
measure: Background radioactive count (MBq)
timeFrame: 12 months
measure: Time to lymph node identification (seconds)
timeFrame: 12 months
measure: Usability of drop in probe (System usability scale)
timeFrame: 12 months
measure: Lymph nodes identified on SPECTCT
timeFrame: 12 months
measure: Concordance of nodes seen on PET MRI/CT and SPECTCT
timeFrame: 12 months
Other outcomes:
Locations:
city: London
country: United Kingdom
facility: University College London Hospital
Study officials:
affiliation: University College London Hospitals
name: Simon Wan
role: PRINCIPAL_INVESTIGATOR
References: