Nushin Mirzaei: Ultra-low dose of tracer identifies sentinel lymph node
Sentinel lymph node (SLN) staging is important for treatment in patients with melanoma and breast cancer. Superparamagnetic iron oxide (SPIO) is a relatively new tracer used to locate the SLN. Nushin Mirzaei’s doctoral thesis demonstrates that an ultra-low dose of SPIO still effectively identify SLN, significantly reducing side effects.
NUSHIN MIRZAEI
Dissertation defense: 24 May 2024 (click for details)
Doctoral thesis: Superparamagnetic iron oxide for sentinel lymph node biopsy
Research area: Surgery
Sahlgrenska Academy, The Institute of Clinical Sciences
The sentinel lymph node is the first lymph node to receive lymphatic drainage from a tumor area. This node is the first affected when cancer spreads.
Today, the sentinel lymph node is routinely removed in patients with conditions such as melanoma and breast cancer. This typically involves a dual technique: a radioactive tracer linked to a carrier protein and a blue dye to locate the sentinel lymph node.
However, the availability of radioactive tracers is limited, and the blue dye can rarely trigger allergic reactions.
Skin discoloration and artifacts
A new technique using an iron-based tracer, superparamagnetic iron oxide (SPIO), has shown comparable results to the dual technique.
“Drawbacks of using SPIO in breast cancer include its potential to cause skin discoloration at the injection site and to induce artifacts in subsequent MRI scans,” Nushin Mirzaei explains.
She is a surgeon specializing in breast cancer and melanoma surgery at Sahlgrenska University Hospital, currently pursuing her doctoral degree at the Institute of Clinical Sciences.
“A 10–20 times lower dose”
What is the focus of your research?
“The recommended dose of SPIO for breast cancer is 1–2 milliliters injected into the breast. The primary aim of my thesis was to evaluate if it’s possible to use a 10–20 times lower dose, an ultra-low dose of SPIO at 0.1 milliliters, to still identify the sentinel lymph node in patients with melanoma and breast cancer. We also explored whether this could lead to reduced skin discoloration and MR artifacts,” says Nushin Mirzaei, adding:
“Additionally, we investigated if MRI imaging after SPIO injection could identify metastases in the sentinel lymph node before surgery.”
Only minor side effects
What are the key research findings?
“Identifying the sentinel lymph node with an ultra-low dose of SPIO tracer was feasible in patients with both melanoma and breast cancer. Our initial study also suggests the possibility of predicting tumor spread to the sentinel lymph node with MRI before surgery, which hasn’t been possible before.”
And what about the MR artifacts and skin discoloration?
“The ultra-low dose of SPIO caused only minor MR artifacts, which generally didn’t affect breast diagnostics. We observed only slight skin discoloration in some patients, who also reported no significant impact.”
“An enlightening research process”
What has been rewarding and challenging about your doctoral project?
“It has been enlightening to be involved in the entire research process. From writing ethical applications, informing and obtaining patient consent, coordinating and structuring follow-up checks to collaborating with all co-authors. Despite occasional challenges in data analysis, the atmosphere within the research team has been remarkably positive.”
Text: Jakob Lundberg