New research has shown that SPECT/CT (single photon emission computed tomography/computed tomography imaging) is helpful in identifying sentinel nodes especially in overweight or obese women, according to a report in the February issue of the Journal of Nuclear Medicine published by SNM (the Society of Nuclear Medicine). Sentinel nodes are the first lymph nodes that gather cancerous cells away from a breast lesion site. Identifying them earlier is very helpful in improving treatment of breast cancer patients.
Lymphoscintigraphy, a nuclear medicine procedure that makes the lymphatic system visible to specialized cameras, in combination with SPECT has been found to boost sentinel node identification both in the general population and for overweight individuals, according to SNM.
“The addition of SPECT/CT with lymphoscintigraphy enhanced sentinel node identification in overweight patients with breast cancer,” said Hedva Lerman, study co-author and vice chair of the nuclear medicine department at Tel-Aviv Sourasky Medical Center in Israel.
It is commonly more difficult to locate the nodes in overweight patients and surgeons need techniques to aid in the process, said Lerman. “While the identification of the sentinel node is an important part of surgical management approaches in breast cancer, obesity is a significant factor in why it fails and inevitably leads to occasional—and unnecessary—full axillary lymph node dissection (a more complex surgery that removes all lymph nodes in the armpit region),” she added.
Identifying the sentinel node before this surgery is key; by removing and examining it, a doctor can determine if breast cancer has spread to lymph nodes.
Knowing whether the cancer has spread helps determine the stage and approach to treatment, Lerman said. She added that “performing lymphoscintigraphy by using SPECT/CT allows detection of sentinel nodes preoperatively in more patients, thus reducing the rate of failure to identify these nodes, especially in overweight patients. It also provides a more precise anatomical localization of the nodes prior to surgery, thus facilitating the surgical procedure.”
For the study Israeli researchers calculated the body mass indexes of 220 female subjects and evaluated 220 women with invasive breast cancer by identifying sentinel nodes in three ways: using an intraoperative blue dye technique, lymphoscintigraphy (pre-operative two-dimensional imaging) and SPECT/CT lymphoscintigraphy.
The researchers found that SPECT/CT lymphoscintigraphy also discovered sentinel nodes that were not identified with the intraoperative blue dye technique in a significant number of patients.
“As the number of integrated hybrid SPECT/CT systems evolves, our results hopefully will encourage the use of lymphoscintigraphic SPECT/CT in other centers,” said Lerman. “Data will continue to be collected in identifying sentinel nodes in problematic subgroups of patients with breast cancer and in those with other solid tumors where nodal staging is indicated,” she said.