Researchers from St. Vincent’s Hospital and Medical Center in New York City and the Hospital of the University of Pennsylvania in Philadelphia have reported new applications for sentinel node (SN) localization in breast cancer patients.
Dr. Suman Jana and colleagues at St. Vincent’s investigated the question: "Is multifocal/multicentric breast carcinoma an absolute contraindication for sentinel node localization?"
"The SN localization technique has usually not been used in this group of cancer patients because we thought we would miss some sentinel nodes," Jana said. To find out whether the SN localization technique is useful in such patients, Jana and colleagues used SN biopsy results from 80 patients. They discussed their results at the 2002 Society of Nuclear Medicine meeting in Los Angeles.
The patients received 10 MBq Tc-99m of unfiltered sulfur colloid in 0.3-0.4 ml injections intra/subdermally above each palpable breast mass, between 2 and 4 hours before surgery. Imaging took place approximately 45 minutes prior to surgery using a Millennium MPR/MPS single-head camera (GE Medical Systems, Waukesha, WI). For the SN biopsy, patients received radiocolloid, blue dye, or a combination of both.
According to the results, the sensitivity for the radiocolloid method was 100%, the negative predictive value (NPV) was 100%, and the accuracy was 100%. The success rate for this method was 94%.
For the blue dye technique, the sensitivity was 96%, the NPV was 96%, and the accuracy was 98%. The success rate was 87%, the authors reported.
Finally, for the combined method, the sensitivity, NPV, and accuracy all came in at 100%. The success rate was 94%.
"The results are suggestive of good negative predictive value, which is comparable to the SN localization in usual patients," Jana concluded. "The next step of research is to conduct a prospective trial with a large group of patients to validate this study."
In a second SNM study, the Pennsylvania group analyzed locoregional and distant recurrence rates among patients with metastatic disease presented in the sentinel lymph node.
Since 1998, Dr. Robert Canter and colleagues from the Hospital of the University of Pennsylvania have maintained the Breast Cancer Sentinel Lymph Node Registration. They have investigated the safety and efficacy of SLN biopsy in patients with invasive breast cancer, regardless of primary tumor size.
The group is also working to determine the effect of SLN biopsy on recurrence rates and survival. Their current study included 369 patients with pathologically confirmed invasive breast cancer and clinically negative axilla with a minimum of 1-year follow-up and median follow-up of 30 months.
Imaging of the patients used 1 millicurie of filtered Tc-99m-labeled sulfur colloid. Of the 55 patients with metastatic disease in the SLN, 5.4% had recurrences (1 locoregional, 2 distant). In 38 of the patients with SLN and nonsentinel lymph node (NSLN) positive nodes, 21% had recurrences (2 locoregional, 6 distant). The difference between the two groups in both overall recurrence and distant recurrence was statistically significant (P < 0.05).
The results were considered important for two reasons. "First, patients with lymph node involvement beyond the SLN have a significantly higher risk of early distant recurrence than patients who are SLN-positive only," Canter said. "Second, in patients with a positive SLN, completion of axillary dissection identifies patients with a higher risk for systemic failure in whom more aggressive therapies may be warranted."
In the future, the University of Pennsylvania researchers will accumulate more patients with longer follow-up in order to determine if these results are valid for survival rates as well.
By Laura RuthAuntMinnie.com contributing writer
August 12, 2002
Related Reading
Sentinel lymph node biopsy backed for breast cancer, June 19, 2002
Radiodetection may find more than one sentinel node, June 17, 2002
Lymphoscintigraphy discussion, August 29, 2001
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