Determining axillary concordance rate for different injection locations in sentinel node mapping of breast cancer: how ambitious can we get?

Concordance Between Intracervical and Fundal Injections for Sentinel Node Mapping in Patients With Endometrial Cancer?

Objective

A major controversy in sentinel node (SN) biopsy of endometrial cancer is the injection site of mapping material. We compared lymphatic drainage pathways of the uterine cervix and uterine body in the same patients by head-to-head comparison of intracervical radiotracer and fundal blue dye injections.

Methods

All patients with pathologically proven endometrial cancer were included. Each patient received 2 intracervical injections of 99mTc-phytate. At the time of laparotomy, the uterus was exposed, and each patient was injected with 2 aliquots of patent blue V (2 mL each) in the subserosal fundal midline locations. The anatomical locations of all hot, blue, or hot/blue SNs were recorded.

Results

Overall, 45 patients entered the study. At least 1 SN could be identified in 75 of 90 hemipelves (83.3% overall detection rate, 82.2% for radiotracer [intracervical] alone, and 81.1% for blue dye [fundal] alone). In 71 hemipelves, SNs were identified with both blue dye (fundal) and radiotracer (intracervical) injections. In 69 of these 71 hemipelves, at least 1 blue/hot SN could be identified (97.18% concordance rate). In 10 patients, para-aortic SNs were identified. All of these nodes were identified by fundal blue dye injection, and only 2 were hot.

Conclusions

Our study shows that lymphatic drainage to the pelvic area from the uterine corpus matches the lymphatic pathways from the cervix, and both intracervical and fundal injections of SN mapping materials go to the same pelvic SNs.

The inextricable axis of targeted diagnostic imaging and therapy: An immunological natural history approach

In considering the challenges of approaches to clinical imaging, we are faced with choices that sometimes are impacted by rather dogmatic notions about what is a better or worse technology to achieve the most useful diagnostic image for the patient. For example, is PET or SPECT most useful in imaging any particular disease dissemination? The dictatorial approach would be to choose PET, all other matters being equal. But is such a totalitarian attitude toward imaging selection still valid? In the face of new receptor targeted SPECT agents one must consider the remarkable specificity and sensitivity of these agents. (99m)Tc-Tilmanocept is one of the newest of these agents, now approved for guiding sentinel node biopsy (SLNB) in several solid tumors. Tilmanocept has a Kd of 3×10(-11)M, and it specificity for the CD206 receptor is unlike any other agent to date. This coupled with a number of facts, that specific disease-associated macrophages express this receptor (100 to 150 thousand receptors), that the receptor has multiple binding sites for tilmanocept (>2 sites per receptor) and that these receptors are recycled every 15 min to bind more tilmanocept (acting as intracellular "drug compilers" of tilmanocept into non-degraded vesicles), gives serious pause as to how we select our approaches to diagnostic imaging. Clinically, the size of SLNs varies greatly, some, anatomically, below the machine resolution of SPECT. Yet, with tilmanocept targeting, the SLNs are highly visible with macrophages stably accruing adequate (99m)Tc-tilmanocept counting statistics, as high target-to-background ratios can compensate for spatial resolution blurring. Importantly, it may be targeted imaging agents per se, again such as tilmanocept, which may significantly shrink any perceived chasm between the imaging technologies and anchor the diagnostic considerations in the targeting and specificity of the agent rather than any lingering dogma about the hardware as the basis for imaging approaches. Beyond the elements of imaging applications of these agents is their evolution to therapeutic agents as well, and even in the neo-logical realm of theranostics. Characteristics of agents such as tilmanocept that exploit the natural history of diseases with remarkably high specificity are the expectations for the future of patient- and disease-centered diagnosis and therapy.