Top Line: With increasingly sensitive methods for detecting isolated tumor cells in lymph nodes, what do we do with that…?
The Study: Staging systems largely fall on the side of ignoring it, but the presence of ITCs clearly impacts clinical decision-making when it comes to adjuvant treatment strategies for endometrial cancer. That’s probably because, as opposed to say breast cancer where most women are getting some form of radiation and systemic therapy, any or no adjuvant therapy is typically left up to the radixation oncologist for early-stage endometrial cancer. Here is a lit review to help us better understand this dilemma in the absence of robust data. First consider that roughly 40% of women with sentinel node involvement have further non-sentinel node involvement. But, while primary tumor risk factors certainly affect this risk, the biggest predictor of non-sentinel node involvement is size of sentinel node disease burden. So the breakdown for risk is more like 60% for macromets, 20% for micromets and 10% for isolated tumor cells. What’s more, while the majority of these patients in the available literature received some form of adjuvant therapy, their recurrence-free survival is consistently excellent, on the order of 95% (e.g. far superior to those with apparent node involvement). In light of this, the authors proceed to offer practical advice on how to address the presence of isolated tumor cells for stable I disease in clinic, and it largely boils down to both primary tumor risk factors and whether a completion dissection was performed. In general, with completion dissection, brachytherapy is bought with the presence of focal lymphovascular space invasion (LVSI) or IB disease and external beam radiation to the pelvis with extensive LVI, grade 2 + IB disease, or any grade 3 disease. What does completion dissection with no additional disease change? In that case, only extensive LVI or grade 3 + IB disease buys pelvic radiation. The only thing missing in this 2022 treatment algorithm is MMR-status.
TBL: The presence of nodal isolated tumor cells for stage I endometrial cancer deserves consideration as a *small* risk factor when determining utility of adjuvant radiation. | Musunuru, Pract Radiat Oncol 2022