Dosimetric and therapeutic effectiveness of high-dose-rate radionuclide sources in breast cancer brachytherapy: A systematic review.
Tsige Gebremariam, Teweldebrhan Gebru, Brhanu Tsegaye et al.
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In 30 seconds
This systematic review compared dosimetric properties and therapeutic evidence for ¹⁹²Ir, ⁶⁰Co, and ¹⁶⁹Yb in high-dose-rate breast cancer brachytherapy. Sixteen studies were included, spanning clinical trials, retrospective cohorts, and simulation studies. Dose rate constants were similar across sources (approximately 1.08-1.20 cGy·h⁻¹·U⁻¹), but dose gradients and tissue penetration differed. ¹⁹²Ir had the most extensive clinical validation, with reported local control rates exceeding 90%; evidence for ⁶⁰Co was limited, and ¹⁶⁹Yb evidence was confined to dosimetric and Monte Carlo investigations.
Key findings
- Dose rate constants were similar among radionuclides, at approximately 1.08-1.20 cGy·h⁻¹·U⁻¹.
- ¹⁶⁹Yb showed the steepest dose fall-off and superior organ-at-risk sparing in dosimetric analyses.
- ¹⁹²Ir had the strongest clinical evidence, with local control rates exceeding 90%.
- Clinical evidence was limited for ⁶⁰Co and absent for ¹⁶⁹Yb, whose evidence was restricted to dosimetric and Monte Carlo studies.
Why it matters
Radionuclide choice can affect dose distribution, tissue penetration, and organ-at-risk exposure, while the depth of clinical evidence differs substantially between sources. The review highlights that dosimetric advantages do not by themselves establish clinical benefit, particularly for ¹⁶⁹Yb. Distinguishing established outcomes from planning-based findings is important when interpreting comparisons and considering treatment objectives.
What to keep in mind
Clinical outcome evidence was limited for ⁶⁰Co and unavailable for ¹⁶⁹Yb; the review reports that ¹⁶⁹Yb evidence was restricted to dosimetric and Monte Carlo investigations.