Imaging for early stage breast cancer

Comparison of effective target volume between MammoSite and 3D CRT

Effective CTV was on average 38% ± 4% smaller than CTV-1.5 and 7% ± 10% larger than CTV-1.0 The effective CTV was on average 16% ± 10% smaller than the MammoSite CTV, suggesting that tissue is stretched during therapy Direction-specific margins from the cavity to the effective CTV was median 1.0 cm (range 0.5-1.5cm)

CTV-1.5 CTV-1.0 CTV effective ~MammoSite Treated

Conclusion: The 1 cm margin used to define the MammoSite CTV treated a smaller volume surrounding the lumpectomy cavity than previously thought and less than that targeted by 3D CRT APBI

Shaitelman et al, IJROBP, 2012