When Is CT-Based Postoperative Seroma Most Useful to Plan Partial Breast Radiotherapy? Evaluation of Clinical Factors Affecting Seroma Volume and Clarity

Cone‐beam computed tomography image guided therapy to evaluate lumpectomy cavity variation before and during breast radiotherapy

“…The RoC before RT was found to be higher in patients with a larger ${\text{CTV}}_{\text{LC}}$ prior to starting RT, whereas ${\text{CTV}}_{\text{LC}}$ volume did not affect the RoC during RT. A comparison of this study with select previous studies ( 2 , 5 , 7 – 19 ) is presented in Table 4.…”

“…A majority of the studies reported an inverse association between the time from surgery to ${\text{CT}}_{\text{sim}}$ and change in LC before ( 2 ) and during RT, ( 5 , 9 , 10 , 12 , 15 , 17 ) with a longer time from surgery associated with a smaller LC change. The results for initial ${\text{CTV}}_{\text{LC}}$ and change in ${\text{CTV}}_{\text{LC}}$ were mixed, with some studies reporting larger volume reduction over time with a larger initial ${\text{CTV}}_{\text{LC}}$, ( 12 , 14 , 16 , 17 ) while others reported no correlation.…”

“…Kader et al ( 2 ) found that the optimal time to perform a ${\text{CT}}_{\text{sim}}$ for PBI patients was within 7–8 weeks from surgery, whereas, if ${\text{CT}}_{\text{sim}}$ was performed after eight weeks from surgery, then difficulties in identifying the LC arose. Our study showed that the LC may be subject to greater variation in size during RT if ${\text{CT}}_{\text{sim}}$ was performed $<\text{six}$ weeks (42 days) from surgery, especially for large initial ${\text{CTV}}_{\text{LC}}$ $\ge 25.7\text{cc}$ (Fig.…”

“…( 1 ) Accurate identification of the LC clinical target volume (${\text{CTV}}_{\text{LC}}$) is essential in identifying breast tissue at highest risk for harboring microscopic disease to ensure tumor control while sparing the normal breast tissue. ( 2 , 3 ) Computed tomography (CT) planning for PBI and WBI has become a standard practice, although defining the surgical cavity using CT alone can pose difficulties in its differentiation from normal breast tissue as the breast density varies among patients. Surgical clips placed during breast conserving surgery can aid visualization of the LC on radiographs and CT to help define the limits of the LC and improve the accuracy of defining the clinical target volumes for PBI and for the breast boost treatment in WBI.…”

Dosimetric impact of post-operative seroma reduction during radiotherapy after breast-conserving surgery

“…In case the boost target volume (TV boost ) on the initial planning CT includes post-operative seroma, it is frequently assumed that it does not change significantly during RT. However, prior studies have demonstrated 36% to 50% seroma reduction prior to RT [3,4], and 22% to 62% during RT [5][6][7][8][9]. Due to seroma reduction, the volume of breast tissue not intended to receive boost RT will become excessive towards the end of treatment, with increasing risk of fibrosis and additional worsening of cosmetic outcome [10,11].…”