Preoperative CT for postoperative radiotherapy planning in breast cancer

Introduction: The exact location of the original tumor should be known for a targeted increase in the dose to the tumor bed after breast cancer surgery. Therefore, at our site, we perform CT examinations of patients in the radiation position before breast cancer surgery. Methods: Preoperative native CT scans were performed in the patients in the planning position for radiotherapy; these data were fused with standard planning CT for boost irradiation. We evaluated whether the tumor was accurately identifiable in preoperative CT scans. We also contoured one irradiation volume in the standard planning CT scans and the other in the fusion CT scans with preoperative examination, and compared these volumes. Results: Out of the total number of 554 patients, we were able to identify the exact location of the breast tumor in 463 cases (83.6 %). In a group of 50 randomly selected patients, the clinical target volume for the boost dose to the postlumpectomy cavity was changed in 20 patients (40%) – decreased in 9 cases (18%) and increased in 11 cases (22%). Conclusion: As shown by the results of our study, preoperative CT in the planning position can be used in patients with confirmed breast cancer. This method allows us to more accurately locate the tumor bed and thus more accurately draw the target volume for boost irradiation. We confirmed that preoperative CT had an impact on the size of the target volume.

Emlőrák miatti szervmegtartó műtétek reszekciós széleinek vizsgálata. Multicentrikus retrospektív elemzés

Introduction: Breast conserving surgery for breast cancer requires the analysis of surgical margins. If the tumor is not removed completely, additional treatments (reoperation, boost irradiation) are generally recommended. Aim: To analyze the information content of histopathology reports on surgical margins in consecutive cases of breast conservation for invasive female breast cancer, to evaluate the frequency of incompletely removed tumors and to estimate the rate of further treatments after incomplete removal. Method: Analysis of margin related data of consecutive histopathology reports from 8 Hungarian pathology units with locoregional treatment related data in case of unsafe margins. Results: 386 reports were analyzed after exclusions. 200 and 32 cases were identified as having unsafe margins according to the previous (<5 mm) and the new (0 mm) definition of unclear margin, respectively. Unsafe margins were more common with lobular carcinomas. Specimens with clear margins weighed more. Reoperations for unsafe margins were performed in 43/180 and 12/22 cases according to the previous and the new definitions, respectively. Only 75/137 patients without reoperation received boost irradiation of the tumor bed; information on boost radiotherapy was often missing. Residual cancer was identified in 15/43 reoperated patients, of whom 9 had >0 mm margin distance. Conclusions: Some pathology reports lack information on surgical margins. Unsafe margin rates decreased with the new definition. Residual cancer may be left behind in case of clear margins with no ink on tumor. Neither reoperation, nor boost radiotherapy is given to some patients with unclear surgical margins. Orv Hetil. 2019; 160(26): 1036–1044.

Tumour bed localisation after oncoplastic breast conservative surgery: a comparative contouring study

PurposeTo investigate the modalities of tumour bed (TB) localisation of target volume delineation [clinically computed tomography (CT), ultrasound (US) compared with surgical clips-guided] and the impact of their differences in delineated TB volumes.Material and methodsIn total, 27 patients who underwent oncoplastic breast conservative surgery with surgical clips insertion (at least three) were included. CT and US imaging for TB localisation were done 3–4 weeks post-operatively in the same treatment position. TB was delineated four times, guided by surgical clips, clinical data, CT (seroma) and US. A plan was done for each TB delineated. The four delineated volumes were compared regarding the volumetric differences, the geographical miss index (GMI) and the overlap index.ResultsComparing the four modalities, median TB volume was for clinical (60.7), CT (60.8) and US (49.3) cm3, in comparison with 59.7 cm3 for clips, p=0.05. Median of GMI (represented the tissue at risk of recurrence and not had been treated) was for clinical (61.8), CT (45) and US (62.4)%, with significant difference of p=0.02. Median of normal tissue index (normal tissue has been included unnecessarily) was for clinical (59.5), CT (49.6) and US (62.3)%, p=0.17. Overlap index with clips-guided was for clinical (0.36), CT (0.42) and US (0.35) with significance of p=0.04. Median superior/inferior direction was 0.72, −0.03 and −0.2 cm for clinical, CT and US, respectively, with significant value of p=0.02, whereas the anterior–posterior was −0.07, −0.15 and −0.09 cm, p-value=0.45 and the medio–lateral was 0.4, −0.13 and 0.09 cm, p=0.60.ConclusionSignificant differences in shifts and indices were detected between each of modalities compared with surgical clips. Thus, in the setting of oncoplastic breast surgery, surgical clips should be routinely used for TB localisation. In view of the larger volumes of breast tissue excised and the extensive remodelling that are inherent to oncoplastic procedures, the concept of TB boost irradiation should be re-challenged.