No abstract

Background Acellular Bovine Pericardium Matrix (ABPM) is a new material in implant-based breast reconstruction (IBBR). Few studies have reported on its outcome and complications worldwide and most studies were without a control group. Our aim was to compare its use in IBBR with the other two conventional implant-based reconstruction methods. Methods A retrospective review of patients undergoing IBBR from January to December 2018 was performed. Patients were assigned to the ABPM-assisted IBBR (group A), latissimus dorsi-assisted IBBR (group B) and two-stage IBBR (group C). Patients’ post-operative complications, cost-effectiveness and Quality of Life were compared. Results 100 patients with 100 breasts were included in the study. No complications occurred in group C ( n = 11). No significant differences were noted between group A ( n = 44) and group B ( n = 45) in terms of overall complications (9.1% vs 11.1%, p = 0.973). Group B had the longest operative duration (310.8 ± 62.3 min, p <0.001). The cost of hospitalization forthe three groups was $8051.3 ± 849.2, $7566.0 ± 1172.7 and $7896.5 ± 1762.2, respectively ( p = 0.128). The postoperative Breast-Q scores  were similar across the three groups. Conclusions ABPM demonstrated acceptable complication rates, cost-effectiveness and quality of life outcomes when compared to LD-assisted IBBR and two-stage IBBR.

dose escalation is limited in favor of organs at risks (OAR) constraints, but very steep dose gradients and very high maximum doses, often in excess of 100 Gy, occur within the target. Small anatomical or positional changes can potentially be critical for the normal tissue due to the high dose gradients in the trial. This study demonstrates how weekly cone beam CT (CBCT) based dose calculations open the possibility to monitor the delivery of escalated doses, thus ensuring the safety of critical OAR close to the target. Materials/Methods: Five NSCLC patients from the dose escalated treatment arm were included in this proof of concept study. CBCT acquired at fraction 5, 10, 15, 20, 25, and 30 were collected and proper HU values were recovered through extensive measurement and Monte Carlo based artefact corrections. This method allows accurate dose calculations to be performed directly on the corrected CBCT images. In order to approximate the patient anatomy situated outside the CBCT scan, the truncated CBCT was embedded in the planning CT. The alignment between CT and CBCT was chosen as the clinical match at the time of treatment. This allowed calculation of the distribution of dose actually delivered to the patient. Delineations of OAR were checked at each CBCT scan and, if necessary, corrected by experienced radiation oncologists. As part of the trial, a standard as well as an escalated treatment plan was prepared and clinically approved prior to treatment. Both plans were recalculated directly on each CBCT scan, and the variation in dose to organs at risk was analyzed from calculated DVHs for lungs, heart, esophagus, trachea, bronchi, and aorta. Results: In general, limited variations of DVH values were observed through the treatment courses, and all dose constraints to OAR were met throughout the treatment course. OAR dose variations in dose escalated plans were very similar to the variations seen in the standard plans. Coefficients of variation (CV) evaluated at the dose-volume points used as constraints in dose planning were similar between standard and escalated plans with 53% (95% CI: 36%-68%) of the CV values being even larger in the standard plan than in the dose escalated plan. Conclusion: With the proper IGRT during treatment and QA as defined in the NARLAL2 trial it appears that the strict dose constraints to critical organs at risks are respected during treatment. Dose variations due to anatomical or positional changes do not appear more extreme for the escalated plans, despite steeper dose gradients. Being able to calculate the dose directly on CBCT scans presents a promising QA work tool in the clinic where the delivered vs planned treatment can be monitored e.g. weekly or even daily if needed.