The role of rectal sparing devices in post-prostatectomy radiotherapy: a review article

Adjuvant or salvage radiotherapy can control biochemical relapse after radical prostatectomy and reduce the risk of distant metastases. Dose-escalated radiotherapy after radical prostatectomy can lead to improved biochemical relapse-free survival. Over the last decades, despite the technological advancements in prostate radiotherapy, radiation-induced rectal toxicity is still the main limiting factor for dose escalation owing to the anatomical proximity of the prostate gland to the rectum. To this end, several rectal sparing devices, including Endorectal balloons (ERBs), prostate-rectum spacers (e.g. SpaceOAR hydrogel), and rectal retractor have been explored to increase the distance between the prostate and the rectum to reduce rectal radiation doses and toxicities. Over the last decade, several studies applied these devices during post-prostatectomy radiotherapy setting. Therefore, the purpose of this review is to evaluate the impact of rectal sparing devices on dose-volume parameters of anorectal, radiation-induced rectal toxicity, and prostate bed motion during post-prostatectomy radiotherapy. The results showed that although using ERBs can lead to stability in the target volume position, it cannot reduce rectal radiation doses, in particular dose to the anterior rectal wall. The application of ERBs can reduce the received dose of the anal wall and increase the geometric reproducibility of the clinical target volume (CTV) position. However, the role of ERBs in reducing the received dose of the rectal wall is still controversial, which can be associated with the displacement of the anterior rectal wall towards the prostate bed (high radiation dose area). The use of SpaceOAR hydrogel can significantly increase the distance between the rectum and the prostate bed and ultimately reduce the dose received by the rectal wall. Also, the use of rectal retractor remarkably reduces rectal radiation doses. The dosimetric and clinical results of the use of SpaceOAR hydrogel and rectal retractor are very promising, and these devices can be used for patients after the necessary evaluations by radiation oncologist in post-prostatectomy radiotherapy. However, further studies will be required to elucidate the efficacy of SpaceOAR hydrogel and rectal retractor in reducing radiotherapy-induced rectal toxicity following post-prostatectomy radiotherapy. Keywords: prostatectomy, prostate cancer, radiotherapy, rectum

The Relationship between Lung and Heart Two-Dimensional Parameters and Three-Dimensional Dose-Volume Data in Adjuvant Radiotherapy for Breast Cancer

Background: Two-dimensional (2D) radiographic parameters have been used to estimate the amount of heart and lung irradiated for minimizing heart and lung complications in breast cancer patients. The aim of this study was to investigate the correlation between traditionally used 2D radiographic and dose-volume parameters during adjuvant radiotherapy of breast cancer. Methods: In this cross-sectional study, we analyzed 121 female patients treated with breast-conserving surgery (BCS) or modified radical mastectomy (MRM) and 3D conformal radiotherapy (3DCRT) using two-field radiotherapy (2FRT) or three-field radiotherapy (3FRT) technique. All patients underwent computed tomography (CT)-planning. Two-D parameters, including central lung distance (CLD), maximum lung depth (MLD), maximum heart length (MHL), maximum heart distance (MHD), and chest wall separation (CWS), were measured using digitally reconstructed radiographs (DRR) and CT images. DVHs for lung, heart, and target were created. The Pearson correlation test was used to evaluate the correlation between 2D radiographic and dose-volume parameters. Results: There was a correlation between CLD and ipsilateral lung V5-20Gy and Dmean and between MLD and ipsilateral lung V5-20Gy. In 2FRT, only moderate correlation between CLD and ipsilateral lung V20Gy (r = 0.453, P = 0.003) and between MLD and ipsilateral lung V20Gy (r = 0.593, P <0.001) were observed. Poor correlation of MHL and heart V25Gy (r = 0.409, P = 0.007) was seen only in 3FRT. There was a correlation between MHD and heart dose-volume data, with a strong correlation between MHD and heart V5-25Gy and Dmean (r = 0.875-0.934, P<0.001) in the 2FRT group. No correlation between CWS and breast Dmax was found. Conclusion: There was a correlation between 2D parameters (i.e., CLD, MLD, and MHD) and the heart and lung dose-volume parameters during adjuvant breast radiotherapy. Although CLD was correlated to ipsilateral lung V5-20Gy and Dmean, the correlation between CLD and ipsilateral lung V20Gy was greater than other dose-volume parameters. MHD provided a close estimation of heart dose-volume parameters

A cohort study on the immunogenicity and safety of the inactivated SARS-CoV-2 vaccine (BBIBP-CorV) in patients with breast cancer; does trastuzumab interfere With the outcome?

Aim To determine the efficacy and safety of inactivated SARS-CoV-2 vaccine (BBIBP-CorV) in patients with breast cancer. Methods In this multi- institutional cohort study, a total of 160 breast cancer patients (mean age of 50.01 ± 11.5 years old) were assessed for the SARS-CoV-2 Anti-Spike IgG and SARS-CoV2 Anti RBD IgG by ELISA after two doses of 0.5 mL inactivated, COVID-19 vaccine (BBIBP-CorV). All patients were followed up for three months for clinical COVID-19 infection based on either PCR results or imaging findings. Common Terminology Criteria for Adverse Events were used to assess the side effects. Results The presence of SARS-CoV-2 anti-spike IgG, SARS-CoV2 anti-RBD IgG, or either of these antibodies was 85.7%, 87.4%, and 93.3%. The prevalence of COVID-19 infection after vaccination was 0.7%, 0% and 0% for the first, second and third months of the follow-up period. The most common local and systemic side-effects were injection site pain and fever which were presented in 22.3% and 24.3% of patients, respectively. Discussion The inactivated SARS-CoV-2 vaccine (BBIBP-CorV) is a tolerable and effective method to prevent COVID-19