Efficacy and Safety of Pectoral Nerve Block (Pecs) Compared With Control, Paravertebral Block, Erector Spinae Plane Block, and Local Anesthesia in Patients Undergoing Breast Cancer Surgeries: A Systematic Review and Meta-analysis.

OBJECTIVE: We aimed to compare the safety and efficacy of pectoral nerve block (Pecs) I and II with control or other techniques used during breast cancer surgeries such as local anesthesia, paravertebral block, and erector spinae plane block (ESPB). METHODS: We searched 4 search engines (PubMed, Cochrane Library, Scopus, and Web of Science) for relevant trials, then extracted the data and combined them under random-effect model using Review Manager Software. RESULTS: We found 47 studies, 37 of them were included in our meta-analysis. Regarding intraoperative opioid consumption, compared with control, a significant reduction was detected in Pecs II (standardized mean difference [SMD]=-1.75, 95% confidence interval [CI] [-2.66, -0.85], P=0.0001) and Pecs I combined with serratus plane block (SMD=-0.90, 95% CI [-1.37, -0.44], P=0.0002). Postoperative opioid consumption was significantly lowered in Pecs II (SMD=-2.28, 95% CI [-3.10, -1.46], P<0.00001) compared with control and Pecs II compared with ESPB (SMD=-1.75, 95% CI [-2.53, -0.98], P<0.00001). Furthermore, addition of dexmedetomidine to Pecs II significantly reduced postoperative opioid consumption compared with Pecs II alone (SMD=-1.33, 95% CI [-2.28, -0.38], P=0.006). CONCLUSION: Pecs block is a safe and effective analgesic procedure during breast cancer surgeries. It shows lower intra and postoperative opioid consumption than ESPB, and reduces pain compared with control, paravertebral block, and local anesthesia, with better effect when combined with dexmedetomidine.

Characterization of irregular electron beam for boost dose after whole breast irradiation.

Irradiating a tumor bed with boost dose after whole breast irradiation helps reducing the probability of local recurrence. However, the success of electron beam treatment with a small area aiming to cover a superficial lesion is a dual challenge as it requires an adequate dosimetry beside a double check for dose coverage with an estimation of various combined uncertainty of tumor location and losing lateral electron equilibrium within small field dimensions. AIM OF WORK: this work aims to measure the electron beam fluence within different field dimensions and the deviation from measurement performed in standard square electron applicator beam flatness and symmetry, then to calculate the average range of the correction factor required to overcome the loss of lateral electron equilibrium. MATERIAL AND METHOD: the electron beam used in this work generated from the linear accelerator model ELEKTA Precise and dosimetry system used were a pair of PTW Pin Point ion chambers for electron beam dosimetry at standard conditions and assessment of beam quality at a reference depth of measurement, with an automatic water phantom, then a Roos ion chamber was used for absolute dose measurement, and PTW 2Darray to investigate the beam fluence of four applicators 6, 10, 14 and 20 cm2 and 4 rectangular cutouts 6 × 14, 8 × 14, 6 × 17 and 8 × 17 cm2, the second part was clinical application which was performed in a precise treatment planning system and examined boost dose after whole breast irradiation. RESULTS: revealed that lower energy (6MeV and 8MeV) showed the loss of lateral electron equilibrium and deviation from measurements of a standard applicator more than the high energy (15 MeV) which indicated that the treatment of superficial dose with 6MeV required higher monitor unit to allow for the loss of lateral electron equilibrium and higher margin as well.