Alterations in pectoralis muscle cell characteristics after radiation of the human breast in situ

Effect of Prepectoral Versus Subpectoral Implant-Based Reconstruction on Post-Mastectomy Radiation Dosimetry

BACKGROUND

The placement of breast implants in a prepectoral plane has become increasingly popular in breast reconstruction, although data on how this affects radiation delivery in women with breast cancer are limited. This study aimed to assess the dosimetric differences in radiation plans for immediate breast reconstruction between prepectoral and subpectoral implants.

METHODS

In this study, a retrospective review and dosimetric analysis of patients with breast cancer who underwent immediate implant-based reconstruction and postmastectomy radiation therapy (PMRT) were performed. Patients with pre- or subpectoral implants were matched 1:1 by use of boost and radiation field. Demographics and complications were compared using the Mann-Whitney U test for continuous variables and the chi-square test for categorical variables. Dosimetric data were analyzed to compare doses to the target, heart, lungs, and pectoralis major using a Mann-Whitney U test.

RESULTS

The study identified 42 patients who met the inclusion criteria. Planning target volume (PTV) coverage was better in the prepectoral group (PTV D95%, 45.61 vs. 43.38 Gy; p = 0.04). The heart and lung doses did not differ. The patients with subpectoral implants had a lower absolute volume of pectoralis major receiving 20 to 45 Gy.

CONCLUSION

This assessment of radiation dosimetry for patients undergoing immediate breast reconstruction found that the primary dosimetric difference between prepectoral and subpectoral implants was the dose to the pectoralis major. Otherwise, no significant difference in target coverage was found. These data suggest that implant placement can be selected to optimize reconstructive outcomes, with less concern for compromise to the oncologic quality of PMRT.

Ultrasound Findings After Breast Cancer Radiation Therapy: Cutaneous, Pleural, Pulmonary, and Cardiac Changes

External beam radiation therapy (RT) can induce toxicity in patients surgically treated for breast cancer. Modern irradiation techniques have lowered the incidence and severity of radiation-induced injuries; however, their side effects on normal tissues remain challenging. This review illustrates early and late changes observed using ultrasound (US) imaging, including echocardiography, at the skin, muscle, pleura, lungs, and heart levels. The US findings and the potential role of this technique in detecting and grading early and late complications of RT are highlighted in this article. US has proven useful in the differential diagnosis of post-RT complications, including but not limited to cancer recurrence and toxicity from other sources, such as anticancer drugs. Additionally, considering the progressive nature of RT-induced injury, early detection of toxicity may be helpful in the individual stratification of damage risk and serve as a tool for patient screening and management. In these cases, US can be used as a radiation-free biomarker of RT side effects at the subclinical stage.

Pectoralis Muscle Dosimetry and Posttreatment Rehabilitation Utilization for Patients With Early-Stage Breast Cancer

PURPOSE

Up to 50% of women treated for localized breast cancer will experience some degree of arm or shoulder morbidity. Although radiation is thought to contribute to this morbidity, the mechanism remains unclear. Prior studies have shown biologic and radiographic changes in the pectoralis muscles after radiation. This study thus aimed to investigate the relationship between radiation to the pectoralis muscles and referrals for rehabilitation services posttreatment for arm and shoulder morbidity.

METHODS AND MATERIALS

A retrospective 1:1 matched case-control study was conducted for patients with breast cancer who were and were not referred for breast or shoulder rehabilitation services between 2014 and 2019 at a single academic institution. Patients were included if they had a lumpectomy and adjuvant radiation. Patients who underwent an axillary lymph node dissection were excluded. Cohorts were matched based on age, axillary surgery, and use of radiation boost. Muscle doses were converted to equivalent dose in 2 Gy fractions assuming an α:β ratio of 2.5 and were compared between the 2 groups.

RESULTS

In our cohort of 50 patients of a median age 60 years (interquartile range, 53-68 years), 36 patients (72%) underwent a sentinel lymph node biopsy in addition to a lumpectomy. Although pectoralis muscle doses were generally higher in those receiving rehabilitation services, this was not statistically significant. Pectoralis major V20-40 Gy reached borderline significance, as did pectoralis major mean dose (17.69 vs 20.89 Gy; P = .06).

CONCLUSIONS

In this limited cohort of patients, we could not definitively conclude a relationship between pectoralis muscle doses and use of rehabilitation services. Given the borderline significant findings, this should be further investigated in a larger cohort.

The impact of local therapies for breast cancer on shoulder muscle health and function

Advances in breast cancer treatment have improved patient survival but have also created complications, such as shoulder morbidity, impacting the patient's quality of life. Local therapies for breast cancer influence shoulder muscle health through changes to the muscular microenvironment, macroscopic muscle morphology, and neuromuscular function. Our findings suggest both surgery and radiation therapy compromise the healthy functioning of shoulder musculature. Mastectomy and post-mastectomy breast reconstruction directly affect shoulder function through muscle morphology and neuromuscular function alterations. Radiation therapy damages satellite cells and myocytes, causing cell death both during treatment and years after recovery. This damage creates an environment limited in its ability to prevent atrophy. However, research to date is limited to a small number of analyses with small experimental populations and a lack of control for covariates. Future research to uncover the pathophysiological mechanisms underlying shoulder morbidity after breast cancer treatment must integrate measures of shoulder muscle health and shoulder function.

Induction of Lactation After Adoption in a Muslim Mother With History of Breast Cancer: A Case Study

INTRODUCTION

With the prevalence of infertility increasing worldwide, many are seeking adoption to fulfill the need to start or expand their family. However, one of the challenges mothers face is the lack of the early maternal bond with the adopted infant, which typically starts during pregnancy, and then continues after birth, while providing care and nourishment to the infant. Breastfeeding is proven to strengthen the maternal-infant bond and provides numerous benefits to the dyad. Reports of induced lactation in non-biological mothers are uncommon, they are even more uncommon to find in women with a history of breast cancer.

MAIN ISSUE

The induction of lactation in a Muslim adoptive mother who had a history of breast cancer.

MANAGEMENT

Pharmacologic methods, which included galactagogues Domperidone and fenugreek, in addition to non-pharmacologic methods that included breast stimulation by using a breast pump. The participant was able to provide her own milk for her adopted infant.

CONCLUSION

When provided with proper support, an adopting mother with a history of breast radiation was able to breastfeed. The participant's need to provide her own expressed milk was met; although, she was counseled on the possibility that her milk production will most likely not be sufficient to entirely meet the infant's needs. Determination and support definitely have a role in cases where the influence of past treatment on human milk production is not known.

Dimensionality analysis of forearm muscle activation for myoelectric control in transradial amputees

Establishing a natural communication interface between the user and the terminal device is one of the central challenges of hand neuroprosthetics research. Surface electromyography (EMG) is the most common source of neural signals for interpreting a user’s intent in these interfaces. However, how the capacity of EMG generation is affected by various clinical parameters remains largely unknown. In this study, we examined the EMG activity of forearm muscles recorded from 11 transradially amputated subjects who performed a wide range of movements. EMG recordings from 40 able-bodied subjects were also analyzed to provide comparative benchmarks. By using non-negative matrix factorization, we extracted the synergistic EMG patterns for each subject to estimate the dimensionality of muscle control, under the framework of motor synergies. We found that amputees exhibited less than four synergies (with substantial variability related to the length of remaining limb and age), whereas able-bodied subjects commonly demonstrate five or more synergies. The results of this study provide novel insight into the muscle synergy framework and the design of natural myoelectric control interfaces.

Detection of early changes in the muscle properties of the pectoralis major in breast cancer patients treated with radiotherapy using a handheld myotonometer

OBJECTIVE

The primary aim was to investigate serial changes in the mechanical properties of the pectoralis major (PM), upper trapezius (UT), and sternoclavicular mastoid muscle (SCM) in breast cancer patients undergoing radiotherapy (RT) using a hand-held myotonometer. The secondary aims were to determine changes in subjective symptoms and to identify correlation with subjective results.

DESIGN

A total of 42 breast cancer patients were enrolled in this longitudinal prospective study. Muscle properties of the PM, UT, and SCM were evaluated before RT, immediately after RT, and 4 months post-RT. Subjective symptom scales of pain and stiffness at rest/stretch of each muscle were evaluated.

RESULTS

The PM showed significant side-to-side differences; the affected PM showed increased tone, stiffness, and decreased elasticity compared with the unaffected PM. The affected PM and UT showed significant time-dependent interactions. Stiffness of the affected PM at stretching was significantly higher 4 months post-RT than baseline. Only the tone and elasticity of the affected PM were correlated with subjective symptoms.

CONCLUSION

In breast cancer patients who received RT after surgery, increased tone, stiffness, and decreased elasticity were observed in the affected PM compared with the unaffected side, which sustained four months post-RT. Change in muscle properties immediately after RT preceded subjective stiffness, which worsened significantly 4 months post-RT compared with baseline.

Perioperatives Management in der Mikrochirurgie – Konsensus-Statement der Deutschsprachigen Arbeitsgemeinschaft für Mikrochirurgie der peripheren Nerven und Gefäße

Perioperative management in microsurgery is a key element of success in reconstructive surgery. There are no uniform concepts for this in the German-speaking countries and individual schemes differ significantly from each other, as ascertained in an expert survey. In the course of the 41st Annual Conference of the German-speaking Working Group for Microsurgery (DAM) held in Munich in November 2019, concepts were evaluated and a survey was carried out and summarised as a position paper in due consideration of the scientific literature.