Mapping respiratory syncytial virus fusion protein interactions with the receptor IGF1R and the impact of alanine-scanning mutagenesis on viral infection

Respiratory syncytial virus (RSV) has two main surface glycoproteins, the attachment glycoprotein (G) and the fusion (F) protein, which together mediate viral entry. Attachment is mediated by the RSV-G protein, while the RSV-F protein makes specific contact with the cellular insulin-like growth factor 1 receptor (IGF1R). This interaction leads to IGF1R activation and initiates a signalling cascade that calls the co-receptor, nucleolin, from the nucleus to the cell surface, where it can trigger viral fusion. We performed molecular docking analysis, which provided a potential set of 35 residues in IGF1R that may be important for interactions with RSV-F. We used alanine-scanning mutagenesis to generate IGF1R mutants and assessed their abundance and maturation, as well as the effect of mutation on RSV infection. We identified several mutations that appear to inhibit IGF1R maturation; but surprisingly, these mutations had no significant effect on RSV infection. This suggests that maturation of IGF1R may not be required for RSV infection. Additionally, we identified one residue, S788, that, when mutated, significantly reduced RSV infection. Further analysis revealed that this mutation disrupted a hydrogen bonding network that may be important for both IGF1R maturation and RSV infection.

The domestication of SARS-CoV-2 into a seasonal infection by viral variants

Introduction

The COVID-19 pandemic was caused by the zoonotic betacoronavirus SARS-CoV-2. SARS-CoV-2 variants have emerged due to adaptation in humans, shifting SARS-CoV-2 towards an endemic seasonal virus. We have termed this process 'virus domestication'.

Methods

We analyzed aggregate COVID-19 data from a publicly funded healthcare system in Canada from March 7, 2020 to November 21, 2022. We graphed surrogate calculations of COVID-19 disease severity and SARS-CoV-2 variant plaque sizes in tissue culture.

Results and Discussion

Mutations in SARS-CoV-2 adapt the virus to better infect humans and evade the host immune response, resulting in the emergence of variants with altered pathogenicity. We observed a decrease in COVID-19 disease severity surrogates after the arrival of the Delta variant, coinciding with significantly smaller plaque sizes. Overall, we suggest that SARS-CoV-2 has become more infectious and less virulent through viral domestication. Our findings highlight the importance of SARS-CoV-2 vaccination and help inform public policy on the highest probability outcomes during viral pandemics.

Actin cytoskeleton remodeling disrupts physical barriers to infection and presents entry receptors to respiratory syncytial virus

RSV is the leading cause of infant hospitalizations and a significant cause of paediatric and geriatric morbidity worldwide. Recently, we reported that insulin-like growth factor 1 receptor (IGF1R) was a receptor for respiratory syncytial virus (RSV) in airway epithelial cells and that activation of IGF1R recruited the coreceptor, nucleolin (NCL), to the cell surface. Cilia and mucus that line the airways pose a significant barrier to viral and bacterial infection. The cortical actin cytoskeleton has been shown by others to mediate RSV entry, so we studied the roles of the RSV receptors and actin remodelling during virus entry. We found that IGF1R expression and phosphorylation were associated with the ability of RSV to infect cells. Confocal immunofluorescence imaging showed that actin projections, a hallmark of macropinocytosis, formed around viral particles 30 min after infection. Consistent with prior reports we also found that virus particles were internalized into early endosome antigen-1 positive endosomes within 90 min. Inhibiting actin polymerization significantly reduced viral titre by approximately ten-fold. Inhibiting PI3 kinase and PKCζ in stratified air-liquid interface (ALI) models of the airway epithelium had similar effects on reducing the actin remodelling observed during infection and attenuating viral entry. Actin projections were associated with NCL interacting with RSV particles resting on apical cilia of the ALIs. We conclude that macropinocytosis-like actin projections protrude through normally protective cilia and mucus layers of stratified airway epithelium that helps present the IGF1R receptor and the NCL coreceptor to RSV particles waiting at the surface.

Loss of Respiratory Syncytial Virus Antibody Functions During the Peak of the COVID-19 Pandemic Mitigation Measures

Studies have linked respiratory syncytial virus (RSV) antibody-mediated phagocytosis and complement deposition to severe RSV infection in humans. This study shows waning of these antibody functions in women of childbearing age in 2020-2021 during the implementation of COVID-19 mitigation measures, in absence of RSV circulation. These functions could be explored as correlates of protection against severe RSV disease.

SARS-CoV-2 infection downregulates myocardial ACE2 and potentiates cardiac inflammation in humans and hamsters

Myocardial pathologies resulting from SARS-CoV-2 infections are consistently rising with mounting case rates and reinfections; however, the precise global burden is largely unknown and will have an unprecedented impact. Understanding the mechanisms of COVID-19-mediated cardiac injury is essential toward the development of cardioprotective agents that are urgently needed. Assessing novel therapeutic strategies to tackle COVID-19 necessitates an animal model that recapitulates human disease. Here, we sought to compare SARS-CoV-2-infected animals with patients with COVID-19 to identify common mechanisms of cardiac injury. Two-month-old hamsters were infected with either the ancestral (D614) or Delta variant (B.1.617.2) of SARS-CoV-2 for 2 days, 7 days, and/or 14 days. We measured viral RNA and cytokine expression at the earlier time points to capture the initial stages of infection in the lung and heart. We assessed myocardial angiotensin-converting enzyme 2 (ACE2), the entry receptor for the SARS-CoV-2 virus, and cardioprotective enzyme, as well as markers for inflammatory cell infiltration in the hamster hearts at days 7 and 14. In parallel, human hearts were stained for ACE2, viral nucleocapsid, and inflammatory cells. Indeed, we identify myocardial ACE2 downregulation and myeloid cell burden as common events in both hamsters and humans infected with SARS-CoV-2, and we propose targeting downstream ACE2 downregulation as a therapeutic avenue that warrants clinical investigation.NEW & NOTEWORTHY Cardiac manifestations of COVID-19 in humans are mirrored in the SARS-CoV-2 hamster model, recapitulating myocardial damage, ACE2 downregulation, and a consistent pattern of immune cell infiltration independent of viral dose and variant. Therefore, the hamster model is a valid approach to study therapeutic strategies for COVID-19-related heart disease.

Waning Immunity Against Respiratory Syncytial Virus During the Coronavirus Disease 2019 Pandemic

Health jurisdictions have seen a near-disappearance of respiratory syncytial virus (RSV) during the first year of the coronavirus disease 2019 (COVID-19) pandemic. Over this corresponding period, we report a reduction in RSV antibody levels and live virus neutralization in sera from women of childbearing age and infants between May to June 2020 and February to June 2021, in British Columbia (BC), Canada. This supports that antibody immunity against RSV is relatively short-lived and that maintaining optimal antibody levels in infants requires repeated maternal viral exposure. Waning immunity may explain the interseasonal resurgence of RSV cases observed in BC and other countries.

Imaging Flow Cytometry and Confocal Immunofluorescence Microscopy of Virus-Host Cell Interactions

Viruses are diverse pathogens that use host factors to enter cells and cause disease. Imaging the entry and replication phases of viruses and their interactions with host factors is key to fully understanding viral infections. This review will discuss how confocal microscopy and imaging flow cytometry are used to investigate virus entry and replication mechanisms in fixed and live cells. Quantification of viral images and the use of cryo-electron microscopy to gather structural information of viruses is also explored. Using imaging to understand how viruses replicate and interact with host factors, we gain insight into cellular processes and identify novel targets to develop antiviral therapeutics and vaccines.

Pharmacological targets and emerging treatments for respiratory syncytial virus bronchiolitis

RSV infection of the lower respiratory tract in infants is the leading cause of pediatric hospitalizations and second to malaria in causing infant deaths worldwide. RSV also causes substantial morbidity in immunocompromised and elderly populations. The only available therapeutic is a prophylactic drug called Palivizumab that is a humanized monoclonal antibody, given to high-risk infants. However, this intervention is expensive and has a limited impact on annual hospitalization rates caused by RSV. No vaccine is available, nor are efficacious antivirals to treat an active infection, and there is still no consensus on how infants with bronchiolitis should be treated during hospital admission. In this comprehensive review, we briefly outline the function of the RSV proteins and their suitability as therapeutic targets. We then discuss the most promising drug candidates, their inhibitory mechanisms, and whether they are in the process of clinical trials. We also briefly discuss the reasons for some of the failures in RSV therapeutics and vaccines. In summary, we provide insight into current antiviral development and the considerations toward producing licensed antivirals and therapeutics.

IGF1R is an entry receptor for respiratory syncytial virus

Pneumonia resulting from infection is one of the leading causes of death worldwide. Pulmonary infection by the respiratory syncytial virus (RSV) is a large burden on human health, for which there are few therapeutic options1. RSV targets ciliated epithelial cells in the airways, but how viruses such as RSV interact with receptors on these cells is not understood. Nucleolin is an entry coreceptor for RSV2 and also mediates the cellular entry of influenza, the parainfluenza virus, some enteroviruses and the bacterium that causes tularaemia3,4. Here we show a mechanism of RSV entry into cells in which outside-in signalling, involving binding of the prefusion RSV-F glycoprotein with the insulin-like growth factor-1 receptor, triggers the activation of protein kinase C zeta (PKCζ). This cellular signalling cascade recruits nucleolin from the nuclei of cells to the plasma membrane, where it also binds to RSV-F on virions. We find that inhibiting PKCζ activation prevents the trafficking of nucleolin to RSV particles on airway organoid cultures, and reduces viral replication and pathology in RSV-infected mice. These findings reveal a mechanism of virus entry in which receptor engagement and signal transduction bring the coreceptor to viral particles at the cell surface, and could form the basis of new therapeutics to treat RSV infection.

Dual Catalytic Synthesis of Antiviral Compounds Based on Metallocarbene-Azide Cascade Chemistry

Aryl azides trap ortho-metallocarbene intermediates to generate indolenones possessing a reactive C-acylimine moiety, which can react with added indole nucleophiles to afford the 2-(3-indolyl)indolin-3-one scaffold found in the antiviral natural product isatisine A. This overall process occurs through a dual catalytic sequence at room temperature. Redox activation of the Cu(OTf)₂ precatalyst by indole results in catalytically competent Cu(I) required for azide-metallocarbene coupling. The Brønsted acid that is also formed from Cu(OTf)₂ reduction is responsible for catalysis of the C-C bond-forming indole addition step. This modular, procedurally simple method allows for rapid assembly of bis(indole) libraries, several of which proved to have anti-infective activity against respiratory syncytial virus and Zika virus.

The Susceptibilities of Respiratory Syncytial Virus to Nucleolin Receptor Blocking and Antibody Neutralization are Dependent upon the Method of Virus Purification

Respiratory Syncytial Virus (RSV) that is propagated in cell culture is purified from cellular contaminants that can confound experimental results. A number of different purification methods have been described, including methods that utilize fast protein liquid chromatography (FPLC) and gradient ultracentrifugation. Thus, the constituents and experimental responses of RSV stocks purified by ultracentrifugation in sucrose and by FPLC were analyzed and compared by infectivity assay, Coomassie stain, Western blot, mass spectrometry, immuno-transmission electron microscopy (TEM), and ImageStream flow cytometry. The FPLC-purified RSV had more albumin contamination, but there was less evidence of host-derived exosomes when compared to ultracentrifugation-purified RSV as detected by Western blot and mass spectrometry for the exosome markers superoxide dismutase [Cu-Zn] (SOD1) and the tetraspanin CD63. Although the purified virus stocks were equally susceptible to nucleolin-receptor blocking by the DNA aptamer AS1411, the FPLC-purified RSV was significantly less susceptible to anti-RSV polyclonal antibody neutralization; there was 69% inhibition (p = 0.02) of the sucrose ultracentrifugation-purified RSV, 38% inhibition (p = 0.03) of the unpurified RSV, but statistically ineffective neutralization in the FPLC-purified RSV (22% inhibition; p = 0.30). The amount of RSV neutralization of the purified RSV stocks was correlated with anti-RSV antibody occupancy on RSV particles observed by immuno-TEM. RSV purified by different methods alters the stock composition and morphological characteristics of virions that can lead to different experimental responses.

Targeting matrix metalloproteinase activity and expression for the treatment of viral myocarditis

Infectious agents including viruses can infect the heart muscle, resulting in the development of heart inflammation called myocarditis. Chronic myocarditis can lead to dilated cardiomyopathy (DCM). DCM develops from the extensive extracellular matrix (ECM) remodeling caused by myocarditis and may result in heart failure. Epidemiological data for viral myocarditis has long suggested a worse pathology in males, with more recent data demonstrating sex-dependent pathogenesis in DCM as well. Matrix metalloproteinases (MMPs), long known modulators of the extracellular matrix, have important roles in mediating heart inflammation and remodeling during disease and in convalescence. This ability of MMPs to control both the inflammatory response and ECM remodeling during myocarditis makes them potential drug targets. In this review, we analyze the role of MMPs in mediating myocarditis/DCM disease progression, their sex-dependent expression, and their potential as drug targets during viral myocarditis and DCM.

Inflammation in myocardial diseases

Inflammatory processes underlie a broad spectrum of conditions that injure the heart muscle and cause both structural and functional deficits. In this article, we address current knowledge regarding 4 common forms of myocardial inflammation: myocardial ischemia and reperfusion, sepsis, viral myocarditis, and immune rejection. Each of these pathological states has its own unique features in pathogenesis and disease evolution, but all reflect inflammatory mechanisms that are partially shared. From the point of injury to the mobilization of innate and adaptive immune responses and inflammatory amplification, the cellular and soluble mediators and mechanisms examined in this review will be discussed with a view that both beneficial and adverse consequences arise in these human conditions.

The Breast Health Center at Women & Infants Hospital: origin, philosophy, and features

The Breast Health Center, a component of the program in Women's Oncology at Women & Infants Hospital, is a multidisciplinary center devoted to the treatment and study of benign and malignant breast diseases. The philosophy, structure, and function of The Breast Health Center are described along with its specific components. The Breast Health Center's three fundamental missions of patient care, education, and research are discussed.

Controversies in benign breast disease

Breast health means more than breast cancer. At least 50% of patients seen at a multidisciplinary breast center have benign conditions. Pain, nipple discharge, and a question of a mass are the usual chief complaints. This article provides contemporary information and management guidelines for the common breast conditions associated with these complaints.

Breast cancer in pregnancy

The traditional view that breast cancer during pregnancy is associated with poor prognosis is no longer tenable. The reported poor prognosis usually is the result of late stage of presentation. It is important for physicians to consider breast cancer in the differential diagnosis of a breast problem discovered during pregnancy. When patients are separated into similar stage at presentation with positive or negative lymph nodes, the 5- and 10-year rates of survival for pregnancy-associated or nonpregnancy-associated breast cancer are identical. The breasts should be carefully examined at least during the first prenatal visit and thereafter if signs and symptoms appear. Operable disease in the first and second trimesters should be treated by modified radical mastectomy, and chemotherapy should be considered if indicated during the second and third trimesters. Breast-conservation treatment presents special problems, and the risks and benefits should be discussed with the patient. There is no evidence that termination of pregnancy improves survival.

Risk factors

Risk factors for breast cancer whose modification would be culturally acceptable have not been established. Nearly all women in the United States are at a substantial risk for the development of breast cancer. The majority of women, however, in whom breast cancer will be diagnosed will live out their lives without recurrence of the disease. Newer strategies include prevention and the development of effective chemopreventive programs. Phase III clinical trials are underway to assess the value of retinoids and tamoxifen. Phase I and II studies are underway to assess the potential of more specific treatments to inhibit growth factors important in maintaining the malignant phenotype. Obviously, more studies are needed to address this major public health problem.

Invasive breast cancer. Surgical treatment alternatives

It is now widely accepted that cancer of the breast is a systemic disease and that some patients will not be cured even with the most extensive local treatment. This acceptance has resulted in a more conservative approach and participation of the patient in treatment planning. A number of factors influence the definitive surgical treatment for breast cancer. Important considerations include the size and histology of the lesion, the skill and experience of the multidisciplinary team, and the wishes of the patient.

Contemporary management of breast cancer

The diagnosis and treatment of breast cancer have changed dramatically during the past two decades. The most important risk factor for breast cancer is advancing age; however, 80% of women with breast cancer have none of the currently identified risk factors. It is undeniable that early detection and treatment of breast cancer reduces morbidity and mortality, and mammography screening is the only method available to detect cancer at the earliest stage when it is most likely to be cured. Although a number of organizations have recommended breast conservation therapy (BCT) as the preferred treatment for early stage breast cancer, marked geographic variations in treatment occur. It is suggested that appropriate education programs be developed for physicians and women to increase familiarity with the selection criteria for BCT and to encourage objective discussions of the treatment options during the patient and physician encounter.

Making the diagnosis

Dramatic changes have occurred in the approach to the diagnosis of breast cancer. Increased screening has resulted in the diagnosis of occult lesions, many of which represent tumors that are not invasive, and smaller invasive cancers. It is now generally accepted that the diagnosis and treatment of breast cancer requires a multidisciplinary approach and that open biopsy not only provides the histologic diagnosis but also may represent definitive surgical treatment. Thus, diagnostic studies should represent the optimal approach to establishing the histology of the lesion without compromising later definitive treatment.

Role of the obstetrician/gynecologist in the management of breast disease

The obstetrician/gynecologist is the primary physician to women. The breast is an organ of reproduction, and complete breast examination is part of the obstetric and gynecologic examination. In addition to history and physical examination, the obstetrician/gynecologist should be prepared to undertake simple diagnostic studies. Cancer, on the other hand, presents a number of challenges. The appropriate role for the obstetrician/gynecologist is one of surveillance and as a resource for patients, including the discussion of risk factors and treatment alternatives.

Breast conservation in elderly women for clinically negative axillary lymph nodes without axillary dissection

BACKGROUND

A prospective study was initiated to explore an approach of limited therapy in elderly patients with early clinical stage breast cancer.

METHODS

Between 1982 and 1989, 73 women with American Joint Committee on Cancer Stage I/II, clinically negative axillary lymph nodes aged 65 years or older (median age, 74 years) were enrolled in a treatment program consisting of tumor excision, breast and regional lymph node irradiation, and, in 66 patients, tamoxifen. Patients were assessed for disease outcome and complications.

RESULTS

At a median follow-up of 54 months, 8-year rates of local and regional lymph node control were 92.5% and 100%, respectively. Eight-year probabilities of disease free, overall, and breast cancer specific survival were 84%, 52.5%, and 93.8%, respectively. There was minimal morbidity associated with either regional irradiation or tamoxifen.

CONCLUSIONS

An approach to early breast cancer in the elderly that seeks to limit the aggressiveness of local and systemic therapies appears to result in a satisfactory disease outcome with few complications.

Supplemental estrogen replacement

In the current aging society, more than 30 million women have an average postmenopausal life expectancy of 28 years. Coronary heart disease is the leading cause of death in older women, and osteoporosis results in an estimated 1.5 million fractures per year. Various studies have suggested that postmenopausal estrogen-replacement therapy could reduce the morbidity and mortality associated with these conditions. Given the uncertainty about hormone interactions and the molecular genetics of breast cancer, it seems unwise to inject yet another element into the prognostic equation, and currently it is not recommended that estrogen-replacement therapy be used routinely in patients who have been treated successfully for breast cancer. The final decision, of course, rests with the patient and her treating physicians and is subject to medical/legal interpretation.

The efficacy of specimen radiography in evaluating the surgical margins of impalpable breast carcinoma

OBJECTIVE

The purpose of this study was to determine if the presence or absence of tumor at the surgical margin in cases of impalpable breast carcinoma could be predicted accurately with specimen radiography.

MATERIALS AND METHODS

We obtained single-view radiographs of 119 consecutive surgical biopsy specimens of impalpable invasive or in situ ductal carcinoma. Radiographic lesions were classified as a mass with moderately well defined margins, a mass with poorly defined margins, or microcalcifications without an associated mass. The radiographic appearance of the impalpable cancer, the margin as judged from the specimen radiograph, the tumor's histologic appearance, and the histologic appearance of the tumor margin were then correlated.

RESULTS

Specimen radiographs showed tumor at the surgical margin in 63 cases; 62 of these were confirmed histologically (positive predictive value, 98%). Specimen radiographs showed tumor-free surgical margins in 56 cases; 18 of these were confirmed histologically (negative predictive value, 32%). These results were independent of the radiographic appearance of the lesion or the tumor's histologic appearance.

CONCLUSION

Decisions based on findings on specimen radiographs were valid only if the radiographs showed tumor at the margin of the specimen.

Breast conservation therapy for early stage breast carcinoma with outstanding 10-year locoregional control rates: a case for aggressive therapy to the tumor bearing quadrant

PURPOSE

Between 1982 and 1988 233 American Joint Committee on Cancer Stage I and II invasive breast carcinomas were prospectively treated in 225 women with conservative tumor excision, careful assessment of histopathological margins, and dose-adjusted irradiation to maximum doses of 70 Gy to the tumor bearing quadrant of the breast.

METHODS AND MATERIALS

The pathological stages at presentation were T1N0 and T1N1 in 57% and 13% and T2N0 and T2N1 in 19% and 10% of the patients, respectively. All patients were irradiated according to a policy that, beyond the 50 Gy to the whole breast and draining lymphatics, the tumor-bearing quadrant was boosted in adjustment to the histopathological margin. Normal tissue margins of < 2 mm were considered positive, margins 2-5 mm close, and margins > 5 mm negative and were boosted with 20, 15, and 10 Gy, respectively. Patients in whom the margin could not be assessed were re-excised or boosted to 20 Gy. Re-excisions with no residual carcinoma were not boosted. Most patients boosted to 20 Gy to the tumor-bearing quadrant received interstitial 192-Ir implantations.

RESULTS

The actuarial local control rates in the treated breast were 97.5% at 10 years with three recurrences having occurred at a median of 4.5 years after completion of radiotherapy. An additional two patients failed regionally outside the irradiation portals. The overall and disease-free survival of the whole group is 87.5% and 77%, respectively.

CONCLUSION

The approach to breast conservation therapy followed in this study has resulted in outstanding local control rates and suggests that there may be a subset of patients that could be irradiated to the tumor bearing quadrant only.

The role of the gynecologist in the management of breast disease

The breast is an organ of reproduction. The diagnosis and treatment of most benign breast conditions and a knowledge of the contemporary treatment of breast cancer are essential components of the current practice of obstetrics and gynecology.

Estrogen-replacement therapy after breast cancer. Risks versus benefits

In the current aging society, more than 30 million women have an average postmenopausal life expectancy of 28 years. Coronary heart disease is the leading cause of death in older women, and osteoporosis results in an estimated 1.5 million fractures per year. Various studies have suggested that postmenopausal estrogen-replacement therapy could reduce the morbidity and mortality associated with these conditions. Based on the results of several "natural experiments," it was proposed that estrogen-replacement therapy should be considered for menopausal women who have been treated successfully for breast cancer. The benefits and risks of estrogen-replacement therapy are reviewed, and recommendations for management and future research are suggested.

Breast cancer. Challenge and responsibility

The diagnosis and treatment of breast cancer has changed dramatically during the last quarter century, a fact perhaps not fully appreciated by many primary care physicians. Breast cancer presents a number of challenges for the obstetrician/gynecologist. The disease is common and the mortality rate is second only to lung cancer. The appropriate role for the obstetrician/gynecologist is one of surveillance, including taking a history and physical examination and selected diagnostic studies, and as a resource for patients, including a discussion of risk factors and treatment alternatives. Because of the increasing involvement of obstetrics and gynecology in molecular genetics and hormone interactions, basic research in genetic alterations and hormonal therapy directed toward decreasing morbidity from cardiovascular disease and osteoporosis is recommended.

Diagnosis of breast disease and the role of the gynecologist

The American Board of Obstetrics and Gynecology has recognized the special role of the obstetrician/gynecologist in the diagnosis and treatment of breast disease and indicated in 1985 that it would require a knowledge of breast disease in its certification process. It was also recommended that the obstetrician/gynecologist provide adequate information concerning screening and perform simple diagnostic studies including aspiration of cysts, fine-needle aspiration, and appropriate follow-up studies for patients treated for breast cancer. Because open biopsy often becomes part of the treatment for breast cancer, the Board stopped short of recommending that every obstetrician/gynecologist perform this procedure. The American College of Obstetricians and Gynecologists also has increased its efforts to more clearly define the role of the obstetrician/gynecologist in the diagnosis and treatment of breast disease. Questions have been raised concerning the lack of national standards to evaluate training in the diagnosis of breast disease surgery, and the College has convened a number of workshops to address these issues. This review discusses the issues raised both by the Board and the College. Diagnostic studies including simple procedures such as aspiration of cysts, fine-needle aspiration, and open biopsy are discussed. The role of the obstetrician/gynecologist in the screening examination is emphasized.

Factors influencing cosmetic outcome and complication risk after conservative surgery and radiotherapy for early-stage breast carcinoma

PURPOSE

The study was undertaken to assess the relationship among cosmesis and complications to factors related to disease presentation, surgical and radiotherapeutic technique, and adjuvant systemic therapy in conservative treatment for early-stage breast carcinoma.

PATIENTS AND METHODS

Between 1982 and 1988, 234 women with stage I/II breast carcinoma were treated with conservation therapy by a highly standardized protocol of limited excision and radiotherapy. Radiation boost and/or reexcision were determined by careful quantitation of the normal tissue margin around the primary tumor. Boosts to 20 Gy were preferentially performed with interstitial iridium-192 (192Ir) implants. Axillary node dissections were performed in all patients aged less than 70 years. Adjuvant therapy consisted of cyclophosphamide, methotrexate, (doxorubicin), and fluorouracil (CM[A]F) six to eight times for node-positive premenopausal women and tamoxifen for node-positive or -negative postmenopausal women. Median follow-up was 50 months (range, 20 to 80 months). Cosmesis was graded by defined criteria, and complications were individually scored.

RESULTS

Factors found to impact cosmesis adversely were palpable tumors (P = .046), volume of breast tissue resected (P = .027), reexcision of the tumor bed (P = .01), number of radiation fields (P = .03), radiation boost (P = .01), and chest wall separation (P = .01). There was a trend toward worse cosmesis (P = .062) in patients receiving tamoxifen. Cosmesis was not adversely affected by interstitial implant in spite of a higher prescribed dose. Factors influencing complication risk were axillary node dissection (P = .02), number of lymph nodes harvested (P = .05), and chemotherapy (P = .03).

CONCLUSIONS

Optimal cosmesis and minimal complication risk require careful attention to the technical details of surgery and radiotherapy. The impact of systemic therapies needs to be more thoroughly examined.

Utilization of screening mammography--1990

Although much has been accomplished in the last few years toward the early detection of breast cancer, we are far from a goal of universal acceptance of the recommended preventive health program of screening mammography. To take an analogy from the Papanicolaou smear, we are somewhere in the 1960s. Both women and physicians have more to learn, and they need to transfer that knowledge into practice.

The relationship of mammographic microcalcification to histologic malignancy: radiologic-pathologic correlation

Forty consecutive cases of nonpalpable breast carcinoma presenting on the mammogram as microcalcifications without an associated mass were reviewed. The precise relationship between the mammographic microcalcification and the histologic carcinoma was determined in each case. In 25 cases (63%), the mammographic calcium was confined to the tumor, and in 13 cases (33%), the calcification was present both within the tumor and contiguous to the tumor margin. In two cases (5%), the calcium was not contained within the tumor but was located next to it. In one of these cases, the calcium was within 4 mm of the malignant neoplasm and in the other it was within 13 mm. No difference was seen between the appearance of the calcifications located within the tumor and the appearance of calcification next to the tumor. Precise histologic analysis revealed that microcalcifications that had prompted biopsy were confined to the tumor in 63%, within and contiguous to the tumor in 32%, and within 13 mm of the tumor in 5%.

Tumor margin assessment as a guide to optimal conservation surgery and irradiation in early stage breast carcinoma

Between 1982 and 1985, 108 women with AJC Stage I and II invasive mammary carcinoma were treated to 115 breasts with conservative surgery and irradiation. The irradiation dose was adjusted to the histopathological normal tissue margin around the carcinoma in the tumor excision specimens. Margins were arbitrarily determined negative, close, and positive with normal tissue margins in the inked tumor excision specimens of greater than 5 mm, 2-5 mm, and less than 2 mm, respectively. Negative, close, and positive tumor margin patients were treated to radiation doses of 60, 65, and 70 Gy, respectively. The boost in excess of 50 Gy was directed to the tumor bearing quadrant of the breast using interstitial Ir-192 implants for doses greater than or equal to 70 Gy. The draining lymphatics were irradiated to 50 Gy except in patients with tumor in the lateral half of the breast and no axillary lymph node metastases. Histopathological evaluation of re-excision specimens revealed the difficulty of obtaining negative margins for tumors greater than 2 cm. By our criteria, 54% of the patients had a positive resection margin. None of the patients experienced a local recurrence at 60 months median follow-up. Three patients failed regionally, two in un-irradiated lymph node areas, one in the skin of the contralateral breast; five patients failed systemically. Overall and disease-free survival for Stages T1/N0, T1/N1, T2/N0 was 100 and 95%, respectively, and for T2/N1, 90 and 80%, respectively. The cosmesis was excellent in 66% of the patients with minimal treatment related complications. Carefully planned standardized irradiation with assessment of resection margins yields both excellent local control rates and cosmetic results.

In situ breast cancer: a multidisciplinary approach

The approach to these lesions is being reexamined in light of results with conservative surgery for invasive breast cancers. According to available data, the invasive potential of in situ lesions varies. Mammographic and pathologic findings may differentiate patients who will benefit from lumpectomy (with or without radiotherapy) from those requiring mastectomy.

Residual breast carcinoma after biopsy: role of mammography in evaluation

The records of 21 consecutive patients referred for breast-conservation treatment of early-stage mammary carcinoma contained insufficient histopathologic documentation of adequate resection margins after tumor excision at other hospitals. All patients underwent postbiopsy mammography before reexcision of the tumor bed. In 12 of the 21 cases, there was pathologic evidence of macroscopic or microscopic residual tumor. In seven of the 12 cases, there was no clinical or mammographic evidence to suggest residual carcinoma. The findings indicate that mammography is insufficient to evaluate the completeness of tumor excision in the absence of histopathologic documentation.

The surgical treatment of breast cancer

Controversy regarding the efficacy of surgical treatment of breast cancer has persisted since the earliest descriptions of this disease in the first and second centuries AD. It has been acknowledged for many years that patients with untreated breast cancer survive for a surprisingly predictable period of 5 yr. Hence, in recommending extensive surgical procedures, the surgeon must recognize the unique biology of breast cancer and the need for long-term follow-up. In spite of a voluminous body of literature concerning the treatment of breast cancer, the distention and contention still continue. However, there is now increasing support for conservative treatment, including the less radical modified mastectomy, and in selected cases, wide local excision, axillary dissection and radiotherapy. As knowledge accumulates, it is clear that the treatment of breast cancer requires a multidisciplinary approach reflecting our understanding of the biology of this disease.

The geographic cluster of microcalcifications of the breast

During a period of two years, nine patients were found who had a solitary geographic cluster of microcalcifications which appeared to be intramammary on two standard mammographic views. In two instances, the women underwent unsuccessful excisional biopsies. In the other seven patients, the true location of the microcalcifications was recognized and proved preoperatively so biopsy was avoided. When intradermal microcalcifications are fortuitously imaged in tangent or when they assume characteristic polygonal shapes with lucent centers, their intradermal location should be suspected. However, if the form is not typical of intradermal calcifications and when the location appears to be intramammary on the routine mammographic views, an excisional biopsy will usually be recommended. If skin is not included in the excised tissue, then the biopsy will be unsuccessful. A simple technique using a metallic marker can confirm the true intradermal location of calcifications.

Outpatient needle localization and biopsy for nonpalpable breast lesions

We reviewed 101 consecutive biopsy specimens of nonpalpable breast lesions obtained by needle localization. Forty-six biopsies were done on outpatients under local anesthesia and 16 more on inpatients under local anesthesia. The remaining 39 biopsies were performed on inpatients under general anesthesia. The complications and accuracy of the outpatient procedure were acceptable and comparable to those of the inpatient procedure. In our institution, there is almost a fivefold cost increase for the performance of this procedure under general anesthesia as an inpatient. We recommend that surgeons and radiologists work together to perfect preoperative localization techniques, and we strongly support the concept that this procedure should be performed on outpatients under local anesthesia for the majority of patients with nonpalpable mammographic abnormalities.

Epidemiology of breast cancer

A number of important factors determine the risk for breast cancer, and the most important of these seem to be related to estrogen and possibly prolactin. Additional research is necessary on the role of endogenous and exogenous estrogens and the effect of diet, drugs, and other factors on the levels of estrogen and prolactin. It is unlikely that with present epidemiologic evidence, breast cancer can be prevented. We cannot alter the age of menarche, and promotion of early pregnancy to protect against breast cancer is not feasible. One risk factor that is alterable is obesity, particularly in the postmenopausal woman. The risk factors associated with exogenous estrogens following the menopause require confirmation by other studies. However, because of the strong association of these drugs with increased risk of endometrial cancer, the physician should be cautious in prescribing them.