Ductal Lavage for Patients With Nonlactational Mastitis: A Single-Arm, Proof-of-Concept Trial

Immune pathogenesis of idiopathic granulomatous mastitis: from etiology toward therapeutic approaches

Idiopathic granulomatous mastitis (IGM) is a noncancerous, chronic inflammatory disorder of breast with unknown causes, posing significant challenges to the quality of life due to its high refractoriness and local aggressiveness. The typical symptoms of this disease involve skin redness, a firm and tender breast mass and mastalgia; others may include swelling, fistula, abscess (often without fever), nipple retraction, and peau d'orange appearance. IGM often mimics breast abscesses or malignancies, particularly inflammatory breast cancer, and is characterized by absent standardized treatment options, inconsistent patient response and unknown mechanism. Definite diagnosis of this disease relies on core needle biopsy and histopathological examination. The prevailing etiological theory suggests that IGM is an autoimmune disease, as some patients respond well to steroid treatment. Additionally, the presence of concurrent erythema nodosum or other autoimmune conditions supports the autoimmune nature of the disease. Based on current knowledge, this review aims to elucidate the autoimmune-favored features of IGM and explore its potential etiologies. Furthermore, we discuss the immune-mediated pathogenesis of IGM using existing research and propose immunotherapeutic strategies for managing this condition.

The Effect of Local Steroid Administration on Idiopathic Granulomatous Mastitis: A Systematic Review andMeta-Analysis

INTRODUCTION

Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory breast disease. Corticosteroids and surgery are the primary treatment options, and a growing number of publications have shown the effectiveness of local steroid administration (intralesional injection and topical corticosteroids). However, less is known about the specific details and effects of this treatment approach. The purpose of this meta-analysis was to summarize the details and evaluate the efficacy of local steroid administration for IGM.

METHODS

The PubMed, Embase, Cochrane Library, and SinoMed databases were systematically searched from inception to July 2023 to identify relevant randomized controlled trials. The quality of the included studies was assessed, and meta-analysis and subgroup analysis were conducted to obtain the pooled effect sizes of the outcomes of interest.

RESULTS

Eight trials comprising 613 patients were included. Local steroid administration included intralesional injection and topical steroid ointment, and control groups were mainly given systemic therapy (oral steroid) and surgical treatment. The meta-analysis showed that local steroid administration had a significant effect on the response rate (risk ratio [RR] = 1.35, 95% CI = [1.14-1.59], P = 0.0004). The incidence of side effects was also lower than that of systemic treatment (RR = 0.24, 95% CI = [0.13-0.43], P＜0.0001). There was no difference in the recurrence rate (RR = 0.8, 95% CI = [1.42-1.51], P = 0.48).

CONCLUSIONS

Local steroid administration can increase the RR and decrease the incidence of side effects for IGM patients. There is no significant difference in the recurrence rate between the local steroid administration group and the control group. Further studies are needed to identify the effect in different stages and among pregnant women.

Factors Affecting Recurrence of Idiopathic Granulomatous Mastitis: A Systematic Review

Idiopathic granulomatous mastitis is a rare and benign disease that primarily affects young women of reproductive age. Various factors have been suggested as possible causes, including pregnancy, breastfeeding, history of taking birth control pills, hyperprolactinemia, smoking, and history of trauma. Due to unknown etiology, opinions on its treatment have varied, resulting in differing recurrence rates and side effects. Therefore, conducting a comprehensive systematic review and meta-analysis can aid in understanding the causes and recurrence of the disease, thereby assisting in the selection of effective treatment and improving the quality of life. A systematic literature review was conducted using predefined search terms to identify eligible studies related to risk factors and recurrence up to June 2022 from electronic databases. Data were extracted and subjected to meta-analysis when applicable. A total of 71 studies with 4735 patients were included. The mean age of the patients was 34.98 years, and the average mass size was 4.64 cm. About 3749 of these patients (79.17%) were Caucasian. Patients who mentioned a history of pregnancy were 92.65% with 76.57%, 22.7%, and 19.7% having a history of breastfeeding, taking contraceptive pills, and high prolactin levels, respectively. Around 5.6% of patients had previous trauma. The overall recurrence rate was 17.18%, with recurrence rates for treatments as follows: surgery (22.5%), immunosuppressive treatment (14.7%), combined treatment (14.9%), antibiotic treatment (6.74%), and observation (9.4%). Only antibiotic and expectant treatments had significant differences in recurrence rates compared to other treatments (p value = 0.023). In conclusion, factors such as Caucasian race, pregnancy and breastfeeding history, and use of contraceptive hormone are commonly associated with the disease recurrence. Treatment should be tailored based on symptom severity and patient preference, with surgery or immunosuppressive options for recurrence.

Treatments for Periductal Mastitis: Systematic Review and Meta-Analysis

Introduction

Periductal mastitis (PDM) is a complex benign breast disease with a prolonged course and a high risk of recurrence after treatment. There are many available treatments for PDM, but none is widely accepted. This study aims to evaluate the various treatment failure rates (TFR) of different invasive treatment measures by looking at recurrence and persistence after treatment. In this way, it sets out to inform better clinical decisions in the treatment of PDM.

Methods

We searched PubMed, Embase, and Cochrane Library databases for eligible studies about different treatment regimens provided to PDM patients that had been published before October 1, 2019. We included original studies written in English that reported the recurrence and/or persistence rates of each therapy. Outcomes were presented as pooled TFR and 95% CI for the TFR.

Results

We included 27 eligible studies involving 1,066 patients in this study. We summarized 4 groups and 10 subgroups of PDM treatments, according to the published studies. Patients treated minimally invasively (group 1) were subdivided into 3 subgroups and pooled TFR were calculated as follows: incision and drainage (n = 73; TFR = 75.6%; 95% CI 27.3-100%), incision alone (n = 74; TFR = 20.1%; 95% CI 0-59.9%), and breast duct irrigation (n = 123; TFR = 19.4%; 95% CI 0-65.0%). Patients treated with a minor excision (excision of the infected tissue and related duct; group 2) were divided into 4 subgroups and pooled TFR were calculated as follows: wound packing alone (n = 127; TFR = 2.1%; 95% CI 0-5.2%), primary closure alone (n = 66; TFR = 37.1%; 95% CI 9.5-64.8%), primary closure under antibiotic treatment cover (n = 55; TFR = 4.8%; 95% CI 0-11.4%), and additional nipple part removal (n = 232; TFR = 9.6%; 95% CI 5.8-13.4%). Patients treated with a major excision (excision of the infected tissue and the major duct; group 3) included the following 2 subgroups: patients treated with a circumareolar incision (n = 142; TFR = 7.5%; 95% CI 0.4-14.7%) and patients treated with a radial incision of the breast (n = 78; TFR = 0.6%; 95% CI 0-3.6%). Group 4 contained patients receiving different major plastic surgeries. The pooled TFR of this group (n = 86) was 3.4% (95% CI 0-7.5%).

Conclusion

Breast duct irrigation, which is the most minimally invasive of all of the treatment options, seemed to yield good outcomes and may be the first-line treatment for PDM patients. Minor excision methods, except for primary closure alone, might be enough for most PDM patients. Major excision, especially with radial incision, was a highly effective salvage therapy. The major plastic surgery technique was also acceptable as an alternative treatment for patients with large lesions and concerns about breast appearance. Incision and drainage and minor excision with primary closure alone should be avoided for PDM patients. Further research is still needed to better understand the etiology and pathogenesis of PDM and explore more effective treatments for this disease.

Multicentre, randomised, open-label, non-inferiority trial comparing the effectiveness and safety of ductal lavage versus oral corticosteroids for idiopathic granulomatous mastitis: a study protocol

INTRODUCTION

The ideal treatment for idiopathic granulomatous mastitis (IGM) remains unclear. In a prospective, single-centre, pilot study, we reported that ductal lavage treatment for non-lactational mastitis patients had a 1-year clinical complete response (cCR) rate of >90%, without any significant adverse events. Thus, in this multicentre, randomised, open-label, non-inferiority trial, we will aim to compare the effectiveness and safety of ductal lavage vs oral corticosteroids as the first-line treatment for patients with IGM.

METHODS AND ANALYSIS

The trial will be conducted at the Breast Tumor Center of Sun Yat-sen Memorial Hospital in China and at least at one participating regional centre. We plan to recruit 140 eligible IGM patients who will be randomised into the ductal lavage group or oral corticosteroid group with a 1:1 ratio. The patients in the oral corticosteroid group will receive meprednisone or prednisone for 6 months. The patients in the ductal lavage group will receive ductal lavage and breast massage, as previously reported. All the participants will be followed up at the clinic for 1 year post randomisation. The primary endpoint of this trial will be the 1-year cCR rate, and the secondary endpoints will include the time to cCR, treatment failure rate, relapse rate and protocol compliance rate. The trial was designed to determine whether ductal lavage is non-inferior to oral corticosteroids (1-year cCR rate assumed to be 90%), with a non-inferiority margin of 15%.

ETHICS AND DISSEMINATION

The ethics committee of Sun Yat-sen Memorial Hospital at Sun Yat-sen University approved the study (2018-Lun-Shen-Yan-No. 30). The results of the trial will be communicated to the participating primary care practices, published in international journals and presented at international clinical and scientific conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03724903); Pre-results.