Risk Factors for Failure of Ultrasound-Guided Fine-Needle Aspiration Therapy for Lactational Breast Abscess

Abstract

Background:

Ultrasound-guided fine-needle aspiration in the treatment of breast abscess has become the preferred treatment. Although fine-needle aspiration has a good therapeutic effect, there are still some patients failed who finally underwent drainage.

Objective:

To analyze the risk factors of ultrasound-guided fine-needle aspiration treatment failure for patients with lactational breast abscess.

Materials and Methods:

The clinical data of 1,472 patients with lactational breast abscess who underwent ultrasound-guided fine-needle aspiration treatment from January 2014 to March 2017 were analyzed in this retrospective study. According to the treatment results, these patients were divided into two groups: fine-needle aspiration failure group (n = 111) and fine-needle aspiration recovery group (n = 1,361). Chi-square test was used to compare the differences between the two groups in terms of postpartum time, age, location of abscess cavity, number of abscess cavities, volume of pus, frequency of aspiration, infected bacteria, treatment time, weaning, and recurrence. Multivariate logistic regression was used to analyze the risk factors of patients with failed fine-needle aspiration treatment.

Results:

Univariate analysis showed statistically significant differences in the location of abscess, volume of pus, treatment time, frequency of aspiration, and weaning between the two groups (p < 0.05). Multivariate analysis showed that the location of abscess, volume of pus, frequency of aspiration, and treatment time were risk factors for the failure of ultrasound-guided fine-needle aspiration treatment (p < 0.05).

Conclusions:

For patients with breast abscess during lactation, abscess in center area, volume of pus >50 mL, frequency of aspiration >3 times and treatment time >14 days, the failure probability of ultrasound-guided fine-needle aspiration treatment was high. Therefore, whether fine-needle aspiration is the preferred treatment for these patients needs to be considered.

Background

Breast abscess was a common disease during lactation. The traditional treatment was surgical incision and drainage. However, surgical trauma was large, the incision healing time was long, and the patient experienced pain. In recent years, ultrasound-guided fine-needle aspiration for the treatment of breast abscess has been widely used in clinical practice, and several studies have shown that this method achieves a good therapeutic effect in the treatment of breast abscess.^1–3 However, there were also failure cases using this method, and no relevant studies to analyze the reasons. Thus, this retrospective study analyzed the clinical data of 111 patients who had failed ultrasound-guided fine-needle aspiration treatment and explored the factors related to the failure of aspiration treatment for breast abscess during lactation, which guided the clinical treatment.

Materials and Methods

General information

Patient data

A total of 1,541 patients with breast abscesses during lactation, treated in our hospital from January 2014 to March 2017, were reviewed.

Inclusion criteria

(1) Patients diagnosed with breast abscess during lactation. The diagnostic criteria for breast abscess during lactation were as follows: (i) lactating women; (ii) a hot, reddened, swollen, and the tender area appeared on the affected breast; also, fever might occur; (iii) fluctuation in physical examination; (iv) breast ultrasound showed mixed echo or no echo region in the breast, and liquid flow was detected in the breast after the probe was pressurized; and (v) pus was withdrawn by aspiration. (2) Patients underwent ultrasound-guided fine-needle aspiration treatment. (3) The pus withdrawn from patients was cultured for the detection of bacteria.

Exclusion criteria

(1) Patients who did not undergo ultrasound-guided fine-needle aspiration treatment (n = 17); (2) patients who did not undergo bacterial culture of pus (n = 28); (3) patients lost to follow-up (n = 24).

Treatment methods

All patients were treated with ultrasound-guided aspiration for abscess. If the clinical symptoms were not relieved after aspiration, sensitive antibiotics were selected as adjuvant therapy according to the drug sensitivity results of the bacterial culture. Moreover, if the clinical symptoms were still not relieved, other treatment was considered, such as a vacuum-assisted biopsy of abscess, abscess catheter drainage, and abscess incision and drainage.

Criteria for recurrence

All patients were followed up for 1 month. The clinical symptoms were recurred during the follow-up period, requiring re-aspiration or surgical treatment.

Follow-up

All patients were followed up for 1 month, including regular outpatient visits and telephone follow-up.

Research methods

The clinical data of 1,541 patients were analyzed in a retrospective study, and a total of 1,472 patients fulfilled the inclusion criteria. These patients were divided into two groups: fine-needle aspiration treatment failure group (n = 111) and fine-needle aspiration treatment recovery group (n = 1,361). The postpartum period, age, location of abscess cavity, number of abscess cavities, maximum amount of pus, frequency of aspiration, infection bacteria, weaning, and recurrence were analyzed statistically.

Statistical analysis

SPSS 21.0 statistical software was used for analysis of data. Chi-square test was used to conduct a univariate analysis of postpartum time, age, location of abscess, number of abscess cavities, maximum volume of pus, frequency of aspiration, infection bacteria, treatment time, weaning, and recurrence. Multivariate logistic regression was used to analyze the aforementioned risk factors, and p < 0.05 was considered statistically significant.

Results

A total of 1,541 patients with breast abscess during lactation, treated in our hospital from January 2014 to March 2017, were reviewed. Among them, 17 patients had ulcerated abscess at the time of consultation and had not undergone ultrasound-guided fine-needle aspiration of abscess, 28 patients did not undergo bacterial culture, and 24 patients were lost to follow-up. After excluding the aforementioned 69 patients, the remaining 1,472 patients with breast abscess during lactation were included in this study. The age of the cohort ranged from 21 to 44 (average: 30) years old.

A total of 1,472 patients were included in this study. Among them, 111 patients had failed ultrasound-guided fine-needle aspiration treatment for abscess, with a failure rate of 7.5%. The remaining 1,361 cases were cured by ultrasonic-guided fine-needle aspiration treatment for abscess, and the cure rate was 92.5%.

Among the 111 patients who failed fine-needle aspiration treatment: (1) 57 people had skin rupture after the fine-needle aspiration and were cured after dressing change. (2) Among the 54 patients who showed poor outcomes after fine-needle aspiration and were transferred to surgical treatment, 25 underwent vacuum-assisted biopsy of abscess, 21 underwent abscess catheter drainage, and 8 underwent abscess incision and drainage, and all recovered after dressing change.

Univariate analysis

The total of 1,472 cases with breast abscess during lactation were enrolled in this study and treated with ultrasound-guided fine-needle aspiration. The results of univariate analysis with chi-square test revealed significant differences in the location of abscess, volume of pus, treatment time, frequency of aspiration, and weaning. However, no significant difference in postpartum time, age, number of abscess cavities, infection bacteria, and recurrence between two groups (Table 1).

Table 1.

Clinical Data of 1,472 Patients with Breast Abscess During Lactation

Factors	Treatment failure group (n = 111)	Treatment recovery group (n = 1,361)	χ²	p
Postpartum time			3.371	0.074
Puerperium	71	748
Nonpuerperal period	40	613
Age (years)			5.045	0.169
<26	9	75
26–30	62	665
31–35	35	507
>35	5	75
Location of cavity			66.156	<0.001^*
Central area^a	71	370
Noncentral area	40	991
No. of cavities			0.249	0.355
Single cavity	85	1,013
Multiple cavities	26	348
Volume of pus			50.812	<0.001^*
≤50 mL	81	1,263
>50 mL	30	98
Frequency of aspiration			17.138	<0.001^*
≤3 times	62	1,008
>3 times	49	353
Bacteria			1.844	0.398
Methicillin resistant	17	247
Nonmethicillin resistant	75	938
No bacteria	19	176
Treatment time			292.166	<0.001^*
≤14 days	73	1,241
>14 days	38	120
Weaning			13.979	<0.001^*
Yes	21	113
No	90	1,248
Recurrence			0.297	0.545
Yes	4	37
No	107	1,324

Represents p-values <0.05.

The central area referred to the lesion located in the nipple and areola region.

Among all the patients enrolled in this study, the central area abscesses and the noncentral area abscesses groups showed significant differences. The failure rate of fine-needle aspiration treatment was significantly higher in patients with central abscess (16.1%, 71/441) than in patients with noncentral abscess (3.9%, 40/1,031).

Among 128 patients in the whole group with pus >50 mL, 30 failed aspiration treatment, with a failure rate of 23.4%. Among a total of 1,344 patients with pus ≤50 mL, 81 failed aspiration treatment, with a failure rate of 6.0%, which was significantly lower than that in the group with pus >50 mL.

A total of 134 patients started breastfeeding after the disease and did not continue breastfeeding. The rate of breastfeeding in the aspiration failure group (18.9%, 21/111) was significantly higher than that in the aspiration cure group (8.3%, 113/1,361).

The average treatment time of the whole group was 7.9 days, and the treatment time of the aspiration failure group (23.1 days) was significantly longer than that of the aspiration cure group (6.6 days).

The average frequency of aspiration of the whole group was three times. And the average frequency of the fine-needle aspiration treatment failure group was 3.9 times, compared with 2.9 times in the cured group. A total of 49 patients with aspiration times >3 times (44.1%, 49/111) were in the aspiration failure group, and 353 patients (25.9%, 353/1,361) were in the cured group, with statistical difference between the groups.

Multivariate analysis

Multivariate logistic regression analysis of all the factors showed that the location of abscess, volume of pus, frequency of aspiration, and treatment time were risk factors for the failure of ultrasound-guided fine-needle aspiration treatment. However, postpartum time, age, number of abscess cavities, infection bacteria, weaning, and recurrence did not differ significantly between the two groups (Table 2).

Table 2.

Logistic Regression Analysis of Related Factors of Failure in the Treatment of Breast Abscess During Lactation by Fine-Needle Aspiration

Influencing factors	Regression coefficient	Standard error	Wald value	p	OR value	95% CI
Postpartum time	0.120	0.248	0.234	0.628	1.128	0.693–1.836
Age (years)
<26	—	—	1.537	0.674		—
26–30	0.662	0.660	1.007	0.316	1.939	0.532–7.070
31–35	0.611	0.523	1.366	0.243	1.842	0.661–5.134
>35	0.477	0.535	0.793	0.373	1.611	0.564–4.601
Location of cavity	1.048	0.240	19.121	<0.001	2.854	1.784–4.566
No. of cavities	0.302	0.277	1.192	0.275	1.352	0.787–2.326
Volume of pus	0.893	0.310	8.309	0.004	2.443	1.331–4.483
Frequency of aspiration	−0.778	0.287	7.323	0.007	0.459	0.262–0.807
Bacteria	0.234	0.206	1.296	0.255	1.264	0.845–1.891
Treatment time	3.105	0.278	124.457	<0.001	22.308	12.929–38.491
Weaning	0.122	0.331	0.137	0.712	1.13	0.591–2.161
recurrence	−0.141	0.645	0.048	0.827	0.869	0.245–3.077
Constant	−8.375	0.852	96.624	0.000	0.000

CI, confidence interval; OR, odds ratio.

Discussion

Breast abscess during lactation was a common breast disease, primarily caused by the rapid progress of acute mastitis or failure to diagnose and treat promptly.⁴ Once an abscess was formed, anti-infection treatment alone could not eliminate the abscess cavity. With the development of minimally invasive techniques, ultrasound-guided fine-needle aspiration treatment for breast abscess had been gradually applied in clinical practice since the 1990s.^5–8 Presently, it has replaced surgical incision and drainage and has become the first choice for the treatment of breast abscess. Although fine-needle aspiration has a satisfactory therapeutic effect in the treatment of breast abscess, some patients with ulcerated abscess or undergone surgical treatment exhibited poor therapeutic effect.

In this study, the clinical data of 111 patients who had failed fine-needle aspiration treatment were collected, and the related factors of treatment failure were analyzed from the aspects of postpartum time, age, location of abscess cavity, number of abscess cavities, the maximum volume of pus, frequency of aspiration, infected bacteria, treatment time, weaning, and recurrence. The results of this study suggested that for patients with breast abscess during lactation whose abscess was in the central area, volume of pus >50 mL, frequency of aspiration >3 times and treatment time was >14 days, the failure probability of ultrasound-guided aspiration treatment was high.

The location of abscess cavity

Clinically, the treatment of breast abscess in the central area (nipple and areola region) was more difficult than that in the other locations. Considering that these patients often had nipple and areola edema, poor milk discharge, and a large number of lesions, the recovery from the disease was slow.^9,10 In addition, the breast abscess in the central area is prone to rupture, which may be related to the concentration of ducts in the nipple and areola area and the less interstitial, subcutaneous adipose tissue, and glandular lobes tissue. The results of this study showed that the aspiration failure rate of breast abscesses in the central area was 16.1%, which was significantly higher than that in the noncentral area (3.9%). The results of univariate analysis with chi-square test revealed significant differences between the two groups. And multivariate logistic regression analysis showed that the location of abscess was the risk factor for the failure of ultrasound-guided fine-needle aspiration treatment. Therefore, for patients with breast abscess in the central area, if the aspiration treatment was not effective or difficult, other treatments should be performed at the earliest, such as a vacuum-assisted biopsy of abscess, abscess catheter drainage, and abscess incision and drainage.

The maximum volume of pus

The more the volume of pus, the larger the abscess cavity. In this study, the maximum volume of pus was 420 mL, and the average volume of pus in the whole group was 17.6 mL. Conversely, the average volume of pus in the failure group was 35 mL, whereas that in the nonfailure group was 16.2 mL, with significant differences between the two groups. Therefore, the results of this study suggested that higher the volume of pus, higher the failure probability of the aspiration treatment. Some studies^11,12 suggested that surgical treatment was the first choice for abscess >5 cm; however, the study by Colin et al.¹³ showed that for patients with abscess >5 cm, ultrasound-guided percutaneous treatment could be used to avoid surgical incision and drainage. Nonetheless, the percutaneous treatment methods in their study included fine-needle aspiration, percutaneous catheter drainage and vacuum-assisted biopsy of abscess, which were different from those in this study. Herein, we explored the simple fine-needle aspiration treatment, and the methods of percutaneous catheter drainage and vacuum-assisted biopsy of abscess were classified as nonaspiration treatment, thereby providing inconsistent results.

The frequency of aspiration

Our study showed the average frequency of aspiration of the whole group was 3.0 times. A total of 49 patients with aspiration times >3 times (44.1%, 49/111) were in the aspiration failure group, and 353 patients (25.9%, 353/1,361) were in the cured group, with statistical difference between the groups. The failure group's aspiration times were higher than cured group, which means that the more aspiration times, the higher probability of the fine-needle aspiration treatment failure.

The treatment time

In this study, the average treatment time of the whole group was 7.9 days, and the average treatment time of the fine-needle aspiration treatment failure group was 23.1 days; the average treatment time of the fine-needle aspiration treatment recovery group was 6.6 days, with significant differences between the two groups. Statistical analysis showed that treatment time >14 days was a risk factor for the failure of fine-needle aspiration treatment; thus, longer the treatment time, higher the failure possibility of aspiration treatment. Because patients with failed fine-needle aspiration treatment often have abscess rupture or are transferred to other treatments (e.g., vacuum-assisted biopsy of abscess, abscess catheter drainage, or abscess incision and drainage), the duration of the treatment is prolonged.

The number of abscess cavities and weaning

Some studies suggested that surgical treatment was the first choice for patients with multicavity abscess; however, the cohort also included some nonlactation patients.¹¹ Moreover, this study enrolled only all lactating patients, and the results suggested that the failure of fine-needle aspiration treatment was not related to multiple abscesses. In the whole group, 374 patients had multiple abscess cavities, and only 26 patients had failed the fine-needle aspiration treatment, whereas the remaining 348 patients were cured by fine-needle aspiration treatment. Therefore, ultrasound-guided fine-needle aspiration treatment was the first choice for patients with multiple breast abscess cavities during lactation. If the aspiration effect was not satisfactory or recurrence occurred, other treatments (e.g., vacuum-assisted biopsy of abscess, abscess catheter drainage, or abscess incision and drainage) could be performed.

Breast surgeons have been working to encourage and improve the rate of breastfeeding in China. Therefore, our department recommended that all patients with breast abscess during lactation continue to breastfeed and provided information about the benefits of breastfeeding. Most of the patients could continue to breastfeed while treating the disease, whereas some patients had milk withdrawal eventually due to fear of disease recurrence. In this study, 134/1,472 patients had milk withdrawal after illness and did not continue breastfeeding; among them, 21 patients had milk withdrawal after failed ultrasound-guided fine-needle aspiration treatment. Univariate analysis showed a statistical difference between the two groups, whereas multivariate analysis did not show any statistical difference between the two groups, suggesting that weaning was not an independent risk factor for failure of fine-needle aspiration treatment, and the failure of fine-needle aspiration treatment did not increase the probability of weaning.

In summary, for patients with breast abscess during lactation whose abscess was in the central area, volume of pus >50 mL, frequency of aspiration >3 times and treatment time >14 days, the failure probability of ultrasound-guided aspiration treatment was high. Therefore, clinically, it should be carefully considered whether fine-needle aspiration is the preferred treatment for these patients. If aspiration treatment was considered as the first choice and poor therapeutic effect was detected, other treatments should be altered at the earliest to avoid delay of the treatment. In the case of patients with breast abscess who failed by fine-needle aspiration treatment, either abscess rupture or surgery was conducted, due to which, their treatment time was prolonged. However, no significant correlation was established between the efficacy of fine-needle aspiration and the patient's age, postpartum time, number of abscess cavities, recurrence of abscesses, infection bacteria, or weaning.

This study was a retrospective study and had some limitations. Thus, future prospective clinical trials are needed for further confirmation.

Conclusions

For patients with breast abscess during lactation, abscess in center area, volume of pus >50 mL, frequency of aspiration >3 times, and treatment time >14 days, the failure probability of ultrasound-guided fine-needle aspiration treatment was high. Therefore, whether fine-needle aspiration is the preferred treatment for these patients needs to be considered. Maybe other treatments (e.g., vacuum-assisted biopsy of abscess, abscess catheter drainage, or abscess incision and drainage) should be considered earlier for these patients.

Footnotes

Authors' Contributions

Y.L. drafted the article with the help of X.-J.M. X.-J.M. critically revised and supervised the study. Both the authors read and approved the final article.

Ethics Approval and Consent to Participate

Neither medical nor ethical approval was required. Our study was a retrospective study. All data are derived from the medical records of patients who have been treated. And all data were processed anonymously.

Availability of Data and Materials

The data sets used and/or analyzed during this study are available from the corresponding author on reasonable request.

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

References

Elagili

, Abdullah

, Fong

, et al. Aspiration of breast abscess under ultrasound guidance: Outcome obtained and factors affecting success. Asian J Surg, 2007; 30:40–44.

Elder

, Brennan

. Nonsurgical management should be first line therapy for breast abscess. World J Surg, 2010; 34:2257–2258.

Kataria

, Srivastava

, Dhar

. Management of lactational mastitis and breast abscesses: Review of current knowledge and practice. Indian J Surg, 2013; 75:430–435.

. ABM clinical protocol #4: Mastitis, revised. March 2014. Breastfeeding Med, 2014; 9:239–243.

Dixon

. Outpatient treatment of non-lactational breast abscesses. Br J Surg, 1992; 79:56–57.

Tan

, Low

. Nonoperative treatment of breast abscesses. Aust N Z J Surg, 1998; 68:423–424.

O'Hara

, Dexter

, Fox

. Conservative management of infective mastitis and breast abscesses after ultrasonographic assessment. Br J Surg, 1996; 83:1413–1414.

Eryilmaz

, Sahin

, Hakan

, et al. Management of lactational breast abscesses. Breast, 2005; 14:375–379.

Gao

, Ma

, He

, et al. Related factor analysis in breast abscess developed from acute lactation mastitis. Chinese J Breast Dis, 2015; 9:35–38.

10.

Gao

, Ma

, He

, et al. Analysis of the clinical features and treatment of the central area of the lactation mastitis. Chin J Gen Pract, 2011; 8:591–592.

11.

Lam

, Chan

, Wiseman

. Breast abscess: Evidence based management recommendations. Expert Rev Anti Infect Ther, 2014; 12:753–762.

12.

Ulitzsch

, Nyman

MKG

, Carlson

. Breast abscess in lactating women: US-guided treatment. Radiology, 200; 232:904–909.

13.

Colin

, Delov

, Peyron-Faure

, et al. Breast abscesses in lactating women: Evidences for ultrasound-guided percutaneous drainage to avoid surgery. Emerg Radiol, 2019; 26:507–514.