Molecular subtyping reveals uniqueness of prognosis in breast ductal carcinoma in situ patients with lumpectomy

The Predictive Role of Mammography, Dynamic Contrast-Enhanced Breast Magnetic Resonance Imaging and Diffusion-Weighted Imaging in Hormone Receptor Status of Pure Ductal Carcinoma In Situ Lesions

Objective

The aim of this retrospective study was to analyze the predictive capabilities of preoperative mammography, dynamic contrast-enhanced-magnetic resonance imaging (DCE-MRI), and diffusion-weighted imaging (DWI) in determining hormone receptor (HRc) status for pure ductal carcinoma in situ (DCIS) lesions.

Materials and Methods

The study included a total of 79 patients who underwent preoperative mammography (MG) and MRI between December 2018 and December 2023 and were subsequently diagnosed with pure DCIS after surgery. The correlation between MG, DCE-MRI, and DWI features and estrogen receptor (ER) and progesterone receptor (PR) status was examined.

Results

Among the lesions, 44 were double HRc-positive (ER and PR-positive), 13 were single HRc-positive (ER-positive and PR-negative or ER-negative and PR-positive) and 22 were double HRc-negative (ER and PR-negative). The presence of symptom (p = 0.029), the presence of comedo necrosis (p = 0.005) and high histological grade (p<0.001) were found to be associated with ER and PR negativity. Amorphous microcalcifications were more commonly observed in the double HRc-negative group, while linear calcifications were more prevalent in both double and single HRc-positive groups (p = 0.020). Non-mass enhancement (NME) with a linear distribution was significantly more common in double HRc-negative lesions (38%), and NME with a segmental distribution in both double (43%) and single (50%) receptor-positive lesions (p = 0.042). Evaluation of DWI findings revealed that a higher lesion-to-normal breast parenchyma apparent diffusion coefficient (ADC) ratio statistically increased the probability of HRc positivity (p = 0.033).

Conclusion

Certain clinicopathological, mammography, and MRI features, along with the lesion-to-normal breast parenchyma ADC ratio, can serve as predictors for HRc status in DCIS lesions.

Spectrum of Ductal Carcinoma In Situ (DCIS) Lesions of the Breast: From Morphology to Molecular Characteristics

Background Specific molecular characteristics of invasive breast cancer have been linked to an increased risk of early relapse. Similarly, ductal carcinoma in situ (DCIS) displays a comparable molecular profile, although their prevalence and implications are not yet fully understood. Aims and objectives The study design defined a multivariable statistical approach aimed at describing the interplay between the histopathological features of ductal carcinoma in situ (DCIS) and their molecular profile. The objective was to explore the correlations between the histopathological features of DCIS (tumor location, DCIS grade, DCIS type, and presence or absence of comedo necrosis) and various biomarkers like estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER2/neu), androgen receptor (AR), and epidermal growth factor receptor (EGFR), in addition to the Ki-67 labeling index. Methods In this retrospective study, we selected and analyzed 100 diagnosed cases of ductal carcinoma in situ (DCIS) to represent various subtypes, grades, and morphological characteristics. A detailed histopathological review and immunohistopathological staining for ER, PR, HER2/neu, AR, EGFR, and Ki-67 were performed on formalin-fixed paraffin-embedded (FFPE) tumor tissue blocks. Molecular subtyping was done based on the biomarker analysis into luminal A, luminal B, luminal HER2/neu, HER2/neu enriched, and triple-negative subtypes. Statistical analysis was done to examine the correlation between tumor location, histopathological features of ductal carcinoma in situ (DCIS), and the expression of the immunohistochemical markers and the molecular subtypes. Results The majority of cases exhibited positivity for estrogen receptor (ER) and progesterone receptor (PR). A strong association was observed between histopathological features (DCIS grade, type, and comedo necrosis) of DCIS and ER/PR status. Additionally, a significant correlation was found between ductal carcinoma in situ (DCIS) grade and HER2/neu status. However, no association was identified between histopathological features and AR or EGFR status. Contrary to expectations, triple-negative DCIS did not show the most aggressive behavior, whereas HER2/neu-positive tumors, particularly high-grade ones, exhibited more aggressive features. No low-grade cases of luminal HER2/neu and HER2/neu-enriched tumors were found. A higher Ki-67 labeling index was found in cases with grade 3 and solid and comedo architectural types of DCIS, while low-grade tumors had a lower Ki-67 labeling index. Conclusion These findings suggest that hormone pathways play a crucial role in ductal carcinoma in situ (DCIS) progression, but the molecular interactions are complex and extend beyond simple binary associations. The complex relationship between the histopathological features of ductal carcinoma in situ (DCIS) and its hormone receptor status warrants further investigation with a larger sample size to fully understand the underlying mechanisms. The results challenge the expectation that triple-negative DCIS is the most aggressive subtype, highlighting the need for further research into the prognostic significance of different DCIS subtypes.

Systematic assessment of HER2 status in ductal carcinoma in situ of the breast: a perspective on the potential clinical relevance

In many countries, hormone receptor status assessment of ductal carcinoma in situ (DCIS) is routinely performed, as hormone receptor-positive DCIS patients are eligible for adjuvant anti-hormonal treatment, aiming to reduce the ipsilateral and contralateral breast cancer risk. Although HER2 gene amplification and its associated HER2 protein overexpression constitute a major prognostic and predictive marker in invasive breast carcinoma, its use in the diagnosis and treatment of DCIS is less straightforward. HER2 immunohistochemistry is not routinely performed yet, as the role of HER2-positivity in DCIS biology is unclear. Nonetheless, recent data challenge this practice. Here, we discuss the value of routine HER2 assessment for DCIS. HER2-positivity correlates strongly with DCIS grade: around four in five HER2-positive DCIS show high grade atypia. As morphological DCIS grading is prone to interobserver variability, HER2 immunohistochemistry could render grading more robust. Several studies showed an association between HER2-positive DCIS and ipsilateral recurrence risk, albeit currently unclear whether this is for overall, in situ or invasive recurrence. HER2-positive DCIS tends to be larger, with a higher risk of involved surgical margins. HER2-positive DCIS patients benefit more from adjuvant radiotherapy: it substantially decreases the local recurrence risk after lumpectomy, without impact on overall survival. HER2-positivity in pure biopsy-diagnosed DCIS is associated with increased upstaging to invasive carcinoma after surgery. HER2 immunohistochemistry on preoperative biopsies might therefore provide useful information to surgeons, favoring wider excisions. The time seems right to consider DCIS subtype-dependent treatment, comprising appropriate local treatment for HER2-positive DCIS patients and de-escalation for hormone receptor-positive, HER2-negative DCIS patients.

Tools to Guide Radiation Oncologists in the Management of DCIS

Similar to invasive breast cancer, ductal carcinoma in situ is also going through a phase of changes not only from a technical but also a conceptual standpoint. From prescribing radiotherapy to everyone to personalized approaches, including radiotherapy omission, there is still a lack of a comprehensive framework to guide radiation oncologists in decision making. Many pieces of the puzzle are finding their place as high-quality data mature and are disseminated, but very often, the interpretation of risk factors and the perception of risk remain very highly subjective. Sharing the therapeutic choice with patients requires effective communication for an understanding of risks and benefits, facilitating an informed decision that does not increase anxiety and concerns about prognosis. The purpose of this narrative review is to summarize the current state of knowledge to highlight the tools available to radiation oncologists for managing DCIS, with an outlook on future developments.

Breast carcinoma arising in a fibroadenoma: A case series of 16 patients and review of the literature

Breast carcinoma arising from a fibroadenoma is an uncommon entity and is frequently detected incidentally during pathological examination or excisional biopsy of a benign breast tumor. Due to only sporadic cases being reported, evidence-based guidelines are not well-established to date. The present report describes 16 patients diagnosed with breast carcinoma arising within a fibroadenoma in the Third Hospital of Nanchang (Nanchang, China) between January 2019 and December 2021 and discusses the clinicopathological characteristics, imaging findings and treatment. The age of patients at diagnosis ranged between 19 and 58 years and a well-defined asymptomatic mass was the most common clinical presentation. Carcinoma occurring in fibroadenoma generally mimics a benign tumor and potential carcinomatous changes may not be detected. Pathologically, carcinoma in situ was the predominant subtype in the present study. Additionally, ductal carcinoma in situ was more common compared with lobular carcinoma in situ in the present case series. Regarding the molecular phenotypes, the majority of cases were categorized as luminal subtype, although other subtypes such as triple-negative and HER2 positive breast cancer were also identified. In the present study, seven patients were treated with breast-conserving surgery and nine patients were treated with mastectomy. Sentinel lymph node biopsy was performed in all patients and none exhibited axillary node metastasis. Additionally, six patients underwent radiotherapy and two received chemotherapy. During the follow-up, all patients were alive and no evidence of disease relapse was observed. In summary, clinicians should be aware of the possibility of carcinoma within a fibroadenoma, which could alter the therapeutical course. Adequate biopsy or excision should be performed in patients with indicators of malignant transformation in a presumed benign breast tumor.

The clinical significance of HER2 expression in DCIS

HER2 is an established prognostic and predictive marker for patients with invasive breast cancer. The clinical and biological significance of HER2 overexpression in patients with ductal carcinoma in situ (DCIS) remains poorly defined. DCIS is a heterogeneous disease and some patients with DCIS will not progress to invasive breast cancer. However, clinically significant recurrence rates have been reported after breast-conserving surgery for DCIS and approximately half of these cases will be life-threatening invasive recurrences. Since the incidence of DCIS is rising due to the widespread use of screening mammography, there is robust interest in selecting high-risk DCIS patients that may benefit from adjuvant therapies. Molecular prognostic and predictive models in early invasive breast cancer help clinicians identify patients that will benefit from chemotherapy. Molecular subtyping and profiling could also be useful in treating DCIS patients. According to current practice guidelines, HER2 testing is not recommended in DCIS patients. Nevertheless, evidence suggests that HER2-positive DCIS cases may be associated with adverse clinicopathological parameters and increased recurrence rates. This review summarizes the existing body of evidence linking HER2 expression and ipsilateral breast cancer recurrence in DCIS. HER2, as well as its correlation with other clinicopathological markers might be a useful prognostic and predictive marker, helping clinical decision-making in DCIS patients.