The clinical relevance of various methods of classifying ipsilateral breast tumour recurrence as either true local recurrence or new primary

Ipsilateral Breast Carcinoma Recurrence: True Recurrence or New Primary? A Clinicopathologic and Molecular Study

Determining whether an ipsilateral breast carcinoma recurrence is a true recurrence or a new primary remains challenging based solely on clinicopathologic features. Algorithms based on these features have estimated that up to 68% of recurrences might be new primaries. However, few studies have analyzed the clonal relationship between primary and secondary carcinomas to establish the true nature of recurrences. This study analyzed 70 breast carcinomas from 33 patients using immunohistochemistry, FISH, and massive parallel sequencing. We compared 35 primary carcinomas with the associated recurrences, identifying 24 (68.6%) as true recurrences, 7 (20%) as new primaries, and 4 (11%) as undetermined. Twenty-eight primary carcinomas were invasive carcinomas (22 of no special type, 5 invasive lobular, and 1 invasive micropapillary carcinoma), and 7 were in situ (6 ductal and 1 lobular). Time to recurrence was longer for new primaries (median 12.8 y) than for true recurrences (median 6.8 y). Among the new primary cases, 6 of 7 (85%) patients had undergone mastectomy as their initial treatment. Clinicopathologic classifications of invasive carcinomas overestimated the number of new primaries (41.6% to 68.6%), partially due to phenotype conversion in 14% of true recurrences. Although 41.7% of recurrences showed private mutations or amplifications relevant to tumor progression, such as PIK3CA, PIK3R1, MAP3K1, AKT1, GATA3, CCND1, MDM4 , or T P 5 3 ; a common mutational progression pattern was not identified. Further studies, including larger series, are necessary to evaluate the prognostic significance of the molecular classification of recurrences.

Do we need reshape rTNM staging system for ipsilateral breast tumor recurrence of breast cancer? A population-based, propensity score matched cohort study

BACKGROUND

The aim of the study was to explore the role of recurrent TNM (rTNM) staging in predicting prognosis for ipsilateral breast tumor recurrence (IBTR) and determine the optimal treatment strategy for IBTR.

METHOD

IBTR cases were identified from the Surveillance, Epidemiology, and End Results (SEER) database spanning the years 2000-2018. Cox proportional hazards analysis was performed to examine factors associated with overall survival (OS) and breast cancer-specific survival (BCSS). Propensity score matching (PSM) was employed to match IBTR with primary early breast cancer (EBC) based on clinicopathological characteristics. Investigations into the impact of different therapies were also included.

RESULTS

Of the 4375 IBTR cases included in the study, the 5-year OS was 87.1%, 71.6% and 58.7% in rTNM stages I, II and III, respectively. After PSM, while IBTR patients had worse survival to primary EBC patients, prognosis of IBTR for different rTNM stage always closely aligned with the corresponding stage of primary EBC. Repeat breast-conserving surgery (BCS) with radiation therapy was equivalent to mastectomy with respect to OS and BCSS. Chemotherapy was favorable for OS and BCSS in estrogen receptor (ER)-negative IBTR or IBTR occurring within a 60-month interval.

CONCLUSIONS

rTNM staging system has an outstanding prognostic value for survival outcome of patients with IBTR, and IBTR and primary EBC may have potentially analogous features in the context of TNM staging. BCS plus radiation therapy may be an alternative. IBTR cases who have experienced recurrence with short intervals and with ER-negative tumors might benefit from chemotherapy.

Ipsilateral breast tumor recurrence after breast-conserving surgery: insights into biology and treatment

Despite modern surgical and irradiation techniques, ipsilateral breast tumor recurrence (IBTR) accounts for 5-15% of all cancer recurrence in women treated with breast conservative treatment. Historically, this event has been treated definitively with salvage mastectomy and completion axillary clearance. However, many local recurrences are small and without nodal involvement at presentation. Thus, there has been an interest in performing a surgical de-escalation procedure in the breast and the axilla. The current guidelines do not provide detailed descriptions and treatment suggestions for these selected patients, resulting in inconsistent treatment strategies. Moreover, the methods to define true recurrence (TR) and new primary tumor (NP) for IBTR remain controversial. Most developed classification methods mainly rely on clinical and pathological criteria, limiting the accuracy of the discerption and causing misclassification. In this editorial, we will discuss the current trends in surgical de-escalation for patients with IBTR. Moreover, we will focus on recent IBTR innovations, highlighting molecular-integrated classification and multimodal staging methods for clinical practice and postoperative surveillance strategies.