Determining the Need for Metastatic Staging in Patients with Bilateral Breast Cancers.

Introduction: Bilateral breast cancers (BBC) diagnosed at an interval apart are uncommon. While metastatic staging guidelines are established in patients with unilateral breast cancer, its role in BBC diagnosed at an interval apart is unclear. We aim to identify the subgroup who would benefit from metastatic staging at contralateral cancer diagnosis. Methods: Eligible patients were divided into three categories: (A) ipsilateral invasive cancer and contralateral ductal carcinoma in situ (DCIS), (B) bilateral invasive cancers and (C) ipsilateral DCIS and contralateral invasive cancer and reviewed retrospectively. We excluded patients with bilateral DCIS, synchronous BBC diagnosed within 6 months from first cancer, patients who were stage IV at first cancer diagnosis and patients with recurrence prior to contralateral cancer. Results: Of 4516 newly diagnosed breast cancer patients, 79 patients were included. Systemic metastasis occurred in 15.6% of patients in Group B. Having nodal positivity of either cancer which were diagnosed ≤30 months apart and nodal positivity of only the contralateral cancer when diagnosed >30 months apart was significantly associated with systemic metastasis (p = 0.0322). Conclusions: Both the nodal status and a 30 months cut-off time interval between the two cancers can be used to identify patients who will benefit from metastatic staging. This finding requires validation in larger studies.

Can the size of chest wall recurrence after mastectomy in breast cancer patients predict the presence of systemic metastasis?

Background: One of the manifestations of recurrence after mastectomy is the presentation of chest wall lesion. However, it is unclear if the size of the chest wall recurrence (CWR) is related to the presence of simultaneous systemic metastasis in these patients. We aimed to determine if the size of the CWR could affect the outcome in these patients. Methods: Stage I-III breast cancer patients who underwent mastectomy and developed invasive ipsilateral CWR were included. Patients with bilateral mastectomy were excluded. Demographic, radiologic and pathological data were analysed between patients with CWR and simultaneous systemic metastasis versus those with isolated CWR. Results: Of the 1,619 patients treated with mastectomy, 214 (13.2%) patients developed recurrences. 57/214 (26.6%) patients had invasive ipsilateral CWR. 48 patients were analysed after exclusion of patients with missing data. Mean age at diagnosis of first cancer and at recurrence were 55.2 years (32-84 years) and 58.5 years (34-85 years) respectively. 26/48 (54.2%) had CWR with simultaneous systemic metastasis. Mean CWR size was 30.7 mm (6-121 mm) and 21.4 mm (5.3-90 mm) for the patients with simultaneous systemic metastasis and those without respectively (P=0.441). Grade (P=0.0008) and nodal status (P=0.0009) at primary diagnosis, grade (P=0.0011) and progesterone receptor (PR) status (P=0.0487) at recurrence were statistically significant for systemic metastasis in patients with CWR. Conclusions: Biologic factors such as grade of primary and recurrent cancer, PR status of recurrent cancer and nodal status at primary diagnosis, instead of CWR size, were associated with simultaneous systemic metastasis in patients with CWR.

Axillary management of breast cancer patients with isolated chest wall recurrence after mastectomy.

Background: National Comprehensive Cancer Network (NCCN) guidelines on the axillary management of breast cancer patients with isolated chest wall recurrence after mastectomy are unclear. Though sentinel lymph node biopsy (SLNB) is possible and may be considered, there is limited data on its usefulness. We aimed to determine if axillary restaging surgery was required in this cohort of patients who developed operable isolated chest wall recurrences after mastectomy. Methods: Breast cancer patients treated at a tertiary institution from 1st September 2005 to 31st October 2017 and developed isolated chest wall invasive recurrences after mastectomy were retrospectively reviewed. We excluded patients with bilateral cancers, concurrent regional or distant metastases, patients without surgery for their chest wall recurrences and patients who were lost to follow-up. The demographics, pathological data and second recurrences were collected from a prospectively maintained database and compared between patients with axillary lymph node dissection (ALND), SLNB and no axillary operation. Results: Of the 1,841 patients who underwent mastectomy, 26 (1.4%) patients developed isolated chest wall recurrences. Twenty two eligible patients were analysed. The mean age at diagnosis of the recurrence was 54.7 years (range, 37-84 years). 1, 2 and 19 patients had ALND, SLNB and no axillary operation respectively. On mean follow-up of 38.3 months, no axillary recurrences were noted. Conclusions: In breast cancer patients with isolated chest wall recurrences after mastectomy, axillary restaging surgery can be safely omitted with no increased axillary recurrences on medium term follow-up. This finding could refine existing guidelines in the management of the axilla for patients with chest wall recurrences after mastectomy.

Pregnancy-associated breast cancer: a multicenter study comparing clinicopathological factors, diagnosis and treatment outcomes with non-pregnant patients.

PURPOSE: Pregnancy-associated breast cancer (PABC), defined as breast carcinoma diagnosed during pregnancy or in the first post-partum year, is one of the most common gestation-related malignancies with reported differences in tumor characteristics and outcomes. This multicenter study aims to review cases of PABC in Singapore, including their clinicopathological features, treatment, and clinical outcomes compared to non-PABC patients. METHODS: Demographic, histopathologic and clinical outcomes of 93 PABC patients obtained from our database were compared to 1424 non-PABC patients. RESULTS: PABC patients presented at a younger age. They had higher tumor and nodal stages, higher tumor grade, were more likely to be hormone receptor negative and had a higher incidence of multicentric and multifocal tumors. Histological examination after definitive surgery showed no significant difference in tumor size and number of positive lymph nodes suggesting similar neoadjuvant treatment effects. Despite this, PABC patients had worse outcomes with poorer overall survival and disease-free survival, OS (P < 0.0001) and DFS (P < 0.0001). Termination of pregnancy did not improve survival. CONCLUSION: Patients with PABC present at a higher stage with more aggressive disease and have poorer outcomes compared to non-PABC patients. Reducing delay in diagnosis and treatment may help improve survival.

Patterns of breast cancer second recurrences in patients after mastectomy.

INTRODUCTION: Little is known about second recurrences in breast cancer patients, especially in patients with mastectomy. We aimed to determine the risk factors, prevalence and patterns of second recurrence in mastectomy patients after first recurrence. METHODS: Stage I-III breast cancer patients treated at a tertiary institution from 1st September 2005 to 31st October 2017 and developed first and second recurrences after mastectomy were retrospectively reviewed. We excluded patients with bilateral cancers and patients who were lost to follow-up. The demographics, pathological and recurrence data were collected from a prospectively maintained database and analysed. RESULTS: Of the 1619 mastectomy patients, 214 (13.2%) patients developed recurrences at a mean 39.9 months from primary cancer diagnosis. 23, 8 and 183 had isolated chest wall recurrences (CWR), regional and systemic metastases, respectively. Excluding 2 CWR patients without surgery, second recurrences occurred in 3/21 (14.3%) and 3/8 (37.5%) in patients with CWR and regional metastasis at 27.7 months (range: 5-42) and 32 months (range: 18-40), respectively. In both groups, systemic metastasis as second recurrence occurred within 2 years after first recurrence, whilst locoregional second recurrences occurred later. No risk factors for second recurrence were identified. CONCLUSION: In patients with mastectomy, second recurrences occurred in 20.7% of patients with treated locoregional first recurrence, with no risk factors identified. Systemic metastases manifesting as second recurrence occurred in the first 2 years after first recurrence. Continued clinical surveillance and restaging patients in the first 2 years after first locoregional recurrence may enable early prognostication and treatment with the newer metastatic drugs.

Association between Breast Cancer Polygenic Risk Score and Chemotherapy-Induced Febrile Neutropenia: Null Results.

BACKGROUND: The hypothesis that breast cancer (BC) susceptibility variants are linked to chemotherapy-induced toxicity has been previously explored. Here, we investigated the association between a validated 313-marker-based BC polygenic risk score (PRS) and chemotherapy-induced neutropenia without fever and febrile neutropenia (FNc) in Asian BC patients. METHODS: This observational case-control study of Asian BC patients treated with chemotherapy included 161 FNc patients, 219 neutropenia patients, and 936 patients who did not develop neutropenia. A continuous PRS was calculated by summing weighted risk alleles associated with overall, estrogen receptor- (ER-) positive, and ER-negative BC risk. PRS distributions neutropenia or FNc cases were compared to controls who did not develop neutropenia using two-sample t-tests. Odds ratios (OR) and corresponding 95% confidence intervals were estimated for the associations between PRS (quartiles and per standard deviation (SD) increase) and neutropenia-related outcomes compared to controls. RESULTS: PRS distributions were not significantly different in any of the comparisons. Higher PRSoverall quartiles were negatively correlated with neutropenia or FNc. However, the associations were not statistically significant (PRS per SD increase OR neutropenia: 0.91 [0.79-1.06]; FNc: 0.87 [0.73-1.03]). No dose-dependent trend was observed for the ER-positive weighted PRS (PRSER-pos) and ER-negative weighted PRS (PRSER-neg). CONCLUSION: BC PRS was not strongly associated with chemotherapy-induced neutropenia or FNc.

Incidence and prognosis of non-metastatic triple negative breast cancer (TNBC) among different races in Southeast Asia.

BACKGROUND AND OBJECTIVES: Triple negative breast cancer (TNBC) carries a worse prognosis compared to the other subtypes. There have been conflicting studies that race may impact the prognosis of TNBC patients. We aim to determine the incidence and prognosis of TNBC among the different ethnic races in Singapore, and to determine its associated risk factors for prognosis. METHODS: Patients diagnosed with invasive breast cancer (BC) from 2005 to 2013 at our tertiary institution were included and divided according to race and subtypes. Demographic and clinical information of non-metastatic TNBC patients were analyzed. Log-rank test, univariate and multivariate Cox proportional hazard regression models were used to find associated risk factors related with overall survival (OS) and disease-free survival (DFS). RESULTS: Among 1227 BC patients, 129 (10.5%) had TNBC. TNBC patients had the worst OS (P: 0.0005) and DFS (P: 0.0016) among the subtypes. However, variations in race did not have any difference in OS or DFS among TNBC patients. Axillary lymph node involvement, invasive lobular histology, larger tumor size, and the presence of lymphovascular invasion (LVI) were factors associated with both poor DFS and OS among TNBC patients. CONCLUSIONS: Racial variation did not have any impact on the prognosis of the TNBC.