Evaluation of the Benefit of Radiotherapy in Patients with Occult Breast Cancer: A Population-Based Analysis of the SEER Database

Abstract

PurposeFew studies for occult breast cancer (OBC) have evaluated the effect of radiotherapy (RT) after mastectomy or axillary lymph node dissection (ALND) with/without breast surgery. Therefore, we investigated clinicopathologic factors of OBC with the impact of postoperative RT to determine its prognostic significance using large population-based data.Materials and MethodsWe performed a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) database from 1983 to 2013. A total of 1,045 eligible patients with OBC were identified. We compared overall survival (OS) using Cox proportional hazards regression with propensity score matching after verifying an imbalance of prognosticators between RT group (n=518) and non-RT group (n=479).ResultsPatients with age < 70 (p=0.033), married marital status (p < 0.001), undergoing ALND (p < 0.001), more examined lymph nodes (LNs) (p < 0.001), and more metastatic LNs (p < 0.001) were more likely to receive RT. Multivariate analysis after propensity score matching (n=798) showed that patients treated with RT survived significantly longer than those without RT (5-year OS, 81.5% vs. 78.3%; p=0.014). A significantly prolonged OS was observed when RT was given to patients treated with mastectomy (p=0.033), those treated with ALND (p=0.036), or those with more than seven metastatic LNs (p=0.016).ConclusionRT may offer survival benefit in OBC even after mastectomy or ALND, especially in patients with more than seven metastatic LNs. Further prospective studies are needed to validate these findings.

Clinicopathological characteristics and treatment outcomes of occult breast cancer: a SEER population-based study

“…In addition, defining ALND by different criteria may affect the survival outcomes. Other SEER database analyses categorized more than three examined LNs as having undergone ALND; 7 , 40 this definition was inconsistent with our definition of ALND as the examination of more than five LNs. Therefore, further clinical studies are needed to evaluate this controversial conclusion and to confirm that ALND is an effective standalone treatment strategy for OBC patients.…”

Outcome of breast-conserving treatment for axillary lymph node metastasis from occult breast cancer with negative breast MRI

“…Non-academic centers or rural hospitals were more likely to perform mastectomy than BCT [ 10 ]. According to population-based studies, approximately 40% of OBC patients have been treated with mastectomy [ 6 , 10 , 25 ]. In a 2004 survey of 776 breast surgeons in the United States, 43% of responders preferred mastectomy while 37% opted for BCT [ 24 ].…”

“…[ 10 ] Population based (NCDB) 1231 2004–2013 NR TM (48.1%) ALND + RT (27.8%) ALND (8.6%) Observation (15.5%) NR NR 80.0% at 5-yrs (OS) 90.8% 76.2% 56.5% – Kim et al. [ 25 ] Population based (SEER) 1045 1983–2013 NR TM (39.3%), BCS (13.4%) NR (RT in 49.6%) NR 81.5% (RT), 5-yr OS 78.3% (non-RT) – Sohn et at al. [ 6 ] Multicenter 142 1990–2009 NR ALND + TM (38.0%) ALND + BCS (39.4%) ALND (22.5%) NR (RT in 59.9%) NR 92.5% at 10- yrs (OS) 98.0% 80.0% About 67% had N1 disease Masinghe et al.…”

“…Prognosis of OBC differed depending on nodal stage in the present study. Advanced nodal stage has been previously reported to have negative impact on survival in OBC [ 6 , 25 ]. According to one study, OBC patients having less than four lymph node metastases (pT0/TxN1) had better survival than pT1N1 patients, and patients with more than four positive lymph nodes (pT0/TxN2 or pT0/TxN3) had similar survival to those with pT1N2/N3 breast cancer [ 6 ].…”

A retrospective study of optimal surgical management for occult breast carcinoma

“…[8] However, there is a controversy about the choice of target area and dose for radiotherapy. [12] Then, the whole breast radiation therapy could possibly lead to breast deformation, which is contrary to the requirement of cosmetic effect.…”