Tumor Location of the Lower-Inner Quadrant Is Associated with an Impaired Survival for Women With Early-Stage Breast Cancer

Abstract

Background: There is growing evidence that tumors of the inner quadrants (especially the lower-inner quadrant) metastasize more often to the internal mammary chain (IMC). As these metastases are not investigated, patients with lower-inner quadrant tumors have an increased risk of being under-staged and under-treated and may therefore have a higher risk of death from breast cancer.Methods: We identified all 1522 women operated for stage I breast cancer between 1984 and 2002 recorded at the population-based Geneva Cancer Registry. We compared breast cancer mortality risk by tumor location with multivariate Cox regression analysis that accounted for all factors linked to tumor location and survival.Results: Ten-year disease-specific survival was 93% (95%CI: 91-94%). Patients with breast cancer of the lower-inner quadrant (n = 118; 7.8%) had an importantly increased risk of dying of breast cancer compared to women with breast cancer of the upper-outer quadrant (multiadjusted Hazard Ratio: 2.3, 95%CI: 1.1-4.5, P = 0.0206). The over-mortality associated with this quadrant was particularly evident for tumors >10 mm (multiadjusted HR: 3.6, 95%CI: 1.6-7.9, P = 0.0016). There was no increased breast cancer mortality risk for tumors located in other quadrants.Conclusions: Tumor location in the lower-inner quadrant is an independent and important prognostic factor of stage I breast cancer. Further research is needed to evaluate if the overmortality of patients with stage I cancer of the lower-inner quadrant is indeed a result of under-treatment due to undetected IMC metastases. If so, patients with stage I breast cancer of the lower-inner quadrant are good candidates for systematic IMC investigation.

The Effect of Adjuvant Radiotherapy on Mortality Differs According to Primary Tumor Location in Women with Node-Positive Breast Cancer

“…Consistent with other studies [20,38,50,53] though not all [13,15], our previous investigations of SEER data have found poorer survival associated with medial tumor location [57]. This poorer survival was observed despite an apparently more favorable ALN profile.…”

“…Medial tumor location has been shown to adversely affect survival in patients with breast cancer (BC) [20,38,50,53], with poorer outcomes attributed to increased risk of internal mammary node (IMN) involvement and distant metastases [14,53]. Higher rates of chest wall recurrence were reported in patients with medial tumors compared to lateral tumors with similar size, grade and stage, following radical mastectomy [53].…”

Wide Tangential Fields Including the Internal Mammary Lymph Nodes in Patients with Left-Sided Breast Cancer

“…Therefore, unavoidable radiation dose outside the target should be kept to a minimum even though the applied dose was low [15]. Despite the fact that some have shown IMN involvement in patients with definite tumor characteristics like primary tumor localization in the central or inner portion of the breast and involved axil- lary lymph nodes, failure rates involving the IMN remain low [6,7,16]. Therefore, the widely accepted practice of not specifically including the IMN seems comprehensible.…”

“…Otherwise, verified internal mammary nodal chain drainage is a prognostic indicator in axillary node-positive breast cancer patients and predicts a threefold increased mortality risk in node-positive patients [24]. The potential benefit of treating the area of the IMN is that microscopic involvement may theoretically represent a source of distant metastases and therefore this node group is assuming new importance [6,12,16].…”

Internal mammary node management in breast cancer. A review

“…The predictive factor for internal mammary chain drainage was location of the tumors in the inner quadrants (P<0.001). There are also data supporting the negative prognostic value of location of tumor in the inner quadrant [41][42] . This difference may be explained by lymph drainage to internal mammary nodes which are usually omitted during breast cancer patient staging and treatment.…”