Lower and central tumor location correlates with lymphoscintigraphy drainage to the internal mammary lymph nodes in breast carcinoma

Survival Outcomes of Breast-Conserving Therapy versus Mastectomy in Early-Stage Breast Cancer, Including Centrally Located Breast Cancer: A SEER-Based Study

Purpose

This study aims to analyze the survival outcomes of breast cancer (BC) patients, especially centrally located breast cancer (CLBC) patients undergoing breast-conserving therapy (BCT) or mastectomy.

Methods

Surveillance, epidemiology, and end results (SEER) data of patients with T1-T2 invasive ductal or lobular breast cancer receiving BCT or mastectomy were reviewed. We used X-tile software to convert continuous variables to categorical variables. Chi-square tests were utilized to compare baseline information. The multivariate logistic regression model was performed to evaluate the relationship between predictive variables and treatment choice. Survival outcomes were visualized by Kaplan–Meier curves and cumulative incidence function curves and compared using multivariate analyses, including the Cox proportional hazards model and competing risks model. Propensity score matching was performed to alleviate the effects of baseline differences on survival outcomes.

Result

A total of 180,495 patients were enrolled in this study. The breast preservation rates fluctuated around 60% from 2000 to 2015. Clinical features including invasive ductal carcinoma (IDC), lower histologic grade, smaller tumor size, fewer lymph node metastases, positive ER and PR status, and chemotherapy use were independently correlated with BCT in both BC and CLBC cohorts. In all the classic Cox models and competing risks models, BCT was an independent favorable prognostic factor for BC, including CLBC patients in most subgroups. In addition, despite the low breast-conserving rate compared with tumors located in the other areas, CLBC did not impair the prognosis of BCT patients.

Conclusion

BCT is optional and preferable for most early-stage BC, including CLBC patients.

Breast Reconstruction Does Not Affect the Survival of Patients with Breast Cancer Located in the Central and Nipple Portion: A Surveillance, Epidemiology, and End Results Database Analysis

Background

Tumors in the central and nipple portion (TCNP) are associated with poor prognosis and aggressive clinicopathological characteristics. The availability and safety of postmastectomy reconstruction in breast cancer patients with TCNP have still not been deeply explored. It is necessary to investigate whether reconstruction is appropriate for TCNP compared with non-reconstruction therapy in terms of survival outcomes.

Methods

Using the Surveillance, Epidemiology, and End Results (SEER) database, we enrolled TCNP patients diagnosed between the years 2010 and 2016. The propensity score matching (PSM) technique was applied to construct a matched sample consisting of pairs of non-reconstruction and reconstruction groups. Survival analysis was performed with the Kaplan–Meier method. Univariate and multivariate Cox proportional hazard models were applied to estimate the factors associated with breast cancer-specific survival (BCSS) and overall survival (OS).

Results

In the overall cohort, a total of 6,002 patients were enrolled. The patients in the reconstruction group showed significantly better BCSS (log-rank, p < 0.01) and OS (log-rank, p < 0.01) than those in the non-reconstruction group (832 patients) after PSM. However, the multivariate Cox regression model revealed that breast reconstruction was not associated with worse BCSS and OS of TCNP patients.

Conclusion

Our study provided a new perspective showing that breast reconstruction did not affect the survival and disease prognosis in the cohort of TCNP patients from SEER databases, compared with non-reconstruction. This finding provides further survival evidence supporting the practice of postmastectomy reconstruction for suitable TCNP patients, especially those with a strong willingness for breast reconstruction.

Breast-Conserving Surgery is Oncologically Safe for Well-Selected, Centrally Located Breast Cancer

OBJECTIVE

The aim of this study was to evaluate the long-term survival outcomes of breast-conserving surgery (BCS) in centrally located breast cancer (CLBC) compared with mastectomy in CLBC and BCS in non-CLBC, based on the Surveillance, Epidemiology, and End Results (SEER) database.

METHODS

Female patients aged < 80 years with unilateral T1-T2 invasive ductal or lobular breast cancer undergoing BCS or mastectomy were enrolled. The differences in clinical-pathological characteristics were evaluated using Chi square tests. Multivariate logistic regression was used to measure the relationship between predictive variables and performing BCS in CLBC. Survival outcomes were estimated using the Kaplan-Meier method and compared using Cox proportional hazards models. To overcome the effects of baseline differences on survival outcome in patients treated with BCS in the central and upper-outer locations, a 1:1 ratio propensity score matching method was performed.

RESULTS

Overall, among 16,522 CLBC patients, 7982 cases (48.3%) underwent BCS between 1998 and 2015. Factors such as older age, Black race, invasive ductal carcinoma (IDC), grade I, small tumor size, none or limited lymph node metastasis, positive progesterone receptor status, and receiving chemotherapy were independently correlated with BCS. BCS was an independent favorable prognostic factor among CLBC patients, based on multivariate Cox analysis. It was also shown that CLBC had similar survival outcomes compared with tumors in the upper-outer quadrant, and had a better breast cancer-specific survival compared with tumors in the lower quadrants, based on multivariate Cox analysis.

CONCLUSIONS

BCS should be an acceptable and preferable alternative to mastectomy for well-selected, early-stage T1 or T2 CLBC.

Clinical value of postoperative sentinel lymph node biopsy

Background

This study analyzed the clinical data and general information of breast cancer patients who were admitted by the Affiliated Hospital of Nantong University and underwent lumpectomy, followed by sentinel lymph node biopsy (SLNB) to investigate the effect of tumor location on the sentinel lymph node (SLN) detection rate, obtain a clear understanding of the SLNB procedure and further promote the use of this procedure in the local area.

Methods

This study involved a total of 118 patients who were diagnosed with breast cancer and admitted by the Affiliated Hospital of Nantong University for lumpectomy and SLNB between July 2015 and June 2019. An analysis was conducted to explore the role of tumor location in the detection of SLNs.

Results

Tumor location was associated with the success rate of post-lumpectomy SLNB. In the case of tumor location in the upper outer quadrant (UOQ) of the breast near the axilla, the SLN detection rate was relatively low. In contrast, when a tumor occurred in any of the other quadrants or the UOQ next to the areola, the tumor location had no significant impact on the SLN detection rate. SLNB indicated that 102 out of the 118 patients had SLNs, with the detection rate of 86.4%. Particularly, for patients whose tumors were located in the UOQ near their axillae, the SLN detection rate was 30% (3/10). As to tumor location in other quadrants or the UOQ next to the areola, the SLN detection rate was up to 90.8% (99/109).

Conclusions

The performance of post-lumpectomy SLNB is associated with tumor location. SLNB is recommended when the tumor site lies in the upper inner/lower outer/lower inner quadrants (UIQ/LOQ/LIQ) of the breast or the UOQ next to the areola. If the SLNB result turns out to be negative, there is no need to perform axillary lymph node dissection (ALND). For tumor location in the UOQ of the breast, especially when it is near the axilla, SLNB is not a favorable option after lumpectomy. It is recommended that the patient receive a core needle biopsy (CNB) before SLNB.

Incidence of internal mammary node in locally advanced breast cancer and its correlation with metastatic disease: a retrospective observational study

OBJECTIVE

To determine incidence of internal mammary nodes (IMN) at baseline CT of locally advanced breast cancer (LABC) and ascertain prognostic implication.

METHODS AND MATERIALS

Retrospective review of all LABC patients from 1 January 2012 through 31 December 2014 was performed after approval from institutional review board. CTs of 182 patients enrolled were reviewed by two radiologists independently, and IMNs were documented based on size, location and relation with location of breast primary. 3-year follow-up was analysed and incidence of metastases was calculated as overall incidence, incidence in patients with and without discernible IMN at baseline imaging. Results are presented as numbers and percentages. Differences in metastases of two groups were compared using χ2 test. 95% CI was calculated and p < 0.05 was considered significant.

RESULTS

77 of 182 had identifiable IMN (42.3% incidence). Majority of identifiable nodes were on ipsilateral side of primary (incidence 90.90%) with higher incidence in patients with upper-outer quadrant tumours (55.9%). Majority were seen in second intercostal space (44.4%). 36 (19.7%) developed distant metastases within 3 years of therapy. Of these, 21 (27.3%) had IMN as compared with 15 (14.3 %) without IMN on baseline imaging. Patients with identifiable IMN on baseline CT had significantly higher incidence of distant metastases (p = 0.0321).

CONCLUSION

Significant number LABC patients have identifiable IMN on baseline imaging with patients showing IMN on baseline CT showing significantly higher rate of metastatic disease following therapy.

ADVANCES IN KNOWLEDGE

Many LABC patients have identifiable IMNs on baseline imaging which show higher incidence of subsequent metastatic disease.

Do breast quadrants explain racial disparities in breast cancer outcomes?

PURPOSE

Tumors of the inner quadrants of the breast are associated with poorer survival than those of the upper-outer quadrant. It is unknown whether racial differences in breast cancer outcomes are modified by breast quadrant, in addition to comparisons among Asian subgroups.

METHODS

Using the Surveillance, Epidemiology, and End Results database, we analyzed data among women diagnosed with non-metastatic invasive breast cancer between 1990 and 2014. We performed Cox proportional hazards regression models to assess the associations of race with breast cancer-specific survival and overall survival, stratified by breast quadrants. The models were adjusted for age, year of the diagnosis, tumor size, grade, histological type, tumor laterality, lymph node, estrogen receptor, progesterone receptor, and treatments.

RESULTS

Among 454,154 patients (73.0% White, 10.0% Black, 7.8% Asian/PI, and 9.2% Hispanic), 54.3% had tumors diagnosed in the upper-outer quadrant of the breast. Asian/PI women were more likely than White to have tumors diagnosed in the nipple/central portion of the breast and were less likely to have diagnosed in the upper-outer quadrant (P < 0.001), despite a similar distribution of breast quadrant between Black, Hispanic, and White women. Compared with White women, the multivariable-adjusted hazard ratios of breast cancer-specific mortality were 1.41 (95% CI 1.37-1.44) in Black women, 0.82 (95% CI 0.79-0.85) in Asian women, and 1.05 (95% CI 1.02-1.09) in Hispanic women. Among Asian subgroups, Japanese American women had a lower risk of breast cancer-specific mortality (HR = 0.68, 95% CI 0.62-0.74) compared with White women. Overall survival was similar to breast cancer-specific survival in each race group. The race-associated risks did not vary significantly by breast quadrants for breast cancer-specific mortality and all-cause mortality.

CONCLUSIONS

Differences in breast cancer survival by race could not be attributed to tumor locations. Understanding the cultural, biological, and lifestyle factors that vary between White, African American, and ethnic subgroups of Asian American women may help explain these survival differences.

Decreased survival in patients with carcinoma of axillary tail versus upper outer quadrant breast cancers: a SEER population-based study

Background

Carcinoma of the axillary tail of Spence (CATS) is a poorly studied type of breast cancer. The clinicopathological characteristics and prognostic features of CATS are unclear.

Methods

Using the Surveillance, Epidemiology, and End Results database, we identified 149,026 patients diagnosed with upper outer quadrant breast cancer (UOBC) (n=146,343) or CATS (n=2,683). The median follow-up was 88 months. The primary and secondary outcomes were breast cancer-specific survival (BCSS) and overall survival. The survival outcomes of UOBC and CATS were compared using competing risks analysis, log-rank test, Cox proportional hazards regression model, and propensity score matching method. Multivariate logistic regression was utilized to present the relationship between CATS and lymph node (LN) metastasis.

Results

CATS presented a higher grade, higher negative hormone receptor rate, and more positive nodal metastasis. The 10-year BCSS rate was worse for CATS than for UOBC (85.1% vs 87.3%, P=0.001). The multivariate Cox analysis showed a higher hazard ratio (HR) for CATS over UOBC (BCSS: HR =1.20, P=0.001; overall survival: HR =1.11, P=0.019). The difference in the BCSS was also observed in a 1:1 matched cohort (BCSS P=0.019). A subgroup analysis revealed the inferior outcomes of CATS in the metastatic LN subgroup and the hormone receptor-negative subgroup. The multivariate logistic regression indicated that CATS is an independent contributing factor to LN metastasis.

Conclusion

CATS had distinct clinicopathological characteristics and was more likely associated with LN metastasis. Compared to UOBC, CATS had adverse impacts on BCSS.

Prognostic implication of the primary tumor location in early-stage breast cancer: focus on lower inner zone

BACKGROUND

The aim of this study was to investigate the prognostic significance of tumor location of lower inner zone (LIZ) on the survival of patients with early-stage breast cancer.

METHODS

We retrospectively identified 961 breast cancer patients from Jan 2000 to Apr 2016 from hospital database. We evaluated overall survival (OS) and disease-free survival (DFS) in patients with tumors in and outside LIZ. Subgroup analyses were performed according to clinicopathological characteristics and treatment strategies.

RESULTS

A total of 838 cases were finally included. Patients with tumor location of LIZ showed significantly lower survival rates than tumors in other sites in terms of DFS (p = 0.028) but not OS (p = 0.106). When stratified into subgroups, tumors in LIZ retained a significant worse prognosis in DFS in patients with HER-2-negative, high ki-67 expression breast cancers, those who received neoadjuvant chemotherapy, axillary nodal negative patients, and patients with lymphovascular invasion. Univariate and multivariate analyses suggested that tumor location of LIZ was an independent prognostic factor for DFS (p = 0.022).

CONCLUSIONS

Our results suggested that tumor location of LIZ was an independent adverse prognostic factor for DFS in patients with early-stage breast cancer. Multicenter studies with larger sample size are needed to confirm the conclusion and anatomical experiments are desired to elaborate the mechanism.

Optimal approach in early breast cancer: Radiation therapy

Radiation therapy significantly reduces by at least 70% the relative risk of local and regional recurrences for breast cancer after surgery. A positive influence on overall survival has been clearly demonstrated, especially for patients with a high absolute risk for locoregional recurrences. However, this is partially counterbalanced by late toxicity (dependent upon the radiation dose) especially to cardiac structures. Apart from this toxicity, a clear influence of radiation-therapy-related factors on functional and cosmetic outcome has also been demonstrated. Over time, technical improvements have led to a marked reduction in dose to the neighbouring organs, with a consequent drop in acute and late toxicity. This has also allowed the introduction of shorter radiation schedules, lowering the burden of treatment to the patient and the hospital. Several tools, techniques and guidelines have been developed to optimise the balance between the desired reduction in recurrence rates and side effects.

The multidisciplinary team should discuss all available treatment options for every individual breast cancer patient. Individualisation of the selection of the optimal combination of treatments, depending on patient and tumour-related factors, is of utmost importance. Apart from direct tumour-related outcomes, cosmesis and potential side effects have to be taken into account. Counselling should include known risk factors for survival and complications, including comorbidity.

Operable breast cancer of the inner hemisphere is associated with poor survival

Purpose

This study investigated the clinicopathological features of operable breast cancer lesions located in different hemispheres of the breast and determined related survival outcomes.

Methods

Data from 5,330 patients with invasive ductal carcinoma were retrospectively analyzed based on tumor location.

Results

The median follow-up time was 68 months (range, 18-176 months). Patients with breast cancer located in the outer hemisphere of the breast had lesions with more advanced nodal stages and more frequently received adjuvant chemotherapy than patients with breast cancer in the inner hemisphere. The 5-year disease-free survival (DFS) rates of patients with tumors located in outer versus inner hemispheres were 81.5% and 77.0%, respectively (p=0.004); the overall survival (OS) rates were 90.7% and 88.8%, respectively (p<0.001). The association between tumor location and the 5-year DFS rate was most apparent in node-positive patients (73.1% vs. 65.8% for outer vs. inner hemisphere lesions, p<0.001) and in patients with primary tumors greater than 2 cm in diameter (78.2% vs. 72.3%, p=0.002). Multivariate analysis showed that tumor location was an independent predictor of DFS (hazard ratio [HR], 1.23; p=0.002) and OS (HR, 1.28; p=0.006). There were no significant differences in 5-year DFS or OS rates between patients with outer versus inner hemisphere tumors when internal mammary node irradiation was performed.

Conclusion

This study demonstrated that tumor location was an independent prognostic factor for operable breast cancer. Internal mammary node irradiation is recommended for patients with breast cancer of the inner hemisphere and positive axillary lymph nodes or large primary tumors.

Tumor location is a prognostic factor for survival of Chinese women with T1-2N0M0 breast cancer

OBJECTIVE

The purpose of this study was to investigate the effects of primary tumor location on the survival of Chinese women with T1-2N0M0 breast cancer.

METHODS

The clinical data of 1044 patients with stage T1-2N0M0 breast cancer who were treated from 1999 to 2007 were retrospectively analyzed. Patients were divided according to the primary tumor location: upper-outer quadrant (UOQ), upper-inner quadrant (UIQ), lower-outer quadrant (LOQ), lower-inner quadrant (LIQ), and nipple and central breast (central). The effect of primary tumor location on recurrence-free survival (RFS) and overall survival (OS) were determined.

RESULTS

The median age at diagnosis was 47 years. The tumor was located in the UOQ in 524 patients (50.2%), the LOQ in 124 (11.9%), the UIQ in 229 (21.9%), the LIQ in 59 (5.7%), and centrally in 108 patients (10.3%). The 5- and 10-year RFS and OS of the LIQ group were significantly poorer than that of patients in the other groups (RFS: 72.1% vs. 82.2-86.7%, P = 0.041; OS: 73.6% vs. 85.3-89.1%, P = 0.024). Multivariate Cox analysis showed that primary tumor location in the LIQ was an independent prognostic factor for RFS (hazard ratio [HR] = 2.977; 95% confidence interval [CI] 1.219-7.273; P = 0.017) and OS (HR = 2.949; 95% CI 1.207-7.208; P = 0.018).

CONCLUSION

Primary tumor location is an important prognostic factor for survival of Chinese women with T1-2N0M0 breast cancer.

Impact of internal mammary lymph node drainage identified by preoperative lymphoscintigraphy on outcomes in patients with stage I to III breast cancer

BACKGROUND

Involvement of internal mammary (IM) lymph nodes is associated with a poor prognosis for patients with breast cancer. This study examined the effect of drainage to IM nodes identified by lymphoscintigraphy on oncologic outcomes.

METHODS

A prospectively maintained breast cancer patient database at the University of Texas MD Anderson Cancer Center was used to identify patients with stage I to III breast cancer who underwent preoperative lymphoscintigraphy with peritumoral injection of colloid and intraoperative lymphatic mapping from 1996 to 2005. Medical records were reviewed of 1772 patients who had drainage to any lymph node basin on lymphoscintigraphy but who did not undergo IM nodal biopsy. Patients with IM drainage, with or without axillary drainage, were compared with patients without IM drainage. Local-regional recurrence, distant disease-free survival (DDFS), and overall survival were evaluated.

RESULTS

We identified IM drainage in 334 patients (18.8%). Patients with IM drainage were significantly younger, less likely to have upper outer quadrant tumors, and more likely to have smaller and medial tumors than patients without IM drainage. Rates of IM irradiation did not differ between the 2 groups. The median follow-up time was 7.4 years. On multivariate analysis, IM drainage was significantly associated with a worse DDFS (hazard ratio, 1.6; 95% confidence interval, 1.03-2.6; P = .04) but not local-regional recurrence or overall survival.

CONCLUSIONS

IM drainage on preoperative lymphoscintigraphy was found to be significantly associated with worse DDFS. Further study is needed to determine the role of lymphoscintigraphy in the personalization of breast cancer staging and therapy.

Comparison of clinical outcome of breast cancer patients with T1-2 tumor and one to three positive nodes with or without postmastectomy radiation therapy

OBJECTIVE

The value of postmastectomy radiation therapy for breast cancer patients with T1-2 tumor and one to three positive nodes remains controversial. The purpose of this retrospective study was to compare the clinical outcomes of breast cancer patients with T1-2 and one to three positive nodes with and without postmastectomy radiation therapy.

METHODS

Between May 1990 and June 2008, of 318 breast cancer patients with T1-2 and one to three positive nodes who had undergone modified radical mastectomy, 163 received postmastectomy radiation therapy and 155 did not. The clinico-pathologic characteristics were analyzed for clinical outcomes including loco-regional recurrence, distant metastasis, disease-free survival and overall survival.

RESULTS

During the median follow-up period of 102 months, the clinical outcomes in postmastectomy radiation therapy versus no-postmastectomy radiation therapy groups were as follows: loco-regional recurrence rate (3.1 versus 11.0%, P= 0.006); distant metastasis rate (20.9 versus 27.7%, P= 0.152); 10-year disease-free survival rate (73.8 versus 61.3%, P= 0.001); and 10-year overall survival rate (82.1 versus 76.1%, P= 0.239). Through a multivariate analysis, a positive nodal ratio of ≥25% (hazard ratio= 4.571, P= 0.003) and positive lymphovascular invasion (hazard ratio= 2.738, P= 0.028) were found to be independent poor prognostic predictors of loco-regional recurrence. The reduction in loco-regional recurrence (hazard ratio= 0.208, P= 0.004) by postmastectomy radiation therapy was found to be significant.

CONCLUSIONS

On the basis of our results, postmastectomy radiation therapy is highly recommended for breast cancer patients with T1-2 and one to three positive nodes, especially for high-risk subgroups with a positive nodal ratio of ≥25% and positive lymphovascular invasion, not only for reducing loco-regional recurrence but also for improving disease-free survival.

Long-term outcome of internal mammary lymph node detected by lymphoscintigraphy in early breast cancer

Purpose

Internal mammary lymph node (IMLN) metastasis is an important prognostic indicator in breast cancer. However, the necessity of internal mammary sentinel lymph node biopsy for accurate staging, for choosing adjuvant treatment, and as a prognostic indicator, has remained controversial.

Methods

From January 2001 to December 2006, 525 female breast cancer patients underwent radical surgery after preoperative lymphatic scintigraphy. We retrospectively analyzed the follow-up results, recurrences, and deaths of all patients.

Results

There was no significant difference in the clinicopathological characteristics between the axilla and the IMLN groups. The median follow-up period was 118.8 months (range, 7-122 months) in the axilla group and 107.7 months (range, 14-108 months) in the IMLN group. During the median follow-up period, the breast cancer-related death rate in the axilla group was 3.6%, which was not significantly different from that of the IMLN group (1.3%) (p=0.484). The five-year survival rates did not differ between the two groups (p=0.306). The overall recurrence rate and the locoregional recurrence rate also did not differ between the two groups (p=0.835 and p=0.582, respectively). The recurrence rate of IMLN (both ipsilateral and contralateral) metastasis was very low, accounting for 0.5% in the axilla group and 1.3% in the IMLN group (p=0.416).

Conclusion

The long-term follow-up results showed that there was no significant difference in both overall outcome and regional recurrence between the two groups. Therefore, the requirement for identification of nodal basins outside the axilla or IMLN sentinel biopsy should be reconsidered.

Internal mammary nodes in breast cancer: diagnosis and implications for patient management -- a systematic review

The management of internal mammary nodes (IMNs) in breast cancer is controversial. Surgical series from the 1950s showed that one third of breast cancer patients had IMN involvement, with a higher risk in patients with medial tumors and/or positive axillary nodes. IMN metastasis has similar prognostic importance as axillary nodal involvement. However, after three randomized trials showed no survival benefit from extended mastectomy compared with radical or modified radical mastectomy, IMN dissection was largely abandoned. Recently, lymphoscintigraphy studies have renewed interest in IMN evaluation. Approximately one fifth of internal mammary sentinel nodes are pathologic, although most centers do not perform IMN biopsies because of concerns about morbidity and lack of established survival benefit. In addition, results from randomized trials testing the value of postmastectomy irradiation and a meta-analysis of 78 randomized trials have provided high levels of evidence that local-regional tumor control is associated with long-term survival improvements. This benefit was limited to trials that used systemic therapy, which was not routinely administered in the earlier surgical studies, although the contribution from IMN treatment is unclear. IMN irradiation has also been shown to cause increased cardiac morbidity. Before mature results from current randomized trials assessing the benefit of IMN irradiation become available, lymphoscintigraphy may be used to help guide decisions regarding systemic and local-regional treatment. However, even in patients with visualized primary IMN drainage, the potential benefit of treatment should be balanced against the risk of added morbidity.

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

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 over-mortality 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.