Abstract
Background and objectives:
Previous studies have identified racial-ethnic differences in the diagnostic patterns and recurrence outcomes of women with phyllodes tumors. However, these studies are generally limited in size and generalizability. We therefore sought to explore racial-ethnic differences in age, tumor size, subtype, and recurrence in a large US cohort of women with phyllodes tumors.
Methods:
We performed an 11-institution retrospective review of women with PT from 2007–2017. Differences in age at diagnosis, tumor size and subtype, and recurrence-free survival according to race-ethnicity.
Results:
Women of non-White race or Hispanic ethnicity were younger at the time of diagnosis with phyllodes tumor. Non-Hispanic Other women had a larger proportion of malignant phyllodes tumors. There were no differences in recurrence-free survival in our cohort.
Conclusions:
Differences in age, tumor size, and subtype were small. Therefore, the workup of young women with breast masses and the treatment of women with phyllodes tumors should not differ according to race-ethnicity. These conclusions are supported by our finding that there were no differences in recurrence-free survival.
Keywords: breast, disparity, diagnosis, recurrence
Introduction
Multiple epidemiologic studies have demonstrated differences in the presentation and outcomes of phyllodes tumors (PT) by various racial/ethnic backgrounds.1–7 Race- and ethnicity-related differences have been identified for (1) age and (2) size at diagnosis, (3) PT subtype (grade), and a single study identifying differences in local recurrence (LR).1–7 Our objective was to evaluate for any racial-ethnic differences in PT presentation in a large, contemporary, multi-institutional cohort.
Multiple previous series identify a significantly younger age at presentation in minority women, including Hispanic, non-Hispanic African Americans, and Asian women, as compared to non-Hispanic White women.1,3–5 Additionally, Black/African American, Asian, and Hispanic women tend to present with larger PT than their White counterparts.2–5 Lastly, multiple series identify a higher proportion of malignant PT in Latina Whites1,2, Black/African Americans3, 6, and Asians1, as compared to non-Hispanic Whites.1–3, 6
Only a single published study has reported differences in LR rates according to race or ethnicity. This study also observed a higher proportion of malignant PT and higher LR rates in Black women, though was severely limited by sample size (N=12).6 Multiple larger studies with follow up ranging from 13–64 months have reported no relationship between LR or survival by race or ethnicity.2–4, 8 Using one of the largest US cohorts of women with PT to date, we sought to determine differences in (1) age and (2) tumor size at diagnosis, (3) PT subtype, and (4) recurrence according to race and ethnicity.
Materials and Methods
Data collection procedures for this cohort have been previously reported.9 In brief, we performed an 11-institution retrospective review of women with PT from 2007–2017. Patient demographic and phyllodes tumor data were abstracted from the electronic health records at each participating institution. Phyllodes tumor subtype (benign/borderline/malignant), patient age at diagnosis, and tumor size were summarized with N (%) and median (IQR), respectively, by race and/or ethnicity. Fisher’s exact or chi-square tests were used to compare PT subtype and Kruskal-Wallis, Wilcoxon rank sum, or t-tests were used to compare age at diagnosis and tumor size across groups. Patients with Not Specified or missing race/ethnicity were excluded from the respective race/ethnicity analyses. The Kaplan-Meier method was used to estimate recurrence-free survival according to race/ethnicity, and the log-rank test was used to compare groups.
Results
In our series (N=550), 59.3% of patients were White (N=326), 15.5% were Black/African American (N=85), 8.6% were Asian (N=47), 7.1% were specifically classified as “Other” (N=39), 0.9% were American Indian (N=5), 0.2% Native Hawaiian/Pacific Islander (N=1) and the remaining 8.5% were either “not specified” in the EHR (N=43) or missing (N=4). Additionally, 72.0% were Non-Hispanic (N=396), 6.7% identified as Hispanic or Latina (N=37), and 21.3% were not specified (N=115) or missing (N=2) (Table I).
Table I.
Age at Diagnosis by Race and Ethnicity
| All Patients (N=550) | Median Age (IQR) | P1 | P2 | P3 | P4 | |
|---|---|---|---|---|---|---|
| Race | 0.002 | |||||
| White | 326 (59.3%) | 46.0 (38–56) | ||||
| Black/African American | 85 (15.5%) | 42.0 (32–52) | 0.003 | |||
| Asian | 47 (8.6%) | 42.5 (34–50) | 0.06 | |||
| Other | 45 (8.2%) | 38.0 (30–50) | 0.005 | |||
| Ethnicity | 0.001 | |||||
| Hispanic/Latina | 37 (6.7%) | 39.0 (33–43) | ||||
| Not Hispanic/Latina | 396 (72.0%) | 46.0 (37–55) | ||||
| Race/Ethnicity | 0.001 | |||||
| NH White | 264 (48.0%) | 46.0 (39–56) | ||||
| NH Black/African American | 70 (12.7%) | 43.5 (31–52) | 0.009 | |||
| NH Asian | 38 (6.9%) | 44.0 (36–50) | 0.19 | |||
| NH Other | 18 (3.3%) | 39.0 (29–53) | 0.08 | |||
| Hispanic/Latina | 37 (6.7%) | 39.0 (33–43) | <0.001 |
Kruskal-Wallis p-value for any differences across all races or all race/ethnicity groups.
Pairwise T-test or Wilcoxon rank sum p-value for difference in specified race vs. White.
Pairwise T-test or Wilcoxon rank sum p-value for difference in specified race/ethnicity vs. NH White.
Wilcoxon rank sum p-value for difference in Hispanic/Latina vs. Not Hispanic/Latina.
NH=Non-Hispanic, IQR=interquartile range.
Our cohort included 69.5% benign, 19.8% borderline, and 10.6% malignant PT (5 missing PT subtype). The age at diagnosis differed by race/ethnicity, with women of non-White race (Black/African American or “Other”) being diagnosed at a younger age than White women (p=0.002; Table I). Similarly, Hispanic/Latina women were also diagnosed at a younger age than Non-Hispanic/Latina women (median 39 vs. 46 years, p=0.001).
There was no difference in tumor size at diagnosis between Black or Asian women compared to White women, and no difference in size according to ethnicity. Women of Other race, however, had larger PT at the time of diagnosis than White women (40 vs. 28.5cm, p=0.002) (Table II).
Table II.
Tumor Size by Race and Ethnicity
| Median (IQR) | P1 | P2 | P3 | P4 | |
|---|---|---|---|---|---|
| Race | 0.02 | ||||
| White | 28.5 (19–45) | ||||
| Black/African American | 29.0 (20–47) | 0.33 | |||
| Asian | 31.0 (20–53) | 0.32 | |||
| Other | 40.0 (28–60) | 0.002 | |||
| Ethnicity | 0.86 | ||||
| Hispanic/Latina | 28.0 (20–44) | ||||
| Not Hispanic/Latina | 30.0 (20–48) | ||||
| Race/Ethnicity | 0.001 | ||||
| NH White | 28.5 (19–45) | ||||
| NH Black/African American | 28.0 (18–47) | 0.41 | |||
| NH Asian | 36.5 (21–74) | 0.09 | |||
| NH Other | 59.0 (42–105) | <0.001 | |||
| Hispanic/Latina | 28.0 (20–44) | 0.79 |
Kruskal-Wallis p-value for any differences across all races or all race/ethnicity groups.
Pairwise T-test or Wilcoxon rank sum p-value for difference in specified race vs. White.
Pairwise T-test or Wilcoxon rank sum p-value for difference in specified race/ethnicity vs. NH White.
Wilcoxon rank sum p-value for difference in Hispanic/Latina vs. Not Hispanic/Latina.
NH=Non-Hispanic, IQR=interquartile range.
There were no differences in the distribution of PT subtype according to race or ethnicity (Table III). However, when race and ethnicity were combined, Non-Hispanic Other women had a higher proportion of malignant PT than Non-Hispanic White women (p=0.002). There was a strong trend toward fewer malignant PT in Asian women and Non-Hispanic Asian women compared to White and Non-Hispanic White (p=0.05, p=0.05; Table III).
Table III.
Distribution of PT Subtype According to Race and Ethnicity.
| All Patients (N=550) |
Benign (N=379) |
Borderline (N=108) |
Malignant (N=58) |
P1 | P2 | P3 | P4 | |
|---|---|---|---|---|---|---|---|---|
| Race | 0.06 | |||||||
| White | 326 (59.3%) | 227 (69.6%) | 64 (19.6%) | 34 (10.4%) | ||||
| Black/African American | 85 (15.5%) | 61 (71.8%) | 13 (15.3%) | 10 (11.8%) | 0.66 | |||
| Asian | 47 (8.6%) | 28 (59.6%) | 16 (34.0%) | 2 (4.3%) | 0.05 | |||
| Other | 45 (8.2%) | 27 (60.0%) | 9 (20.0%) | 9 (20.0%) | 0.16 | |||
| Not specified/Missing | 47 (8.6%) | 36 (76.7%) | 6 (12.8%) | 3 (6.4%) | ||||
| Ethnicity | 0.19 | |||||||
| Hispanic/Latina | 37 (6.7%) | 28 (75.7%) | 8 (21.6%) | 1 (2.7%) | ||||
| Not Hispanic/Latina | 396 (72.0%) | 258 (65.2%) | 84 (21.2%) | 50 (12.6%) | ||||
| Not specified/Missing | 117 (21.3%) | 93 (79.5%) | 16 (13.7%) | 7 (6.0%) | ||||
| Race/Ethnicity | <0.001 | |||||||
| NH White | 264 (48.0%) | 179 (67.8%) | 53 (20.1%) | 31 (11.7%) | ||||
| NH Black/African American | 70 (12.7%) | 47 (67.1%) | 13 (18.6%) | 9 (12.9%) | 0.94 | |||
| NH Asian | 38 (6.9%) | 21 (55.3%) | 14 (36.8%) | 2 (5.3%) | 0.05 | |||
| NH Other | 18 (3.3%) | 8 (44.4%) | 2 (11.1%) | 8 (44.4%) | 0.002 | |||
| Hispanic/Latina | 37 (6.7%) | 28 (75.7%) | 8 (21.6%) | 1 (2.7%) | 0.26 | |||
| Not specified/Missing | 123 (22.4%) | 96 (78.1%) | 18 (14.6%) | 7 (5.7%) |
Chi-square test p-value for any differences across all races or all race/ethnicity groups.
Pairwise Chi-square or Fisher’s exact test p-value for difference in specified race vs. White.
Pairwise Chi-square or Fisher’s exact test p-value for difference in specified race/ethnicity vs. NH White.
Fisher’s exact test p-value for difference in Hispanic/Latina vs. Not Hispanic/Latina.
Data presented as N (%) with column percentages for All Patients and row percentages for all other data.
Percentages may not add up to 100 due to rounding or missing values.
NH=Non-Hispanic.
Lastly, there were 15 local and 3 distant recurrences in our cohort. We did not identify differences in recurrence-free survival according to race (log-rank test, p=0.52) or ethnicity (p=0.93), or the combination or race/ethnicity (p=0.67). Tumor factors associated with recurrence have been previously reported.9
Discussion
The existing literature suggests that Black/African American and Hispanic women tend to present younger, and with larger and more aggressive PT than White women.1–7 However, this has not translated into definitive evidence of higher LR rates or inferior survival. In this multi-institutional cohort, we have confirmed that Black/African American and Hispanic/Latina women are diagnosed with PT at a significantly younger age than White or Non-Hispanic/Latina women. However, this difference was only 4–8 years, and the subtype distribution was similar across these groups. Lastly, there was no difference in local recurrence by race, ethnicity, or the combination, therefore all women should be similarly treated and followed post-operatively.
While this is one of the largest cohorts of PT reported in the literature, our results may have been limited by Not Specified or missing classifications, and the limited number of racial categories included, highlighted by the significant findings noted in the Other racial category. The classification of “Other” was directly abstracted from the EHR and “Not Specified” was abstracted as an absence of a racial category listed. This highlights the need for accurate race/ethnicity classification in the EHR to support ongoing epidemiologic research and to facilitate a more in depth understanding of tumor biology and epidemiology.
Conclusion:
Neither the evaluation of a young patient with a breast mass nor the management of young women with PT should change according to the patient’s race or ethnicity. This conclusion is supported by our findings that racial-ethnic differences were small and did not translate into differences in recurrence-free survival.
Synopsis:
Differences in phyllodes tumor characteristics and recurrence-free survival were explored in a cohort of 550 US women. Despite differences in age at diagnosis, tumor size, and tumor subtype according to race-ethnicity, there were no differences in recurrence-free survival.
Funding:
This publication was made possible (in part) by philanthropic funds through the generosity of Sara and Bruce Brandaleone. Statistical support was funded by the Duke Cancer Institute through NIH grant P30CA014236 (PI: Kastan).
Abbreviations
- PT
phyllodes tumor
- LR
local recurrence
- IQR
interquartile range
- NH
non-Hispanic
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