Study: Breast cancer disparities among the LGBTQ+ community

IN-DEPTH REVIEW OF RESEARCH

Study background

Very little is known about the quality of breast cancer care among people from sexual and gender minority groups, in part because few clinics record patient data on sexual orientation or gender identity. In addition, the frequency of patients who disclose their sexual orientation and gender identity to their doctors varies widely and is likely influenced by a patient’s perception of safety in the clinic space, ease of disclosing their sexual orientation and gender identity in other spaces, as well as their age, race and ethnicity.

Because no data has been established on treatment quality and outcomes among breast cancer patients from sexual and gender minority groups, a National Academies report in 2020 called for adding sexual orientation and gender identity to data collected in clinics.  This study is an initial analysis of some of this newly collected data.

Researchers of this study wanted to know

The researchers wanted to evaluate the quality of breast cancer treatment and the frequency of breast cancer recurrence among people from sexual and gender minority (SGM) groups compared to their heterosexual cisgender counterparts.

Populations looked at in this study

The study population included 92 patients from SGM groups who were treated for breast cancer at Stanford University between January 1, 2008, and January 1, 2022. The median age at diagnosis was 49 years. Most of the patients were cisgender (80.4%) or white (73.8%) lesbians. Identities other than lesbian women included cisgender bisexual women (12%), heterosexual transgender men (4.3%), one asexual transgender man (1.1%) and one gay transgender man (1.1%).

Most participants were white. The second most prevalent ethnic group was Latine (13%). A few people were from other ethnic groups, which included Asian or Pacific Islander (3.3%) and Black (2.2%). Two people (2.2%) did not report their ethnicity.

The study took socioeconomic status (SES) into account by looking at data on the participants' sources of medical insurance and residential address. Participants were mostly affluent: 63 percent were in the top two SES groups according to their mailing address. Most participants (66.3%) had private health insurance.

Participants in the SGM group:

• were less likely to have undergone childbirth (17% compared to 64% in the group of heterosexual cisgender women)
• were less likely to have children (typically no children compared to an average of 2 children in the group of heterosexual cisgender women).
• had higher alcohol use (13% compared to 4.3% in the group of heterosexual cisgender women).
• had higher cannabis use than the control group (25% compared to 7.6% in the group of heterosexual cisgender women).
   

Participants in both groups had many similar hormonal risk factors:

• • age at first menstrual period
  • age at first delivery
  • menopausal status
  • use of oral birth control pills
  • use of hormone replacement therapy
     

Both groups had similar rates of coronary artery disease, diabetes and obesity.

Study design

The researchers used a retrospective case-control study design. The 92 people from an SGM group (the study group) were matched to 92 heterosexual cisgender women who had breast cancer during the same time period as the SGM participant  and were treated at Stanford University or other Northern California hospitals. The two groups were matched by age within five years, year of breast cancer diagnosis within seven years and tumor characteristics (exactly matched for tumor stage, estrogen receptor status and Her2 receptor status).

Researchers looked at specific quality of care indicators: missed screening, appropriate genetic testing and surgery received (mastectomy or lumpectomy). The researchers also noted whether the patient received the following recommended therapies as indicated by their diagnosis:

• chest or breast reconstruction after mastectomy
• radiation therapy after lumpectomy
• chemotherapy prior to surgery for stage III breast cancer
• anti-estrogen therapy (for example, tamoxifen, Arimidex) for 5 years if a diagnosis was estrogen receptor-positive cancer
• therapy for Her2-positive breast cancer (for example, Herceptin)

In addition, the researchers collected data on patients who declined their recommended therapy.

Study findings

Both groups had the same median age at breast cancer diagnosis (49 years) and similar SES and health insurance types. The groups included different racial and ethnic representations: The heterosexual cisgender group had fewer white patients (63% vs 74%), fewer Hispanic people (7% vs. 13%) and more Asian or Pacific Island people (25% vs. 3%). 

Researchers looked at whether factors related to medical history and health-related behaviors influenced breast cancer outcomes.

Breast cancer diagnosis was delayed

People in the SGM group with breast cancer symptoms (for example, a breast lump) experienced more frequent delays in breast cancer diagnosis compared to people in the heterosexual cisgender group. The median time from symptom onset to diagnosis was 64 days in the SGM group and 34 days in the heterosexual cisgender group. This difference could not be explained by ethnicity, SES or insurance type. Both groups had breast cancer screening with similar frequency.

Many aspects of cancer care were similar

No differences were found between the two groups in rates of:

• diagnosis based on breast cancer symptoms (e.g., breast lump) or diagnosis based on screening results
• genetic testing referral
• clinical trial engagement
• time to first treatment
• mastectomy or lumpectomy for localized disease (i.e., the patient was offered a choice of surgery)
• radiation therapy after lumpectomy
• chemotherapy prior to surgery for stage III disease
• Her2-directed therapy (e.g., Herceptin)

Therapy choices differed

Participants in the SGM group were more likely to decline therapy that was recommended by an oncologist.

• Anti-estrogen therapy was declined more often than other therapies.
• SGM participants who started anti-estrogen therapy did not typically complete a full five years of hormonal therapy; however, this was not significantly different from the heterosexual cisgender group. It is not clear if the difference in the completion rate of hormonal therapy was due to provider behavior, patient adherence to taking daily pills or intolerable side effects. Since the difference was not statistically significant, it may have been due to chance.
• The SGM group was more likely to use alternative medicines compared to the control group (46% vs. 30%).

Recurrence occurred more frequently

Recurrence outcomes were significantly different, with higher rates of breast cancer recurrence in the SGM group.

Compared to the heterosexual cisgender group, the SGM group:

• more frequently had a cancer recurrence (32.2% compared to 13.3% in the heterosexual cisgender group).
• more frequently had a local recurrence—in the same breast or near the surgery scar after mastectomy (17.3% compared to 2.5% in the heterosexual cisgender group).
• more frequently had a metastatic recurrence—breast cancer outside the breast and not near the mastectomy scar (24.7% compared to 13% in the heterosexual cisgender group).
• had two participants with stage IV breast cancer at the time of diagnosis (the same as the heterosexual cisgender group).

The difference in recurrence rates could not be explained by differences in race or ethnicity, SES or insurance type.

Strengths and limitations

Strengths

• Other than sexual orientation and gender identity, the study minimized the differences between the GSM group and the non-GSM group as much as possible to focus analysis on those issues.
• The patients were treated for breast cancer in the same geographic area during the same time frame, so differences in treatment and outcomes between the groups were unlikely to be due to regional differences or differences in the standard of care.

Limitations

• The differences in race, ethnicity and hormonal risk factors (e.g., childbearing) between the groups may have contributed to differences between the groups that are not explained by their SGM status.
• Since the study was conducted in only one region of the U.S., and most of the participants were white and affluent, the study results are less likely to be generalizable to other places and to more diverse populations.   

Conclusions

Breast cancer patients from SGM groups are a high-risk population. The reasons the SGM group experienced a longer time to diagnosis and higher breast cancer recurrence rates were most likely due to discrimination within the healthcare system and social stigma, rather than biological differences (e.g., hormonal factors) or other factors that increase risk. The magnitude of the difference in diagnosis delay and recurrence rates is much greater than the differences in the groups’ underlying risk factors.

Historically, researching health disparities in the SGM population has been challenging because sexual orientation and gender identity were largely undocumented. While avoiding care due to a distrust of the healthcare system may partly explain the delayed diagnosis SGM people experienced, another possible cause is the failure of the healthcare team to adequately evaluate symptoms in SGM patients. Patients’ past experiences with healthcare discrimination may have resulted in distrust of the healthcare system. This may have resulted in the SGM group’s higher rates of declining recommended therapy and increased use of alternative medicines, and ultimately, worse breast cancer outcomes.  

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posted 6/28/2023