To the Editor:
Gender minority individuals (GMIs) face unique challenges in cancer diagnosis and care.1,2 Disproportionate burden of lung cancer is expected among GMIs because of their high smoking rate and known disparities in cancer screening.3 However, population-based cancer registry data have not been fully used in assessing the cancer disparities among GMIs,1 even though population-based cancer registries do collect sex information beyond male and female.4 We found one previous study using national cancer surveillance data that identified lung cancer as the most common cancer for transgender indivduals.5 We hypothesized that the vulnerable GMIs may be subject to identifiable disparities in lung cancer care and outcomes. To test this hypothesis, we used the population-based Californian Cancer Registry (CCR) database to examine lung cancer incidence records. Our primary goal was to identify disparities in case distributions between gender minority and majority lung cancer patients along the cancer care spectrum.
Methods
The sex identification categories, other than male and female, in the CCR database have evolved over time, with additions that currently include: Other (intersex, disorders of sexual development), Transsexual or Transgender (people who desire, plan to undergo, or have undergone sex change surgery), which we used as a proxy for GMIs. Using CCR’s December 2018 Research File, we reviewed all lung cancer cases diagnosed between 1988 and 2016, of which 499,994 were identified as male or female, constituting the gender majority (M&F), and the number of GMIs (representing the gender minority) was small, in the range of 40 to 100 (Fig 1). We used all available lung cancer cases in the CCR data without sampling.
Figure 1.
CONSORT diagram for study case selection using California Cancer. Registry (CCR) data, 1988-2016.aTo comply with the data suppression rules for small numbers of the California Cancer Registry to protect confidentiality, only a range of numbers is provided for the GMI count. GMI = gender minority individual.
We calculated the percentages of case distribution by sociodemographics, tumor characteristics, treatment modality, and survival time within GMI and M&F groups, respectively, then computed the ratio of the two group percentages (GMI : M&F) for each covariate stratum with 95% CI based on Poisson distribution. Fisher exact test was performed on case distributions by gender group and each covariate to assess the overall association between them, to accommodate the small numbers in the GMI group. These measures allow us to comply with CCR data disclosure policy on small numbers and to provide meaningful analysis of CCR’s GMI data. Analyses were performed using SAS version 9.4 (SAS Institute Inc).
Results
As shown in Table 1, compared to M&F cases, the distribution of GMIs significantly increased with time (ratio of percentages = 2.30 for 2011 and later; 95% CI, 1.42-3.52) and was more likely to be in age group 41 to 69 years (1.82; 95% CI, 1.28-2.50) and of non-Hispanic black (2.39; 95% CI, 1.03-4.70). Year of diagnosis, age at diagnosis, and race/ethnicity are significantly associated with the different case distributions between GMI and M&F lung cancer patients (Fisher exact test P < .0001 for each of these covariates). Socioeconomic status, histologic subtype, and tumor stage were significantly associated with the differences in case distribution between GMI and M&F patients (Fisher exact test P = .009, = .002, and < .0001, respectively). However, the group differences within each of these covariates did not reach statistical significance. GMI and M&F lung cancer patients seemed to have rather similar proportions of surgical, chemo, and radiation therapies as well as similar distributions by survival time.
Table 1.
Ratios of Percentage Distributions Between Gender Minority Individuals (GMI) and Combination of Males or Females (M&F) by Sociodemographics, Tumor Characteristics, Treatment Modality, and Survival Time, Cancers of Lung and Bronchus, California, 1986-2016
| Characteristics | Categories | Ratio of Percentages (GMI : M&F) | 95% CIs | Fisher Exact Test P Value |
|---|---|---|---|---|
| Year of diagnosis | 1999 and earlier | 0.27 | (0.09-0.63) | |
| 2000-2010 | 1.09 | (0.66-1.71) | <.0001 | |
| 2011 and later | 2.30 | (1.42-3.52) | ||
| Age at diagnosis, y | ≤40 | 0.00 | (0.00-8.71) | |
| 41-69 | 1.82 | (1.28-2.50) | <.0001 | |
| 70+ | 0.33 | (0.14-0.65) | ||
| Race/ethnicity | Non-Hispanic white | 0.74 | (0.48-1.09) | <.0001 |
| Non-Hispanic black | 2.39 | (1.03-4.70) | ||
| Hispanic | 1.77 | (0.71-3.64) | ||
| API+AIAN+Other | 1.26 | (0.41-2.94) | ||
| Socioeconomic status | Low SES | 1.24 | (0.77-1.90) | .009 |
| Middle SES | 0.90 | (0.41-1.71) | ||
| High SES | 0.83 | (0.47-1.37) | ||
| Histologic subtype | Adenocarcinoma | 0.96 | (0.55-1.57) | .002 |
| Squamous cell | 0.84 | (0.34-1.72) | ||
| Other | 0.91 | (0.42-1.72) | ||
| Unknown | 1.28 | (0.68-2.19) | ||
| Tumor stage at diagnosis | In situ | 0.00 | (0.00-75.05) | <.0001 |
| Stage I | 0.70 | (0.23-1.63) | ||
| Stage II/III | 1.15 | (0.59-2.01) | ||
| Stage IV | 1.45 | (0.92-2.18) | ||
| Unknown/unavailable | 0.43 | (0.14-1.01) | ||
| Surgical treatment | Yes | 1.04 | (0.50-1.90) | .1407 |
| No/Unknown | 0.99 | (0.69-1.38) | ||
| Chemotherapy | Yes | 1.09 | (0.62-1.77) | .1131 |
| No/unknown | 0.96 | (0.64-1.37) | ||
| Radiation | Yes | 0.95 | (0.53-1.57) | .1219 |
| No/unknown | 1.03 | (0.69-1.46) | ||
| Survival time | ≤12 mo | 1.00 | (0.66-1.44) | .1167 |
| 12+ mo | 1.01 | (0.59-1.61) |
AIAN = American Indian and Alaska Native; API = Asian and Pacific Islander; SES = socioeconomic status.
Discussion
The increasing number of GMI lung cancer diagnoses over time are likely attributable to a variety of factors, including the increased social awareness and inclusion of GMIs, the improved reporting and identification of GMIs, as well as long-term high rates of smoking in this population, combined with other exposures that may interact with the smoking effect. The higher concentrations of GMIs in the 41-69 years age group and the non-Hispanic black population underline the need for targeted interventions for lung cancer prevention and control efforts in these groups. No significant disparities between GMI and M&F patients in lung cancer treatment and survival were identified.
Using the population-based CCR data with novel analytical approaches, we were able to reveal significant increase in GMI lung cancer patients over time and to identify the significant disparities in GMI lung cancer patient distributions in specific population subgroups by age and 41-69 years age group, as well as the lack of disparities in lung cancer treatment and survival, as compared with their M&F counterparts. Although we need to be mindful of the small numbers of the GMI cases included in this study and the potential underreporting of GMI identity in cancer registry data, our findings highlight the need for more focused research on the GMI community and its disproportionate cancer burden. Research discoveries at population level should not negate any negative individual experiences or undermine the efforts against social injustice in health care for the GMI population.
Acknowledgments
Other contributions: The authors also thank Dr Ming Li, PhD, for statistical review and advice.
Role of sponsors: The sponsor had no role in the design of the study, the collection and analysis of the data, or the preparation of the manuscript.
Footnotes
FINANCIAL/NONFINANCIAL DISCLOSURES: None declared.
FUNDING/SUPPORT: The collection of cancer incidence data used in this study was supported by the California Department of Public Health pursuant to California Health and Safety Code Section 103885; Centers for Disease Control and Prevention’s (CDC) National Program of Cancer Registries, under cooperative agreement 5NU58DP006344; the National Cancer Institute’s Surveillance, Epidemiology and End Results Program under contract HHSN261201800032I awarded to the University of California, San Francisco, contract HHSN261201800015I awarded to the University of Southern California, and contract HHSN261201800009I awarded to the Public Health Institute. The ideas and opinions expressed herein are those of the authors and do not necessarily reflect the opinions of the State of California, Department of Public Health, the National Cancer Institute, and the Centers for Disease Control and Prevention or their Contractors and Subcontractors.
References
- 1.Kent E.E., Wheldon C.W., Wilder Smith A., Srinivasan S., Geiger A.M. Care delivery, patient experiences, and health outcomes among sexual and gender minority patients with cancer and survivors: a scoping review. Cancer. 2019;125(24):4371–4379. doi: 10.1002/cncr.32388. [DOI] [PubMed] [Google Scholar]
- 2.Margolies L. Current state of knowledge about cancer in lesbians, gay, bisexual, and transgender (LGBT) people. Semin Oncol Nurs. 2018;34(1):3–11. doi: 10.1016/j.soncn.2017.11.003. [DOI] [PubMed] [Google Scholar]
- 3.Buchting F. Transgender use of cigarettes, cigars, and e-cigarettes in a national study. Am J Prev Med. 2017;53(1):e1–e7. doi: 10.1016/j.amepre.2016.11.022. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Gomez S.L., Duffy C., Griggs J.J., John E.M. Surveillance of cancer among sexual and gender minority populations: where are we and where do we need to go? Cancer. 2019;125(24):4360–4362. doi: 10.1002/cncr.32384. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Nash R., Ward K.C., Jemal A., Sandberg D.E., Tangpricha V., Goodman M. Frequency and distribution of primary site among gender minority cancer patients: an analysis of U.S. national surveillance data. Cancer Epidemiol. 2018;54:1–6. doi: 10.1016/j.canep.2018.02.008. [DOI] [PMC free article] [PubMed] [Google Scholar]