It has been widely reported that patients who identify as LGBTQ+ (lesbian, gay, bisexual, transgender, queer, or other gender-diverse characteristic) have more health risks than the cisgender and/or heterosexual population. According to previous studies, most of the disparity has been attributed to the minority stress theory: Members of these communities disproportionally experience discrimination, and this results in mistrust in medical settings—further increasing stress.

Regarding cancer specifically, these society-derived stressors have been reported to lead to lower rates of timely screening, higher rates of infection with cancer-causing viruses, and higher rates of health risk behaviors—increasing the potential risk for various cancers in the LGBTQ+ community. Another issue builds on the aforementioned minority stress theory, which can result in avoidance because of the fear that a health care provider will refuse to care for them. Importantly, the LGBTQ+ communities are diverse, and cancer incidences may differ within specific gender identities and/or sexual orientations (SOs). Because of insufficient details from previous studies, accurate data regarding cancer incidence in specific groups have been lacking.

A study appearing in Cancer (doi: 10.1002/cncr.35356) adds new evidence of the disproportional cancer burden faced by sexual minoritized people. Study author Aimee K. Huang, MD, MPH, a junior faculty member at Massachusetts General Hospital and Harvard Medical School in Boston, Massachusetts, says that most prior studies relied on indirect approximations of incidence and prevalence. “However, for studies that were able to directly measure incidence, the scopes of their investigations were often limited to the most common cancers, unidimensional SO measurements, or had other methodological challenges due to data limitations,” she says.

For the study, researchers culled SO and cancer diagnosis data (from 1989 to 2017) from the Nurses’ Health Study II (NHSII), a longitudinal cohort of 101,543 nurses across the United States. The mean ages and race/ethnicity compositions were similar across all the groups.

The primary outcome was the self-disclosed and electronic health record–verified incidences of cancer among four different sexual minority groups: heterosexual with a past same-sex attraction/behavior/identity (n = 5034), mostly heterosexual (n = 1825), bisexual (n = 394), and lesbian (n = 996). These groups were compared to a “reference” group that self-identified as lifelong heterosexual (n = 93,294). The researchers also determined the case numbers, incidence rates, and age-adjusted incidence rate ratios (aIRRs) of 21 site-specific cancers for each group. Using aIRRs, they compared incidence rates between the reference group and the four SO subgroups.

The researchers reported that the cancer incidence rate (cases per 100,000 person-years) was highest for those who self-described as lesbian (516). Participants in the reference group had an incidence of 428, which was slightly lower than for heterosexual women with past same-sex attractions/partners/identity (449) and the mostly heterosexual cohort (439). Those who self-described as bisexual constituted the smallest cohort, and the researchers did not feel that an accurate conclusion could be reached. They found that lesbian people were approximately twice as likely to be diagnosed with three types of cancer: thyroid cancer (aIRR, 1.87), basal cell carcinoma (aIRR, 1.85), and non-Hodgkin lymphoma (aIRR, 2.13).

The study found sexual minority women to have a lower risk of lung cancer diagnosis despite earlier studies that reported higher prevalences of smoking and lung cancer among these groups. The study also found no lung cancer cases among lesbians and found heterosexual women with a prior same-sex history to have a lower incidence of lung cancer. The study authors believe that these findings in the NHSII cohort might be due to lower rates of smoking in this nursing population versus the general public. “As such, our finding of a lower lung cancer incidence in sexual minority women with low case numbers should be interpreted with caution,” they wrote. (For more details on the prevalence of each cancer type in each of the five groups, see Table 2 in the study.)

据广泛报道，LGBTQ+（女同性恋、男同性恋、双性恋、跨性别者、酷儿或其他性别多元化特征）的患者比顺性别和/或异性恋人群面临更多的健康风险。根据之前的研究，大部分差异归因于少数群体压力理论：这些社区的成员不成比例地遭受歧视，这导致了对医疗环境的不信任——进一步增加了压力。

具体到癌症方面，据报道，这些来自社会的压力源导致及时筛查率降低、致癌病毒感染率升高以及健康风险行为发生率升高，从而增加了 LGBTQ+ 群体患各种癌症的潜在风险。另一个问题建立在上述少数群体压力理论的基础上，该理论可能会导致回避，因为担心医疗保健提供者会拒绝照顾他们。重要的是，LGBTQ+ 社区是多样化的，特定性别认同和/或性取向 (SO) 内的癌症发病率可能有所不同。由于之前的研究细节不足，因此缺乏有关特定群体癌症发病率的准确数据。

《癌症》杂志上发表的一项研究 (doi: 10.1002/cncr.35356) 添加了新的证据，表明性少数群体面临着不成比例的癌症负担。该研究的作者 Aimee K. Huang（医学博士、公共卫生硕士）是马萨诸塞州总医院和马萨诸塞州波士顿哈佛医学院的初级教员，她表示，大多数先前的研究都依赖于发病率和患病率的间接近似值。 “然而，对于能够直接测量发病率的研究，其调查范围通常仅限于最常见的癌症、一维 SO 测量，或者由于数据限制而面临其他方法学挑战，”她说。

在这项研究中，研究人员从护士健康研究 II (NHSII) 中挑选了 SO 和癌症诊断数据（从 1989 年到 2017 年），该研究是一个由美国各地 101,543 名护士组成的纵向队列。所有组的平均年龄和种族/民族构成相似。

主要结果是四个不同性少数群体中自我披露和电子健康记录验证的癌症发病率：过去有过同性吸引/行为/身份的异性恋者 ( n = 5034)，大多数是异性恋者 ( n = 1825)，双性恋 ( n = 394) 和女同性恋 ( n = 996)。将这些群体与自我认定为终生异性恋的“参考”群体进行比较（ n = 93,294）。研究人员还确定了每组 21 种特定部位癌症的病例数、发病率和年龄调整发病率比 (aIRR)。他们使用 aIRR 比较了参考组和四个 SO 亚组之间的发病率。

研究人员报告说，自称女同性恋的人的癌症发病率（每 10 万人年的病例数）最高 (516)。参考组参与者的发病率为 428 例，略低于过去有过同性吸引/伴侣/身份的异性恋女性 (449) 和大多数异性恋群体 (439)。那些自称为双性恋的人构成了最小的群体，研究人员认为无法得出准确的结论。他们发现女同性恋者被诊断出患有三种癌症的可能性大约是女同性恋者的两倍：甲状腺癌（aIRR，1.87）、基底细胞癌（aIRR，1.85）和非霍奇金淋巴瘤（aIRR，2.13）。

该研究发现性少数女性患肺癌的风险较低，尽管早期研究报告这些群体吸烟和肺癌的患病率较高。该研究还发现女同性恋者中没有肺癌病例，并且发现有同性性行为史的异性恋女性肺癌发病率较低。研究作者认为，NHSII 队列中的这些发现可能是由于该护理人群的吸烟率低于普通公众。他们写道：“因此，我们对病例数较少的性少数女性肺癌发病率较低的发现应谨慎解释。” （有关五组中每种癌症类型患病率的更多详细信息，请参阅研究中的表 2。）