Cancer Screening Rates Among Asian Americans: A Cross-Sectional Secondary Data Analysis Study

Abstract

Purpose

This study aims 1) to investigate recent cancer screening rates among Asian Americans and 2) to test the relationship between race/ethnicity and cancer screening rates.

Methods

This is a cross-sectional secondary data analysis study using data from the 2019 National Health Interview Survey. The screening rates of prostate cancer, colorectal cancer, cervical cancer, and breast cancer among non-Hispanic (NH) Asian Americans, Hispanics, NH Whites, NH African Americans, and NH American Indian and Alaska Natives (AIAN) were analyzed in July 2022. The variables were recoded and analyzed using descriptive analysis and chi-square test. The SPSS version 27 software was used.

Results

Descriptive analysis showed a general low screening rate of cancers among Asian Americans, which ranged from 40.5% to 67.5%. The chi-square test suggested significant associations between race/ethnicity and the screening rates of colorectal cancer (P = .002), cervical cancer (P < .01), and breast cancer (P = .021), but not the prostate cancer (P = .472).

Conclusion

Necessary intervention programs should be designed to increase the uptake rates of cancer screening among Asian Americans.

Introduction

Background

Asian Americans are one of the major racial groups in the United States. In 2017, Asian Americans numbered nearly 17.3 million and represented 5.6% of the U.S. population. ¹ With the fastest growing speed, the population of Asian Americans is expected to exceed 40 million by 2050. ²

While heart disease was the leading cause of death in the United States for the overall population, the leading cause of death among Asian Americans was cancer.^3,4 Cancer accounted for 25% of all deaths among Asian Americans in 2018.^3,4 Screening cancers is an efficient way to detect cancers at the early stage, which can significantly increase the survival rates of cancers. However, despite high mortality rates of cancers, screening rates of cancers among Asian Americans are significantly lower than those in other racial groups. ⁵

Colorectal Cancer Screening

Among all genders, colorectal cancer is the third leading cause of cancer-related deaths in the United States. ⁶ Yet, over the past two decades, colorectal cancer incidence and mortality rates have decreased secondary to colorectal cancer screening programs. ⁷ For individuals aged 45 to 75 years, it is recommended to receive colonoscopy screening every 10 years or test through other methods (eg, fecal occult blood test and sigmoidoscopy).^8,9 Although colorectal cancer screening has been widely recommended by different health organizations, the screening rate among Asian Americans remains low compared to those in Whites and African Americans. ¹⁰ In a recent localized study in California, results showed that the up-to-date colorectal cancer screening rate for Asian Americans was 79.8% vs 77.6% in non-Hispanic (NH) Whites in 2016. ¹¹ Although studies like this provided evidence about colorectal cancer screening rate among Asian Americans, studies conducted in a localized population cannot represent the national population.

Prostate Cancer Screening

Prostate cancer is the most commonly diagnosed cancer in males and the second most common cause of cancer-related deaths. ¹² In 2020, it is estimated that 21% of newly diagnosed cancers were caused by prostate cancer and 10% of cancer-related death was contributed by prostate cancer. ¹² The prostate-specific antigen (PSA) test is commonly used to detect prostate cancer. Since the PSA test was introduced in 1987, the mortality rate of prostate cancer has decreased about 4% per year from 1992. ¹³ In the United States, although the United States Preventive Services Task Force (USPSTF) recommended that men over the age of 55 to 69 years with a prostate cancer concern go over the PSA test with the physician’s recommendation, ¹⁴ PSA-based screening for prostate cancer is an individualized decision which should involve discussions with the physicians. With a PSA less than 2.5 ng/mL, the American Cancer Society recommended screeners to be retested every 2 years. ¹⁵ Among all the populations, it is reported that Asian Americans less commonly participated in the PSA screening services than NH Whites. ¹⁶ According to Ma et al, ¹⁷ the uptake of prostate cancer screening is very low in Asian American men, with more than three-quarters (78%) reporting never-screened.

Cervical Cancer Screening

Cervical cancer is quite commonly diagnosed in females globally. In 2018, it is estimated that 13,240 American females were diagnosed with cervical cancer and 4170 died from the disease. ¹⁸ Since the implementation of widespread cervical cancer screening, the mortality rate of cervical cancer has decreased significantly from 2.8 deaths per 100,000 women in 2000 to 2.3 deaths per 100,000 women in 2015. ¹⁹ According to the recommendation from the USPSTF, ²⁰ women aged 21 to 65 years should screen cervical cancer regularly with 3-yearly cytology-based Papanicolaou (Pap) tests, although women 30 to 65 years old can have 5-yearly human papillomavirus (HPV) molecular screening tests instead or combined. ²¹ Given the widespread recommendations, previous research still showed that Asian American women had a lower rate of obtaining a recent Pap test (70%) than NH White women (81%; P = .001). ²²

Breast Cancer Screening

Breast cancer is a leading cause of death and is the most commonly diagnosed cancer in women in the United States. ²³ Screening breast cancer with regular mammogram is an efficient early detection method to decrease breast cancer’s morbidity and mortality. ²⁴ Although there is a slight discrepancy regarding the breast cancer screening guidelines between the American Cancer Society (ACS) and the USPSTF, the practice guidelines generally suggest receiving an annual or biennial mammogram for average-risk middle aged women. Comparing the detailed guidelines for the breast cancer screening, the ACS guideline includes larger range of high-risk population and more specific screening frequency for different age-ranged population. It is consistent with the criteria for the breast cancer screening guidelines in other countries (eg, China) and it is more frequently used, compared to the USPSTF guideline for breast cancer screening. According to the recommendations from the ACS, women aged between 45 and 54 years should receive mammogram every year, and women aged 55 years and older should screen breast cancer at least every 2 years. ²⁵ From 2015 to 2016, self-reported mammography screening rates among California NH White and Asian American women were 68.06% and 65.97%, respectively. ²⁶ The result showed the mammography breast cancer screening rate was lower in Asian Americans than that in NH White population locally.

Significance of This Study

Exploring the health disparities of cancer screening among Asian Americans is necessary. Although a study based on the National Health Interview Survey (NHIS) in 2010 provided some data about the screening rates of cervical, colorectal, and breast cancers among Asian Americans, ²⁷ the results reported 10 years ago may not be representative for the Asian American population one decade later. Recently, some researchers reported the cancer screening rates among different race/ethnicity in their studies^28–30; however, their studies’ focuses were slightly or largely differed. This study extended the focus and specifically focused on the cancer screening health disparity in Asian Americans. Also, due to the small sample size of Asian Americans included in most dataset which made the data analysis not feasible, most of the studies investigating cancer screening rates aggregated data of Asian Americans and American Indian and Alaska Native (AIAN). ³¹ Furthermore, official guidelines of most cancer screenings were updated recently, for example, the guideline of prostate cancer screening enacted by the USPSTF was updated in 2018, the guideline of cervical cancer screening enacted by the USPSTF and the ACS was updated in 2018 and 2020, respectively,^15,20 the colorectal cancer screening guideline enacted by the USPSTF and the ACS was updated in 2016 and 2018, respectively, and the breast cancer screening guideline enacted by the USPSTF and the ACS was updated in 2016 and 2015, respectively,^9,32 which may impact the screening uptake rates of the cancers.

Methods

Aims

The purpose of this study is 1) to investigate the recent screening rates of cancers among Asian Americans and 2) to test the relationship between race/ethnicity and cancer screening rates. Results from this study could potentially help researchers and health care providers get deeper insight into the cancer screening issues among Asian Americans and help to design relevant intervention programs to mitigate health disparities in Asian American populations.

Design

This study is a cross-sectional secondary data analysis using the 2019 NHIS data. The NHIS was conducted by the National Center for Health Statistics (NCHS) in the Centers for Disease Control and Prevention (CDC). ³³

Sample

The target population of the NHIS was the civilian noninstitutionalized population living in the United States during the time of the interview. The geographically clustered sampling technique was used to select the sample of dwelling units for the NHIS. The publicly released data files for the 2019 NHIS contained data for 31,997 adults and 9193 children from 33,138 households. ³³ This study used the sample adult data file (n = 31,997), including 4152 Hispanics, 21915 NH Whites, 3483 NH African Americans, 1648 NH Asian Americans, and 212 NH AIAN. Participants who refused to answer the questions, didn’t ascertain, or didn’t know about their races were excluded in the data analysis.

Data Collection

Data were collected using the cross-sectional household face-to-face interview survey. Data on the NHIS were continuously collected by 750 Census interviewers, that is, from January to December annually. The NHIS team contacted 54,231 households, and the total household response rate was 61.1%. ³³

Ethical Considerations

Since this study is a secondary data analysis study, this study was waived ethics approval by the IRB of the university. All the data collected in the survey was de-identified. No participant can be identified by the data.

Measurements

Race/Ethnicity

In the NHIS, race/ethnicity was assessed with the recoded variable HISPALLP_A. According to the NHIS coding book, possible responses were coded as 1. Hispanic, 2. NH White only, 3. NH black/African American only, 4. NH Asian only, 5. NH AIAN only, 6. NH AIAN and any other group, 7. other single and multiple races, 97. refused, 98. not ascertained, and 99. don’t know. We analyzed data which clearly indicated respondents’ ethnicities. Ambiguous responses which did not provide a clear answer (eg, “refused,” “not ascertained,” and “don’t know”) were excluded from the data analysis.

Up-to-Date Screening Status

Colorectal Cancer Up-to-Date Colonoscopy Screening Status

One main outcome variable was self-reported colorectal cancer screening status, which was measured by the following two questions: “These next questions are about colorectal cancer screening. Colonoscopy and sigmoidoscopy are exams to check for colon cancer. Have you ever had either of these exams?” (COLORECTEV_A) and “About how long has it been since your most recent colonoscopy?” (COLWHEN_A). People aged 50 to 75 years who responded having the last colonoscopy within the past 10 years were considered having up-to-date colonoscopy.

Prostate Cancer Up-to-Date PSA Screening Status

The prostate cancer screening status was measured by the following two questions: “Have you ever had a PSA test?” (PSATEST_A) and “About how long has it been since your most recent PSA test?” (PSAWHEN_A). Men aged 55 to 69 years who responded having the last PSA test within the past 2 years were considered having up-to-date PSA test.

Cervical Cancer Up-to-Date Cytology Screening Status

The cervical cancer screening status was measured by the following two questions: “Have you ever had a test for cervical cancer?” (CERVICEV_A) and “When did you have your most recent test to check for cervical cancer?” (CERVICWHEN_A). Women aged 21 to 65 years who responded having the Pap tests within the past 3 years were considered having up-to-date cytology cervical cancer screening.

Breast Cancer Up-to-Date Mammogram Screening Status

The breast cancer screening status was measured by two questions: “Have you ever had mammogram?” (MAMEV_A) and “About how long has it been since your most recent mammogram?” (MAMWHEN_A). Those who had the last mammogram within the past year in women aged 45 to 54 years and within the past 2 years in women aged 55 or older were considered having up-to-date mammogram.

Never Screeners and Not Up-to-Date Screening Status

Possible responses for each of the aforementioned first question identifying the screening status were coded as 1. yes, 2. no, 7. refused, 8. not ascertained, and 9. don’t know. Participants who choose “no,” “refused,” “not ascertained,” or “don’t know” for each of the first question were included into a category for never screeners. Respondents who selected “yes” for each of the first question but selected “not ascertained,” “don’t know,” “refused,” or “10 years ago or more” for colonoscopy, “2 years ago or more” for the PSA test; “within the past 5 years,” “within the past 10 years,” “10 years ago or more” for cervical cancer screening; screened beyond the time range for mammogram based on their ages for the second question were considered not having up-to-date screening. The data recoding method is consistent with the statistic method used by the research team of Kim and Han, ³⁴ and also with the consideration of sample size.

Demographic Characteristic

The demographic characteristic analyzed in this study was the variable measuring age (AGEP_A). For each screening status, age in years was recoded into different groups according to the screening guideline: 1) <45, 45 to 75, and >75 for colorectal cancer screening; 2) <55, 55 to 69, and >69 for prostate cancer screening; 3) <21, 21 to 65, and >65 for cervical cancer screening; and 4) <45, 45 to 54, and >54 for mammogram. Respondents with the age range between 50 and 75 for colorectal cancer screening, 55 and 69 for prostate cancer screening among males, 21 and 65 for cervical cancer screening, and over 45 years old for mammogram among females were included in the data analysis.

Data Analysis

The 2019 NHIS was a complex survey using a multistage probability complex sampling design. It incorporated stratification, clustering, and oversampling of some subpopulations (eg, Hispanics, African Americans, and Asians); sampling weights were used to produce representative estimates and standard errors. In this study, we used SPSS version 27 in July 2022 to perform the descriptive statistics. We also utilized SPSS Complex Samples to compute statistics and standard errors from complex sample designs by incorporating sample designs into survey analysis. The variables were recoded and analyzed. Percentages were used to describe the participants’ demographic characteristics and screening rates. The associations between the race/ethnicity and cancer screening statuses (up-to-date screening rate, not up-to-date screening rate, and never-screening rate) were analyzed by the chi-square test. P value was set at the .05 level. The significance was examined by 2-sided P value. This study was reported following the STROBE checklist (Supplemental A).

Rigor

The interviews were observed by supervisors periodically to ensure the reliability and validity of the data. ³³ Data analysis process in this study was conducted by the first author and verified by the second author. The STROBE reporting checklist for cross-sectional studies was followed.

Results

Demographic Characteristics

The participants’ racial characteristics are shown in Table 1. The sample consisted of 68.5% of NH Whites, 13.0% of Hispanics, 10.9% of NH African Americans, .7% of NH AIAN, 5.2% of NH Asian Americans, and 1.7% of other populations.

Table 1.

Demographic Characteristics.

Variablea		Hispanic		NH White		NH black/African American		NH Asian		NH AIAN
		N (n = 4152)	% 13.0	N (n = 21915)	% 68.5	N (n = 3483)	% 10.9	N (n = 1648)	% 5.2	N (n = 212)	% 0.7
Gender b
	Male	1892	45.6	10282	46.9	1447	41.5	761	46.2	89	42.0
	Female	2260	54.4	11631	53.1	2036	58.5	886	53.8	123	58.0
Age	Mean ± SD	44.3 ± 17.0		54.5 ± 18.3		50.2 ± 17.8		46.7 ± 17.6		50.5 ± 18.5

NH: non-Hispanic; AIAN: American Indian and Alaska Native.

^a587 respondents including 248 respondents who identified them as NH AIAN and any other group, and 339 respondents who identified them as other single and multiple races were not included in the analyses.

^b3 respondents refused to disclose their gender, including 2 NH White respondents and 1 NH Asian respondents.

Colorectal Cancer Screening Rates

Results in Table 2 show that the up-to-date colorectal cancer screening rate among NH Asian Americans was 53.1%, a rate far lower than that of NH Whites (67.6%). Of all the ethnic groups analyzed, Hispanic respondents had the lowest screening rate (50.0%). A significant association between race/ethnicity and the colorectal cancer colonoscopy screening rate was suggested by Pearson’s chi-square test (X² = 20.887, P = .002). Noticeably, the never screener rate of colorectal cancer was quite high among NH Asians, which was 45.7% and just below that rate in Hispanics (46.9%).

Table 2.

Screening Status for Colorectal Cancer, Prostate Cancer, Cervical Cancer, and Breast Cancer ^a .

	Colorectal cancer screening			Prostate cancer screening			Cervical cancer screening			Breast cancer screening
Race/ethnicity	Up-to-date screener %	Not up-to-date screener %	Never screener %	Up-to-date screener %	Not up-to-date screener %	Never screener %	Up-to-date screener %	Not up-to-date screener %	Never screener %	Up-to-date screener %	Not up-to-date screener %	Never screener %
Hispanic	50.0	3.1	46.9	39.1	10.4	50.5	67.3	10.0	22.7	66.5	25.0	8.5
NH White	67.6	4.3	28.1	47.6	11.8	40.6	71.3	18.5	10.2	66.0	28.1	5.9
NH black/African American	66.3	1.9	31.8	43.2	11.7	45.1	73.1	10.6	16.3	69.6	22.9	7.5
NH Asian	53.1	1.2	45.7	40.5	6.7	52.8	67.5	7.6	24.9	60.9	26.5	12.6
NH AIAN	58.2	2.4	39.4	23.5	17.6	58.9	60.4	18.8	20.8	51.9	36.4	11.7
P value	.002 b			.472			<.01 b			.021 b

NH: non-Hispanic; AIAN: American Indian and Alaska Native.

^aScreening rates are based on the weighted sample population.

^bSignificant results at the .05 level.

Prostate Cancer Screening Rates

The up-to-date prostate cancer screening rate among NH Asian Americans was 40.5%, which was lower than those among NH White population (47.6%) and NH African Americans (43.2%), but higher than those among Hispanics (39.1%) and NH AIAN (23.5%) (Table 2). Race/ethnicity was not associated with the prostate cancer screening rate (X² = 5.581, P = .472). The never screener rate of prostate cancer was high among NH Asians, which was 52.8% and followed that in NH AIAN (58.9%).

Cervical Cancer Screening Rates

Results in Table 2 show that the up-to-date cervical cancer screening rate among NH Asian Americans was 67.5%, which was lower than those among NH White population (71.3%) and NH African Americans (73.1%), but higher than those among Hispanics (67.3%) and NH AIAN (60.4%). A significant association between race/ethnicity and the cervical cancer cytology screening rate was suggested by Pearson’s chi-square test (X² = 104.416, P < .01). Noticeably, the never screener rate of cervical cancer was quite high among NH Asians, which was 24.9% and the highest in all populations.

Breast Cancer Screening Rates

The up-to-date breast cancer screening rate among NH Asian Americans was 60.9%, which was lower than those among NH White population (66.0%), NH African Americans (69.6%), and Hispanics (66.5%), but higher than that among NH AIAN (51.9%). A significant association between race/ethnicity and the breast cancer screening rate was suggested by Pearson’s chi-square test (X² = 22.34, P = .021). Similarly, same as the never screener rate of cervical cancer screening, the never screener rate of breast cancer was the highest among NH Asians (12.6%).

Discussion

This secondary data analysis systematically investigated the screening rates of colorectal cancer, prostate cancer, cervical cancer, and breast cancer among different racial groups. Based on national representative data, we found that the health disparities of cancer screening existed in different types of cancers for minority populations. Health promotion programs which aim to increase cancer screening rates among minority populations need to consider different racial groups’ response mechanisms to the health messaging. Culturally tailored health promotion intervention programs could help to overcome the barriers for minority populations to screening cancers.

Data analysis results showed significant associations between race/ethnicity and the screening rates of colorectal cancer, cervical cancer, and breast cancer, but not the prostate cancer. This result was consistent with the findings reported previously,^35,36 both of which suggested the existence of racial/ethnic differences for the participation in cancer screening services. In the study conducted by Goel et al, ³⁵ it showed that compared to White respondents, the African American respondents were as or more likely to report having screened for cancers; however, Hispanic, Asian American, and Pacific Islander respondents were significantly less likely to report having screened for most cancers. ³⁵ Lee et al ³⁶ also reported that compared to Whites, African Americans were more likely to receive Pap tests (OR: 1.92, 95% CI: 1.44-2.55, P < .001), mammogram (OR = 1.96, 95% CI: 1.46-2.64, P < .001), and colorectal cancer screening (OR = 1.28, 95% CI: 1.02-1.60, P < .05). Although no data about Asian American population’s screening were reported in Lee et al.’s study, they concluded that there were racial/ethnic differences in the likelihood of participating in cancer screening services, based on their observation of cancer screenings among Hispanic/Latino population, NH African American, and NH other. Echoing to the findings of Goel et al.’s and Lee et al.’s studies, our study provided updated data about cancer screening rates among different racial groups and included multiple neglected and vulnerable populations. Although reasons for the associations between race/ethnicity and the screening rates were not clear, low screening rates of cancers among Asian Americans were generally noted.

Compared to NH Whites (67.6%) and African Americans (66.3%), the up-to-date colorectal cancer colonoscopy screening rate was low in NH Asian American population (53.1%) in 2019. The year 2019 is the time when COVID-19 began, and the pandemic may impact people’s cancer screening behaviors henceforth. Also, the updated guidelines of colorectal cancer screening may have some impact on people’s screening behaviors. However, the result was consistent with the report from NHIS in 2016, ³⁷ when it was before the COVID-19 pandemic and guidelines updated, which showed that the up-to-date screening rate of colorectal cancer was highest among NH White (65.6%) adults, followed by NH black (60.3%), NH Asian American (52.1%), and Hispanic (47.4%) adults. Also, according to the data from the NHIS in 2010, the percentages of receiving up-to-date colorectal cancer screening in 2010 were highest among NH Whites (59.8%), followed by NH African Americans (55%), NH AIAN (49.5%), NH Asian Americans (46.9%), and Hispanics (46.5%). ²⁷ Results from this study were consistent with those findings; however, an increase in the up-to-date colorectal cancer screening rates among all populations was noticed in the current study. Possible reasons for the increasing up-to-date colorectal cancer screening rates among all populations may be related to the implementation of colorectal cancer screening programs and increased awareness of colorectal cancer severity in public. ³⁸

Compared to the NH Whites and African Americans (47.6% and 43.2%, respectively), the up-to-date prostate cancer screening rate was also lower in NH Asian American population (40.5%). The high prostate cancer screening rates among White and African Americans were consistent with the data reported in a localized study published in 2011, ³⁹ which showed the prostate cancer screening rates were highest among Whites (63.2%) and African Americans (54.4%). Reasons for the low up-to-date prostate cancer screening rate among Asian Americans were probably attributed to not well-established routine preventive care and language barriers for Asian Americans to seek the PSA test. ⁴⁰

Compared to NH African Americans (73.1%) and Whites (71.3%), the up-to-date cervical cancer cytology screening rate ranked third among NH Asian American population (67.5%), followed by Hispanics (67.3%) and NH AIAN (60.4%). However, this result was partly consistent with the result from CDC, ⁴¹ which showed the up-to-date cervical cancer screening rate in 2018 was highest among African American (84.7%), followed by Whites (81.1%), Hispanics (79.5%), AIAN (74.8%), and Asian Americans (64.0%) in women aged 21-64 years. Also, according to the data from the NHIS in 2010, the percentages of receiving up-to-date cervical cancer screening in 2010 were highest among African Americans (85%), followed by Whites (83.4%), AIAN (78.7%), Hispanics (78.7%), and Asian Americans (75.4%). ²⁷ A noticeable change in the up-to-date cervical cancer screening rates among diverse populations is the rank of cervical cancer screening rate increasing among Asian Americans. Possible reasons for the positive change may be contributed by the implementation of cervical cancer screening programs and increased access to health care among Asian Americans. ⁴²

Compared to NH African Americans (69.6%), Hispanics (66.5%), and Whites (66%), the up-to-date breast cancer screening rate ranked fourth among Asian Americans (60.9%). However, this result was partly consistent with the result from the ACS, ⁴³ which showed in 2018 the up-to-date breast cancer screening rate was highest among African Americans (66%), followed by Whites (64%), AIAN (64%), Hispanics (60%), and Asian Americans (55%). In addition, according to the data from the NHIS in 2010, the percentages of receiving up-to-date breast cancer screening in 2010 were highest among African Americans (73.2%), followed by Whites (72.8%), Hispanics (69.7%), AIAN (69.4%), and Asian Americans (64.1%). ²⁵ Although the up-to-date breast cancer screening rates among different populations were not consistent in the studies, all of them reflected a low up-to-date breast cancer screening among Asian Americans compared with other populations. Possible reasons for the low up-to-date breast cancer screening rate among Asian Americans may be related to the logistical barriers to cancer screening, including lack of time, scheduling, poor facility, location, and the cost of the screening. ⁴⁴

In the study, general lower up-to-date cancer screening rates were noticed in NH Asian Americans compared to the NH Whites. This result is consistent with the evidence provided in a previous study conducted by CDC. ⁴⁵ Compared with NH Whites, lower up-to-date screening rates for cervical cancer (75.4% vs 83.4%), breast cancer (64.1% vs 72.8%), and colorectal cancer (46.9% vs 59.8%) were noticed in Asian Americans. Consistently, results showed that never screener rates of cancers among surveyed Asian Americans were high. The high opt-out rates suggest that multiple barriers to cancer screening may exist among Asian Americans. Previous studies have suggested several barriers for Asian Americans to screening cancers, including language barriers ⁴⁶ and neighborhood environment. ⁴⁷ Further intervention programs addressing these barriers should be implemented to mitigate health disparities among Asian Americans. Culturally tailored health education workshops, individual shared decision-making process with physicians, and easily accessed medical translation services should be provided.

Limitations

Although this study provided the recent data on the cancer screening rates among different ethnicities and pointed out some cancer disparities related to the cancer screening in Asian Americans, it had some limitations. First, although sample size for the populations with different ethnicities is sufficient in the data analysis, sample size for the populations with different characteristics of cancer screening is not large enough. Weighted data can potentially reduce the sample bias; however, further analysis with larger sample size of the populations with different characteristics of cancer screening is needed. Second, the colorectal cancer screening rate may be under-reported in this study since some individuals may opt to undergo the fecal immunochemical test (FIT) or the guaiac-based fecal occult blood test (gFOBT) at regular intervals for screening colorectal cancer. A previous study also showed that non-white participants were more likely to opt for gFOBT compared to Whites. ⁴⁸ Since gFOBT and FIT were not included as a screening option in the analysis, conclusions drawn from this study should be interpreted with caution. Third, we didn’t include respondents who chose to have 5-yearly HPV molecular screening tests for the cervical cancer screening and didn’t exclude respondents who have had a hysterectomy or not having a cervix in the study; this may bring sample bias although we assumed the impact should be minimal. Generally, the hysterectomies or lacking a cervix are relatively uncommon; however, this situation should still be considered in the future analysis. Lastly, confounding factors such as education level, health insurance coverage, length of US residence, income, and access to health care were not studied in this study, which may be the factors leading to the differences of the screening rates. Further exploring the confounding factors in the cancer screening context would be necessary and essential for improving cancer screening in minority populations.

Implications for Future Research

Since this is a cross-sectional secondary data analysis study which analyzed national survey data collected from respondents, this study can only describe one-time point results but cannot explain the cause-effect relationships between dependent and independent variables. Thus, this study cannot provide enough information on the reasons why the screening rates were low among Asian Americans. Hence, studies with a longitudinal design or experimental design are necessary to be conducted to explain these variations. Additionally, cancer screening behaviors vary widely among Asian American subgroups (Japanese, Chinese, Korean, Vietnamese, Filipino, etc.). Other studies utilizing the NHIS dataset have reported significant variation in the breast and cervical cancer screening rates across Asian American subgroups. ⁴⁹ The reported aggregated data of screening may obscure the important disparities across Asian American subgroups and minimize the larger differences that potentially exist between specific Asian American subgroups and NH Whites or other populations. Further studies exploring cancer screening behaviors among Asian American subgroups are needed. Lastly, since 2019 is the year when COVID-19 began, further exploring cancer screening behaviors by combining datasets obtained after 2019 could be meaningful to evaluate the pandemic’s impact. According to the 2019 NHIS survey manual, it utilized a different data collection method of the large-scale survey, and the data had not been collected during the pandemic until the year of 2020. Given the methodological and contextual changes, it would be interesting to include the 2021 NHIS data in the analysis, to compare the changes across the years.

Conclusions

This study investigated the screening rates of colorectal, prostate, cervical, and breast cancer among different ethnicities, with a specific emphasize on the health disparities of cancer screening among Asian Americans. This study provided evidence for the low cancer screening rates among Asian Americans; however, reasons for the low cancer screening rates and optimal intervention methods for increasing cancer screening rates among Asian Americans have not been fully studied. Future research looking at these aspects should be further initiated.