Together we can: Collaborative Efforts to Reduce the Cancer Burden on Guam and Save Lives

Abstract

Cancer remains the second leading cause of death for Guamanians. Guam Cancer Registry (GCR) for two decades has provided epidemiological and demographic data needed to understand the unique cancer burden in Guam. Cancer data, along with data on behavioral risk factors and screening, have helped public health practitioners to target areas of need in cancer prevention, control, and research for Guam and our Pacific neighbors. These targeted efforts enable efficient use of limited resources. While cancer in its many forms remains a formidable foe, we now have a toolbox of evidence-based interventions (EBI), culturally-appropriate programs, community-based coalitions, and research unique to our region. Quality cancer data will remain a key component of this toolbox. This paper reports on the most recent cancer data for Guam for 2007–2015, and Guam’s progress toward finding a “cure for cancer” through screening, early detection and treatment, and local research. Together, we can.

Introduction

Cancer is the second leading cause of death for Guamanians. Twenty years have passed since cancer became a reportable disease and the Guam Cancer Registry (GCR) was started via enactment of Public Law 24–198 in May 1998. [1] The mission of the GCR is to “aid in reducing the burden of cancer in Guam by providing basic island-wide, population-based cancer incidence and mortality data for the facilitation of cancer research and the evaluation of cancer control programs.” [2] Much has been learned about the epidemiology of cancer in Guam and other Pacific Islands, yet cancer remains a significant burden in Guam. [3] There is a need to dispel the myth that cancer is an automatic death sentence. Cultural attitudes, beliefs and behaviors often result in late-stage presentation and death from cancers which are largely preventable and treatable when caught early. This paper describes collaborative efforts to improve this situation.

Since 2004, Guam’s Department of Public Health and Social Services (DPHSS) has embarked on a Guam Comprehensive Cancer Control Program (GCCCP) and Planning Process, which engages numerous stakeholders interested in preventing and controlling cancer and improving lives of persons diagnosed with cancer. These partners include representatives from other public health programs, the Guam Comprehensive Cancer Control Coalition (GCCCC), the acute health care sector, cancer survivors, researchers from the University of Guam (UOG), policy makers and many others. Several years later, the Non-Communicable Disease (NCD) Consortium was formed to further leverage prevention and policy programs working in conjunction with the GCCCP and community coalition. Cancer surveillance data provided by the GCR guides priority activities, strategies and evidence-based interventions that target numerous risk factors for developing cancer. Guam. Other outcomes of public health efforts continue to inform policy and health planning. [13] It is important to note that improvements in cancer outcomes (i.e., new cases, survival time and deaths from cancer) resulting from these collaborative efforts may not be seen for another generation.

Background data on risk factors related to development of cancer

The Behavioral Risk Factor Surveillance System (BRFSS), developed by the Centers for Disease Control (CDC) in 1984, has been a reliable, consistent and widely-used data resource for Guam since 1997. BRFSS is a representative telephone survey that DPHSS conducts monthly over landline and cellular telephones using a standardized questionnaire. It collects prevalence data among Guam residents regarding their risk behaviors, preventive health practices, and health conditions. [19] Recent findings from 2016 that are relevant to cancer screening of the colon, prostate, breast and cervix, respectively, are noted here. Among Guam adults age 50–75, 41% had a colonoscopy in the past 10 years, and 2.5% had a sigmoidoscopy in the past five years. One in five men (20.9%) age 40 and over had a prostate specific antigen test within the past two years. [20] Almost three-fourths (75.3%) of Guam women age 50–74 reported having had a mammogram in the past two years. In 2016 about two-thirds of women (65.7%) age 21–65 reported they had had a Pap test in the past three years. The proportion of Guam smoking rates have gradually decreased from 2014 (29.3%) to 2017 (26.4%). However, Guam’s rates are still higher than the U.S. median in all four years. [20] CDC s 2017 Global Youth Tobacco Survey (GYTS) showed a significant decline in Guam students ages 13–15 who reported using any form of tobacco compared to the GYTS survey in 2014. The 2017 survey for the first time reported on use of electronic cigarettes, with results showing about one third of middle schoolers currently “vape.” [26] Cervical cancer screening and treatment is accessible through private and federally assisted programs in Guam. Despite this access, a recent analysis of the US-Affiliated Pacific Islands (USAPI) Breast and Cervical Cancer Early Detection Program (BCCEDP) revealed a higher proportion of abnormal Pap smears (CIN2 or worse) compared to the rest of the US BCCEDP programs. Additionally, one-third (32%) of Pap screens with results warranting follow-up or diagnostic testing had no data recorded on diagnostic tests or follow-up done. [18]

Review of relevant policies and research to reduce cancer risk

Given the very high burden of NCD in the US Pacific jurisdictions, many declared State of Emergencies or similar proclamations in 2010 to mobilize all-of-government responses to combat this epidemic. In order to maximize impact, Policy, Systems and Environmental (PSE) approaches to improve the health of the larger public have been a major focus on Guam. One of the first major policy successes occurred in 2010. Guam P.L.30–80, sponsored by then Vice-Speaker B.J. Cruz, and supported by the Outreach Team of UOG’s Cancer Research Center, GCCCC, and American Cancer Society-Guam, increased taxes on cigarettes ($2.00 a pack) and other tobacco products to raise government revenues. The majority (72%) of the revenues went into a “Healthy Futures Fund” for tobacco, alcohol and drug prevention, health promotion and tobacco cessation. Fifteen percent was put into a “Guam Cancer Trust Fund” for cancer services, and one percent of revenues was allocated to the GCR. This gave GCR some measure of fiscal sustainability at a time when continued federal funding was uncertain. [23] Some tobacco control laws passed include: a) P.L.32–160: Prohibits sale of e-cigarettes to minors; b) P.L.32–132: Establishes tax rate parity for tobacco products; c) P.L.31–102: Prohibits smoking in a motor vehicle when a child is present, d) P.L.30–63: Prohibits smoking within 20 feet of an entrance or exit of a public place where smoking is prohibited, and e) P.L.34–01: raises the minimum age of legal access to tobacco products and e-cigarettes to 21, effective January 1, 2018. [27]

The University of Guam/University of Hawaii Cancer Center Partnership to Advance Cancer Health Equity has been studying areca (betel) nut and cancer since 2006. Early studies began with basic descriptive epidemiology, including the distribution of betel nut use in Micronesia. Along with collaborators including the Children’s Healthy Living Program and stakeholders of the islands’ BRFSS, the partnership’s investigators have documented the prevalence of adult betel nut chewing in the FSM (94% in Yap, 76% in Palau, 51% in Pohn-pei, 21% in Chuuk, 11% in Kosrae), 3% in the Marshall Islands, 24% in the CNMI and 11% in Guam. [14,15] Two distinct patterns of betel nut chewing were identified in Guam: 1) those that chew the mature areca nut without the husk, occasionally add the Piper betle leaf, and ingest the masticated materials; and 2) those that chew the young areca nut with the husk, often add the Piper betle leaf with tobacco and slaked lime, but discard the masticated materials and juices. The latter chewers were more likely to have oral precancerous lesions and conditions and have been targeted for a cessation program currently under study (clinicaltrials.gov, ). [17]

Methods used in cancer data reporting and analysis

All cancer registries in the US adhere to stringent national guidelines for coding and registry operations as determined by the CDC, National Program of Cancer Registries (NPCR), the North American Association of Central Cancer Registries (NAACCR) and the National Cancer Institute (NCI). GCR and Pacific Regional Central Cancer Registry (PRCCR) use abstracting and editing software (Abstract Plus) provided by the CDC NPCR. GCR staff abstract cancer information from medical records of patients seen in Guam’s hospitals, public health clinics and private offices, clinics and free-standing radiation oncology and surgery centers. Data are reviewed for accuracy by the GCR supervisor, a certified tumor registrar, then electronically submitted through a secure CDC website to the PRCCR staff based at UOG. The PRCCR registrar further reviews the cases to verify accuracy and to ensure there is no duplicate reporting. Final quality review is done with assistance of the PRCCR staff at the University of Hawaii, then submitted to the CDC NPCR annually.

Data presented in Tables 1–4 are from a recent analysis of 2007–2015 cancer cases in adults age 20 or older, as reported by GCR to PRCCR as of July 2018. PRCCR staff used Guam’s 2010 population data, along with the US Standard population (2000) and the World Standard population (2000) to calculate crude and age-adjusted incidence (new cancers) rates per 100,000 population for each of 16 age groups for all malignant cancers. Crude rates are useful to track trends in the population of interest over time. Incidence rates adjusted to standard populations are used to compare the cancer burden between different geographic or demographic groups despite differences in population size. The data was also analyzed to determine the proportion of those who survived their disease for five years or more. Stage at diagnosis information is also presented, comparing early to late stage (Stage 3 or higher). Stage 1 cancers are the earliest’ cancers that are confined to the organ or tissues where the cancer cells originated. Stage 3 or higher cancers have spread beyond the site of origin, to regional or distant lymph nodes or other distant sites and are associated with poor 5-year survival rates. [4]

Table 1.

Guam Top 6 Adult Cancers (combined), 2007–2015

Cancer Site	Cases	Crude*	US STD**	World Std^	Five-year Survival Proportion	% Dx’d Stage 1	% Dx’d Stage 2 or higher
All Sites	2858	312.5	284.4	211.5	65%	24	73%
Lung & Bronchus	504	55.1	54.2	38.5	31%	9%	89%
Breast	435	96.9	79.1	61.4	90%	34%	64%
Prostate	362	77.7	88.5	60.3	88%	52%	47%
Colon & Rectum	303	33.1	29.7	22.3	75%	18%	75%
Liver	147	16.1	13.0	10.4	26%	12%	85%
Cervical Cancer	63	14.0	10.3	8.8	73%	16%	73%

Source: Pacific Regional Central Cancer Registry (PRCCR), 2007–2015 adult, invasive incident cases, as of July 2018

Crude*= Crude average annual incidence rate age-adjusted using Guam 2010 census data

US Std **= Average annual incidence rate age-adjusted to US Standard Population (2000), using Guam 2010 census data

World Std^= Average annual incidence rate age-adjusted to the World Standard population (2000); using Guam 2010 census data

Table 4.

Tobacco and Betel nut-related cancers in Guam adults, 2007–2015

Cancer Site	Cases	Crude*	US Std**	World Std^	Five-year Survival Proportion	% Dx’d Stage 1	%Dx’d Stage 3 or higher
Lung & Bronchus	504	55.1	54.2	38.5	31%	9%	89%
Nasopharynx	59	6.5	5.0	4.0	69%	7%	93%
Tobacco-related Oral Cavity & Pharynx	50	5.5	4.6	3.5	64%	20%	72%
Esophagus	29	3.2	2.9	2.2	31%	21%	72%
Stomach	67	7.3	7.3	5.1	51%	10%	90%

Source: Pacific Regional Central Cancer Registry (PRCCR), 2007–2015 adult, invasive incident cases, as of July 2018

Crude*= Crude average annual incidence rate age-adjusted using Guam 2010 census data

US Std **= Average annual incidence rate age-adjusted to US Standard Population (2000), using Guam 2010 census data

World Std^= Average annual incidence rate age-adjusted to the World Standard population (2000); using Guam 2010 census data

Results - PRCCR analysis of Guam cancer data 2007 – 2015

There are many challenges when calculating incidence and mortality rates for small populations such as Guam’s. [21] Data must be interpreted with extreme caution because of small case numbers in the less frequent cancers. To discourage misinterpretation of rates or counts that are unreliable because of the small number, incidence rates are not shown in tables if the case counts are below 16. [10]

Table 1. An average of 318 new cancer cases per year were diagnosed in Guam residents age 20 and above from 2007–2015. About a quarter (24%) of these new cancer patients were diagnosed early -stage with better prognoses and treatment options. Three-quarters were late-stage diagnoses - showing evidence of disease spread. Almost two-thirds (65%) of all cases diagnosed during this period survived for at least five years.

The overall top five cancer sites in Guam by number of cases - lung & bronchus, breast, prostate, colon & rectum, and liver - have been stable for the past decade. They account for more than half of all cancers diagnosed. Cervical cancer has been added as a top cancer of interest although it is eighth by number of cases (n=63). It remains a priority in Guam and USAPI cancer control efforts due to its high prevalence among our young women of childbearing age. Seventy-three percent of women diagnosed with invasive cervical cancer in 2007–2015 presented at late-stage.

Two of the five cancers that comprise the majority of incident cases in Guam - Lung & Bronchus and Liver - typically are diagnosed at later stages and have high mortality rates. [6,8] This is confirmed in the present analysis; 89% of lung cases presented late-stage with 31% five-year survival; 85% of liver cases were late-stage with 26% five-year survival. Breast and prostate cases were on the more positive side of the spectrum. Although more than half of breast cases were diagnosed at later stages, 90% survived for at least five years post-diagnosis. Prostate cancers had the highest percentage (52%) of early-stage diagnoses, and 88% five-year survival.

Tables 2 and 3. Guam males had a slightly higher crude rate of incident cancers than females (323.8 vs. 300.6 per 100,000). Both sexes had an almost identical profile of stage at diagnosis: one-fourth of their cancers were early-stage and three-fourths late-stage. Five-year survival proportions differed, however, with men at 59% and women at 73% for all cancer sites. This is consistent with previous analyses of Guam cancer mortality. [6,8] The colorectal cancer incidence rate for Guam males is significantly higher than for Guam women (39.1 vs. 27.0 per 100,000, respectively). The stage-at-diagnosis profile is very similar - 18% early-stage for both sexes, about three-fourths late-stage. Five-year survival is 78% for women, 73% for men.

Table 2.

Guam Top 5 Cancers in Adult Males, 2007–2015

Cancer Site	Cases	Crude*	US Std**	World Std^	Five-year Survival Proportion	% Dx’d Stage 1	%Dx’d Stage 3 or higher
All Sites - Male	1509	323.8	326.4	236.0	59%	24%	74%
Prostate	362	77.7	88.5	60.3	88%	52%	47%
Lung & Bronchus	334	71.7	76.2	53.6	30%	8%	90%
Colon & Rectum	182	39.1	36.9	27.8	73%	18%	76%
Liver	124	26.6	21.6	17.5	26%	12%	85%
Leukemia	59	12.7	14.5	9.7	71%	0%	100%

Source: Pacific Regional Central Cancer Registry (PRCGR), 2007–2015 adult, invasive incident cases, as of July 2018

Crude*= Crude average annual Incidence rate age-adjusted using Guam 2010 census data

US Std **= Average annual incidence rate age-adjusted to US Standard Population (2000), using Guam 2010 census data

World Std^= Average annual incidence rate age-adjusted to the World Standard population (2000); using Guam 2010 census data

Table 3.

Guam Top S Cancers in Adult Females, 2007–2015

Cancer Site	Cases	Crude*	US Std**	World Std^	Five-year Survival Proportion	% Dx’d Stage 1	%Dx’d Stage 3 or higher
All Sites - Female	1348	300.6	252.4	193.1	73%	24%	72%
Breast	435	96.9	79.1	61.4	90%	34%	64%
Lung & Bronchus	170	37.9	35	25	32%	11%	88%.
Uterus	125	27.9	21.8	17.6	88%	37%	56%
Colon & Rectum	121	27.0	23.2	17.3	78%	18%	74%
Thyroid	102	22.7	16.2	14.3	97%	41%	56%

Source: Pacific Regional Central Cancer Registry (PRCCR), 2007–2015 adult, invasive incident cases, as of July 2018

Crude*= Crude average annual incidence rate age-adjusted using Guam 2010 census data

US Std **= Average annual incidence rate age-adjusted to US Standard Population (2000), using Guam 2010 census data

World Std^= Average annual incidence rate age-adjusted to the World Standard population (2000); using Guam 2010 census data

Table 4. Soon after GCR began collecting cancer data, lung cancer was identified as being the most common and resulting in the highest deaths from cancer in all Guam residents. [5] Community efforts focused on reducing Guam’s high rates of tobacco use, as self-report surveys from 2007–2008 showed Guam’s smoking rates for both adults and youth to be the highest in the nation. [5] The current analysis of tobacco and betel nut-related cancers in Guam shows an increase in average annual crude rates of all five cancers - lung, nasopharynx, tobacco-related oral cavity and pharynx, esophagus, and stomach - compared to crude rates reported for 2008–2012. [6] Due to small case numbers or some of these cancers, the noted increases may not be significant. However, then the low five-year survival proportions, clearly correlate with high percentages of late-stage diagnoses for all five cancer sites.

Discussion

Several articles have previously described the epidemiological and demographic profile of cancer in Guam and the USAPI. [5,6,7,8] This newer data shows the same top five major sites (Lung & Bronchus, Breast, Prostate, Colorectal, and Liver cancers). It should be noted that three of these cancers can be screened and detected earlier, yet the screening rates as noted on the BRFSS are low and fall short of the US Healthy People 2020 goals. Many liver cancers, like cervical cancer, can be prevented through completion of the vaccinations for hepatitis B and human papillomavirus (HPV), respectively. Cervical cancer can be detected and treated when it is at the pre-cancer stage - and with good screening and follow-up, is almost entirely preventable. Overall, cancer incidence and mortality rates in the US exceed those on Guam; however, incidence rates of nasopharynx, liver and cervical cancers in Guam are more than those in the US. Cancer disparities are most striking when disaggregated by race and ethnicity. Several studies have documented the disparately high cancer rates in the indigenous populations of USAPI including Hawaii. Prior studies, as well as a more detailed analysis not presented in this paper, confirm that Guam’s indigenous Chamorus and its largest migrant population from Chuuk bear the heaviest burdens from cancer. [5,6,7,8]

Potential limitations of this analysis include small numbers (compared to the overall US), which can lead to less “stable” incidence rates. However, the overall distribution of the top five cancers has been stable for more than 20 years. There is likely still some under-counting of annual cancer cases due to some patients not presenting early enough to be diagnosed or late reporting by facilities and physicians. Accurate staging of the cancer at the time of diagnosis can be hampered by patients presenting at the end of their life, when they are too weak or with concurrent serious medical illness such that the staging (by CT scan) is not able to be done. Uninsured patients often cannot afford the cost of a staging workup or full treatment. Mortality rates are not yet calculated for any of the US-API jurisdictions, including Guam, because of chronic challenges with correctly coded Death Certificates.

Public Health & Community-based collaborations to reduce the cancer burden

Between 2012–2017, the GCCCP and the GCCCC’s Screening, Early Detection and Treatment Action Team (SEDAT) led efforts, together with the Policy and Advocacy and Prevention Action Teams, to promote the use of the most current US Preventive Services Task Force (USPSTF) Screening Guidelines. The guidelines addressed screening for breast, cervical, and colorectal cancers. Adherence is ultimately expected to contribute to the early detection and prevention of cancer. In 2013 and early 2014, SEDAT administered a survey to ten large groups of healthcare providers to assess their use and adherence to USPSTF guidelines. This information established a baseline understanding of the community’s needs. A pocket guide was printed and distributed, along with many educational sessions presented at the largest health facilities and the Guam Medical Society. By late 2014, 100% of medical doctors randomly surveyed stated that their facility used the USPSTF breast, cervical and colorectal cancer screening guidelines. GCCCP, the Cancer Coalition, NCD and U54 continue to educate the public on the importance of cancer screenings in accordance with CDC recommendations. [12] Currently, GCCCP and the Cancer Coalition are working to increase HPV vaccination rates and colorectal cancer screening rates by enhancing patient reminder systems with partner clinics through evidence-based interventions such as small media, reducing barriers, and postcard mail outs.

The Guam Breast and Cervical Cancer Early Detection Program (GBCCEDP), funded by the CDC, enhances existing systems for breast and cervical cancer screening, follow-up and support services for low-income populations including the uninsured or underinsured, older, medically underserved, lesbians, and women with disabilities. The program provides clinical breast examinations, mammograms, Pap tests, pelvic examinations, HPV testing, and diagnostic testing if results are abnormal. [12] The GBCCEDP aims to increase: screening through collaboration with community’ partners through outreach at health fairs and conferences, implementing interventions (usually focused on health system changes and/or policies), and patient navigation for non-GBCCEDP patients. The GBCCEDP works with numerous community and agency partners to promote the referral of eligible women into j the program. They are also building on prior worksite j wellness successes to include time for Government of Guam employees to receive their recommended cancer screenings. The GBCCEDP is pilot testing a Patient Reminder and Recall System at one local clinic to improve receipt of screening and any necessary follow-up. [25]

The finding that 73% of cancers are diagnosed at late¹ stage, even with screening programs available, is troubling and points to the need for more public education, evaluation of cultural and socioeconomic barriers to health care, and continued efforts to improve health systems and financing that pose significant barriers to care for those at most risk. Despite the late stages at diagnosis, it is a credit to the treatment available on Guam that more than three-fourths of patients with breast, colorectal and cervical cancer survive longer than five years after diagnosis. This points to the need to address j survivorship and quality of life issues for cancer survivors, for their numbers will only increase. Survivors are our strongest advocates for collaborations to improve prevention, early detection, timely treatment and improved programs and resources for cancer survivors and their families. Together, we can.