Ethnic disparities in early-onset colorectal cancer incidence, screening rates and risk factors prevalence in Guam.

Objective: Colorectal cancer (CRC) is one of the four most common cancers and the third leading cause of cancer-related deaths in Guam. This study investigated CRC incidence, screening, and risk factors of early onset CRC across Guam's ethnic groups using data from the Guam Cancer Registry (1998-2020) and the Guam Behavioral Risk Factor Surveillance System (2018-2019). Methods: Incidence rate ratios (IRRs) were calculated to compare incidence rates across different age groups stratified by sex, ethnicity, and stage. Incidence rate differences (IRDs) were used to test for significant differences across sex and ethnicity. The Pearson chi-square test was used to assess differences in CRC screening rates by age, sex, education, income, healthcare coverage, and ethnicity, and to examine ethnic group disparities in the prevalence of CRC risk factors. Results: The steepest increase in CRC incidence was observed between the 35-39 and 40-44 age groups (IRR = 2.01; 95 % CI: 1.14-3.53) and between the 40-44 and 45-49 age groups (IRR = 1.99; 95 % CI: 1.34-2.97). CHamorus exhibited rate increases at younger ages compared to Filipinos. CRC screening prevalence and associated risk factors showed considerable variation among ethnicities. Conclusions: Elevated early-onset CRC rates were observed for both CHamorus and the broader Guam population under 50. The findings support the new recommendation to begin screening at age 45 and efforts to increase screening in Guam.

Knowledge, Attitudes, Beliefs, Practices Regarding Human Papillomavirus (HPV), and Barriers to Vaccination Against HPV Infection: A Cross-Sectional Survey of Guam Residents.

Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States and is linked to several cancers. In Guam, the HPV vaccination rate falls short of the National Healthy People 2030 goal. Only half of eligible Guam teens have received the HPV vaccination series. Additionally, research on Guam HPV vaccination is limited. A cross-sectional survey was conducted, and a representative sample of Guam residents (n=775) was surveyed to examine their knowledge, attitudes, beliefs, practices regarding HPV, and barriers to HPV vaccination. Aggregated scores were calculated for these scale items: attitude, knowledge, subjective norms, and perceived behavioral control regarding HPV. One-way Analysis of Variance (ANOVA) was used to compare the means of the scores and check for significant differences. Binary logistic regression helped to identify significant predictors of HPV vaccination among respondents with children. Significant differences were found for sex, education, income, and ethnicity. Women and those with higher education and income demonstrated higher positive attitudes and knowledge about HPV vaccination. Also, those with health insurance and those who were advised by their physician were more likely to get their children vaccinated. These results will guide the implementation of effective strategies for developing targeted behavioral and other appropriate interventions to increase HPV vaccination in Guam.

Disparities in Colorectal Cancer Incidence among Asian and Pacific Islander Populations in Guam, Hawai'i, and the United States.

Colorectal cancer (CRC) ranks among the three most common cancers in Guam (GU), Hawai'i (HI), and the mainland United States (US). CRC prevalence in these areas is high among Filipinos, and indigenous CHamorus and Native Hawaiians; however, data on these populations are frequently aggregated in epidemiological studies, which can mask true CRC disparities. We examined CRC cumulative incidence rates (CIRs) among CHamorus in GU, Filipinos in GU, HI, and the US, and Native Hawaiians in HI and the US. CRC CIRs were calculated for two age groups (20-49 years; early onset, and 50-79 years; senior) and four time periods (2000-2004, 2005-2009, 2010-2014, and 2015-2019), stratified by ethnicity, sex, and location. Data analyzed included all invasive CRC cases reported to the Surveillance, Epidemiology, and End Results 9-Registry (n = 166,666), the Hawai'i Tumor Registry (n = 10,760), and the Guam Cancer Registry (n = 698) between 2000 and 2019. Senior CIRs were highest in HI and lowest in GU throughout all time periods, with a downward trend observed for senior CIRs in the US and HI, but not GU. This downward trend held true for all ethnic groups, except for CHamorus in GU, females in GU, and females of CHamoru ethnicity in GU. In contrast, early onset CIRs increased across all locations, sexes, and ethnic groups, except for Filipinos in HI and males of Filipino ethnicity in HI. Our findings provide crucial insights for future research and policy development aimed at reducing the burden of CRC among indigenous populations.

The Betel Nut Intervention Trial (BENIT)-A Randomized Clinical Trial for Areca Nut and Betel Quid Cessation: Primary Outcomes.

BACKGROUND: Areca nut and betel quid (ANBQ) chewing is a widespread carcinogenic habit. The BENIT (ClinicalTrials-NCT02942745) is the first known randomized trial designed for ANBQ chewers. METHODS: We compared the intensive behavioral treatment intervention condition (IC) with the control condition (CC) in the BENIT and included a 5-stage early stopping rule. We report the primary analysis at stage 3. English-literate adults in Guam and Saipan who self-identified as ANBQ chewers with tobacco were enrolled between August 2016 and August 2020. IC participants (n = 88) received five in-person sessions over 22 days and a brochure containing quitting advice. CC participants (n = 88) received only the brochure. Participants were assessed at baseline and on day 22 of follow-up. Self-reported chewing status at day 22 was determined by a composite of two survey items with disparate wording and response options for cross-verification. RESULTS: Cessation rates were 38.6% (IC) and 9.1% (CC). Proportional hazards regression revealed a p = 0.0058, which met the Stage 3 criteria for significance, and an estimated reduction in ANBQ chewing for IC compared to the CC of 71% (95% CI: 41%-88%). CONCLUSIONS: Robust self-reported intervention effects at day 22 suggest that intensive cessation programs such as BENIT should be further developed and implemented on a larger scale.

Cervical Cancer and HPV Knowledge and Awareness: An Educational Intervention among College Students in Guam.

BACKGROUND: Compared to the U.S. population, cervical cancer (CC) incidence is significantly higher among the CHamoru, Micronesian, and Caucasian populations in Guam. From 2008-2012, CC was the fifth most common cancer diagnosed on the island. Despite the prevalence of CC and low HPV vaccine uptake, there is a concerning lack of awareness and preventative behavior among young adults.  This study was aimed at influencing college students' knowledge and awareness of CC, CC screening, HPV, and the HPV vaccination. METHODS: We delivered a 30-minute educational intervention to a sample of 108 university students in a classroom setting. The effect of the educational intervention was measured through a pre-and post-test on CC and HPV health behaviors, knowledge, and awareness. Results were analyzed using SPSS and an exact McNemar's test was used to examine the difference in the proportion of correct answers to the tests. Two-way mixed ANOVA was used to examine between (gender, ethnicity, and class level) and within subjects (pre-and post-test) program effects. RESULTS: Of the 108 participants, only 39 (36.1%) reported being vaccinated for HPV, 23 (21.3%) had not been vaccinated, and 46 (42.6%) did not know if they had been vaccinated for HPV.  Only forty-one (60.3%) female participants had had a Pap smear. When comparing the pre-to-posttest responses, most questions had an increase in correct responses. Time also influenced CCA and HPV knowledge and awareness scores as there was a significant increase in scores from the pre- to post-test. CONCLUSION: The educational intervention was an effective tool for increasing knowledge and awareness of CC, HPV, and HPV vaccination among college students. While study results demonstrate the educational intervention's success as a baseline measure of knowledge, the inclusion of behavioral outcome measures, such as intent to get vaccinated or screened, could result in more robust future studies.

Salivary Areca and tobacco alkaloids for bioverification in the Betel Nut Intervention Trial.

BACKGROUND: The Betel Nut Intervention Trial (BENIT) is the first known randomized controlled intervention trial designed to help minority Pacific Islanders in Guam and Saipan quit chewing the carcinogenic Areca catechu nut (AN). We report the BENIT's saliva bioverification results against the self-reported chewing status ("quitter" or "chewer") at day 22 follow-up. MATERIAL AND METHODS: AN-specific (arecoline, arecaidine, guvacoline, and guvacine) and tobacco-specific (nicotine, cotinine, and hydroxycotinine) alkaloids were analyzed in saliva from 176 BENIT participants by an established and sensitive liquid chromatography mass spectrometry-based assay. RESULTS: The combined four AN alkaloid levels decreased from baseline in quitters (n = 50) and chewers (n = 108) by 32% and 9%, respectively. In quitters, decreases were significant for arecoline (p = 0.044)-the most prominent AN alkaloid, along with arecaidine (p = 0.042) and nicotine (p = 0.011). In chewers, decreases were significant only for hydroxycotinine (p = 0.004). Similar results were obtained when quitters and chewers were stratified by treatment arm. DISCUSSION: Salivary AN alkaloid levels generally agreed with self-reported chewing status, which suggests the former can be used to verify the latter. CONCLUSION: Our results can help to objectively evaluate compliance and program effectiveness in AN cessation programs.

Technical note: Low clinical efficacy, but good acceptability of a point-of-care electronic palpation device for breast cancer screening for a lower middle-income environment.

BACKGROUND: Late-stage breast cancer rates in the Pacific where mammography services are limited are exceedingly high: Marshall Islands (61%), Palau (94%), and Samoa (79%). Due to the limited medical resources in these areas an alternative accessible technology is needed. The iBreast Exam (iBE) is a point-of-care electronic palpitation device that has a reported sensitivity of 86%. However, little is known about the performance and acceptability of this device for women in the Pacific. METHODS: A total of 39 women (ages 42-73 years) were recruited in Guam with 19 women having a mammogram requiring biopsy (Breast Imaging-Reporting and Data System [BI-RADS] category 4 or above) and 20 women with a negative screening mammogram before the study visit. Participants received an iBE exam and completed a 26-item breast health questionnaire to evaluate the iBE. Furthermore, the performance characteristics of the iBE were tested using gelatin breast phantoms in terms of tumor size, tumor depth, and overall breast stiffness. RESULTS: The iBE had a sensitivity of 20% (two true positives to eight false negatives) and specificity of 92% (24 false positives to 278 true negatives) when analyzed based on the location of the tumor by quadrant. The iBE also had generally poor agreement according to a Cohen's kappa value of 0.068. The phantom experiments showed that the iBE can detect tumors as deep as 2.5 cm, but only if the lesion is greater than 8 mm in diameter. However, the iBE did demonstrate acceptability; 67% of the women reported that they had high trust in iBE as an early detection device. CONCLUSIONS: The iBE had generally poor sensitivity and specificity when tested in a clinical setting which does not allow its use as a screening tool. IMPACT: This study demonstrates the need for an alternative screening method other than electronic palpation for lower-middle-income areas.

Prediction of breast cancer risk among women of the Mariana Islands: the BRISK retrospective case-control study.

OBJECTIVES: To develop a breast cancer risk prediction model for Chamorro and Filipino women of the Mariana Islands and compare its performance to that of the Breast Cancer Risk Assessment Tool (BCRAT). DESIGN: Case-control study. SETTING: Clinics/facilities and other community-based settings on Guam and Saipan (Northern Mariana Islands). PARTICIPANTS: 245 women (87 breast cancer cases and 158 controls) of Chamorro or Filipino ethnicity, age 25-80 years, with no prior history of cancer (other than skin cancer), residing on Guam or Saipan for at least 5 years. PRIMARY AND SECONDARY OUTCOME MEASURES: Breast cancer risk models were constructed using combinations of exposures previously identified to affect breast cancer risk in this population, population breast cancer incidence rates and all-cause mortality rates for Guam. RESULTS: Models using ethnic-specific relative risks performed better than those with relative risks estimated from all women. The model with the best performance among both ethnicities (the Breast Cancer Risk Model (BRISK) model; area under the receiver operating characteristic curve (AUC): 0.64 and 0.67 among Chamorros and Filipinos, respectively) included age at menarche, age at first live birth, number of relatives with breast cancer and waist circumference. The 10-year breast cancer risk predicted by the BRISK model was 1.28% for Chamorros and 0.89% for Filipinos. Performance of the BCRAT was modest among both Chamorros (AUC: 0.60) and Filipinos (AUC: 0.55), possibly due to incomplete information on BCRAT risk factors. CONCLUSIONS: The ability to develop breast cancer risk models for Mariana Islands women is constrained by the small population size and limited availability of health services and data. Nonetheless, we have demonstrated that breast cancer risk prediction models with adequate discriminatory performance can be built for small populations such as in the Mariana Islands. Anthropometry, in particular waist circumference, was important for estimating breast cancer risk in this population.

Acculturation and Cancer Risk Behaviors among Pacific Islanders in Hawaii.

Background: To communicate research to the public, the National Cancer Institute developed the Health Information National Trends Survey (HINTS). However, as with most national health surveillance, including the Behavioral Risk Factor Surveillance System, HINTS data are not sufficient to address unique demographic subpopulations such as US Pacific Islanders (PIs). National sampling methods do not adequately reach participants from small, medically underserved populations. Aim: This study aims to document the cancer-relevant knowledge, attitudes, behaviors, and information-seeking practices of PIs in Hawaii (HI). Methods: We conducted a cross-sectional survey during 2017-2018 of Native Hawaiians, Chuukese, and Marshallese in HI using Respondent Driven Sampling (RDS) to recruit these geographically diffuse groups. The modified HINTS survey included questions about cancer knowledge, attitudes and behaviors, health communications, and cultural practices. Results: A total of 515 Native Hawaiians, 305 Chuukese, and 180 Marshallese completed the survey. Differences were found across a variety of cancer-related attitudes, knowledge, and behaviors. These groups also differed regarding acculturation, health locus of control, and trust in medical professionals. Native Hawaiians were significantly more acculturated (P=.0001) than Chuukese or Marshallese and more likely to smoke cigarettes (P=.0001). Among participants aged >50 years, we found no significant differences across ethnic groups (P=.30) for those completing a colon cancer screening (37%). However, only 27% were referred to screening by a physician. Conclusions: Cancer prevention programs are greatly needed for PIs in HI. This study provides knowledge concerning the efficiency of RDS to recruit participants, and the role of culture in communications influencing cancer risk behaviors, which may be generalizable to migrant PIs in the United States.

Cumulative Incidence Rates of Breast Cancer by Age for Filipinos and Chamorros in Guam.

Breast cancer is the second leading cause of cancer-related death among women on Guam and Hawai'i. Breast cancer incidence rates are described here for the multiethnic population in Guam, a United States (US) Pacific island territory, and compared to Hawai'i and other US populations, to understand the risk by age and race/ethnic group in this understudied group. The study included all breast cancer cases (n=576) reported to the Guam Cancer Registry, all breast cancer cases (n=8345) reported to the Hawai'i Tumor Registry and all breast cancer cases (n=678,637) reported to the Surveillance, Epidemiology, and End Results program from 2000 to 2009. Cumulative incidence rates by age were calculated for two time periods: 2000-2004 and 2005-2009. Differences were seen in cumulative incidence rates by age, ethnicity, and place of residence. Cumulative incidence rates by age 40 were the highest (0.7%) among Filipinos in Guam but, after age 40, the rates for Chamorros (indigenous Pacific Islanders of Guam) increased rapidly. The lifetime cumulative incidence rates were the highest for Chamorros in Guam (15.3%), close to the US rate (15.5%). Results were similar for 2005-2009. Women in Guam are at high risk for breast cancer, with the indigenous Chamorros having the highest risk, and the most prevalent Asian group of Filipinos, having a younger age at diagnosis. These patterns are similar to the comparable Pacific Islander and Filipino populations in Hawai'i and the US generally.

Cultural Considerations for Conducting the Health Information National Trends Survey with Micronesian Communities: Lessons from a Qualitative Study.

A critical barrier to addressing health disparities among minorities is the lack of data, particularly on Pacific Islanders. Typically, national health surveillance systems do not have the resources to ensure proper representation of these small population groups. This study reports factors that guided the cultural adaptation and administration of the National Cancer Institute's Health Information Trends National Survey (HINTS) for a United States-dwelling Pacific Islander population in Hawai'i. To adapt the survey, four focus groups were conducted with 32 purposively-selected Micronesian migrants. Themes on health, healthcare barriers, cancer and methods to implement the survey were extracted from the analyses of the focus group narratives. Key cultural factors were identified that impact health practices, including religious and cancer fatalism, racism, health locus of control and other barriers. Using information from the focus group participants, the HINTS questionnaire was modified and the survey was implemented. The survey data provided will inform the future delivery of health promotion strategies for this unique medically underserved population.

Rationale and design of a randomized, controlled, superiority trial on areca nut/betel quid cessation: The Betel Nut Intervention Trial (BENIT).

BACKGROUND: Areca nut (AN) is the seed endosperm of the Areca catechu L. palm and a Group 1 carcinogen chewed by 10-20% of the world population. AN is often chewed with Piper betle L. leaf, slaked lime, and tobacco to form a betel quid (BQ). The negative health effects associated with AN/BQ consumption warrant the need for an evidence-based cessation program. However, systematic research on AN/BQ cessation is rare. METHODS/DESIGN: The Betel Nut Intervention Trial (BENIT; trial #NCT02942745) is a randomized controlled trial designed to test the efficacy of an intensive AN/BQ cessation program. The trial is ongoing in Guam and Saipan with adult chewers who include tobacco in their BQ. Enrolled participants are assessed for their primary (chewing status) and secondary (saliva bio-verification) outcome at baseline, 22 days, and 6 months. Participants randomized into the control arm receive an educational booklet while those randomized into the intervention arm receive the educational booklet and a 22-day cessation program modeled after a smoking cessation program and led by trained facilitators. Information on chewing behavior (history, reasons for chewing, and AN/BQ composition and dependency) are collected. The intervention effectiveness is assessed using the logistic mixed model to compare cessation status between randomization groups. DISCUSSION: AN/BQ chewing affects a large population of people, many of whom live in low and moderate income countries in the Asia-Pacific region. Although the BENIT focuses on chewers in Guam and Saipan, it has the potential for greater regional and global importance.

The efficacy of respondent-driven sampling for the health assessment of minority populations.

BACKGROUND: Respondent driven sampling (RDS) is a relatively new network sampling technique typically employed for hard-to-reach populations. Like snowball sampling, initial respondents or "seeds" recruit additional respondents from their network of friends. Under certain assumptions, the method promises to produce a sample independent from the biases that may have been introduced by the non-random choice of "seeds." We conducted a survey on health communication in Guam's general population using the RDS method, the first survey that has utilized this methodology in Guam. It was conducted in hopes of identifying a cost-efficient non-probability sampling strategy that could generate reasonable population estimates for both minority and general populations. METHODS: RDS data was collected in Guam in 2013 (n=511) and population estimates were compared with 2012 BRFSS data (n=2031) and the 2010 census data. The estimates were calculated using the unweighted RDS sample and the weighted sample using RDS inference methods and compared with known population characteristics. RESULTS: The sample size was reached in 23days, providing evidence that the RDS method is a viable, cost-effective data collection method, which can provide reasonable population estimates. However, the results also suggest that the RDS inference methods used to reduce bias, based on self-reported estimates of network sizes, may not always work. Caution is needed when interpreting RDS study findings. CONCLUSIONS: For a more diverse sample, data collection should not be conducted in just one location. Fewer questions about network estimates should be asked, and more careful consideration should be given to the kind of incentives offered to participants.

Risk factors for breast cancer in the breast cancer risk model study of Guam and Saipan.

BACKGROUND: Chamorro Pacific Islanders in the Mariana Islands have breast cancer incidence rates similar to, but mortality rates higher than, those of U.S. women. As breast cancer risk factors of women of the Mariana Islands may be unique because of ethnic and cultural differences, we studied established and suspected risk factors for breast cancer in this unstudied population. METHODS: From 2010-2013, we conducted retrospective case-control study of female breast cancer (104 cases and 185 controls) among women in the Mariana Islands. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each of various lifestyle-related factors from logistic regression of breast cancer, in all women and in pre- and postmenopausal women separately. Tests for interaction of risk factors with ethnicity were based on the Wald statistics for cross-product terms. RESULTS: Of the medical and reproductive factors considered - age at menarche, breastfeeding, number of live births, age at first live birth, hormone use, and menopause - only age at first live birth was confirmed. Age at first live birth, among parous women, was higher among cases (mean 24.9 years) than controls (mean 23.2 years); with increased breast cancer risk (OR=2.53; 95% CI, 1.04-6.19 for age≥30y compared to <20y, P for trend=0.01). Of the lifestyle factors -body mass index, waist circumference, physical activity, alcohol and betel-nut intake, and education - only waist circumference (OR=1.65; 95% CI 0.87-3.14 for the highest tertile group compared to the lowest, P for trend=0.04) was significantly associated with breast cancer risk and only in Filipino women. The association with many other established risk factors, such as BMI, hormone use and physical activity, were in the expected direction but were not significant. Associations for family history of breast cancer and alcohol intake were not evident CONCLUSIONS: The results provide a basis for cancer prevention guidance for women in the Mariana Islands.

Health Information Seeking, Source Trust, and Culture: A Comparative Analysis of Health Information Trends and Needs Between Guam and the United States.

UNLABELLED: The Guam population offers a unique glimpse into Americans of Pacific Island ancestry and their communication and information-seeking behaviors, experiences, and needs relevant to cancer. National surveys do not typically include the U.S. territories, so there are limited data on the health and cancer information-seeking behaviors of these populations, in which health disparities persist. To fill this information gap, we conducted a survey on health communication in Guam using a modified version of the Health Information National Trends Survey instrument supplemented with items measuring specific cultural factors and communication practices. The results of the survey (N = 511) revealed some differences in health and cancer information-seeking patterns in Guam and the mainland United States. Sociodemographic variables, including sex, age, education, income, and employment, were significantly associated with health and cancer information seeking and Internet use. Levels of trust in various information sources were differentiated in the Guam and mainland U.S. SAMPLES: Logistic regression models revealed differences in factors predicting health and cancer information seeking and Internet use. The results suggest that these health information-seeking patterns and factors should be taken into account when developing communication strategies for more effective prevention and control programs.

Screening for oral potentially malignant disorders among areca (betel) nut chewers in Guam and Saipan.

BACKGROUND: The Mariana Islands, including Guam and Saipan, are home to many ethnic subpopulations of Micronesia. Oral cancer incidence rates vary among subpopulations, and areca (betel) nut chewing, a habit with carcinogenic risks, is common. Our objectives were to conduct a screening program to detect oral potentially malignant disorders (OPMD) in betel nut chewers, measure their betel nut chewing practices, and assess the prevalence of the oral human papillomavirus (HPV) infection in a subset of betel nut chewers in these islands. METHODS: A cross-section of 300 betel nut chewers ≥18 years old [in Guam (n = 137) and in Saipan (n = 163)] were recruited between January 2011-June 2012. We collected demographic, socioeconomic, and oral behavioural characteristics. Latent class analysis was used to identify chewing patterns from selected chewing behaviours. Following calibration of OPMD against an expert, a registered oral hygienist conducted oral examinations by house to house visits and referred positive cases to the study dentist for a second oral examination. Buccal smears were collected from a subset (n = 123) for HPV testing. RESULTS: Two classes of betel nut chewers were identified on 7 betel nut behaviours, smoking, and alcohol use; a key difference between the two Classes was the addition of ingredients to the betel quid among those in Class 2. When compared on other characteristics, Class 1 chewers were older, had been chewing for more years, and chewed fewer nuts per day although chewing episodes lasted longer than Class 2 chewers. More Class 1 chewers visited the dentist regularly than Class 2 chewers. Of the 300 participants, 46 (15.3%; 3.8% for Class 1 and 19.4% for Class 2) had OPMD and one (0.3%) was confirmed to have squamous cell carcinoma. The prevalence of oral HPV was 5.7% (7/123), although none were high-risk types. CONCLUSIONS: We found two patterns of betel nut chewing behaviour; Class 2 had a higher frequency of OPMD. Additional epidemiologic research is needed to examine the relationship between pattern of chewing behaviours and oral cancer incidence. Based on risk stratification, oral screening in Guam and Saipan can be targeted to Class 2 chewers.

Cancer mortality following polychlorinated biphenyl (PCB) contamination of a Guam village.

UNLABELLED: Beginning more than 10 years after the release of polychlorinated biphenyl (PCB) contamination in the favored fishing grounds of Merizo village, an increase in the proportional cancer mortality rate was observed among residents of the village. This increased rate continued for approximately 20 years after which it returned to near island-wide Guam levels. Although the temporal association between PCB contamination of the environment of this village and an increase in cancer mortality is intriguing, it does not necessarily demonstrate a cause and effect relationship. OBJECTIVE: To investigate a possible temporal relationship between PCB contamination of the Cocos Lagoon and cancer deaths in the adjoining village of Merizo. METHODS: Data utilized in the study included deaths recorded by the Guam Cancer Registry (years 2000 to 2007) and data collected from original death certificates (years 1968-1999). To check whether there was a significant difference in the proportion of deaths due to cancer in Merizo compared with the rest of Guam, deaths were grouped in four 10-year periods, 1968-1977, 1978-1987, 1988-1997, and 1998-2007, and the Pearson Chi-Square test was calculated for each period separately RESULTS: While the number of new cancer cases recorded in the village of Merizo were insufficient in number to draw a statistically significant conclusion when single year incidence rates were compared to the rest of the island, a proportional mortality study showed a distinct increase for the village of Merizo compared to other villages for the period 1978-1997. CONCLUSION: While it is not possible to conclude with certainty that PCB contamination of the Cocos Lagoon was responsible for the observed increase in the proportion of cancer deaths in Merizo village beginning during the 10-year period 1978-1987, that increase and the subsequent decrease as PCB levels also decreased presents the possibility that these trends may be related.