Agreement between self-reported and central cancer registry-recorded prevalence of cancer in the Alaska EARTH study

Figures & data

Table 1. Demographic characteristics of Alaska EARTH study participants (n=3680) who correctly self-reported a history of cancer, compared to 67 who incorrectly reported either that they had a cancer not recorded in the tumour registry (n=54) or who failed to report a cancer that was recorded in the registry (n=13)^†

		“Correct” reporting		“Incorrect” reporting
	Alaska EARTH (all) n=3,747	Alaska EARTH (no cancer and reported no cancer) n=3,594	Alaska EARTH (had cancer and reported it) n=86	Alaska EARTH (Reported cancer, but didn’t have it) n=54	Alaska EARTH (had cancer but didn’t report it) n=13	p-Value
Age (years, mean [SD])*	40.3 (15.0)	39.8 (14.7)^a	57.0 (13.5)^b	47.6 (13.3)^c	58.4 (13.3)^b,c	<0.0001
Sex (% female)	2,181 (60.9)	2,162 (60.2)	64 (74.4)	43 (79.6)	12 (92.3)	0.0001
Educational attainment (% ≤12 years)	2,193 (59.4)	2,112 (59.6)	49 (57.7)	22 (40.7)	10 (76.9)	0.0218
Residence (% rural)	1,910 (51.0)	1,852 (51.5)	29 (33.7)	20 (37.0)	9 (69.2)	0.0008
Language (% English as the primary language at home)	2,504 (67.1)	2,405 (67.1)	56 (66.7)	40 (74.1)	3 (23.1)	0.0056

*For continuous variables, statistically significant differences between groups assessed using Tukey’s test, and indicated by different letters associated.

^†Details for the full Alaska EARTH cohort (n=3,821) were previously reported by Redwood and colleagues [39].

Table 2. Independent associations of demographic characteristics with incorrect reporting of cancer history^a (n=3,612^b who reported their cancer history correctly; n=67 who reported their cancer history incorrectly)

	Odds ratio	95% CI	p-Value
Sex (male vs. female)	2.8	1.49–5.31	0.0014
Age group (<50 years vs. >50 years)	2.5	1.53–4.12	0.0003
Education (<12 vs. >12)	1.4	0.85–2.38	0.1829
Rural (rural vs. urban)	0.8	0.49–1.43	0.5217
Language (English vs. non-English)	1.2	0.69–1.99	0.5698

^aOutcome = reported cancer status correctly (yes/no).

^bSample size varied between 361 and 3,680 due to missing values for covariate data.

Table 3. Agreement of self-reported and tumour registry for cancer (all-sites), as well as the three leading prevalent cancers among the Alaska EARTH participants (female breast, colorectal and prostate cancers).^a

	Prevalence
	ANTR	Self-report	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)	Kappa
Cancer (all-sites)	99	140	86.9 (80.2–93.5)	98.5 (98.1–98.9)	61.4 (53.4–69.5)	99.6 (99.4–99.8)	0.71 (0.64–0.78)
Breast (F)	34	33	85.3 68.9–95.1)	99.8 (99.7–99.9)	87.9 (71.8–96.6)	99.8 (99.7–99.9)	0.86 (0.78–0.95)
Colorectal	14	21	78.6 (49.2–95.3)	99.7 (99.5–99.9)	52.4 (29.8–74.3)	99.9 (99.8–99.9)	0.63 (0.44–0.81)
Prostate (M)	7	8	100 (54.1–100)	99.9 (99.8–99.9)	75.0 34.9–96.8)	100 (99.9–100)	0.86 (0.66–1.0)

^aFor the purposes of these comparisons, ANTR was treated as the reference. However, PPV and NPV, respectively, reflect sensitivity and specificity if self-report is substituted for the reference.

Table 4. Agreement between self-reported and tumour registry for cancer (all-sites), among Alaska EARTH participants, stratified by demographic and clinical characteristics.^a

	Sensitivity		Specificity		PPV		NPV		Kappa
	(%)	95% CI^a	(%)	95% CI	(%)	95% CI	(%)	95% CI	(%)	95% CI
Cancer (all-sites)
Sex
Male	95.6	78.1–99.9	99.3	98.6–99.6	66.7	48.2–82.0	99.9	99.6–100.0	0.78	0.66–0.90
Female	84.2	74.0–91.6	98.1	97.4–98.6	59.8	49.9–69.2	99.5	99.0–99.7	0.68	0.61–0.77
Age at enrolment (years)
18–50	90	74.3–98.0	98.8	98.3–99.2	45.9	33.1–59.2	99.9	99.7–99.9	0.6	0.48–0.72
50+	85.3	74.6–92.7	97.7	96.5–98.6	73.4	62.3–82.7	98.9	98.0–99.5	0.77	0.69–0.85
Education (years)
<12	86.1	70.5–95.3	98.9	98.0–99.7	79.5	63.5–90.7	99.4	98.5–99.8	0.81	0.72–0.91
≥12	89.4	76.9–96.5	98.1	97.3–98.7	54.6	42.8–65.9	99.7	99.1–99.8	0.67	0.57–0.76
Residence
Rural	76.3	59.8–88.6	98.9	98.4–99.4	59.2	44.2–73.0	99.5	99.1–99.8	0.66	0.54–0.78
Urban	93.4	84.1–98.2	98.1	97.3–98.7	62.6	51.9–72.6	99.8	99.4–99.9	0.74	0.66–0.82
Primary language
English	94.8	85.9–98.9	98.3	97.8–98.8	58.3	47.8–68.3	99.9	99.6–99.9	0.71	0.63–0.80
Non-English/both	73.7	56.9–86.6	98.8	98.0–99.4	66.7	52.4–80.4	99.2	98.5–99.6	0.69	0.57–0.81
EARTH study region
Southcentral	93.8	82.8–98.7	97.8	97.0–98.6	61.6	49.5–72.8	99.8	99.3–99.9	0.73	0.64–0.82
Southeast	83.9	66.3–94.6	98.4	97.3–99.1	65	48.3–79.4	99.4	98.6–99.8	0.72	0.60–0.84
Southwest	75	50.9–91.3	99.2	98.6–99.6	55.6	35.3–74.5	99.7	99.2–99.9	0.63	0.47–0.79

^aFor the purposes of these comparisons, ANTR was treated as the reference. However, PPV and NPV, respectively, reflect sensitivity and specificity if self-report is substituted for the reference.

Redwood DG, Lanier AP, Johnston JM, et al. Chronic disease risk factors among Alaska Native and American Indian people, Alaska, 2004–2006. Prev Chronic Dis. 2010 Jul;7(4):A85. PubMed PMID: 20550843; PubMed Central PMCID: PMC2901583. eng.

 PubMed Web of Science ®Google Scholar