Table 1.

Study characteristics for IMPC cases and first index cancer controls

MECWHI
CasesControlsCasesControls
(n = 965)(n = 6,969)(n = 420)(n = 2,657)
Age of index cancer; mean (SD)68.3 (7.8)68.0 (8.3)70.1 (7.0)69.7 (9.0)
Age of second cancer; mean (SD)72.6 (8.0)NA74.2 (7.3)NA
Follow-up time, y; mean (SD)9.4 (3.3)13.7 (1.9)9.6 (3.7)12.7 (2.3)
Sex; n (%)
 Male549 (56.9)3,930 (56.4)
 Female416 (43.1)3,039 (43.6)420 (100)2,657 (100)
Race/ethnicity; n (%)
 European American254 (26.3)1,534 (22.0)372 (88.6)2,088 (78.6)
 African American235 (24.4)1,419 (20.4)37 (8.8)412 (15.5)
 Hispanic194 (20.1)1,581 (22.7)6 (1.4)96 (3.6)
 Asian232 (24.0)2,045 (29.3)4 (0.95)b58 (2.2)b
 Pacific Islander50 (5.2)390 (5.6)
 Indian/Native AmericanNANA1 (0.24)3 (0.11)
Smoking status; n (%)
 Never352 (36.9)2,843 (41.4)174 (41.4)1,292 (48.6)
 Former421 (44.1)3,064 (44.6)200 (47.6)1,123 (42.3)
 Current182 (19.1)959 (14.0)42 (10.0)212 (8.0)
 Missing, n10103430
Pack-yearsa; mean (SD)21.9 (17.0)18.0 (15.7)15.3 (22.0)11.0 (19.1)
 Missing, n312601490
Index cancer site; n (%)
 Breast265 (27.5)1,970 (28.3)82 (19.5)906 (34.1)
 Prostate278 (28.8)2,906 (41.7)NANA
 Colorectal164 (17.0)987 (14.2)67 (16.0)433 (16.3)
 Lung24 (2.5)175 (2.5)43 (10.2)291 (11.0)
 Otherc234 (24.2)931 (13.4)228 (54.3)1,027 (38.7)
Secondary cancer site; n (%)
 Breast164 (17.0)NA133 (31.7)NA
 Prostate111 (11.5)NANANA
 Colorectal158 (16.4)NA49 (11.7)NA
 Lung120 (12.4)NA65 (15.5)NA
 Otherc412 (42.7)NA173 (41.2)NA
Stage of index cancer; n (%)
 Localized683 (70.8)5,153 (73.9)288 (68.6)1,651 (61.1)
 Regional215 (22.3)1,346 (19.3)86 (20.1)640 (24.1)
 Distant67 (6.9)470 (6.7)46 (11.0)366 (13.8)
Diagnosis year for index cancer, mean (SD)1998 (3.4)2000 (3.7)2002 (3.5)2003 (3.7)
Diagnosis year for second cancer, mean (SD)2002 (3.2)NA2006 (3.7)NA

Abbreviation: NA, not applicable.

  • aPack-years for ever smokers only.

  • bCounts for Asian and Pacific Islanders.

  • cThe four most common other cancer sites include bladder, endometrium, leukemia, melanoma, and non-Hodgkin lymphoma; enumeration for these sites can be found in Table 2.