A population-based study of cutaneous melanoma in Alberta, Canada (1993-2002).

BACKGROUND: There is evidence to suggest that melanoma incidence rates continue to rise in Canada and the United States. OBJECTIVE: Our objective was to determine cutaneous melanoma trends from 1993 to 2002 in the province of Alberta and to compare the results to previously published provincial analyses for the decade of 1967-1976. METHODS: A retrospective study of 3479 patients with cutaneous melanoma diagnosed in Alberta between 1993 and 2002 was conducted. Estimates of relative survival compared the survival of melanoma patients with the Alberta population to derive the likelihood of surviving melanoma in the absence of other causes of death. Further comparison to published Canadian data was also conducted. RESULTS: For the period 1993-2002, the annual melanoma age-standardized incidence rates per 100,000 person-years ranged between 11.1 and 15.9 and between 9.8 and 14.1 among men and women, respectively. These rates are considerably higher than the previously reported (1976) highest Alberta incidence rates of 4.1 and 4.8 in men and women, respectively. The rates increased slightly for the period 1993-1999 with an average annual percentage change of +3.5%, but appeared to decrease for the interval 1999-2002 with an average annual percentage change of -6.4%. The majority of the tumors were less than 1.0 mm in thickness for both genders. On univariate analysis the following parameters were associated with decreasing patient survival: male gender, increasing age, head and neck tumors, Clark level of invasion, and Breslow tumor thickness. Multivariate analysis demonstrated that the strongest determinant of survival was Breslow tumor thickness. LIMITATIONS: Melanomas in-situ were not included in this study. CONCLUSIONS: Although melanoma incidence rates in Alberta are higher than previously reported, the incidence rates over the study period of 1993 to 2002 appear to have leveled and may in fact be declining over the past several years.

A population-based study of tumor-node relationship, resection margins, and surgeon volume on gastric cancer survival.

BACKGROUND: Gastric cancer surgery literature is conflicting. Two European level I randomized controlled trials refute Asian lesser level evidence promoting more radical resections. Population-based study evidence is undefined. METHODS: Using this study design we examined the overall survival, the tumor-node relationship, margins, and surgeon volume on gastric cancer survival in a Canadian province. RESULTS: Between 1991 and 1997, 577 (71 +/- 13 years 60% male) gastric adenocarcinomas were diagnosed in Northern Alberta (population 1.7 million). Respectively, median survival in months for stage I (n = 67) was 77, stage II (n = 55) 75, stage III (n = 155) 12, stage IV (n = 235) 3, and 65 unstaged (n = 65) 4. Five-year survival for T1N0 (n = 28) was 68% versus T1N1 (n = 7) 71% (P = 0.80); for T2N0 (n = 29) 58% versus T2N1 (n = 19) 58% versus T2N3 (n = 7) 29% (P = 0.08); for T3N0 (n = 33) 57%, versus T3N1 (n = 98) 9% versus T3N2 (n = 47) 0% versus T3N3 (n = 8) 0% (P < 0.0001). Median gastrectomy survival (months) in stage III was 15 months margin negative versus 8 months margin positive versus 6 bypass and 5 for no surgery (P = 0.0004). In stage IV it was margin positive 8 versus margin negative 6 (nonsignificant), bypass 3 versus no surgery 2. Five-year survival for surgeons doing fewer than 20 gastrectomies (n = 196 patients) was 29% (median 1.4 years) versus 35% (median 2.3 years; n = 72 patients) for surgeons doing 20 or more (n = 4; P = 0.325). CONCLUSIONS: From these population data we conclude that (1) few patients present with "curable" gastric cancer, (2) node negative or small gastric cancer survival is not influenced by nodal stage, (3) positive margin resection survival is better than bypass or no surgery in stage IV but not stage III disease, and (4) surgeon volume does not appear to influence patient survival.