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• Update on skin cancer statistics• Use of tanning equipment• Tanning equipment and skin cancer
Most common cancers, Ontario, 2007*
0 5000 10000 15000 20000 25000 30000 35000
Non-HodgkinLymphoma
Colorectum
Lung
Breast
Prostate
Skin
Estimated number of new cases, Ontario, 2007
• 32,000 Ontarians will be diagnosed with skin cancer in 2007
• 1/3 of all new cancers • 2,000 are melanoma
Source: Canadian Cancer Statistics 2007
Melanoma incidence and mortality rates*, Ontario, 1971-2004
•Incidence & mortality higher in males
•Incidence increasing again• Following a period of
decline/stability
•Mortality increasing steadily in both sexes
0
2
4
6
8
10
12
14
16
18
1972 1977 1982 1987 1992 1997 2002Year of diagnosis/death
Age-s
tand
ardi
zed r
ate p
er10
0,000
Male incidence Female incidenceMale mortality Female mortality
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007).*3-year moving averages standardized to the Canadian 1991 population.
0
10
20
30
40
50
60
70
80
1972 1977 1982 1987 1992 1997 2002
Year of diagnosis
Age-s
tanda
rdize
d rate
per 1
00,00
0
15-34 55-74
35-54 75+
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007). * 3-year moving averages standardized to the Canadian 1991 population.
Melanoma incidence rates*, by age,Ontario, males, 1971-2004
•Increasing very recently in 15-34 year olds, after long period of stability/decline
•Declining in 35-54 yr olds•Increasing at older ages
0
10
20
30
40
50
60
70
80
1972 1977 1982 1987 1992 1997 2002
Year of diagnosis
Age-s
tanda
rdize
d rate
per 1
00,00
0
15-34 55-74
35-54 75+
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007). * 3-year moving averages standardized to the Canadian 1991 population.
Melanoma incidence rates*, by age, Ontario, females, 1971-2004
•Increasing in 15-34 year olds, after a period of stability or decline
•Stable for 35-54 yr olds•Increasing at older ages•Rates much lower than for males at older ages (55+)
NOTE: Rate scale is same as for males
0
5
10
15
20
25
1972 1977 1982 1987 1992 1997 2002
Year of diagnosis
Age-s
tanda
rdize
d rate
per 1
00,00
0
Males 15-34 Females 15-34
Males 35-54 Females 35-54
Melanoma incidence rates*, for those <55, Ontario, by sex, 1971-2004
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007). *3-year moving averages standardized to the Canadian 1991 population.
•Using a better scale for younger age groups, we can more clearly see trends
•Males and females have similar trends, but females have higher incidence
0
5
10
15
1972 1977 1982 1987 1992 1997 2002
Year of diagnosis
Age-s
tanda
rdize
d rate
per 1
00,00
0
Males 15-24 Females 15-24
Males 25-34 Females 25-34
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007). *3-year moving averages standardized to the Canadian 1991 population.
Melanoma incidence rates*, for young adults, Ontario, by sex, 1971-2004
•Rates are increasing for both 15-24 and 25-34 year olds of both sexes
Common cancers of young adults, Ontario
• 10% of cancers in 15-34 year olds are melanomas
• Tied for second rank• Only thyroid cancer is
more common
Thyroid19%
Testis10%
Melanoma10%
Hodgkin lymphoma
9%
Breast8%
Non-Hodgkin lymphoma
7%
Cervix uteri5%
Leukemia 5%
Brain5%
Other22%
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007) Cases diagnosed at ages 15-34 in 2002-2004.
(N=504)
Use of tanning equipment
Use of tanning equipment in Ontario: Adolescents (ages 13-18)
• In 2006, 11% of grade 11/12, 7% of grade 9-10 and 2% of grade 7-8 girls used tanning equipment in the past year
• 3-4% of boys had used• Most did so at a tanning salon• Parents pay at least some of
the time for >50% of users
Source: Canadian Cancer Society, Ontario Division. Skin cancer and ultraviolet radiation: Focus on artificial tanning (2007)
Why do Ontario teens use tanning equipment?
Source: Youthography Inc. poll commissioned by Canadian Cancer Society, Ontario Division, October 2006.
0 20 40 60 80 100
Pre-vacation tan
Prolong tan
Special occasion
To look better
Build a base tan
% of users
Boys
Girls
Beliefs about tanning, tanning equipment users vs. non-users, Ontario teens
0 10 20 30 40 50 60 70 80 90 100
Bed use not at all harmful
Bed less skin aging thansun
Bed less risky than sun
Feel pampered at salon
Tan looks healthy
Tan looks more attractive
Leather skin from longterm tanning
Can be too tanned
% agree/strongly agree
Non-user
User
Source: Youthography Inc. poll commissioned by Canadian Cancer Society, Ontario Division, October 2006.
Use of tanning equipment in Ontario: Young adults
0
20
40
60
80
100
Per
cent
of O
ntar
ians
in re
leva
nt
age
grou
p
Unprotected time in sun
Adults (18+)
Tanning equipmentYoung adults (18-34)
SunburnsAdults (18+)
Cancer 2020 target Male, reporting PHUs Female, reporting PHUs
Source: Report on Cancer 2020 (2006). Data from Rapid Risk Factor Surveillance System for 5 PHUs (2003).
• In 2003, 12% of men & 29% of women aged 18-34 used tanning equipment in the past year (5 PHUs)
In Canada:
• In 2006, 18% of females and 8% of males used tanning equipment in past year (Second National Sun Survey)
Why the discrepancy?• Same questions• Different context• Different geography• Different times of year• Preliminary NSS2 data only
Tanning equipment and skin cancer
• Meta-analysis #11 (10 studies to April 2004)– Ever vs. never use: RR = 1.25 (95% CI: 1.05-1.49)– First use as young adult vs. never: 1.69 (95% CI: 1.32-2.18) – Later studies have results similar to earlier studies (when > UVB)
• Meta-analysis #22 (19 studies to March 2006)– Ever vs. never use: RR = 1.15 (95% CI: 1.00-1.31)– First use before age 35: 1.75 (95% CI: 1.35-2.26)
Sources: 1. Gallagher et al. Cancer Epidemiol Biomarkers Prev 2005 2. IARC Working Group on artificial UV light and skin cancer. Int J Cancer 2006
Melanoma & use of tanning equipment
Squamous cell carcinoma• Meta-analysis #21 (3 studies to March 2006)
– Ever vs. never use: RR = 2.25 (95% CI: 1.08-4.70)– 1 study2 found odds ratio increased by 20% for each decade younger at first
use
Basal cell carcinoma• Meta-analysis #21 (4 studies to March 2006)
– Ever vs. never use: RR = 1.03 (0.56-1.90)– 1 study2 found odds ratio increased by 10% for each decade younger at first
use
Sources: 1. IARC Working Group on artificial UV light and skin cancer. Int J Cancer 2006 2. Karagas et al. JNCI 2002.
Non-melanoma skin cancer & use of tanning equipment
• Tanning equipment (TE) emits both UVB and UVA– % UVB generally somewhat less than in sunlight (about 5%)
• Exposure to sunlamps or sunbeds is a human carcinogen (Report on Carcinogens, National Toxicology Program, 2002)
• Strength of UVR may be higher than the sun per unit time, especially in the UVA range– The high doses of UVA represent a new phenomenon– Total body dose is greater - more skin area is exposed
• All parts of the body – whether rarely or frequently exposed to the sun - get similar exposure– Generally consistent with ‘intermittent’ exposure to rarely exposed sites like the back– Intermittent exposure to UVR is especially important in the etiology of melanoma and probably BCC
• Exposure to UVR early in life is particularly important to the development of melanoma
Does it make sense?
• The prevalence of using tanning equipment is on the rise everywhere – even in Australia!
• The age at first use is getting younger and younger • The tanning industry has been very successful at marketing to youth, keeping use-
related regulation at bay and making claims about health benefits – and emerging vitamin D evidence certainly makes their lives easier
• The tanned look is ‘in’ with teens• I predict increases in melanoma in young adults – especially women - over the next 2
decades….– We may already be on the way…– They are already seeing this in the US
• RED Act (federal) regulates equipment and marketing practices only
Sobering final thoughts
0
5
10
15
20
25
30
35
40
1972 1977 1982 1987 1992 1997 2002
Year of diagnosis
Age-s
tand
ardi
zed
rate
per 1
00,00
0
15-34 55-74
35-54 75+
Melanoma incidence rates* by age group, Ontario females
Source: Cancer Care Ontario (Ontario Cancer Registry, 2007). *3-year moving averages standardized to the Canadian 1991 population.
Will we see this?
2015
So what should we do?
How much impact would we have, even if all the CCS (Ontario) recommendations
were enacted?
Acknowledgements
Sandrene ChinCheong, Cancer Care Ontario
Canadian Cancer Society, Ontario Division
UVA vs. UVB in the skin
• UVB is 1000x more biologically active than UVA• UVB is responsible for squamous cell ca of skin• UVB is responsible for production of vitamin D
• UVB and UVA probably both play a role in melanoma• UVA penetrates more deeply into the skin
– 14% of UVB and 50% of UVA reaches melanocytes– UVA penetrates deeper into the dermis
Melanoma & sun exposure
Recent meta-analysis of epidemiologic studies
• “Intermittent” pattern of exposure:– Sunbathing, water sports, sunny vacations: RR = 1.6 (1.3,2.0)
– Sunburn: RR = 2.0 (1.7, 2.4)• Slightly stronger for childhood vs. adult burns
• “Chronic” exposure (more continuous pattern): – Outdoor work: RR = 0.95 (0.9, 1.0)
Source: Gandini et al. Eur J Cancer 2005
Intermittent exposure hypothesis
Pattern and amount of exposure important• Risk increased by either:
• increased total amount of exposure for a fixed degree of intermittency
or
• increased degree of intermittency for a fixed amount of exposure
Intense sun exposure in youth may be especially harmful
• Melanoma occurs at relatively young ages
• Young age at migration to Australia increases risk
• Most nevi (moles) arise prior to age 20– nevi are related to sun exposure
– many nevi increases the risk of melanoma
• Melanoma body site distribution in young adults favours sites not usually exposed (trunk & limbs vs. head & neck)
• Some epidemiologic studies show stronger associations with early age at exposure - not consistent or convincing
• One study