Testicular Cancer

Background

Testicular cancer cases have been steadily increasing over the last several decades [1]. Approximately 1,200 Canadian men will be diagnosed with testicular cancer in 2022 [2]. Even though testicular cancer is rare, it is the most prevalent cancer in men aged 15 to 25 years [3].

Risk factors associated with testicular cancer include undescended testicle (cryptorchidism), family history of testicular cancer, personal history of testicular cancer, calcium deposits in the testicle, and tall adult height [1]. Occupational exposures, such as some pesticides and work as a firefighter, may also play an important role in the development of testicular cancer [1,4].

Possible occupational risk factors

    • DDT (4,4′-dichlorodiphenyltrichloroethane) [4-5]
    • N,N-Dimethylformamide [4]
    • Occupational exposure as a firefighter [4,6-7]
    • Perflurooctanoic acid (PFOA) [4]
Key Findings

Protective Services

Increased risk of testicular cancer was observed in firefighters and police in the ODSS. It is well documented that firefighters are exposed to various known and suspected carcinogens in fire and smoke [8]. Firefighters may have been exposed to PFOA, which was used in fire-fighting foam in the past [4]. Occupational exposures related to risk of testicular cancer in police is less understood. There is some evidence that microwave emissions from radar guns may be a risk factor due to the proximity of hand-held radar guns to the testicles [5,9-11].

    • Protective service occupations- 1.46 times the risk
      • Firefighters- 2.56 times the risk
      • Policemen and detectives, government- 1.31 times the risk

Product Fabrication and Manufacturing

Elevated risk of testicular cancer was observed in workers involved in aircraft manufacturing, assembly, and repair, which has been observed in previous studies [5,12-13]. Product fabrication and manufacturing occupations may have been exposed to PCBs present in older electrical products and equipment manufactured prior to the 1977 ban on PCB, as the legislation allowed for continued use of PCB equipment until the end of its service life [14]. Electrical product industry workers may have been exposed to PCBs through handling electrical equipment and cable insulation [14-16]. Construction workers in power lighting and wire communications may have been exposed to materials containing PCBs, such as electrical equipment, cable insulation, and adhesives [14-16], and PFOAs, found in electrical wire casing [17]. Workers in other product fabricating, assembling, and repairing occupations may have been exposed to PCBs through oils used in motors and hydraulic systems [14-16]. There is also limited evidence for exposure to hydrocarbon carcinogens and glycol ethers in aircraft handling occupations [5,12-13].

    • Product fabricating, assembling, and repairing occupations- 1.15 times the risk
      • Fabricating and assembling, metal products, not elsewhere classified – 1.46 times the risk
        • Motor vehicle fabricating and assembling, not elsewhere classified- 1.43 times the risk
        • Aircraft fabricating and assembling, not elsewhere classified- 1.85 times the risk
        • Industrial, farm, construction and other mechanized equipment and machinery fabricating and assembling, not elsewhere classified- 1.62 times the risk
        • Inspecting, testing, grading, sampling, fabricating and assembling metal products, not elsewhere classified- 2.23 times the risk
      • Transportation equipment industries- 1.28 times the risk
        • Aircraft and aircraft parts manufacturers- 1.43 times the risk
        • Railroad rolling stock – 2.13 times the risk
      • Mechanic and repair occupations, except electrical- 1.27 times the risk
        • Motor vehicle mechanics and repairmen- 1.29 times the risk
        • Aircraft mechanics and repairmen- 2.02 times the risk
        • Industrial, farm and construction machinery mechanics and repairmen- 1.39 times the risk
        • Mechanics and repairmen, except electrical, not elsewhere classified- 1.38 times the risk
      • Electrical products industries- 1.11 times the risk
        • Communication and electronic equipment manufacturers- 1.64 times the risk
      • Electrical power lighting and wire communications equipment erecting, installing, and repairing occupations- 1.26 times the risk
        • Construction electricians and repairmen- 1.31 times the risk
      • Metal shaping and forming occupations
        • Forging – 2.09 times the risk
        • Welding and flame cutting – 1.05 times the risk

Transportation

Increased risk of testicular cancer was observed in various transportation occupations and industries in the ODSS. Whole body vibration [18] and diesel engine exhaust [4,19] have been linked to other cancer sites and may be potential risk factors in transportation workers. However, there is a lack of evidence supporting associations of these exposures with testicular cancer.

    • Transportation industries- 1.11 times the risk
      • Air transport- 1.38 times the risk
      • Moving and storage, used goods, uncrated- 1.70 times the risk
      • Urban transit systems- 1.39 times the risk
      • Other transportation- 2.03 times the risk
    • Transport equipment operating occupations- 1.29 times the risk
      • Motor transport operating – 1.33 times the risk
        • Bus drivers- 2.07 times the risk
        • Taxi drivers and chauffeurs- 3.13 times the risk
        • Truck drivers- 1.21 times the risk
        • Motor transport operating, not elsewhere classified- 1.61 times the risk
Relative Risk by Industry and Occupation

Figure 1. Risk of testicular cancer diagnosis among workers employed in each industry group relative to all others, Occupational Disease Surveillance System (ODSS), 1999-2020

The hazard ratio is an estimate of the average time to diagnosis among workers in each industry/occupation group divided by that in all others during the study period. Hazard ratios above 1.00 indicate a greater risk of disease in a given group compared to all others. Estimates are adjusted for birth year and sex. The width of the 95% Confidence Interval (CI) is based on the number of cases in each group (more cases narrows the interval).

Figure 2. Risk of testicular cancer diagnosis among workers employed in each occupation group relative to all others, Occupational Disease Surveillance System (ODSS), 1999-2020 

The hazard ratio is an estimate of the average time to diagnosis among workers in each industry/occupation group divided by that in all others during the study period. Hazard ratios above 1.00 indicate a greater risk of disease in a given group compared to all others. Estimates are adjusted for birth year and sex. The width of the 95% Confidence Interval (CI) is based on the number of cases in each group (more cases narrows the interval).

Table of Results

Table 1. Surveillance of Testicular Cancer: Number of cases, workers employed, and hazard ratios in each industry (SIC)

SIC Code * Industry Group Number of cases Number of workers employed Hazard Ratio (95% CI) †
1 Agriculture 34 28403 0.81 (0.58-1.14)
2/3 Forestry, Fishing and
Trapping
6 10252 0.46 (0.21-1.03)
4 Mines, Quarries and
Oil Wells
25 24246 1.02 (0.69-1.51)
5 Manufacturing 690 545155 0.98 (0.89-1.07)
6 Construction 245 216708 0.89 (0.78-1.02)
7 Transportation, Communication
and Other Utilities
212 177059 1.14 (0.99-1.32)
8 Trade 482 314398 1.12 (1.01-1.24)*
9 Finance, Insurance and
Real Estate
14 16336 0.83 (0.49-1.41)
10 Community, Business and
Personal Service
371 271710 1.03 (0.92-1.16)
11 Public Administration and
Defense
156 127829 1.21 (1.03-1.43)*
         
* SIC: Standard Industrial Classification (1970)  
† Hazard rate in each group relative to all others  

 

Table 2. Surveillance of Testicular Cancer: Number of cases, workers employed, and hazard ratios in each occupation (CCDO) group

CCDO Code * Occupation Group Number of cases Number of workers employed Hazard Ratio (95% CI) †
11 Managerial, administrative
and related
19 16805 1.71 (1.09-2.70)*
21 Natural sciences, engineering
and mathematics
31 22729 1.36 (0.96-1.95)
23 Social sciences and
related fields
5 7817 0.63 (0.26-1.52)
25 Religion 0 64
27 Teaching and related 9 11761 1.04 (0.54-2.01)
31 Medicine and health 22 19780 1.15 (0.75-1.75)
33 Artistic, literary,
recreational and related
11 9792 0.95 (0.52-1.71)
41 Clerical and related 130 102632 1.03 (0.86-1.23)
51 Sales 117 78714 1.05 (0.87-1.27)
61 Service 286 204019 1.14 (1.00-1.29)*
71 Farming, horticultural
and animal husbandry
56 43001 0.91 (0.70-1.19)
73 Fishing, hunting,
trapping and related
0 547
75 Forestry and logging 9 10328 0.65 (0.34-1.25)
77 Mining and quarrying,
including oil and gas field
10 13358 0.75 (0.40-1.40)
81 Processing
(mineral, metal, chemical)
83 65388 1.00 (0.80-1.25)
82 Processing
(food, wood, textile)
77 70440 0.81 (0.65-1.02)
83 Machining and related 212 173664 1.00 (0.86-1.15)
85 Product fabricating,
assembling and repairing
369 274701 1.15 (1.03-1.29)*
87 Construction trades 256 227776 0.96 (0.84-1.10)
91 Transport equipment
operating
209 166522 1.29 (1.11-1.49)***
93 Materials handling and related,
not elsewhere classified
171 128719 0.96 (0.82-1.12)
95 Other crafts and
equipment operating
32 23358 1.24 (0.88-1.77)
99 Other occupations not elsewhere classified 259 183819 1.00 (0.88-1.14)
         
* CCDO: Canadian Classification Dictionary of Occupations (1971)  
† Hazard rate in each group relative to all others  

Please note that ODSS results shown here may differ from those previously published or presented. This may occur due to changes in case definitions, methodological approaches, and the ongoing nature of the surveillance cohort.

References

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  14. Health Canada. PCBs [Internet].[cited 2022 Jun 6].
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