Cancer incidence in California farm workers, 1988-2010

Farmers and farm workers have previously been found to experience decreased risk of some causes of death but elevated risks of certain types of cancer. A previous report on cancer incidence in a farm worker labor union between 1987 and 1997 found increased leukemia, brain, stomach, and uterine cervix cancer rates in this working population.

A roster of farm workers was created and electronically linked to the database of the California Cancer Registry. Proportionate cancer incidence (PCIR), stage, and age at diagnosis and histological subtypes of cancer were compared between the United Farm Workers (UFW) members and the Hispanic population of California as well as to the non-Hispanic whites (NHW).

In this population of 139,000 farm workers in California, more than 3,600 cancer diagnoses were recorded between 1988 and 2010. Proportionately more cancer was noted in the UFW than among California NHW for kidney and renal pelvis cancer (PCIR = 1.60), liver (PCIR = 4.24), prostate (PCIR = 1.13), and uterine cervix cancer (PCIR = 2.08). Proportionately less breast (PCIR = 0.85), lung (PCIR = 0.75), skin melanoma (PCIR = 0.18), and urinary bladder cancer (PCIR = 0.59) was found. Stage at diagnosis was more advanced in the farm workers for several cancer sites, although, not for colorectal cancer.

These farm workers experience proportionally more prostate, kidney and renal pelvis, brain, liver, stomach, cervix and leukemia and less breast, melanoma, and colorectal cancer than reference populations. For many sites, cancer is not diagnosed as early in the farm workers as in the comparison groups, except for colorectal cancer in females and melanoma in males.