Definitions of Reported Measures

  • Acute lymphocytic leukemia (ALL) starts in the lymphoid cells and is the most common type of leukemia in young children. While a few things, such as radiation exposure, exposure to certain chemicals, and certain inherited syndromes (such as Down syndrome) are risk factors for ALL, little is understood about the causes of this disease. 
  • Acute myeloid leukemia (AML) is a cancer that starts in the bone marrow, but often spreads to the blood. Smoking is one of the few known risk factors for AML.
  • Bladder cancer forms in the cells lining the urinary system. Smoking and the work environment are the two biggest risk factors for bladder cancer.
  • Brain cancer occurs in the tissues of the brain and central nervous system. Little is known about the causes of brain cancer and how to prevent it from occurring.
  • Breast cancer occurs when a malignant tumor forms in the tissue of the breast. Women are recommended to perform breast self-examination and receive regular mammograms to increase chances of early detection.
  • Chronic lymphocytic leukemia starts in the white blood cells in the bone marrow and can spread to other parts of the body. Little is known about the risk factors for CLL.
  • Esophageal cancer affects the esophagus, the muscular tube that leads from the larynx to the stomach.
  • Kidney and renal pelvis cancers form in and around the kidneys. Risk factors include smoking, long-term use of certain pain medications, and some genetic factors. This category of cancer also includes Wilms tumor, a rare kidney cancer affecting children under five.
  • Larynx cancer (also called laryngeal cancer) is a cancer of any part of the throat below the pharynx and above the esophagus.
  • Leukemia includes a diverse group of cancers that begin in white blood cells. Leukemia is more common in adults than children.
  • Liver and intrahepatic bile duct cancers are seen most often in people who have hepatitis B or C infection (whether they have symptoms of hepatitis or not), chronically abuse alcohol, or have autoimmune diseases affecting the liver.
  • Lung cancer forms in the tissues of the lung and bronchus cancer forms in the tube connecting the windpipe to the lung. Smoking is the most common cause of lung and bronchus cancer.
  • Melanoma is the rarest but most serious of skin cancers. Data reported here are for invasive melanoma of the skin only, although there are other types of melanoma and other parts of the body where melanoma can develop. Risk factors for developing melanoma include frequent and prolonged exposure to sun; having fair skin, blue or green eyes, or blond or red hair; using tanning beds; or having a weakened immune system.
  • Mesothelioma is a rare cancer affecting the linings of internal organs, most often the lungs. It is most often caused by exposure to asbestos and takes many years after exposure to develop. As with many types of cancer, early detection can mean a better prognosis.
  • Non-Hodgkins lymphoma is cancer that begins in the lymphoid system and can spread to other organs.
  • Pancreatic cancers are malignancies of the pancreas, the gland organ below the stomach that produces insulin and other hormones as well as digestive juices. 
  • Pharynx cancer (also called pharyngeal cancer) affects the area of the throat directly below the mouth and nose, but above the larynx.
  • Thyroid cancer occurs when the cancer begins in the thyroid gland. Known risk factors for thyroid cancer include iodine intake and hormonal factors.

How to Read Tables, Charts, and Maps

  • Conventional rates express the number of outcomes relative to the size of the population.  N/A indicates that the data are not available due to the number of events being less than 12.
  • Modeled rates are similar to conventional rates except that they further take into account the frequency of events in surrounding areas.  Modeled rates can be useful when there aren't enough events in an area to calculate rates in the conventional manner, and they are often useful for examining regional trends.
  • Some counties have a greater proportion of people who are old or young than other counties, which makes it difficult to draw conclusions about cancer risk when looking at multiple counties or a single county over time.  Scientists often fix this problem through a technique called age adjustment so comparisons can be made for cancer risk.  The rates presented here are age-adjusted rates.
  • The 95% confidence interval (CI) is the range of values that likely contains the true rate in the population. 
  • Total counts are listed next to conventional rates unless the total number of events is less than 12. They are typically not listed next to modeled rates.

Data Sources

  • The California Cancer Registry works with medical treatment facilities and scientists to receive reports of cancer while following strict patient privacy rules. All types of cancer are reported except basal and squamous skin cell cancer and cervical cancer.
  • It takes about three years for the data to be complete and checked for accuracy. Rates were calculated based on these numbers along with the National Center for Health Statistics (NCHS) bridged population estimates to give the number of people from each age group in each county.


  • Cancer categories were defined using the International Classification of Disease for Oncology, Third Edition, 2000 (ICD-O-3):

Adult cancers:

Cancer TypesICD-O-3 Codes Used
Acute lymphocytic leukemia
9826, 9835:9837
Acute myeloid leukemia
9840, 9861, 9866, 9867, 9871:9874, 9895:9897, 9910, 9920
Bladder (including in situ)
C670:C679 (Excl. M-9050:9055, 9140, 9590:9989)
Brain and other nervous system (ONS)
C710:C719 (Excl. M-9050:9055, 9140, 9530:9539, 9590:9989)
Chronic lymphocytic leukemia
C420, C421, C424 with histology 9823
C150-C159; excluding histologies 9050-9055, 9140, 9590-9989
Female breast
C500:C509 (Excl. M-9050:9055, 9140, 9590:9989)
Kidney and renal pelvis 
C649, C659; excludes histologies: 9050-9055, 9140, 9590-9989
LarynxC320-C329; excluding histologies 9050:9055, 9140, 9590:9989
Liver and intrahepatic bile duct 

C220, C221; excludes histologies: 9590-9989, 9050-9055, and 9140
Lung and bronchus
C340:C349 (Excl. M-9050-9055, 9140, 9590:9989)
C440-C449, histologies 8720-8790
Non-Hodgkin lymphoma9590:9596, 9670:9671, 9673, 9675, 9678:9680, 9684, 9687, 9689:9691, 9695, 9698:9702, 9705, 9708:9709, 9714:9719, 9727:9729 (9823, 9827), all sites except C420, C421, C424
C250-C259; excluding histologies 9050:9055, 9140, 9590:9989
C000-C009, C019-C069, C079-C119, C129-C140, C142-C148; excludes histologies 9050-9055, 9140, 9590-9989
ThyroidC739 (Excl. M-9050:9055, 9140, 9590:9989)

Pediatric Cancers:

Cancer TypeICD-O-3 Codes Used
Acute Myeloid Leukemia9861/C00.0-C80.9
Central Nervous System

9380 (C72.3), 9381, 9400-9441 (C00.0-C80.9), 9383, 9390-9394/(C00.0/C80.9), 9380 (C70.0-C72.2, C72.4-C72.9), 9380 (C72.3), 9381, 9400-9441 (C00.0-C80.9), 9383, 9390-9394/C00.0/C80.9, 9380 (C70.0-C72.2, C72.4-C72.9)

Leukemia9800-9804, 9820-9827, 9830, 9840-9842, 9850, 9860-9864, 9866, 9867, 9868, 9870-9894 9900, 9910, 9930-9941/C00.0-C80.9

Limitations of the Data

  • Veteran's Health Administration (VHA) hospitals in California stopped reporting cancer cases to the California Cancer Registry beginning in 2005. Although there is no way to know how many unreported cancer cases were diagnosed in these facilities since that time, in the past VHA-reported cases made up about 4 percent of all new cancers in men, and a very small proportion of cancers in women. Therefore, the rates of cancers in men in these data since 2005 are likely slightly lower than the true rate, which would include cancers diagnosed in VHA hospitals.

Suggested Citation

Tracking California, Public Health Institute. Cancer data. Accessed [Month/Day/Year] from

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