CA 19-9 is an antigen (cell surface glycoprotein complex) produced by adenocarcinoma cells of pancreas, stomach, gallbladder, colon, ovary and lung.

Historically, it is one of the most commonly used tumor markers for diagnosing, managing, and prognosticating pancreatic ductal adenocarcinoma.

Elevated levels of CA 19-9 are used as an indication for surgery in conditions of benign formations suspected of early malignancy.

High values are found in various neoplastic diseases of the gastrointestinal tract of different location and nature.

Another common application of CA 19-9 includes its use as an aid in the diagnosis of cholangiocarcinoma.

Its sensitivity is greatest for pancreatic cancer and is used in the differential diagnosis with chronic pancreatitis.

Recently used in gastrointestinal cancers (colorectal and esophageal).

With the dosage of CA 19-9 it is also possible to investigate UROLOGICAL, GYNECOLOGICAL, PULMONARY and THYROID pathologies.

It may be a potential therapeutic target in PANCREATIC DUCTAL ADENOCARCINOMA and ACUTE PANCREATITIS.

Approximately 6% of the Caucasian population and 22% of the non-Caucasian population are perpetually NOT producers of CA 19-9.

In recent-onset diabetes mellitus (which may be a sign, especially in the elderly of PDA), CA 19-9 may be elevated if blood glucose is uncontrolled. Patients with glycemic control and persistence of elevated CA 19-9 appear to have a higher risk of PDA.

DIAGNOSIS AND STAGING OF PANCREATIC DUCTAL ADENOCARCINOMA (PDA):

CA 19-9 can be used as an aid in the diagnosis of imaging tests such as contrast-enhanced CT, which is the gold standard, and not in isolation. Levels above 37-40 U/mL confirm the diagnosis.

10 to 50% of benign pancreatic disorders (eg, pancreatitis) and precursor lesions (eg, intraductal pancreatic mucinous neoplasms (IPMNs), pancreatic intraepithelial neoplasia) have resulting elevated CA 19-9 levels, not able to differentiate with PDA.

CA 19-9 levels are often prognostic in PDA (>100 U/mL has worse prognosis).

MANAGEMENT OF PANCREATIC DUCTAL ADENOCARCINOMA (PDA):

CA 19-9 level may predict PDA unresectableness. However, in contrast to established diagnostic values, there is significant variability in the ideal cutoff values used to determine unresectable disease, ranging from 37 to 1000 U/mL (sensitivity 69% to 93% and specificity 78% to 98% ).

Preoperative CA 19-9 may guide the performance of staging laparoscopy prior to resection surgery. The largest studies support laparoscopic staging for:

• CA 19-9 150 U/mL and tumor size >3 cm in patients with radiologically resectable disease
• CA 19-9 preoperative > 130 – 400 U/mL

MANAGEMENT AND PROGNOSIS OF PANCREATIC DUCTAL ADENOCARCINOMA (PDA):

CA 19-9 plays a role in monitoring response to neoadjuvant treatment, which is increasingly taking hold in PDA, by predicting resectability and prognosis.

Patients treated with neoadjuvant FOLFIRINOX with CA 19-9 after neoadjuvant treatment >=91.8 U/mL did not benefit from resection. In another study, a >50% drop in CA 19-9 in patients using FOLFIRINOX or GENCITABINE predicted RO resection in 40 borderline resectable patients.

Neoadjuvant therapy and resection with curative intent have demonstrated that a >= 50% reduction in CA 19-9 correlates with a better prognosis and increased overall survival.

CA 19-9 <90 U/mL after resection surgery has demonstrated better survival with adjuvant chemotherapy (CT). Unlike CA 19-9 >= 90 U/mL after resection, it has not demonstrated benefit in performing adjuvant CT.

Failure to normalize or increase postoperative CA 19-9 levels has been recognized as a predictor of PAD recurrence.

Elevation of CA 19-9 may precede clinical or radiological recurrence of PAD by 2-6 months. To define early salvage therapy it may be superior to imaging which has postoperative artifacts, which often make interpretation difficult. However, there is still a need for radiological recurrence for salvage therapy, which is the focus of many studies.

Normal values 

Below 25 U /mL

(Attention, the reference ranges may differ from one laboratory to another, therefore refer to those present on the report).

Increase in CA 19-9 values 

Pancreatic cancer
Gastric cancer
Hepatobiliary cancer
Lung cancer
Breast cancer
Hepatoma
Hepatitis and jaundice
Acute and chronic pancreatitis
Polyposis
Pancreatic cystic fibrosis