Latent Mycobacterium Tuberculosis Infection Among Cancer Patients
TB AND TB TESTS:
Patients with cancer are considered "immunocompromised." This means that, because of the
cancer and the cancer treatment, the immune system does not function normally, which
decreases its ability to fight off infection and disease. This immunocompromised condition
places these patients (who probably had been in contact with the TB bacteria, resulting in
latent, or inactive, TB) at risk for active TB. Latent TB does not cause symptoms or signs
of active TB infection. It is very important to identify patients who are at risk for
developing active TB, so that they can receive timely treatment for TB.
The Tuberculin skin test (TST) is currently used to detect latent TB. The TST is considered
to have low detection sensitivity, which means that it may not always detect latent TB,
which may then turn into an active TB infection.
The T-SPOT.TB is a new test that researchers want to study to see whether it may be more
effective and accurate than the TST at identifying patients at risk for developing active
If you agree to take part in this study, you will have the following tests done and steps
- You will have extra blood (about 1 to 2 teaspoons) drawn. It will be done at the same
time as your routine clinic visit to M. D. Anderson or as a regular blood draw if you
are already admitted in the hospital. This blood will be used to perform the T-SPOT.
If you have had a TST (or tuberculin skin test) performed at M. D. Anderson in the past 45
days, it may probably not be necessary to repeat the TST. However, the research staff will
decide if you need to have a new TST.
You may have the TST performed before or after your blood is drawn. In any case, you will
rest for 10 minutes after the blood draw.
- You will receive a fluid called tuberculin in order to have the TST performed.
Tuberculin will be injected just beneath the surface of the skin on your forearm. You
should then see a very small raised area of skin where the injection was given. This
reaction will wear off in a few days.
- After 2-3 days (48-72 hours later), you will return to M. D. Anderson (if you are not
in the hospital), and a health care professional will look at and measure any swelling
or redness at the site of TST. The doctor will then learn if your TST result is
positive or negative. If your TST is positive the study doctor will discuss it with ,
your primary doctor for further evaluation and treatment.
Although you will be informed about the TST result, you will not be informed about the
T-SPOT. TB test result because the T-SPOT. TB test is just used for investigational purposes
in this study and will not be used for diagnostic purposes. The study doctor will use the
results of the T-SPOT. TB test to make research comparisons with the TST test results.
LENGTH OF STUDY:
Your participation will be over in this study once both TB tests have been performed and the
TST has been checked by a health care professional.
This is an investigational study. The TST is FDA approved and commercially available. The
T-SPOT.TB test is not FDA approved or commercially available. It is authorized for use in
research only. Up to 200 patients will take part in this study. All will be enrolled at M.
Observational Model: Case-Only, Time Perspective: Prospective
Rate of Positive Results of T-SPOT.TB (%)
Number participants with postitive T-SPOT.TB test results compared to total positive results, derived from Center for Disease Control (CDC) Criteria used for LTBI positive skin test (i.e. a tuberculin skin test (TST) with 5 mm or more of induration). For those individuals with >5 mm induration on TST, chest radiograph performed. Fisher's exact test used to assess the association between categorical variables and the testing results of T-SPOT.TB or TST.
Study period 2 Years
Amar Safdar, MD
M.D. Anderson Cancer Center
United States: Institutional Review Board
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