MULTICENTER FEASIBILITY STUDY OF THE SENTINEL NODE PROCEDURE IN PATIENTS WITH MULTIPLE BREAST TUMORS

Lymphoscintigraphy in breast cancer patients can determine the lymphatic
drainage pattern and the location of the first draining lymph node, the
sentinel node. The sentinel node is likely to be the first node to harbor tumor
cells, which may alter the patients* management. Multifocal and multicentric
carcinomas have a higher percentage of lymph node metastases compared to
unifocal breast cancer.Multicentric breast tumors are defined by the presence
of two or more clearly separated tumors located in more than one quadrant of
the breast. Multifocal tumors are located in one quadrant of the breast. If
only one tracer injection is administered in or around the tumor with for
example the largest tumor diameter, lymphatic drainage related to that tumor
only will be detected, instead of the drainage patterns of each tumor
separately. A (tumor-positive) sentinel node might be missed. Therefore we feel
that a better staging will be provided if a protocol is tested in which each
tumor is injected to evaluate any difference in lymphatic drainage compared to
only one injection of the radiopharamaceutical.

The aim of the study is to validate the sentinel node procedure in breast
cancer patients with multiple tumors and to investigative whether an
intratumoral injection of the radiopharmaceutical in each tumor will result in
additional sentinel nodes and/or extra lymphatic drainage locations compared to
an intratumoral injection of the radiopharmaceutical in the largest tumor only.

Inclusion criteria:
1. Patients presenting at one of the participating centers with multiple
invasive tumors in one or more quadrants of the breast.
2. The minimal distance between two different invasive foci must be two
centimeters .
3. The minimal diameter of an invasive focus (of one tumor) must be one
centimeter.

Exclusion criteria:
1. The maximum diameter of an invasive focus (of one tumor) must be five
centimeters
2. The maximum number of present invasive foci in one breast must be three foci
/ tumors
3. Evidence of other breast-cancer related disease such as palpable or
ultrasound detected lymph node metastases or distant metastases.
4. Exclusive presence of ductal carcinoma in situ (DCIS).
5. Incapacity or unwillingness of participant to give written informed consent

The radiation dose for the axilla that results from a dose of 99mTc-nanocolloid
is 2x10-4 mSv/MBq. In this study, a dose of 120 MBq will be injected in the
first tumor on the first day. On the second day, a total dose of 140 MBq will
be divided and injected in the remaining tumors. If two tumors are left, each
tumor will receive a dose of 70 MBq. Importantly, the number of particles
should be the same for each injection. This total dose is within the limits
that are indicated by the *Gezondheidsraad*, in the *Normen voor de toediening
van radioactieve stoffen aan vrijwilligers*.