Adjuvante Therapy in a non metastatic situation, after the primary tumor is removed usually a chemotherapy will be started
Antibody                        Antibodies are proteins with very specifiy binding properties, produced by the body to recognize patogenes or other foreign surface molecules. Antibodies attach to them and immune cells are eliminating/destroying these binding complexes.
Antigene An antigene is the area/molecule where the antibody specifically binds to. I.E. Receptor molecules in the membrane of cells are very often binding targets for antibodies. 
Aromatase inhibitor Aromatase inhibitors stop the production of estrogen in postmenopausal women. Aromatase inhibitors work by blocking the enzyme aromatase, which turns the hormone androgen into small amounts of estrogen in the body. This means that less estrogen is available to stimulate the growth of hormone-receptor-positive breast cancer cells. http://www.breastcancer.org/treatment/hormonal/aromatase_inhibitors  
Biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When only a sample of tissue is removed with preservation of the histological architecture of the tissue’s cells, the procedure is called an incisional biopsy or core biopsy. When a sample of tissue or fluid is removed with a needle in such a way that cells are removed without preserving the histological architecture of the tissue cells, the procedure is called a needle aspiration biopsy. Biopsies are most commonly performed for insight into possible cancerous and inflammatory conditions. https://en.wikipedia.org/wiki/Biopsy 
cell-free DNA (cfDNA) These are short pieces/fragments of DNA floating freely in the blood stream. They are debris from dead cells. These fragments can be sequenced and used i.e. for mutation detection. 
CETC, CTC Circulating (epithelial) tumor cells. These are cells released from a solid tumor. They are very stable even for many years. A small fraction of them (depending on the tumor and its aggressiveness) can have stem cell character to form new metastasis. In many cases CTCs can be measured even years after a cancer disease occurred. 
EpCAM Antibody EpCAM = Epithelial Cell Adhesion Molecule Antibody. This molecule is the most common molecule on epithelial cells. Carcinomas are of epithelial origin and have this antigene on their surface. EpCAM is therefore the only marker to quantify tumor cells in the blood stream. In a healthy human there are usually no epithelial cells in the blood. 
Her2/Neu   Her2/neu (human epidermal growth factor receptor 2, erb-B2, c-erbB2) belongs to the epidermal growth factor receptor (EGF receptor) family. HER2/neu stimulates cell proliferation via the RAS-MAP kinase pathway and inhibits programmed cell death (apoptosis) via the mTOR pathway. Her2/neu plays an important role in the treatment and diagnosis of mammary carcinoma (breast cancer). In about 20% of all invasive breast carcinomas, the receptor is highly overexpressed. Its effect is thus multiplied, resulting in a poor survival prognosis, or comparatively worse disease progression. Whether the disease course is influenced by Her2/neu overexpression can be detected by immunohistochemical methods. The determination of detected overexpression is designated as “HER2-positive”.
Hormone Therapy Hormonal therapy in oncology is hormone therapy for cancer and is one of the major modalities of medical oncology (pharmacotherapy for cancer), others being cytotoxic chemotherapy and targeted therapy (biotherapeutics). It involves the manipulation of the endocrine system through exogenous administration of specific hormones, particularly steroid hormones, or drugs which inhibit the production or activity of such hormones (hormone antagonists). Because steroid hormones are powerful drivers of gene expression in certain cancer cells, changing the levels or activity of certain hormones can cause certain cancers to cease growing, or even undergo cell death. Surgical removal of endocrine organs, such as orchiectomy and oophorectomy can also be employed as a form of hormonal therapy. https://en.wikipedia.org/wiki/Hormonal_therapy_(oncology) 
Liquid Biopsy Liquid Biopsy is a method to diagnose tumor cells or tumor DNA in blood. 
Maintrac(TM) Maintrac is an ISO 15189 based method to detect in a quantitative way tumor cells in the patient’s blood. Maintrac is able to differentiate between dead and living tumor cells. With this method we can even measure the killing rate of chemotherapeutic on tumor cells over time. also OPlease see this explanation. 
Metastatic Situation This means the original, primary tumor released cell into the blood stream which by now already formed new metastasis. In this situation doctors are usually free in treating the patient with whatever means since their is no real guideline available.  
Neo-Adjuvant Neoadjuvant therapy is the administration of therapeutic agents before a main treatment. One example is neoadjuvant hormone therapy prior to radical radiotherapy for adenocarcinoma of the prostate. Neoadjuvant therapy aims to reduce the size or extent of the cancer before using radical treatment intervention, thus making procedures easier and more likely to succeed, and reducing the consequences of a more extensive treatment technique that would be required if the tumor wasn’t reduced in size or extent.Another related concept is that neoadjuvant therapy acts on micrometastatic disease. The downstaging is then a surrogate marker of efficacy on undetected dissemination, resulting in improved longtime survival compared to the surgery-alone strategy.
This systemic therapy (chemotherapy, immunotherapy or hormone therapy) or radiation therapy is commonly used in cancers that are locally advanced – where clinicians plan an operation at a later stage. The use of such therapy can effectively reduce the difficulty and morbidity of more extensive procedures.The use of therapy can turn a tumour from untreatable to treatable by shrinking the volume. Often it can be unclear which surrounding structures are directly involved in the disease and which are just showing signs of inflammation. By administering therapy a distinction can often be made. Some doctors give the therapy in the hope that a response will be seen so that they can then decide what is the best course of action. Unfortunately, not everyone is suitable for therapy in this way because it can be extremely toxic. Some patients react so severely that further treatments, especially surgery, are precluded because the patient is rendered unfit for anesthetic. https://en.wikipedia.org/wiki/Neoadjuvant_therapy 
Tamoxifen Therapy  Tamoxifen is a hormone therapy for breast cancer in both women and men. It lowers the risk of early breast cancer coming back (recurring) after surgery or developing in the other breast. It can also control advanced breast cancer for some time.
Tumor Cell Analysis Tumor cells can be tested for certain surface molecules (Her2/NEU, EGFR, PR, PSMA PDL-1,…) or also for genetic mutations to disclose potential target molecules für certain drugs.
Target MoleculeA target molekule is usually a protein which has influence on tumor growth. When these proteins can be blocked (with antibodies or chemical molecules), the tumor growth can be inhibited or even stopped. Or the target molecule will be marked that macrophages (killer cells) can bind and destroy the tumor cells.