What is Medical Oncology?
Medical Oncology is the medical specialty that deals with cancer. Cancer is generically defined as a “solid tumor” having developed from a solid organ of our body such as the breast, prostate gland or lung or as a “liquid tumor” having developed from the blood (leukemia) or lymph gland (lymphoma). In all cases, the diagnosis of cancer is typically made on a biopsy or sampling of a part of the body thought to be involved by the process. These biopsies, often performed by either surgeons or by a special group of radiologists (interventional radiologists) are reviewed and read by pathologists, doctors trained in looking at tissues of our body. Once a diagnosis is made, patients need to have their cancer “staged”. Doctors often use confusing terms to refer to cancer and you should always ask for clarification when you hear the terms “nodules”, “lumps”, “bumps”, “tumors” or “lesions” since these may or may not refer to cancer.
What is Cancer Staging?
Once a diagnosis of cancer is made, the next step is to determine how advanced the cancer is. This is called “staging” and is done on the basis of both a physical examination as well as with the assistance of special laboratory or X-ray tests. Cancer is typically assigned a stage ranging from Stage I (the most localized) to Stage IV (the most advanced) with that determination often based on whether the cancer has spread beyond the site of its’ primary location (where it arose). Involvement of surrounding structures, spread to local lymph nodes or spread to distant sites is the critical determinant of how advanced the cancer is and often has implications as to how it is treated. Importantly, cancer is only staged once, when it is first diagnosed. Cancer that returns after an initial surgery or treatment is considered “recurrent” or “metastatic”. Some people use the term “Stage IV” to equate to metastatic disease and while accurate, it is not always correct in the way that we “stage” patient’s cancer.
The tools we use to stage cancer may include various imaging tests such as routine X-rays, computed tomographic (CT) scans, magnetic resonance imaging (MRI) scans or positron emitting tomography (PET) scans. Each of these is described in the “Imaging” section of the website for further clarification. Blood tests, looking for proteins in the blood that might indicate the presence of cancer are often called “tumor markers”. These often represent proteins produced by the cancer cells themselves and as a result, their presence in the blood stream may indicate remaining or relapsed cancer. Some examples of tumor markers are prostate specific antigen (PSA) in prostate cancer and alpha feto protein (AFP) in hepatocellular (primary liver) cancer. Some markers may be associated with cancer, such as carcinoembryonic antigen (CEA) or CA 125, but these markers can be elevated not only in cancer but in other disorders. For example, people who smoke may have higher CEA levels than non-smokers unrelated to having any cancer. Hence, some “tumor markers” are more sensitive and specific than others and you doctor can discuss this with you. Once the “stage” of a patient’s cancer is determined, patients and doctors can have meaningful discussions regarding treatment options. Importantly, it is often the case that an accurate stage cannot be determined until a surgical procedure is performed and hence your doctor may not be able to answer all of your questions about treatment options prior to that time. While patients with very early cancer may have a high chance of being cured of their cancer, those with more extensive disease, such as cancer that has already metastasized are considered treatable but not typically curable. There are exceptions to this circumstance and of course our goals in cancer care are always to try and improve outcomes, including the ability to cure previously incurable cancers.
How Did I Get Cancer?
Cancer is a disease characterized by uncontrolled growth of a mutated or changed cell. It generally arises from a normal cell that undergoes changes or “mutations” that may promote the ability of the cell to survive beyond what is normal. All cells live for a period of time and then undergo a process of cell death. The technical term for this is apoptosis which means programmed cell death. If the affected cell develops an ability to avoid apoptosis then it has the ability to become “immortal” and survive for longer than normal periods of time. This process results in the cells acquiring additional internal genetic changes which may make it grow more rapidly leading to the accumulation of a series of identical cells. Eventually, if this cluster of cells develops independence from all normal limits, it can evolve into a malignancy or cancer.
Cancer can arise on the basis of both environmental (exposure) as well as genetic (hereditary) factors. Not all cancers are hereditary and in only a select few do we truly worry about the risk of other family members being diagnosed with the same cancer to the point where testing of family members needs to be done. Environmental factors include things like smoking cigarettes (for example lung cancer and esophageal cancer), being exposed to too much sun (skin cancers such as melanoma) or excessive alcohol use (head and neck cancer). In some cases, multiple factors can amplify or increase the risk of cancer such as when smokers are exposed to asbestos leading to an even higher risk of lung cancer or mesothelioma (a cancer of the lining of the chest). Changing habits, even after being diagnosed with cancer, can have a positive outcome and can result in better results of treatment. If applicable, discuss this with your doctor.
In contrast to environmental factors, genetic risk or heredity is not something that can be changed. The genes we receive from our parents that determine things like our hair and eye color also determine how we will respond to many medications and whether our bodies are at an increased risk for developing damage to our cells that may eventually develop into cancer. Understanding genetic risk is important because as we get older, our family members are also aging and may be diagnosed with diseases that have implications for you as a patient. Being familiar with your family history, especially as it relates to diagnoses of cancer may be important in the lives of future generations. For example, a diagnosis of cancer in a brother or sister may be an indication of an increased genetic risk and should be related to your primary care physicians at each annual visit. In the current strategy of treating cancer, knowing about genetic risk can not only help family members by promoting them to have screening performed (such as mammography in breast cancer or colonoscopies in colon cancer) but can also aid in the determination of the best treatment since many of our new therapies take this into consideration.
How Do I Treat Cancer?
Cancer treatment typically requires a team of medical professionals, all working together, to achieve the best outcome for patients and their families. These may include:
Surgeons: Surgery may be considered for your cancer if its removal has the potential to either completely remove all evidence of the cancer (striving for cure) or to significantly reduce the amount of cancer in your body. In addition, surgery may be used to avoid complications possibly caused by the cancer including blockages or bleeding. Risks of surgery may vary and would be discussed with you by the surgeon involved in your case. Often, surgery is the first consideration for treatment and the results of the surgery are interpreted by a specialist called a pathologist.
Pathologists: Pathology is the science and study of tissues and organs. Pathologists are the doctors who review biopsies as well as organs or tissue removed by the surgeon. They use special tools which include stains that help us understand where a cancer may have arisen and have the ability to test tumors for specific genetic changes which can help predict the likelihood of benefit of certain treatments. Review of pathology specimens can take several days and may take longer for complicated cases where consultation with national leaders is in the field is required. Ultimately, the information from pathologists needs to be interpreted and discussed with your medical doctors to yield the best date for planning treatment. Certain critical information related to surgery may include whether or not lymph nodes that drain the tumor site are involved, whether the margins of the surgery are negative for tumor or whether additional surgery needs to be performed.
Radiation Oncologists: Radiation is the use of high energy beams produced by a machine to kill cancer cells in a specific location. Radiation works only in the areas to which the beam is directed and typically this is considered a local therapy. Examples of the use of radiation may include radiation therapy after limited breast surgery to prevent local relapse or its use in patients with limited but surgically unresectable disease. Surgery may not be able to be performed on some tumors based on their location or whether or not they involve normal structures of organs (such as critical blood vessels) that cannot be removed. There are different types of radiation treatments and this can sometimes be confusing in that the technology is rapidly advancing. Brachytherapy is use of localized radiation therapy using radioactive seeds or beads as well as temporary catheters which emit a dose of radiation to treat a local problem. Examples of cancers where this is commonly used include localized breast cancer, prostate cancer and cervical cancer. Stereotactic radiosurgery (STRS) is a technique where the radiation doctors use computers to pinpoint the location of the tumor and deliver much higher doses of radiation to the local tumor while giving less radiation to the surrounding normal tissue. There are a variety of other radiation therapy technologies and these can be addressed by your doctor.
Medical Oncologists: Medical Oncology is the specialty of treating cancer with medical therapies. The types of treatments available include chemotherapy, immunotherapy and targeted treatments. The value for each of these in selected cancer patients varies and not all of these treatment options have been shown to be effective in all types of cancer. Chemotherapy is the terms given to drugs that work to kill cancer cells. They typically kill rapidly growing cells and as a result, have side effects that are common among cancer patients including temporary hair thinning or hair loss, temporary lowering of the blood counts (including white blood cells that help fight infection, platelets that help the blood to clot and red blood cells that carry oxygen and nutrients to organs), numbness or tingling of fingers or toes and nausea and vomiting. Because cancer cells may have varying degrees of sensitivity to these drugs, not all chemotherapy drugs are effective for all cancers. Hence, the selection of which drugs to use is often based on where your cancer started as well as on things like your general health and well-being. Immunotherapy is the use of medications or treatments to stimulate your body’s immune system to fight the cancer. In this regard, there are two basic examples, drugs that actively stimulate the immune system, such as the family of drugs called interferons or interleukins, or those that provide a target for the immune system, such as cancer vaccines. Immunotherapy typically uses the body’s own immune system to fight the cancer and therefore has different side effects compared to chemotherapy. Often activation of the immune system can cause side effects similar to when one has a flu or infection (because the immune system fights those too) and may be comprised of fevers, chills, achiness and similar complaints. Only a small percentage of cancers have been shown to be effectively treated by immunotherapy and these include melanoma, kidney cancer and prostate cancer. Targeted Therapy is the term given to treatments that are directed against a specific aspect of the cancer cell that is required for its survival and growth. In this circumstance, drugs can be developed that block a specific signal in the cancer cell, effectively turning off the cancer cell’s ability to grow or spread. Some of these drugs are highly specific and affect only (or almost only) the cancer cells. An example of this situation is the treatment of a rare form of leukemia called chronic myeloid leukemia. In this blood cancer, a genetic mutation in the leukemic cells creates a new protein that is responsible for causing the cancer. By creating a drug that turns off that protein, the leukemic cells die and the patient’s bone marrow returns to normal. While highly effective however, this treatment is not a cure because some leukemic cells can go into hibernation and develop additional mutations that make them resistant to the effects of the first drug. Hence, scientists are constantly developing new treatments to try and overcome this resistance. In solid tumor cancers (cancers like lung cancer, breast cancer, etc) targeted therapies may have either great or limited utility. As we understand more and more about what makes a cancer cell “tick”, we can begin to unravel the options that might identify the critical protein or step in the cell’s growth that is vulnerable to a new treatment.
Sometimes, different modalities of treatment are used together. For example, it is often the case that patients with cancer might receive chemotherapy with radiation therapy at the same time. This might be done because the chemotherapy may make the cancer cell more sensitive to the radiation treatment’s effects. Combinations of chemotherapy with targeted drugs or immunotherapy are also common and can be discussed with your doctor.
Pain Specialists: Oftentimes, cancer can cause significant problems for patients depending on the location of spread or sites of metastases. One such problem is that of pain, which can be associated with pressure on nerves or simply because the cancer is in a sensitive area such as a bone. While treating the cancer is often an effective way of resolving pain, the use of appropriate pain medications is critical to ensure that patient’s do not suffer from severe pain or from associated side effects such as loss of appetite, confusion, constipation and fatigue. Pain specialists are doctors, typically anesthesiologists, who have a keen understanding of the causes and best treatments of pain. Including them into the “multi-disciplinary” team caring for a cancer patient is critical to ensuring that patient’s have the best possible outcomes.
What is Diagnostic Imaging?
In order to determine whether or not cancer has spread and where it is located you doctor may order radiology tests otherwise known as diagnostic images. These tests use a variety of modalities to take pictures of different parts of the body in order to look at the differences between normal and abnormal organs. The different types of imaging techniques include CT scans, PET scans, MRI scans, nuclear medicine scans or routine X-rays. Each are described below.
What is a CT Scan?
A CT scan or computerized tomography is a radiology test that uses x-rays to reconstruct the particular area of the body being imaged. Computer programs take the imaging