Cervical cancer used to be the leading cause of cancer death for cervix-having individuals living in the United States, according to statistics shared by the Centers for Disease Control and Prevention (CDC). But since the late 1970s, the numbers of deaths caused by cervical cancer have steadily declined, thanks to preventative measures like Pap smears and human papillomavirus (HPV) vaccines and testing.
That’s not to say cervical cancer is no longer a problem. The American Cancer Society estimates that, in 2018, approximately 13,240 new cases of invasive cervical cancer will be diagnosed and about 4,170 individuals diagnosed with cervical cancer will die because of it. While that’s far lower than the 63,000 cases of uterine cancer the American Cancer Society predicts will be diagnosed in 2018, it’s clear that there’s still more to be done when it comes to preventing and treating cervical cancer.
What Causes Cervical Cancer?
Cervical cancer develops when healthy cells in the cervix, the narrow lower portion of the uterus that opens into the vagina, undergo genetic changes that cause them to mutate into abnormal cells.
While healthy cells grow, multiply, and die at a set rate, cancer cells grow and multiply rapidly without ever dying off. As more and more of these abnormal cells accumulate, they form a cancerous mass—a tumor. The cancer cells then continue to multiply, causing the initial tumor to grow larger. Not only do the cancerous cells begin to invade healthy surrounding tissue, but they can also break off and spread to elsewhere in the body, a process known as metastasization.
So, what are the causes of cervical cancer? It’s not entirely clear, but experts agree that human papillomavirus (HPV), the most common sexually transmitted infection in the United States, plays a central role in its development. Yet in most cases—an estimated 14 million occur each year—HPV does not progress to cervical cancer, so other factors must play a role too.
The CDC predicts that between 80% and 90% of sexually-active individuals will be infected with at least one type of HPV (there are over 200 different strains) at some point in their lives. To be infected with HPV, your skin or mucous membranes must come in contact with the skin or mucous membranes of someone with the virus. It’s entirely possible to transmit HPV to someone else without ever realizing you had it to begin with, which is part of why the incidence rate is so high. Many people with HPV will never experience any symptoms and the infection will clear up on its own. Certain strains, however, can cause unpleasant issues like genital warts, while others can spur the development of cervical cancer.
There are two types of sexually-transmitted HPV: low-risk HPVs and high risk HPVs. Low-risk HPV doesn’t lead to cancer, but does cause the growth of potentially irritating and uncomfortable genital warts. Most genital warts are caused by HPV strains 6 and 11. High-risk HPVs are called high-risk precisely because they can cause cancer. Researchers have identified roughly a dozen strains of high-risk HPV, but have found that just two—strains 16 and 18—cause most cases of HPV-related cervical cancer.
There are two primary types of cervical cancer as well: squamous cell carcinoma and adenocarcinoma. The most common is squamous cell carcinoma, which begins in the squamous cells, the thin, flat cells lining the outer part of the cervix that projects into the vagina. Adenocarcinoma begins in the column-shaped glandular cells lining the cervical canal that link the cervix and uterus. In some cases, both types of cells begin to mutate, while in very rare instances, the cancer develops in an entirely different type of cervical cell.
8 Cervical Cancer Symptoms You Should Never Ignore
In the early stages of cervical cancer, most people notice no symptoms at all. That’s why screening and other preventative measures are such important ways of combating this kind of cancer.
Symptoms of cervical cancer typically begin to appear once the cancerous cells have penetrated into the tissues beneath the top layer, at which point the diagnosis becomes invasive cervical cancer. And still, the symptoms that appear at this stage are often interpreted as harmless, or attributed to other causes. Here are a few early signs of cervical cancer.
1. Irregular Vaginal Bleeding
Irregular vaginal bleeding is one of the most common symptoms of cervical cancer. The bleeding may occur between menstrual periods, after sex, or even after menopause, according to Dr. Taraneh Shirazian, a gynecologist at NYU Langone Health. Unfortunately, this symptom often gets dismissed as spotting. It’s true that cervical cancer is certainly not the only cause of vaginal bleeding between periods, but to be safe, it’s a good idea to consult a gynecologist whenever you experience unusual bleeding. For those who are postmenopausal, vaginal bleeding is definitely a cause for concern and should be evaluated by a medical professional.
2. Changes to Menstrual Cycle
Again, many factors can cause menstrual cycles to shift, some of which are no cause for alarm. But proactively discussing menstrual cycle changes with a doctor is a good way to assess whether there are any screenings or treatments that could be beneficial. This is especially true if the changes are dramatic, like a period that lasts for two weeks, or two periods within a single month.
3. Abnormal Vaginal Discharge
The appearance and smell of vaginal discharge can be indicative of a range of vaginal health issues. Some indicators of cervical cancer include discharge that is:
In some cases, discharge may contain chunks of tissue, technically referred to as necrotic material. And since masses and tumors secrete fluid, continuous, inexplicable watery discharge can also be a sign of cervical cancer.
Any of these types of discharge are good cause for scheduling a gynecologist appointment.
When cervical cancer becomes more advanced, the symptoms can present in different ways. Signs to watch for include the following.
4. Persistent Nausea and Indigestion
Advanced cervical cancer causes the cervix to become so enlarged, it begins to swell into the abdominal cavity. This compresses the gastrointestinal tract and stomach, which can cause nausea and acid reflux. Since nausea can result from many other causes, it’s best to address this symptom first with a primary care physician, rather than a gynecologist.
5. Unintentional Weight Loss
The severe cervical swelling that comes in the advanced stages of the disease can also lead to weight loss, since a compressed stomach can’t hold very much food. Ongoing nausea and indigestion also make eating a far less pleasant activity than it can be under other circumstances. Individuals who have lost between 5% and 10% of their body weight over the course of six months without trying should consult with a medical professional.
6. Pelvic or Back Pain
Pelvic pain can definitely be an indicator that something’s amiss with the cervix. If cervical cancer spreads to the bladder, intestines, liver, or lungs, it can cause back pain. In some cases, that pain can even radiate down the legs. Both back and leg pain only occur when the cervical cancer is quite advanced, since the cervix itself doesn’t affect many nerves.
To determine whether or not cervical cancer is the cause of ongoing pelvic or back pain, speak with a primary care physician.
7. Intense Fatigue
This is a universal symptom of cancer, and again, one that appears once cervical cancer has progressed to an advanced stage. One reason for fatigue that’s specific to cervical cancer is abnormal vaginal bleeding, which can lower the amount of red blood cells and oxygen in the body, leading to deep and prolonged fatigue.
Checking iron levels and red blood cell levels is a routine part of diagnosing the cause of chronic fatigue.
8. Frequent, Uncomfortable Urination
Advanced cervical cancer can result in kidney blockages, which cause urination to become uncomfortable. In some cases, it may lead to frequent urges to urinate, even when the bladder is not full. It can also become difficult to urinate.
Preventing and Screening for Cervical Cancer
The implementation of effective preventative measures and screening tests has been instrumental to lowering the number of deaths caused by cervical cancer. Here are eight ways to prevent as well as screen for cervical cancer.
1. HPV Vaccine
Given that HPV plays such a crucial role in the development of cervical cancer, the HPV vaccine can have a significant effect on preventing it. Gardasil, the most common and most effective HPV vaccine, protects against HPV strains 16 and 18, which cause 70% of cervical cancers, as well as strains 6 and 1, which cause 90% of genital warts. Because the vaccine is only effective prior to infection, the goal is to inoculate children before they become sexually active.
The CDC’s current recommendations for the Gardasil vaccine are as follows:
- Children ages 11 to 12: At this age, all children should get two HPV vaccine shots 6 to 12 months apart. If the shots are given less than five months apart, a third will be needed.
- Adolescents ages 15 and older: If a first dose is not given before age 15, then three doses are recommended over the course of six months.
- Young adults: HPV vaccines are recommended for cervix-having individuals through age 26, and for penis-having individuals through age 21.
After a valid series of HPV vaccines has been completed, no additional doses will be needed. There are numerous side effects to consider before opting for the HPV vaccine. We explore those considerations in this article.
2. Pap Smear
According to the CDC, 6 out of every 10 individuals diagnosed with cervical cancer have never received a Pap smear or have not been tested in the past five years. Dr. Eloise Chapman-Davis, a gynecological oncologist at Weill Cornell Medicine and New-York Presbyterian says not having regular Pap smears is one of the biggest risk factors for cervical cancer.
The Pap smear, one of the most reliable cancer-screening tests available, detects abnormal, precancerous cells. When caught early, treatments can address these abnormal cells before they develop into full-fledged cancer.
The Office on Women’s Health recommends regular Pap smears to look for changes to cervical cells beginning at age 21, as well as HPV tests between the ages of 30 and 65. The general guidelines for Pap smears, per the Office on Women’s Health, are as follows:
- Age 21 to 29: Get a Pap smear every three years.
- Age 30 to 64: Continue to get a Pap smear every three years, or get a Pap smear and HPV test together every five years.
- Age 65 and older: Doctors may decide that pap smears are no longer necessary.
Gynecologists and primary care doctors can perform Pap smears during routine pelvic exams. During a Pap smear, a doctor swabs the cervix to collect cells for examination under a microscope.
It takes only seconds to collect the sample, and while the procedure can involve some discomfort, even then, it’s quite mild. The HPV test can be carried out using cervical cells collected from a Pap smear.
If abnormal cells are identified under a microscope, that may lead to a diagnosis of cervical dysplasia which can range from mild to severe and can develop into cervical cancer. There are four ways to classify cervical dysplasia:
- Atypical cells of undetermined significance (ASCUS): This classification refers to any mildly abnormal changes. Underlying causes could be anything from simple, treatable infections to the growth of precancerous cells. Further confirmatory testing is needed before a diagnosis of cervical dysplasia is given.
- Atypical glandular cells of undetermined significance (AGUS): This is used to describe abnormalities in the mucus-producing glandular cells. This is a rare classification used for less than 1% of all Pap smear results. It can be indicative of a serious underlying condition, but not the kind of cellular changes that lead to cervical cancer.
- Low-grade squamous intraepithelial lesion (LGSIL): The most common diagnosis when abnormal cells are found, this refers to mild dysplasia. Typically, the cellular changes identified resolve on their own within two years and no further treatment is required.
- High-grade squamous intraepithelial lesion (HGSIL): This classification is reserved for more concerning findings which, if left untreated, will likely develop into cervical cancer.
Whenever a Pap smear yields abnormal findings, it’s extremely important to follow through on the recommendations made by the doctor in charge of the case.
3. HPV Test
The HPV test, which also involves swabbing cervical cells and examining them under a microscope, can identify certain types of HPV infections. It can be done using a sample of cells collected during a Pap smear. If the results of a Pap smear are abnormal, an HPV test is often the next course of action to determine what has caused the cellular changes.
If a Pap smear results in abnormal findings, the next step is often to conduct a colposcopy. During this procedure, a colposcope—a lighted, magnifying instrument—is used to examine the vagina and cervix to see if any tissue changes are visible. The colposcope remains outside the vagina during the exam. Images from the instrument are sometimes projected onto a screen so they can be seen with more detail.
Doctors sometimes perform biopsies during the colposcopy so that a pathologist can examine a sample of cervical tissue to assess it for disease-related changes.
5. Punch Biopsy
This is the most common kind of biopsy performed when a sample of cervical tissue is needed. A doctor uses a device similar to a paper punch to collect the sample. Depending on what the colposcopy revealed, samples may be needed from a few areas of the cervix. The procedure does involve pain, but takes only seconds to complete and the discomfort is reported to be fleeting.
6. Endocervical Curettage
This type of cervical biopsy involves using a small brush or a curette (a spoon-shaped instrument) to collect tissue from the endocervical canal, a narrow tunnel that connects the cervix to the uterus. It’s important not to take aspirin or blood thinners before coming in for the procedure, as well as to abstain from tampon use, sexual intercourse, and douching for three days prior.
This procedure tends to be more painful than a punch biopsy; reportedly, it’s equivalent to bad menstrual cramps. Mild symptoms like localized pain and cramping can linger for days following the procedure. There may also be some bleeding or dark discharge. It’s recommended to continue to avoid tampon use, sexual intercourse, and douching until the endocervical canal has healed and the symptoms resolve.
7. Cone Biopsy
Some colposcopy findings require a larger biopsy to be carried out, either to confirm a diagnosis of cervical cancer or to remove tissues so that they do not become cancerous. Often, this leads to a cone biopsy being performed.
As the name indicates, the procedure removes a cone-shaped piece of tissue and is done under general anesthesia. It’s common to experience pain and bleeding for a few days following the procedure. In some cases, it can result in increased menstrual pain, decreased fertility, and what’s called an “incompetent cervix,” which can cause premature vaginal delivery during pregnancy. The location and size of the biopsy determine the symptoms experienced after the procedure, as well as how long healing will take.
8. Loop Electrosurgical Excision Procedure (LEEP)
This alternative to a cone biopsy is also done under general anesthesia. During a LEEP, an electrically-charged wire loop is used to remove a tissue sample. It’s more likely that this procedure will be used when precancerous cells need to be removed than when a potential diagnosis of cervical cancer needs to be confirmed.
The after-effects of a LEEP are nearly identical to those of a cone biopsy: pain and bleeding for the days following the procedure, and a chance of increased menstrual pain, decreased fertility, and an incompetent cervix.
What Are the Stages of Cervical Cancer?
Once a diagnosis of cervical cancer has been confirmed, the next step is to assess whether the cancer cells have spread, and if so, how far they have spread. This process is called staging, because the information gathered determines the stage of the disease. And the stage of the disease, in turn, determines the course of treatment.
There are three ways that cancer spreads through the body: tissue, lymph system, and blood.
- Tissue: The most localized way cancer can spread is by growing into nearby tissue.
- Lymph system: Cancer can also get into the lymph system and travel through the lymphatic vessels—a network of thin tubes that carry lymph and white blood cells—to other parts of the body.
- Blood: When cancer gets into the bloodstream, it can—as it does via the lymphatic vessels—travel from its place of origin to any other place in the body.
Metastasis is the medical term for when cancer spreads to another part of the body by breaking off from the original tumor where the cancer cells first developed and entering the lymph system or bloodstream. When tumors grow in other parts of the body, they’re still related to the same type of cancer as the initial tumor. So if cervical cancer spreads to the stomach, for instance, that’s referred to as metastatic cervical cancer, not stomach cancer.
These eight tests and procedures are used to determine how far a case of cervical cancer has progressed:
- Computerized axial tomography scan (CAT scan or CT scan): A CT scanner, essentially an x-ray tube, looks like a large doughnut standing on its sides. Patients lie on a narrow, motorized table that slides into the “hole” in the middle of the “doughnut.” The x-ray tube then rotates around to take a series of images from different angles around your body to create cross-sectional photos of the bones, blood vessels, and soft tissues inside the body. Sometimes, to help organs and tissues show up more clearly, a dye is injected into a vein or swallowed.
- Positron emission tomography scan (PET scan): A PET scanner looks similar to a CT scanner, and in some medical institutions, a combined CT-PET scanner is used. The purpose of a PET scan is to find malignant tumor cells inside the body. A small amount of radioactive glucose is injected into a vein. Then the PET scanner rotates around the patient’s body and takes pictures of where the glucose is being used in the body. Because malignant tumors use more glucose than healthy cells do, they’re clearly lit up in the resulting scans.
- Magnetic resonance imaging (MRI): Most MRI machines are, in simple terms, giant, tube-shaped magnets. The magnetic field inside the machine temporarily realigns hydrogen atoms inside the body, then radio waves cause those aligned atoms to give off faint signals which are used to create cross-sectional images of the body. An MRI machine can produce very detailed pictures of areas inside the body.
- Ultrasound exam: During most ultrasound exams, a technician presses a small, hand-held device called a transducer to the area of the body being examined. The device emits high-energy sound waves—ultrasounds—which bounce off internal tissues and organs, creating echoes. These echoes form an image called a sonogram that can be used for diagnostic purposes.
- Chest x-ray: In certain cases, a standard chest x-ray can be a useful tool for assessing how far cervical cancer has spread through the body. An x-ray is a kind of energy beam that can travel through the body and onto film, resulting in a picture of the inside of the body.
- Cystoscopy: This procedure uses a thin, tube-like instrument called a cystoscope to check the inside of the bladder and urethra for abnormalities. A cystoscope has a light and a lens for viewing, and in some cases, a tool to remove tissue samples, which are checked under a microscope for signs of cancer.
- Laparoscopy: This surgical procedure allows doctors to check organs inside the abdomen for signs of disease. A laparoscope, a thin, lighted tube, is inserted through small cuts in the abdomen. Different tools can be inserted through those same incisions to take tissue samples or even to remove organs.
- Pretreatment surgical staging: Typically done only as part of a clinical trial, this type of surgical procedure can determine whether cancer has spread within the cervix as well as to other parts of the body. Sometimes, cancerous tissue in the cervix can be removed at the same time.
Doctors use five stages to classify the progression of cervical cancer: carcinoma in situ (stage 0), stage I, stage II, stage III, and stage IV. Here’s some more detailed information about what differentiates the stages.
Carcinoma in Situ (Stage 0)
This is the most preliminary stage. When abnormal cells are found in the innermost lining of the cervix, doctors may diagnose that as carcinoma in situ, or stage 0, as there’s a chance those cells could become cancerous and spread to nearby, healthy tissue. In other cases, similar findings will be termed high-grade or severe cervical dysplasia.
The primary criteria for this stage is that cancerous cells are found only in the cervix and nowhere else in the body. This stage is divided into IA and IB, depending on how large the cancerous mass in the cervix has become. Each stage is then subdivided again into IA1 and IA2 and IB1 and IB2, again, depending on size.
In stage IA1 cervical cancer, a very small amount of cancerous tissue that can only be seen with the assistance of a microscope has been found in the cervix. The cancerous tissue is not more than 3 millimeters deep and not more than 7 millimeters wide. For reference, a sharp pencil point is about 1 millimeter wide, a new crayon point is about 2 mm wide, and a new pencil eraser is about 5 millimeters wide.
In stage IA2, the cancerous tissue is between 3 and 5 millimeters deep and as with IA1, not more than 7 millimeters wide.
In stage IB1, the size of the cancerous growth ranges from a minimum of 5 millimeters deep, 7 millimeters wide, and is visible only through a microscope up to a total size of 4 centimeters or smaller that’s visible without a microscope.
When a cancerous growth reaches stage IB2, it can be seen without a microscope and exceeds 4 centimeters in size.
By stage II, the cancer has spread beyond the cervix, but has not reached the lower third of the vagina or the pelvic wall. There are three subcategories to this stage: stage IIA1, stage IIA2, and stage IIB.
In stage IIA1, the cancer has spread into the upper two-thirds of the vagina, but not to the tissues surrounding the uterus. The tumor can be seen without a microscope but is not more than 4 centimeters in size.
The only difference between stage IIA1 and stage IIA 2 is that in the second, the tumor has grown larger than 4 centimeters.
By stage IIB, the cancer has spread to the tissues surrounding the uterus, but not to the pelvic wall.
In order for cervical cancer to progress to stage III, it must spread to the lower third of the vagina and to the pelvic wall, to begin to cause kidney problems, or any combination of the three. This stage is divided into IIIA and IIIB, depending on the how far the cancer has spread inside the body.
In stage IIIA, the cancer has reached the lower two-thirds of the vagina, but has not yet spread to the pelvic wall.
In stage IIIB, the cancer has either spread to the pelvic wall, or the tumor has become large enough to block the ureters (the tubes connecting the kidney to the bladder), or both. When the ureters are blocked, this interferes with kidney function, causing one or both kidneys to swell in size or to stop working altogether.
By stage IV, the final stage of cervical cancer, one, or more than one, of three things has happened. Either the cancer has spread beyond the pelvis, or the cancer can be seen in the lining of the bladder or rectum, or it has spread to other areas of the body. Again, in some cases, a combination of these may transpire.
Stage IV is split into stage IVA and IVB, based on which parts of the body the cancer has spread to. In stage IVA, the cancer has progressed solely to nearby organs, such as the bladder or rectum. In stage IVB, the cancer has spread farther, reaching places such as the intestines, liver, lymph nodes, lungs, or bones.
Cervical Cancer Treatment Options
Treatment options for cervical cancer depend on a number of factors, such as the type of cancer, the stage of cancer, the patient’s age, and the patient’s desire to have children. Cancer cachexia is a common condition that emerges in the face of advanced cancer, and can be treated with essential amino acids to help reduce muscle loss and improve outcomes. Read more about cancer cachexia and amino acids.
There are four standard types of treatment available for patients with cervical cancer: surgery, radiation therapy, chemotherapy, and targeted therapy. Other treatment methods are currently being tested in clinical trials. These research studies are designed to improve current treatments and to develop new, more effective treatments. When the results of a trial show that a new treatment can outperform one of the current standard treatments, it can end up becoming a standard treatment.
There are a number of different surgical operations that can be used to treat cervical cancer. Here’s a brief introduction to some of the top options.
Conization, also called a cone biopsy, can also be used to diagnose cervical cancer as well as to treat the early stages of cervical cancer. These procedures remove cone-shaped pieces of tissue from the cervix and cervical canal. We discussed two of these methods earlier as ways of diagnosing cervical cancer.
First, a cold-knife conization (or cone biopsy), during which a doctor uses a scalpel to remove the abnormal or cancerous tissue. For a loop electrosurgical excision procedure, or LEEP, a doctor uses a thin wire charged with an electrical current to achieve the same end. It’s also possible to use a laser beam to make bloodless cuts and remove abnormal growths. Doctors determine which method is best based on where the cancer cells are located in the cervix and the type of cervical cancer.
A total hysterectomy is used to remove the whole cervix as well as the entire uterus. When this is done by removing the uterus and cervix through the vagina, it’s called a vaginal hysterectomy. If they’re taken out through a cut made in the abdomen, it’s called a total abdominal hysterectomy. And if they’re removed using a laparoscope, the operation is called a total laparoscopic hysterectomy.
For a radical hysterectomy, not only are the cervix and uterus removed, but also part of the vagina and a wide swath of ligaments and tissues surrounding the organs. The ovaries, fallopian tubes, and nearby lymph nodes may also be removed.
A modified radical hysterectomy is quite similar, but not as many tissues or organs are removed.
When the cervix, nearby tissues, lymph nodes, and upper part of the vagina are removed, but not the uterus or ovaries, that’s called a radical trachelectomy.
A bilateral salpingo-oophorectomy is used to remove both ovaries as well as both fallopian tubes.
In some cases, a pelvic exenteration is needed. This surgery removes the cervix, vagina, ovaries, nearby lymph nodes, lower colon, rectum, and bladder. Artificial openings, called stoma, are created so that liquid and solid waste can be excreted into collection bags. Plastic surgery may be required as a follow-up surgery in order to create a vagina.
2. Radiation Therapy
This cancer treatment approach uses high-energy x-rays or other types of radiation to either kill cancer cells or to prevent them from growing. The type of radiation therapy used—either internal or external—depends on the type and stage of cervical cancer being treated.
External radiation therapy uses a machine located outside the body to direct radiation toward the cancer cells. There are ways to do this that prevent the radiation from damaging healthy tissue surrounding the cancer cells. One method, called intensity-modulated radiation therapy (IMRT), uses a computer to create pictures of the size and shape of the tumor. Thin beams of radiation with varying strengths are then directed at the tumor from multiple angles.
For internal radiation therapy, a radioactive substance is sealed in needles, wires, catheters, or small seeds that emit radioactive material as they break down. All these methods deliver the radioactive substance either directly into or adjacent to the cancerous cells.
This class of cancer-treating drugs either kills the cancer cells or prevents them from growing and dividing. There are different ways to administer chemotherapy drugs depending on the type and stage of cancer that needs to be treated. Regional chemotherapy, which can be administered directly into the cerebrospinal fluid, an organ, or a body cavity like the abdomen, targets cancer cells located in those specific areas. When the drugs enter the bloodstream, either because they’re taken orally or injected into a vein or muscle, that’s called systemic chemotherapy and it can be used to reach cancer cells throughout the body.
4. Targeted Therapy
This interesting treatment category includes several drugs or other substances that can identify and attack cancer cells without causing damage to healthy cells.
One such approach, called monoclonal antibody therapy, uses laboratory-made antibodies that can identify substances on cancer cells as well as substances that help cancer cells grow. The antibodies attach to the substances, which can prevent cancer cells from spreading, halt their growth, and even kill them.
A monoclonal antibody known as bevacizumab, for instance, binds to a specific substance—a protein called vascular endothelial growth factor (VEGF)—which stops the growth of new blood vessels, in turn preventing tumors from continuing to expand. This treatment is used for cervical cancer that has metastasized as well as for recurrent cervical cancer.
Monoclonal antibodies, which are injected into the bloodstream by intravenous infusion, can be used on their own or to carry drugs, radioactive material, or other toxins straight to cancer cells.
What About Clinical Trials?
For some patients, the best treatment option may be participating in a clinical trial. Because the results of potential new treatments need to be compared to the ones currently in use, patients who participate may receive the standard treatment or they may receive an experimental one.
Participating in clinical trials helps to improve the way cancer will be treated in the future. Some trials enroll only participants who have not yet received any treatment for their cancer, while others evaluate options for patients who have received treatment but whose cancer has not gotten better. Still more trials look at how to prevent cancer from coming back, as well as how to reduce the side effects of cancer treatments.
For more information on clinical trials, check out this database of privately and publicly funded studies being conducted around the world.