Diseases & Conditions

Building Cancer Diagnosis

When a person shows symptoms of cancer, it is in his or her best interest to see a doctor immediately. Though the symptoms he or she may be experiencing are a sign of the presence of cancer, there is no way of knowing for sure until a doctor performs a proper diagnosis. Diagnosing cancer may require several tests to be performed, including blood tests and x-rays. When each successive leads a doctor to believe that cancer is present, the doctor will then perform a biopsy. A biopsy is considered, in most cases, to be the sure way to tell if a patient has developed cancer or not. Imaging tests on the other hand, such as x-rays and MRIs, can show the size and spread of the cancer.

The reason why doctors do not perform a biopsy right from the start is because they need more information first so that they can pinpoint the problematic area. First, the doctor may begin imaging test depending on the nature and location of the patient's symptoms. The imaging test will help show abnormalities that may be present in the area where the symptoms are experienced. In addition, a doctor may make a decision to perform a blood test as well. A lot of information can be gathered from a blood test. The content of the blood will show how well each organ in the body is working and if there are any abnormalities, the problem can usually be pinpointed to one organ or area of the body. Once a doctor has discovered an abnormality using these methods, successive imaging tests can provide further detail in that location. A biopsy can then be performed. The biopsy can usually be tough to perform and doctors usually avoid invasive procedure before they know enough information. In some cases, imaging tests and biopsies can be performed all in one procedure.

Imaging Tests

There are several types of imaging tests that can be performed on patients, all utilizing different technologies and capabilities. They all have advantages and disadvantages, while some can only be used on certain parts of the body. The decision to use one or over another depends on the situation of the patient.

MRI Scan:

An MRI scan is a type of imaging technique which allows a doctor to observe a detailed image of the internal structure of the body. The MRI scan has proven to be a useful imaging technology, developed in the 1970s as an alternative to CT scans. The contrast between different types of tissues and bones is unparalleled to other imaging techniques and is preferred by a lot of doctors. In addition, MRI tests are considered to be safer as well because they do not use potentially dangerous ionizing radiation to create images which CT scans use. Utilizing the high hydrogen content of organisms, MRIs use powerful magnets to align the nuclear magnetization of the hydrogen atoms. Then radio frequency fields are activated, changing the alignment of the magnet, and in turn, rotating the magnetic fields of the hydrogen atoms. This rotation is then picked up by the MRI, creating the detailed images.

The MRI machine consists of three main components--The primary magnet, gradient magnets, and the coil. The primary magnet is the largest part of the machine and is responsible for creating the strong magnetic field that wraps around the patient. The magnetic field is about 1.5 to 3 Tesla, about 20,000 greater than the strength of earth's magnetic field. The gradient magnets are three smaller magnets which fine-tune the magnetic field to specific parts of the body. The coil wraps around the area of the body which is being imaged. It is responsible for emitting the radiofrequency, allowing the image to be formed. These machines are operated by MRI technicians, and can be used for basic MRI scans and MRI contrast scans as well.

CT Scan:

A CT scan, also known as a computed tomography, is an advanced x-ray imaging tool, which is capable of taking multiple image cross sections of a patient's body. A CT scan will show a patient's soft tissues, blood vessels, and bones. CT scans are capable of picking up images which cannot be shown on a normal x-ray, and as a result, a CT scan is an instrumental tool for finding tumors which would normally go unnoticed. A CT scan uses radio waves to pick up images inside a patient, and though many believe that CT scans come with long-term negative effects, the procedure is considered to be relatively safe. In fact, most researchers feel that the benefits of CT scans greatly outweigh any chance of negative effects from receiving one.

The primary use of a CT scan is to scan and image the area from the chest to the abdomen. Its unique ability to image organs, bone, and blood vessels makes it instrumental for finding cancers early. CT scans have proven to be an effective tool against certain forms of extremely deadly cancers. These include lung cancer, which is normally found in later stages, and pancreatic cancer, also found in later stages. The CT scan could help doctors find these cancers in their earlier, treatable forms. In addition, CT scan technology is being improved all the time, allowing for more advanced images to be taken and in a quicker amount of time. CT scans take only a fraction of the amount of time to complete than an MRI scan.

Ultrasound:

An ultrasound is a device that is used in a variety of ways so that doctors can examine the inside structure of a person's body. It uses sound waves which are of a frequency well beyond what a human ear can pick up. The sound waves deflect off organs, bones and other structures inside a patient's body and a computer converts these "echoes" into an image that is placed on a monitor. An ultrasound is useful in cancer diagnosis because sound waves generally bounce off of tumors in a different manner and is displayed differently on the monitor. There are several types of ultrasounds that have been developed to examine parts of the human body for cancer:

Transvaginal ultrasound

Breast ultrasound

Transrectal ultrasound

Endoscopic ultrasound

The endoscopic ultrasound is especially important because it is a smaller version of the ultrasound attached to a device called an endoscope. The endoscope can be inserted into the air passages or esophagus of a patient through the mouth or nose. This can be used to find a variety of different cancers, such as esophageal cancer, pancreatic cancer, or lung cancer. It is more effective than placing an ultrasound device outside of a person's skin because it gets closer and as a result, it picks up more detailed images.

PET Scan:

A PET scan is a very useful tool in diagnosing cancer in patients. In most cases, PET scans are used to diagnose tumors, heart disease, and infections of the nervous system. A PET scan uses radiation to produce a very detailed image of the part of the body that is being examined. Different tissues and nerves are usually highlighted by a spectrum of contrasting colors so that they can be easily distinguished and identified. Normally, a tumor will produce a different color than surrounding healthy tissue. PET scans are also useful because they can be combined with CT scans so that a clearer, more defined image can be produced for examination. 

There are some disadvantages of a PET scan. It uses about the same amount of radiation as having two x-rays at once. Though this is a relatively low amount of radiation, especially compared to a CT scan, this can come with some risks for people who are exposed to radiation at work or other places. Also, PET scans cost a lot of money as well as the machines needed to perform the scan are very expensive, limiting their use.

Blood Tests

Blood tests are very useful to physicians in assisting the cancer diagnosis of a patient. There are many blood tests that can be done, each detecting the presence and levels of chemicals within the patient's blood. If a level of a certain chemical is above or below normal, a doctor can usually narrow down the reasons for this be attributing its cause to one or two organs. This may mean that something is wrong with the organ, and a cancer may be present. Irregular blood levels do not always mean that cancer has developed inside a person, as the irregular levels may be caused by infections or other reasons. For this reason, blood tests are only used to help narrow down possible reasons if a patient is experiencing symptoms.

The following are different blood tests that are performed to help detect the presence of cancer:

Complete Blood Count

Blood Protein Test

Tumor Marker Test

Biopsy

There are several different ways a biopsy can be performed. In any of these types of procedures, a biopsy involves taken a sample of tissue from an area that a doctor believes may be cancerous or contain cells that are precancerous. The tissue sample is then examined under a microscope to determine the cause of symptoms. If enough tissue samples are collected and a pathologist diagnoses the sample, the results of the biopsy should be conclusive and accurate. This is usually the final judgement when cancer is suspected to be present in a patient.

Years ago, technology only allowed biopsies to be performed through surgery, which was usually invasive in nature. This meant that the patient needed time to recover after the biopsy and the surgery was often risky. Today, biopsies can be performed while avoiding this invasive technique through several different methods.

Fine Needle Aspiration

Core Needle Biopsy

Endoscopic Biopsy

Excisional Biopsy

Punch Biopsy

Some biopsies are done during other diagnosing techniques. An endoscopic biopsy is done while a doctor examines a person's internal organs through an endoscope. A biopsy can also be done after a tumor is removed from a patient to determine the nature of the tumor and whether or not it is malignant. 

Pap Smear

A pap smear, often referred to as a pap test, is a diagnostic method involving the removal of cells from the vagina, uterus, and cervix to be examined under a microscope. A specially trained pathologist can then determine whether or not the cells that were removed are abnormal.  If they are found to be abnormal, they may be in a precancerous stage and treatment can be performed to prevent cancer from forming. The most common form of cancer which can be found from a pap smear is cervical cancer, caused by the human papilloma virus. A pap smear, while essential for diagnostic purposes, is also a common screening test, performed routinely on women by gynecologists. 

With the development of the pap smear test, cervical cancer cases have dropped dramatically by over 70 percent. Using this diagnostic test, the five year survival rate for cases of cervical cancer, or precancerous conditions which could lead to cancer, are about 90 percent. Most cases of advanced forms of cervical cancer are due to a woman not receiving regular pap smear tests.