Laryngeal/Voice Box: Composed of vocal folds, muscles, and framework cartilages; key for voice, breathing, airway protection
Early Cancer: T1 = affects only one site on larynx, no spread, normal vocal fold motion; T2 = involves more than one site on larynx, vocal fold function abnormal but still moving
Advanced Cancer: T3 = complete non-movement of one vocal fold; T4=invades thyroid cartilage or structures outside of the voice box
T, tumor type; N, lymph nodes involved; M, spread to other body parts or metastasis
Vocal Folds (also called Vocal Cords): A pair of specialized tissues in the voice box that vibrates for sound production; comprised of ordered layers of epithelium, superficial lamina propria, vocal ligament, and thyroarytenoid muscle.
How is advanced laryngeal cancer diagnosed?
A physician specializing in throat disorders (otolaryngologist) can diagnose a tumor in the larynx.
Step 1: History and Physical Exam
The first step is to obtain a thorough history of the patient’s symptoms and perform a complete, careful physical examination (table exam, anatomy diagram) of the patient’s head and neck.
Step 2: Examination of the Voice Box
The voice box or larynx must be evaluated thoroughly. This evaluation can be done either with a mirror or with a thin flexible lighted fiberoptic scope that passes through the nose or the mouth into the back of the throat, allowing the physician to look down the throat into the larynx and entrance into the swallowing passage. There are also rigid, non-flexible telescopes that some physicians use for the same purpose. Although this examination may cause some anxiety on the part of the patient, it is actually well tolerated and usually does not cause much more than minimal discomfort for a very brief period of time. The examination using a scope is called laryngoscopy. (For more information, see Laryngoscopy/Stroboscopy.)
Step 3: Pathological Analysis of Tumor Tissue
If laryngoscopy detects a mass that may be cancerous, a biopsy will be performed. A biopsy involves a very fine needle inserted into the mass, usually without any significant discomfort, to obtain cells for analysis. These cells are analyzed under a microscope by a specialized physician (pathologist).
In some cases of advanced laryngeal cancer, an individual may have a tumor that has spread to the lymph nodes in the neck, causing a mass or swelling of the neck. A biopsy of the neck mass can usually be done without significant discomfort. If this mass has tumor cells, the physician can usually advise the patient if the cells most likely came from a primary tumor in the larynx. Treatment discussions can then begin without a trip to the operating room for a biopsy of the primary tumor in the larynx.
Step 4: Microlaryngoscopy
If the physician observes something suspicious upon examination, a better look at the mass will be necessary. The larynx can be examined with specialized instruments in the operating room, with the patient under anesthesia. While the patient is asleep, the physician can get a good look at the throat and biopsy any area that looks suspicious for cancer (abnormal size, shape, surface, etc.). This process is a usually referred to as direct laryngoscopy.
Direct laryngoscopy is done in the operating room for two reasons:
- A patient not under anesthesia will exhibit the gag reflex, preventing the physician from getting a good look at the mass or touching it with instruments. Direct laryngoscopy allows the region to be examined in great detail. Soft tissue can be moved with instruments for better visualization.
- During a direct laryngoscopy, a biopsy of the lesion can be taken. This will give the physician a better idea of the extent of the tumor and its involvement with surrounding structures in the larynx.
- After direct laryngoscopy, the patient usually goes home the same day without much discomfort. The pathology reports from the biopsies often take four to five days for processing. The report is given to the physician for discussion with the patient.
Pathology Analysis of Specimen Key to Cancer Diagnosis
The main way that cancer is diagnosed is through pathology analysis of a biopsy specimen or the excised tumor itself. Briefly, pathology analysis involves the highly magnified study of the tissues under a microscope. Pathology analysis determines whether cancer cells (which look different than normal cells) are present.
While clinical examination and scans are important in determining the extent of a tumor, the actual diagnosis can only be made when a biopsy is taken from a suspicious area and examined by a pathologist.
- A pathologist can give the surgeon an approximate diagnosis within an hour of a biopsy submission, using a technique called “frozen section analysis.” However, a more reliable pathologic diagnosis takes longer – about four to six days – because of the necessary preperation time of biopsy section slides for the pathologist to examine.
Because of Technique limitations, tumor stage is upgraded (upstaging) after pathology analysis in 20 to 30 percent of cases.
- Sometimes, pathology analysis of a tumor and/or lymph nodes will reveal that the tumor had spread more extensively than was initially apparent to the physician, since a lymph node may be of normal size but have cancer cells.
- This discovery results in an “upstaging” from one TNM stage to a higher one. When this occurs, it is important to realize that the initial TNM stage was not a “mistake,” but rather a result of the limitations of the diagnostic techniques available today. An estimated 20 to 30 percent of head and neck cancer cases are upstaged.
What are some future directions in cancer diagnoses?
Several innovations are currently in practice or are being tested to improve our ability to diagnose laryngeal cancer.
Emerging Role of PET Scans in Detecting Cancer
The use of PET scans (positron emission tomography) in cancer detection is gaining wider application and acceptance in the medical cancer field. A PET scan, a nuclear medicine technique, can detect cancer cells by discerning the higher metabolic rate in cancer cells compared to other cells in the body.
Basis of the PET Scan
A radioactive sugar, injected into a patient’s vein, becomes concentrated in tumor cells because their metabolism is higher than that of normal cells. A PET scan takes an x-ray of the area of the body that is of concern. Tumor cells “light up” on the x-ray film because of their concentrated radioactivity.
Combination CT Scan + PET Scan
Some medical centers have a combined CT (computed tomography) scanner and PET (positron emission tomography) scanner, enabling the use of both scanning technologies simultaneously. Adding a CT scanning image to PET image – a CT-PET fusion image – provides superior localization of cancer lesions and gives greater information about its association with surrounding structures. Combination CT-PET fusion scans may play a more important role in detecting repeat cancers than in the initial detection of a tumor.
Molecular Margin Analysis
Identifying Cancer Cells Earlier and More Accurately
A major thrust of cancer research has been the enhancement of early detection of cancer cells. Early detection leads to early treatment, which in turn leads to better control or cure of cancer.
A Promising New Technique
Molecular margin analysis is one promising technique now being examined in a large, multi-center study. Molecular margin analysis involves a very sensitive laboratory technique that can detect altered or cancerous DNA in cells. When this test is applied to the edges of the tumor after surgical removal, it can detect cancer cells more accurately than current-day microscopic exam by an experienced pathologist.
Time to Full Application Still a Hurdle to Overcome
One of the main obstacles to molecular margin analysis is the time that the laboratory takes to detect cancerous, altered DNA in the margins. This delay makes it difficult for the surgeon to immediately excise more tissue to ensure that all of the cancer is removed. However, faster techniques, which have very recently been developed, make routine use of molecular margin analysis a possible addition to pathologic evaluation of tissues removed at surgery.
Any and all airway problems require immediate attention
Patient education material presented here does not substitute for medical consultation or examination, nor is this material intended to provide advice on the medical treatment appropriate to any specific circumstances.
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