Surgery – Diagnostic testing – Sampling nonliquid body material
Reexamination Certificate
2001-05-04
2002-12-17
Walberg, Teresa (Department: 3742)
Surgery
Diagnostic testing
Sampling nonliquid body material
C604S001000, C606S161000
Reexamination Certificate
active
06494845
ABSTRACT:
FIELD OF THE INVENTION
The present invention is directed to a method and apparatus for obtaining transepithelial specimens of body surfaces using a non-lacerating technique. Specifically, the invention is directed to retractable tools such as a brush, used with endoscopes, for sampling squamous epithelium from lesions found from the nose to the throat and in similar body tissues. The invention is also directed to an improved apparatus for non-lacerational testing of lesions that involve the epithelium of the nasopharynx, hypopharynx, pharynx, trachea, larynx, and the upper esophagus.
BACKGROUND OF THE INVENTION
Cancers of the oral cavity and pharynx are a major cause of death from cancer in the U.S., exceeding the U.S. death rates for cervical cancer, malignant melanoma and Hodgkin's disease. According to the American Cancer Society's Department of Epidemiology and Surveillance, an estimated 30,750 new cases of oral cancer were diagnosed in the U.S. during 1997, a figure which accounts for 2% to 4% of all cancers diagnosed annually.
Despite advances in surgery, radiation, and chemotherapy, the mortality rate of oral cancer has not improved in the last 20 years. Ultimately, 50% of patients die from their malignancy, and 8,440 U.S. deaths were predicted for 1997. There are several reasons for the high mortality rate from oral cancer, but undoubtedly, the most significant factor is delayed diagnosis. Studies have demonstrated that the survival and cure rate increase dramatically when oral cancer is detected at an early stage. For example, the 5-year survival rate for patients with localized disease approximates 79% compared to 19% for those with distant metastases. Unfortunately, approximately two thirds of patients at time of diagnosis have advanced disease, and over 50% display evidence of spread to regional lymph nodes and distant metastases.
Delay in the diagnosis of oral and pharynx cancer is often the result of the limited diagnostic tools available in the prior art. The dentist or physician who detects such a lesion which is not clearly suggestive of a precancer or cancer clinically, and who is limited to the prior art tools and methods, is faced with a quandary. Approximately 5-10% of adult patients seen in a typical dental practice exhibit some type of oral lesion, yet only a small proportion (approximately 0.5% to 1%) are precancerous or cancerous. These oral lesions are commonly evidenced as a white or reddish patch, ulceration, plaque or nodule in the oral cavity. The overwhelming majority of these lesions are relatively harmless; however, the multitude of poorly defined lesions in the oral cavity can be confounding to the clinician. A diverse group of oral lesions may be easily confused with malignancy, and conversely, malignancy may be mistaken for a benign lesion. Benign tumors, reactive processes, traumatic lesions, oral manifestations or systemic diseases, inflammatory oral disorders, and bacterial, viral and fungal infections all display similar oral features thereby impeding establishment of an accurate clinical diagnosis.
The only reliable means currently available in the prior art to determine if a suspect oral lesion is pre-cancerous or cancerous, is to incise or excise (i.e. lacerate) the lesion surgically with either a scalpel or a laser so that a histological section of the removed tissue can be prepared for microscopic evaluation. Histology can be generally defined as the microscopic inspection or other testing of a cross section of tissue. This prior art form of oral surgical biopsy is generally performed by a surgeon, and is often inconvenient, painful, and expensive.
Since the majority of oral abnormalities detected clinically prove benign when tested microscopically, and given the limitations of biopsy, including cost, inconvenience, pain and potential for complications, relatively few oral lesions are subjected to biopsy. It is primarily for this reason that only oral lesions with clinical features strongly suggestive of cancer or precancer are referred for biopsy as described in the prior art. As a result, many patients with ominous, but visually less suggestive lesions are allowed to progress to advanced oral cancer, with their condition undiagnosed and untreated.
The oral epithelium is substantially identical to the epithelium of the nasopharynx, hypopharynx, pharynx, trachea, larynx, and the upper esophagus. As a result, otolaryngology currently suffers from the effects of the same diagnostic dilemma which affects dentistry, i.e. the inability to clinically distinguish between common benign-appearing lesions and identically appearing pre-cancerous and early cancerous lesions. Thus, the only two cancers in the U.S. which have not improved in mortality in the last thirty years are oral cancer and laryngeal cancer.
In many environments including those identified above, endoscopes are used to examine interior parts of the body which are inaccessible to ordinary visual observation. Observation of these inner parts with an endoscope is for purposes of locating pathological areas, trying to identify them using the endoscopic visual instrument and determining how to diagnose and treat such visualized areas.
Potential abnormalities in various portions of the body may be apparent to a visual observer because of certain lesions appearing at the visualized tissue in the organ or area being observed.
Common, benign-appearing nose and throat lesions are usually noticed by the otolaryngologist during a routine, office examination of the throat which is typically conducted using a type of endoscope, known as a flexible nasopharyngoscope. This thin optical tube is easily threaded from the patent's nose into the throat and requires only a local anesthetic sprayed into the nose. This routine office procedure is performed by the average otolaryngologist many times each day.
The diagnostic dilemma for the otolaryngologist that is posed by the identical appearance of benign and pre-cancerous lesions is actually more acute than it is for the dentist. Although invasive and therefore avoided, a scalpel biopsy of the oral cavity is typically performed as an office procedure. Only local anesthetic is required, and bleeding from a scalpel biopsy of the oral cavity does not pose any aspiration danger. In contrast, a scalpel biopsy in many areas of the throat cannot be performed as an office procedure. This is because a scalpel biopsy in many areas of the throat may result in potentially dangerous aspiration of blood if the procedure is not performed under general anesthesia.
Referral of the patient for an operating room procedure requiring general anesthesia is both expensive and intrusive, and may expose the patient to other risks such as anesthesia and infection risk. The otolaryngologist is therefore hesitant to scalpel biopsy most benign-appearing throat lesions although they may represent the most treatable stage of a pre-cancer or cancer.
In many body sites, but not the oral cavity, a technique known as cytology is commonly utilized as an alternative to performing a lacerating biopsy and histological evaluation. In these body sites, pre-cancerous and cancerous cells or cell clusters tend to spontaneously exfoliate, or “slough off” from the surface of the epithelium. These cells or cell clusters are then collected and examined under the microscope for evidence of disease.
Since prior art cytology is directed towards the microscopic examination of spontaneously exfoliated cells, obtaining the cellular sample is generally a simple, non-invasive, and painless procedure. Exfoliated or shed cells can often be obtained directly from the body fluid which is contiguous with the epithelium. Urine can thus be examined for evidence of bladder cancer, and sputum for lung cancer. Alternatively, exfoliated or shed cells may be obtained by gently scraping or brushing the surface of a mucus membrane epithelium to remove the surrounding mucus using a spatula or soft brush. This is the basis for the well known procedure known as the Pap smear used to detect early stage c
Campbell Thor
Levisohn, Lerner, Berger & Langsam LLP
Oralscan Laboratories, Inc.
Walberg Teresa
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