Surgery – Diagnostic testing – Sampling nonliquid body material
Reexamination Certificate
1999-07-23
2001-07-10
O'Conner, Cary (Department: 3736)
Surgery
Diagnostic testing
Sampling nonliquid body material
C600S562000
Reexamination Certificate
active
06258044
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 tools for sampling squamous epithelium from lesions found in the oral cavity and in similar body tissues. The invention is also directed to an improved method of testing all lesions that involve the epithelium of the oral cavity and/or similar body tissues.
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 cancer is often the result of the limited diagnostic tools available in the prior art. The dentist or physician who detects an oral 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. Furthermore, since the greatest number of oral cancers develop on the lateral border of the tongue and floor of the mouth, the difficulty and potential complications of biopsying these lesions, including pain, bleeding, and scar formation, can be significant. Not infrequently, biopsy is delayed either by the patient due to fear of the procedure, or by the clinician due to technical difficulty in obtaining an adequate specimen.
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.
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 cervical cancer.
Because of the ease by which a cellular sample can be obtained from these body sites, prior-art cytology is typically utilized to screen asymptomatic populations for the presence of early stage disease. In the cervical Pap smear, for example, the entire surface area of the cervical regions where cancer generally occurs is gently scraped or brushed to collect and test the mucus from those regions. Abrasion of the underlying cervical epithelium is undesired, as it can cause bleeding and discomfort to the patient. This procedure is thus typically performed when no particular part of the cervix appears diseased, and when no suspect lesion is visible.
The design of prior art cytology sampling instruments reflects their use to sweep up cells which were spontaneously exfoliated and present on the superficial epithelial surface. Since prior-art cytology brushes need only to gently remove surface material, they are designed of various soft materials which can collect the cervical mucous with minimal abrasion to the underlying epithelium. These cytology sampling instruments therefore either have soft bristles, soft flexible fimbriated or fringed ends, or even, as in the case of the cotton swab or spatula, no bristles at all.
Examples of prior art cytological sampling tools include the wooden, metal or plastic spatula. According to the traditional method of Pap smear sampling, the spatula is placed onto the surface of the cervix and lightly depressed or scraped across the surface of the cervix to pick up exfoliated cells.
Further examples of prior art cytological sampling tools include the Cytobrush®; a device which uses soft and tapered bristles to sample shed cells from the cervical canal. U.S. Pat. No. 4,759,376, which allegedly covers this product, likewise describes a conical tapered soft bristle brush (a mascara brush shape) which is placed into the cervical canal and rotated for endocervical sampling. U.S. Pat. No. 4,759,376 teaches that the bristles “are to be relatively soft such as that of a soft toothbrush to more readily bend and avoid damaging the tissues.” By way of further example, physicians have long used the common swab, commercially known as the Q-Tip®, to perform endocervical sampling.
Other prior art cytological sampling tools designed to obtain a cytological sample from the cervix may combine both endocervical and exocervical sampling regi
Lonky Neal M.
Papadopoulos Jeremy James Michael
Levisohn, Lerner, Berger & Langsam
Marmor II Charles
O'Conner Cary
Oralscan/Trylon Joint Venture
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