Surgery – Radioactive substance applied to body for therapy – Radioactive substance placed within body
Reexamination Certificate
2002-04-23
2003-11-25
Gilbert, Samuel G. (Department: 3736)
Surgery
Radioactive substance applied to body for therapy
Radioactive substance placed within body
Reexamination Certificate
active
06652442
ABSTRACT:
RELATED APPLICATION
There are no related applications.
FIELD OF INVENTION
The present invention is generally directed toward the treatment of breast cancer and more specifically toward the intraductal brachytherapy treatment of abnormal tissue and cells in the mammary breast ducts of women by placing a cartridge containing seeds or a construct which is treated to produce localized radiation via a cannula at the duct tissue site.
BACKGROUND OF THE INVENTION
A leading disease incurred by women is breast cancer. Breast cancer is the second leading cause of death for women of all ages and the leading cause of death for women aged 25-55 with approximately one in eight women incurring breast cancer in their lifetimes. Approximately 220,000 surgeries are performed annually in the United States with almost 20 percent requiring the complete removal of the breast. The current medical standard for determining breast cancer in women is mammography. For breast cancer detection, other than clinical examination and self-examination, women rely almost exclusively on mammography. It is estimated that more than 30 million mammograms are performed each year in the U.S. alone. Mammography is so insensitive that typically the average size of the tumor detected is ranges between 1 and 2 cms. At approximately 1.5 cm. size, a tumor has probably been growing, undetected, for nearly 8 years on average. In fact, two-thirds of mammographically detected breast cancer is invasive. In addition, mammography is notorious for “false positive” readings, which lead to many unneeded biopsies. However mammography fails to detect up to 20% of breast cancers in women over 50 and up to 40% of breast cancers in younger women.
Medical researchers have long recognized that nearly all breast cancer originates in the epithelial lining of the mammary duct system. Furthermore, it is well established that, in its early stages, most breast cancer develops very slowly and remains confined to the mammary ducts for up to 7-10 years. If these very early stages of premalignant and malignant disease could be detected and treated while the cancer is within the mammary duct system, the result would be a substantially better medical treatment outcome.
After detection breast cancer is generally treatable in three ways: surgery, radiation and chemotherapy. Surgery and radiation, of course, have risks and disadvantages well known to those skilled in the art. Chemotherapy also can be particularly disadvantageous as, for example, when the drugs involved cause sickness to the patient when they enter the blood stream.
Today's primary treatment of breast cancer is traditional surgery, either mastectomy or lumpectomy with radiation therapy. Surgery is, by definition, invasive and traumatic. Because the exact margins of cancerous growth are difficult to pinpoint, a surgeon may remove more breast tissue than is necessary or not remove enough.
Breast tumors are often treated with a combination of tumor removal (lumpectomy) followed by external beam radiotherapy to the whole breast. This has been found in several studies to result in the same cure rate as total breast removal. Surprisingly, only one third or so of women choose to keep their breast. One of the reasons for this low number may be that the external radiotherapy can take as long as 7 weeks to give, and this can be too much time away from home or work for some women.
Internal source radiation therapy (referred to as brachytherapy) places capsules of radioactive material inside the patient in proximity to the tumorous tissue. Brachytherapy is a general term covering medical treatment which involves placement of a radioactive source near a diseased tissue and may involve the temporary or permanent implantation or insertion of a radioactive source into the body of a patient. The radioactive source is thereby located in proximity to the area of the body which is being treated. This has the advantage that a high dose of radiation may be delivered to the treatment site with relatively low dosages of radiation to surrounding or intervening healthy tissue.
Dose and placement are accurately controlled by the physical positioning of the isotope. Cancer Treatment Centers of America has a treatment program that uses 5 days of brachytherapy (temporary radiation implant) instead of 5-7 weeks of external beam radiotherapy. This shorter time period is of a great benefit to all patients, but especially working women, those who live a distance away from a treatment center as well as those who just want to get the treatment over with as quickly as possible. So far, three hospitals in North America have published early results using similar techniques (Breast Brachytherapy). Each has so far reported a 98%-100% tumor control rate in the breast.
Some of the potential benefits of intraductal brachytherapy are:
1. The entire treatment takes days instead of weeks.
2. The radiation dose is concentrated in the area of the mammary duct where the DCIS is located thus less radiation will reach the skin, lungs, heart, ribs, the healthy part of the breast, and the body as a whole.
3. Because the treatment is so short, the intraductal brachytherapy can be given before chemotherapy is started (if chemotherapy is required). Radiation appears to be more effective if it can be given earlier rather than later.
Although brachytherapy is a proven treatment for cancer, using brachytherapy instead of external beam radiation for intraductal breast cancer is a recent idea. Benign conditions that can lead to abnormal intraductal assessment include intraductal papilloma, hyperplasia and atypical ductal hyperplasia and these can be removed without requiring invasive surgery. Likewise, hormonal therapies, and pharmaceutical agents (Tamoxifen) may control the growth of intraductal cancerous lesions. All women should have biopsies or intraductal samplings (lavage) that document the presence of atypia or malignant disease before an intraductal brachytherapy procedure is performed. The mammary duct should also be assessed by office ductoscopy to exclude the possibility of intraductal papiliomas, which can be treated with a simple resection. In addition, mama ductoscopy may reveal women who have multi-focal abnormal epithelia tissue and thus may be candidates for more extensive intraductal therapy.
Brachytherapy has been proposed for use in the treatment of a variety of conditions, including arthritis and cancer, for example breast, brain, liver and ovarian cancer and especially prostate cancer in men (see for example J. C. Blasko et al., The Urological Clinics of North America, 23, 633-650 (1996), and H. Ragde et al., Cancer, 80, 442-453 (1997)). Treatment may involve the temporary implantation of a radioactive source for a calculated period, followed by its subsequent removal. Alternatively, the radioactive source may be permanently implanted in the patient and left to decay to an inert state over a predictable time. The use of temporary or permanent implantation depends on the isotope selected and the duration and intensity of treatment required.
Examples of permanently implantable sources include Iodine-125 or Palladium-103 as the radioisotope. The radioisotope is generally encapsulated in a titanium casing to form a “seed” which is then implanted. Temporary implants for the treatment of prostate cancer may involve Iridium-192 as the radioisotope.
Conventional radioactive sources for use in brachytherapy include so-called “seeds”, which are smooth sealed containers or capsules of a biocompatible material, for example of metals such as titanium or stainless steel, containing a radioisotope within a sealed chamber but permitting radiation to exit through the container/chamber walls (U.S. Pat. No. 4,323,055 and U.S. Pat. No. 3,351,049). Such seeds are only suitable for use with radioisotopes which emit radiation which can penetrate the chamber/container walls. Therefore, such seeds are generally used with radioisotopes which emit gamma.-radiation or low-energy X-rays, rather than with .beta.-emitting radioisotopes.
In brachytherapy
Acueity, Inc.
Gilbert Samuel G.
Olson & Hierl Ltd.
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