Ablative Technologies in Gynecology

(From “Ablation Technologies Worldwide Market, 2009-2019”, report #A145)

There are several conditions in the field of gynecology that lend themselves well to ablative technologies. These include menorrhagia, or excessive menstrual bleeding; fibroids; and cervical dysplasia. Stress incontinence has also been included under the heading of gynecology because it is primarily a disorder of women who have borne children.

Menorrhagia

Menorrhagia is defined as menstruation at regular cycle intervals but with excessive flow and duration. Clinically, menorrhagia is defined as total blood loss exceeding 80 ml per cycle or menses lasting longer than seven days. It is one of the most common gynecologic complaints. It may be caused by abnormal blood clotting, disruption of normal hormonal regulation of periods or disorders of the endometrial lining of the uterus.

The World Health Organization reports that 18 million women aged 30-55 years perceive their menstrual bleeding to be exorbitant. Reports show that only 10% of these women experience blood loss severe enough to cause anemia or be clinically defined as menorrhagia. In practice, measuring menstrual blood loss is notoriously difficult; therefore the diagnosis is usually based upon the patient’s history.

Current and Emerging Treatment Trends.

Current treatments are either pharmaceutical or surgical. Pharmaceutical therapies include insertion of an intra-uterine device (IUD), non-steroidal anti-inflammatory drugs (NSAIDs), and combined oral contraceptive pills to prevent proliferation of the endometrium. Injected progestogen (e.g. Depo provera) or gonadotrophin-releasing hormone (GnRH) agonists (e.g. Goserelin) may also be prescribed.

Surgical and radiological treatments include endometrial ablation, uterine artery embolization (UAE), hysteroscopic myomectomy to remove fibroids over 3 cm in diameter, or hysterectomy. A dilation and curettage (D&C) is generally no longer performed for cases of simple menorrhagia, although it may be used for diagnostic purposes. It is not used for treatment because it provides only short-term relief, on the order of 1-2 months. Most of the surgical treatments destroy the lining of the uterus, thus preventing the woman from being able to bear more children.

Transcervical resection of the endometrium (TCRE) has been considered the criterion standard cure for menorrhagia for many years. This procedure requires the use of a resectoscope (i.e., hysteroscope with a heated wire loop), and it requires time and skill. The primary risk is uterine perforation

Roller-ball endometrial ablation essentially is the same as TCRE, except that a heated roller ball is used to destroy the endometrium, instead of a wire loop. It has the same requirements, risks, outcome, success and satisfaction rates as TCRE.

Hysterectomy provides a definitive cure for menorrhagia. This procedure is major surgery, is more expensive and results in greater morbidity than ablative procedures. It also leaves the woman unable to bear children and puts her body immediately into menopause, which may entail prescription of hormone therapy.

Applicable Ablation Technologies: Rationale for Use and Effect on Tissues.

There are a number of ablation technologies now in use for the treatment of menorrhagia. These include endometrial laser ablation, thermal balloon therapy, the HydroThermAblator, cryoablation, microwave ablation and the NovaSure RF ablation system.

Endometrial laser ablation requires Nd:YAG laser equipment and optical fiber delivery system. The laser is inserted into the uterus through the hysteroscope while transmitting energy through the distending media to warm and eventually coagulate the endometrial tissue. Disadvantages include the high expense of the equipment, the lengthy time required for the procedure, and the risk of excessive fluid uptake from the distending media infusion and irrigating fluid. Endometrial laser ablation has largely been replaced by the nonresectoscopic systems.

In thermal balloon therapy, a balloon catheter filled with isotonic sodium chloride solution is inserted into the endometrial cavity, inflated, and heated to 87°C for 8 minutes. Uterine balloon therapy cannot be used in irregular uterine cavities because the balloon will not conform to the cavity. Studies report a 90% satisfaction rate and a 25% amenorrhea rate. Long-term studies are ongoing.

The HydroThermAblator (HTA) is an office procedure in which heated normal saline is infused into the uterus via the hysteroscope. The solution is heated to 194°F (90°C) for 10 minutes under direct visualization. This procedure requires only local anesthesia, and may be used in patients with irregularly shaped endometrial cavities and/or fibroids. The most reported complications are vaginal and skin burns.

Cryoablation uses liquid nitrogen to freeze the endometrium. The procedure is performed in approximately 10 minutes under ultrasound guidance. Patients usually experience 1 week of watery vaginal discharge following the procedure. Risks include perforation and suboptimal ablation of the entire uterine cavity.

Microwave endometrial ablation (MEA) uses high-frequency microwave energy to cause rapid but shallow heating of the endometrium. MEA requires 3 minutes of time and only local anesthetic. It is proving to be as effective as TCRE. This procedure was developed and has been used in Europe since 1996.

The NovaSure Radiofrequency system is a detailed microprocessor-based unit with a bipolar gold mesh electrode array. It contains a system for determining uterine integrity based upon the injection of CO 2. The device is placed transcervically, the array is opened and electrical energy is applied for 80-90 seconds, desiccating the endometrium.

Fibroids

Fibroids, which are also known as myomas or leiomyomas, are extremely common benign tumors of the uterus which can substantially impact quality of life. Symptoms can include heavy or irregular menstrual bleeding, pelvic cramps, urinary frequency or urgency, and infertility or pregnancy loss. According to the U.S. Dept. of Health & Human Services, 25% of all women (16 million) suffer from fibroid symptoms, leading to 250,000 annual hysterectomies. The problem is so widespread that as much as 33% of all U.S. women have undergone hysterectomy by age 60, with fibroids being the most common reason.

As many as one out of five women in the U.S. suffer from fibroids, according to the National Institutes of Health. Women can take drugs, or opt for a get a surgical procedure, but until recently gynecologists told patients that the only real cure was major surgery: a hysterectomy. About 625,000 women get hysterectomies in the U.S. each year; about half of these procedures are conducted to treat uterine fibroid growths that cause painful cramping and bleeding,

Current and Emerging Treatment Trends.

Current fibroid therapies include watchful waiting (i.e. no treatment), hysterectomy, myomectomy, uterine artery embolization and hormone therapy. Watchful waiting is the most common approach due to the lack of satisfactory alternatives. Hysterectomy is the current gold standard treatment, but it is major surgery requiring 4-6 weeks of recovery, and it destroys the woman’s fertility. Consequently, many women suffer with fibroids for years because they wish to avoid hysterectomy.

Myomectomy can be useful in women who wish to retain their uterus and/or fertility. It refers to the surgical removal of uterine fibroids. In contrast to a hysterectomy the uterus remains preserved and the woman retains her reproductive potential. Since myomectomy can be associated with large blood loss, this procedure is often reserved for cases of a single or few fibroids. Risks include large blood loss or recurrence of fibroids.

Hormone therapy is another option, but this includes menopausal side effects such as hot flashes and osteoporosis, and the fibroids return if the medication is stopped. The fibroids may be removed surgically in a procedure called a myomectomy, depending upon where in the uterus the fibroids are located. This procedure is expensive, requires 2-4 weeks of recovery, and relatively few gynecologists have the training to perform the surgery.  Uterine artery embolization requires an overnight hospital stay and the involvement of a radiologist, and may reduce the woman’s fertility or trigger early menopause. It also requires 7-11 days for full recovery.

Applicable Ablation Technologies: Rationale for Use and Effect on Tissues.

An MRI-guided HIFU treatment is one ablative option. It is effective, but it is also expensive, takes three hours, and requires a radiologist and the an MRI facility.

Mirabilis Medica is developing an ultrasound-guided, therapeutic ultrasound system to eliminate fibroids. According to the company, this will be the first non-invasive solution for use by gynecologists in the office setting. Mirabilis’ patented technology employs therapeutic ultrasound under real-time guidance using imaging ultrasound. Pain, side effects, and recovery (less than one day) will be substantially improved relative to invasive alternatives.

Cervical Dysplasia and Cancer

Cervical dysplasia is abnormal cell growth on the outside of the cervix, usually found through an irregular PAP smear. Dysplasia is not cancer, but it can develop into cancer if it is not treated properly and if appropriate follow-up is not conducted. The outside of the cervix and the vagina are covered by a layer of flat cells called squamous cells, and the cervix itself is lined by columnar cells. Squamous and columnar cells meet at the squamo-columnar junction or the transformation zone. It is in this transformation zone that abnormal growth or dysplasia develops.

Current and Emerging Treatment Trends.

There are several ways to treat cervical dysplasia, including surgery, radiotherapy and (for cancer) chemotherapy. Factors influencing the choice of treatment for cervical dysplasia include the extent and severity of the dysplasia, the age of the woman, and whether or not she has any other gynecological problems. Often the experience of the physician or other clinician, and the availability of equipment—which can be expensive—are also major factors.

The most common methods of treating cervical dysplasia are loop electrode excision (LEEP), cryosurgery, and cone biopsy.

In the case of cervical intraepithelial neoplasia (CIN), abnormal tissue may be removed using LEEP, i.e. wire loops heated by electric current, or cone biopsy. Carcinoma in situ may be removed using loop electrode excision, cryosurgery, or laser ablation. In cryosurgery, liquid nitrogen is circulated through a probe, which is applied to the cancerous tissue. Freezing temperatures destroy the cancer cells. Laser ablation involves using a laser to destroy the cancerous tissue.

Applicable Ablation Technologies: Rationale for Use and Effect on Tissues.

Cryotherapy is one of the treatments applicable to this condition. The main advantages are that it is relatively simple to do and uses inexpensive equipment. One problem with it is that the depth of freezing cannot be precisely controlled, so abnormal cells may be left behind. This may be acceptable when dealing with small areas of mild to moderate dysplasia, but it becomes problematic in the presence of severe dysplasia and carcinoma-in-situ. Another problem with cryotherapy is that when the cervix heals, the squamo-columnar junction is often inside the canal of the cervix, making future evaluations difficult.

A carbon dioxide laser vaporizes the abnormal cells. A laser treatment can usually be done in the office with little discomfort, and the patient returns immediately to normal activities. The laser is directed through the colposcope so that the area and depth of treatment can be precisely controlled. Healing after laser treatment is faster than after freezing because dead tissue is not left behind. Studies using the latest techniques of laser treatment are showing lower failure rates with the laser than with freezing. Another important advantage is that the cervix usually heals with the squamo-columnar junction visible, so that future evaluation is easily carried out. Probably the major disadvantage of the laser over cryotherapy is that laser requires sophisticated equipment, and most gynecologists do not have a laser in their office. It is much more expensive to do laser if it has to be done in the hospital. In centers where it is available, laser is often the gynecologist’s treatment of choice for most cases of CIN.

Also known as ‘LEEP’, loop excision uses a fine wire loop with electrical energy flowing through it to remove the abnormal area of the cervix. The tissue removed is sent to the laboratory for examination. This procedure, therefore, can often treat and diagnose the problem at the same time. Loop excision is commonly done under local anesthesia and usually causes little discomfort. This can often be used as a substitute for cone biopsy.

A cone biopsy removes a cone-shaped or cylinder-shaped piece of the cervix. It is usually done in an operating room and can be done with a laser or with conventional surgical instruments (cold-cone). A cone biopsy may be done for diagnosis or for treatment, although a diagnostic cone may simultaneously treat the problem. In a small percentage of cases, a cone biopsy may interfere with childbearing. Many cases which required cold cone biopsy in the past can today be treated with the laser or with the loop with a lower chance of complications. The cone biopsy is therefore not used very often today.

Although laser vaporization and cryotherapy are effective treatments for dysplasia, they are not suitable for invasive cancer because the tissue is destroyed. The physician, therefore, must be absolutely certain that there is not invasive cancer before treating with the laser or with cryo. If the physician cannot positively rule out invasive cancer on the basis of colposcopy, then an excisional biopsy of the transformation zone of the cervix is mandatory.

(See “Ablation Technologies Worldwide Market, 2009-2019”, Report #A145, MedMarket Diligence, LLC.)

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