Medical treatment for endometriosis have been based on Sampson’s theory of retrograde menstruation and implantation. The objectives of treatment have been to reduce or eliminate cyclic menstruation, thereby decreasing the amount of menstrual tissue and the likelihood of new lesions will develop. At the same time, it is assumed that by suppressing the normal uterine lining (the endometrium), the same suppression will happen with existing endometriosis lesions.
Medical treatment for pain
Medical treatment is often used to reduce the menstrual flow and menstrual pain. Sometimes medical treatment may be recommended before resorting to surgical treatment unless there is evidence to suggest an acute process. There is no evidence that one medical treatment is more superior than other. They have similar effectiveness in pain relief and recurrence rates.
Medical treatment for infertility
Medical treatment does not improve pregnancy rate in women with endometriosis and infertility, in part because ovulation is suppressed with medical treatment. In older women with more limited time to conceive, medical therapies may adversely affect their chance of pregnancy by delaying conception. Generally medical treatment is not effective for endometriosis cyst on the ovary (endometrioma) or pelvic adhesions.
Hormonal birth control
Any one of the hormonal methods of birth control reduces menstrual bleeding and menstrual pain. These include birth control pill, skin patch, vaginal ring, shot, hormonal IUD and implant. Up to 75-90% of women with pain associated with endometriosis can experience effective relief when combination of birth control pill is taken continuously.
Non-steroidal anti-inflammatory medication (NSAIDs)
Gonadotropin releasing hormone agonist (GnRH agonist)
GnRH agonists (e.g. leuprolide, nafarelin, buserelin) work by “turning off” the ovaries, causing a temporary and reversible menopause. They are given as an injection, an implant, or nasal spray. They are very effective in relieving pain in women with endometriosis. Side effects include hot flashes, mood swing, irritability, joint pain and muscle ache. They cannot be used for longer than six months consecutively due to risk of bone loss (osteoporosis). In an effort to prevent the bone loss problem with GnRH agonist, combined estrogen-progestin add-back regimens have been studied. Numerous clinical trials have shown that hormone add-back regimens protect bone and reduce symptoms of hot flashes without sacrificing control of pain associated with endometriosis.
GnRH agonists are sometimes used to decrease the size of endometriomas, but not to eliminate them. Generally endometrioma larger than 1cm does not respond well to GnRH agonist or other medical treatment.
Although not approved by the Food and Drug Administration (F.D.A.) for the treatment of endometriosis, aromatase inhibitors (anastrozole 1mg daily, letrozole 2.5mg daily) have been found in several small studies to be effective for the treatment of pain associated with endometriosis. Aromatase inhibitors suppress estrogen production by blocking the last biochemical step where testosterone (a male sex hormone) is converted to estrogen ( a female sex hormone).
Side effects of aromatase inhibitors include bone loss and hot flashes. They can also stimulate multiple ovarian cysts, thereby making it necessary to be used in combination with a GnRH agonist or synthetic progesterone (e.g. norethindrone acetate 5mg daily) to avoid the complication.
While the objectives of medical treatment for endometriosis are to reduce or eliminate cyclic menstruation, objectives of surgical treatment for endometriosis are
to eradicate all visible endometriosis lesions,
to remove pelvic adhesions, and
to restore normal anatomical relationships.
Surgical treatment for pain
Surgical treatment of pain associated with endometriosis is reported in one study to give pain relief in about two-thirds of women six months after surgery. Other trials have reported success in pain relief anywhere from 70-100% of women with endometriosis. As in medical treatment of pain associated with endometriosis, recurrent disease and pain after conservative treatment with surgical removal of endometriosis are common. About 10-20% per year for women treated with surgery is expected to have recurrence of pain. Pain recurrence is in part due to recurrence of endometriosis lesions in the same or neighboring areas of the pelvis.
Deeply infiltrating endometriosis in the vagina or rectum requires extensive surgery with thorough dissection. Often a portion of the upper vagina may be removed along with a short segment of the rectum but excellent pain relief can be achieved.
Surgical treatment for infertility
The effectiveness of surgical treatment of infertility depends on the amount and extent of the disease. A multi-center Canadian trial found that surgical treatment (removing the lesions) of mild endometriosis among women with infertility was twice as effective (to become pregnant) as in untreated women. In another smaller Italian trial, no difference between surgical treatment or no treatment was found. When the data from these two studies are combined, a smaller (about 60%) improvement in infertility is found.
No study has been done to compare surgical treatment versus no treatment among women with moderate to severe endometriosis and infertility. Small studies have reported successful pregnancy anywhere from 30% to 50% within 1-3 years after surgical treatment of moderate to severe endometriosis.
Surgical treatment of endometrioma
Ovarian endometriosis cysts (endometriomas) bigger than 1cm generally do not respond to medical treatment. The wall of the endometrioma must be removed (peeled from the adjacent normal ovarian tissue) in order to minimize recurrence of cyst and pain, and to maximize fertility among women who were infertile. Surgical removal of endometrioma can sometimes lead to compromised ovarian function. Excessive ovarian tissue may be removed at the time of surgery or the blood flow to the ovary may be compromised. Because of this potential risk, it is generally recommended to remove endometrioma only if it is symptomatic (painful) or large (bigger than 3cm).
Laparoscopic treatment of endometriosis
Except in rare cases where laparoscopy is contra-indicated, laparoscopy (as opposed to the traditional surgery with laparotomy) is the surgical method of choice in the treatment of endometriosis. Laparoscopy offers a proper diagnosis of endometriosis, giving definitive information on the amount, location and depth of endometriosis (staging of the disease). It also offers an opportunity for the surgeon to treat the diseases at the same operation. Additional surgical steps can be taken to restore the pelvis to normal. The endometriosis lesions may be eradicated with a number of methods (laser, electrical cauterization or simple cutting away the lesions). Adhesions may be removed to free up the ovary and the tube. Sometimes the occluded tube(s) may be repaired.
Hysterectomy is the removal of the uterus. The ovaries may or may not be removed. Endometriosis is less likely to come back if the ovaries also are removed. Hysterectomy is a last resort when medical treatment and conservative surgery have not worked, extensive disease, and a woman no longer wishes to have any children. Unfortunately, in spite of hysterectomy and removal of the ovaries, there is a small chance that pain symptoms will come back.
Combined medical and surgical treatment
For a woman with primarily pelvic pain associated with endometriosis and fertility is not her immediate concern, post-op medical treatment (continuous or cyclic hormonal birth controls) may be appropriate especially in women with extensive disease or significant residual disease that could not be completely removed at the time of surgery.
Because the highest pregnancy rates after conservative surgery in infertile women with endometriosis are observed in the first year after operation, medical treatment (which suppresses ovulation) after surgery will eliminate that benefit. Generally young woman with limited disease and has no additional reason for her infertility can be given a short duration (usually for 6-9 mos) to attempt to conceive on her own after surgical treatment.
For older women, women with longer durations of infertility, or advanced degree of endometriosis, an aggressive treatment approach (after surgical treatment) to actively pursue pregnancy (controlled ovarian stimulation and intrauterine insemination or in-vitro fertilization) is recommended.