Turning the spotlight on lasers

Over the last few years, there has been increasing interest in the use of lasers to treat vulvovaginal atrophy (VVA) and a variety of other urogenital conditions such as vulvodynia and urinary stress incontinence (USI). Whilst some practitioners have adopted this new treatment modality quickly, others have been more cautious. Lasers first came to prominence in gynecology as part of the ‘vaginal rejuvenation’ industry. Anecdotal claims for its success and glamorous marketing have led to many clinicians being wary of becoming involved with a therapy that has had a non-clinical connotation. However, more recently, a series of more clinical studies, backed up with histological data, have started to emerge that suggest that, for certain indications, particularly VVA, this modality may offer an alternative to our traditional treatments^1–7.

Readers of this journal will be very familiar with the prevalence and clinical problems posed by VVA (or genitourinary syndrome of menopause, GSM) and the central role of vaginal estrogens in its management⁸. However, there remain some women in whom vaginal estrogens are not the answer. These largely fall into three categories: those who cannot take estrogens, e.g. women who have had breast cancer; those who will not take estrogens, e.g. because they are frightened of the perceived risks; and finally those in whom they are not effective. Whilst many clinicians would still consider vaginal estrogens a reasonable option in all these groups, with appropriate advice and counseling, there remains a significant cohort of women in whom vaginal estrogens may not be the answer. Other treatments such as lubricants, moisturizers, ospemifene and dehydroepiandrosterone are also appropriate options. Vaginal laser treatment is now being considered as another alternative, but what is it, is it safe and what is the evidence for its use?

Laser (light amplification by stimulated emission of radiation) was first described by Einstein back in 1917, but it was not until 1960 that the first laser was built and the mid-1960s before it started coming into clinical use, primarily as a cutting tool. By the 1980s, the laser was in widespread use in many disciplines including gynecology as an energy source for precision cutting, vaporizing and coagulating. Lower energy levels were also used for tissue-stimulating properties in treating ulcers, bedsores, etc. However, it is now the thermal properties of the laser that are the focus of interest. In dermatology, the use of pulsed ablation and heat denaturation results in the dermis being stimulated to produce new collagen with limited damage to the epidermis, whilst the skin is allowed to cool between pulses, thus minimizing thermal damage. Similar applications are now being deployed in the vagina.

Lasers have several unique characteristics compared to other sources of electromagnetic radiation. For instance, the electromagnetic waves are all of a similar wavelength, the light emitted is highly directional and can travel large distances, and its brightness, which is due to the power emitted and low beam divergence, allows the generation of energy. When light hits tissue, it can be reflected, transmitted, scattered and absorbed depending on the wavelength of the energy and the optical properties of the tissue (e.g. X-rays pass through the body but Er : Yag is easily absorbed). The energy absorbed by the tissue is then converted to other energy, e.g. thermal. Depending on the laser energy delivered and the time during which it is delivered, the tissue effects can range from destruction (e.g. tissue ablation) to a purely thermal effect (e.g. coagulation).

Different types of lasers have been developed around new wavelengths and the waveform. Some are solid state, e.g. erbium (Er), others are gas, e.g. CO₂. Much of the original work has been done in dermatology but both these types of laser have now been adapted for use in gynecology. The vaginal wall with its four distinct layers (mucosal epithelium, lamina propria, muscularis and adventitia) provides the opportunity for varying effects dependent on the depth and type of laser energy employed. Thermal energy from the laser in a water-rich environment like the vagina is thought to enhance the collagen component and promote tissue vascularization, which leads to collagen remodeling and new collagen synthesis.

In the vagina, the laser energy is delivered through specially designed devices that are inserted into the vagina and the laser energy is deployed using a carefully controlled preset pulsing sequence. There are many potential variables that will differ between the lasers used. A full course of treatment usually involves two or three treatments in the first 12 weeks. The two lasers currently in clinical use are the CO₂ and the Er : Yag. The main difference between them is that the CO₂ laser has ablative characteristics and is given in a fractional way, with an initial short burst that ablates columns of epithelial tissue to expose the underlying water-rich connective tissue to its thermal effects. It is delivered in short pulses with rapid movement across the epithelium precisely to control the depth of ablation and degree of thermal damage. In contrast, the Er : Yag laser creates heat pulses which heat the collagen layer without damaging the mucosa. The temporal distribution of energy delivered with the special SMOOTH mode produces a fast sequence of laser pulses, allowing the heat to dissipate into the mucosa and thus giving a controlled deep thermal effect without causing mucosal damage. As yet, there is no evidence that one method is superior to the other and there have been no head-to-head comparisons.

Salvatore and colleagues¹ first reported that fractional CO₂ laser treatment was effective in improving symptoms of VVA in a small cohort of women with a 12-week follow-up. The technique was well tolerated and easy to perform and also improved sexual function². Shortly after that, Gambacciani and colleagues³ also reported significant improvement of GSM symptoms with the Er : Yag laser which lasted up to 6 months post-treatment. Subsequent to this, a number of other studies have been reported, but overall the number of trials on laser treatment for VVA remains small and most of the studies have been restricted to observation up to 12 weeks after the end of treatment. However, all the studies have been quite consistent in their findings that VVA symptoms are significantly improved, and the procedures are well tolerated with no reported serious adverse events. The longest published follow-up with the CO₂ laser was 15 months⁴, although the numbers at that time point were too small to draw meaningful conclusions; 47% of the women completed the 12-month follow-up with continued benefit. With the erbium laser, the longest follow-up is 18 months⁵ and the authors reported an ongoing beneficial effect, but again the numbers are small. Two studies have shown equal efficacy with vaginal estriol^3,5, the latter study highlighting that the effects of laser last for 18 months whereas the effects of estriol wear off soon after the treatment is discontinued. There have been no reported comparative studies with vaginal moisturizers or ospemifene. The relationship between laser treatment and the estrogen status of the vagina warrants further investigation, for instance, what impact does laser treatment have on estrogen receptors and does estrogen treatment enhance or prolong the laser response?

One of the groups of women who may benefit the most from laser treatment are those with previous breast cancer. Several of the studies have included women with breast cancer in their cohort⁴ and a recent prospective study⁶ looked specifically at this group, reporting significant improvement in VVA symptoms.

Overall, vaginal laser treatment appears to be well tolerated with no more than minor discomfort or irritation reported after the first treatment. However, the need for randomized, placebo-controlled trials with sham devices is highlighted by the first such trial published⁹. In a study of 45 women, the authors found that, although laser alone or in combination with vaginal estriol was as effective as estriol alone for VVA symptoms, there was an unexpected reported increase in sexual pain in the laser group. None of the clinical studies to date have reported any serious adverse advents, and the safety profile in other modalities such as dermatology has also been cited as further evidence of its safety. However, extrapolating data from other areas of the body should be done with caution, and recent experiences with other interventions, such as vaginal mesh, should make clinicians wary about the widespread adoption of new treatments in the vagina without appropriate long-term safety and efficacy data¹⁰.

Away from VVA, there have been a number of studies reporting symptomatic improvement in women with mild USI with both the erbium and CO₂ lasers^7,11. This may be an effect of the increased collagen remodeling provoked by the laser but, at this stage, the data are not robust enough to be able to draw any significant conclusions. Several randomized trials are now under way, the results of which may give some indication of whether or not this may be a potential additional treatment for USI. Laser therapy has also had some reported success in a number of vulval conditions such as vulvodynia, vestibulitis and lichen sclerosis⁷, but again appropriate clinical trials are needed to establish the potential role of laser treatment in these conditions.

Whether an invasive treatment in an already uncomfortable or painful vagina is an option most women would choose remains to be established but, from the evidence to date, the use of vaginal laser treatment certainly appears successful and promises to be a potential addition to our array of treatments for VVA, particularly for those women with previous breast cancer. However, there are many issues that remain to be determined such as, what is the placebo effect, are there any long-term adverse effects, what is the most effective treatment session interval and is it cost effective?

At present, the use of laser for treatment of VVA has not been approved by the FDA and the ACOG has cautioned against its use for that indication without careful fully informed consent. Other regulatory bodies have yet to make any official comment.

The spotlight is now on those doing the research in this area to produce the appropriate robust evidence to establish the future role of laser therapy in VVA.

Conflict of interest

The author reports no conflict of interest. The author alone is responsible for the content and writing of this paper.

Source of funding

Nil.