Imagine paying for a series of treatments, going back month after month, and feeling clearly better a year later.
It would be natural to think the treatment worked.
A new study shows why that conclusion can be wrong.
Researchers in Barcelona tested a popular vaginal laser treatment on breast cancer survivors. Women who got the real laser did improve. But women who got a fake laser, one that looked and sounded the same but delivered no real treatment, improved just as much.
Aromatase inhibitors often cause painful side effects
Many women who have had breast cancer take medicines called aromatase inhibitors. They lower estrogen in the body, which helps prevent the cancer from coming back.
But low estrogen has side effects. One of the most common is vaginal dryness, irritation and pain during sex. Doctors call this the genitourinary syndrome of menopause.
It can seriously affect quality of life and relationships. And because hormone treatments are often avoided after breast cancer, these women have limited options.
That has made them a key market for vaginal laser treatment, which uses a carbon dioxide laser to make tiny marks in the vaginal tissue, with the aim of stimulating it to heal and renew.
84 survivors got a real or a sham laser for a year
The study took place at Hospital Clínic of Barcelona.
- 84 breast cancer survivors, average age about 54, took part.
- Half got the real laser. Half got a sham laser, a fake treatment designed to feel like the real thing.
- Each woman had five sessions, one a month.
- Neither the women nor the researchers measuring the results knew who got which.
For ethical reasons, the researchers didn’t want anyone left without help. So every woman also received free first-line care: vaginal moisturizers, lubricants and a vibrator, plus access to sexual health counseling.
The researchers followed the women for a full year. 67 completed the whole study.
Both groups improved just as much
Everyone got better. Across the whole group, over 12 months:
- Pain during sex roughly halved, from about 7 to about 3.5 on a 10-point scale.
- A standard sexual function score rose by about 4.5 points.
- 85% of the women were sexually active at the end, and about half of those who had stopped having sex because of their symptoms started again.
- Vaginal health and body image improved.
But here’s the key result: the improvements were the same whether a woman got the real laser or the fake one.
On the main sexual function score, the laser group actually improved slightly less than the sham group, although the difference was small enough to be due to chance. None of the other measures, including pain, vaginal health, body image or lab tests of the vaginal tissue, showed any advantage for the real laser.
Simple, inexpensive care given to everyone did the work
If the laser wasn’t doing the work, what was?
The researchers point to several things:
- The free basic care. Almost 9 in 10 women kept using the moisturizers and vibrators, which are recommended first-line treatments.
- The extra attention. Regular visits, specialist sexual health assessments and the feeling of being looked after can make a real difference.
- Expectations. Most women, including 60% of those who got the fake laser, believed they had received the real treatment.
Feeling better doesn’t prove a treatment worked
This is the most important lesson, and it goes far beyond lasers.
When people feel better after a treatment, it’s tempting to credit the treatment. But many other things can be happening at the same time:
- people often use other remedies alongside it
- symptoms naturally go up and down
- expecting to feel better can genuinely change how we feel
- being cared for and paid attention to helps
The only way to separate these from the treatment itself is to compare it with a convincing fake, a placebo, where people don’t know which they’re getting.
That’s exactly what this study did. And it’s what many earlier studies didn’t.
According to the authors, around 25 studies of vaginal laser in breast cancer survivors have been published. Reviews of those studies concluded the laser helped. But most of those studies didn’t include a fake treatment for comparison. The few trials that did, including this one, found no benefit beyond placebo.
The authors put it bluntly: the better designed the study, the smaller the benefit of the laser appears to be.
Devices can be sold ahead of the evidence
Medical devices can sometimes reach clinics and patients before there’s strong proof they work. Early studies without proper comparisons can make a treatment look effective, and that can be enough for it to spread.
The authors note that most regulatory bodies and medical societies already advise against offering this laser treatment outside research studies.
The basics are a sensible first step
The study doesn’t tell any individual what to do, but some reasonable takeaways follow:
- Start with the basics. Moisturizers, lubricants and vibrators are inexpensive, recommended first steps, and in this study they were linked to real improvements.
- Ask about the evidence. Before paying for any treatment, it’s fair to ask: Has this been tested against a placebo or sham? What did those trials find?
- Be wary of before-and-after claims. “Patients felt better afterwards” isn’t proof the treatment caused it.
- Talk to your cancer team. Don’t stop or change cancer medication because of side effects without medical advice. Ask what options are available.
What the study doesn’t show
This is a peer-reviewed randomized trial, but it has limits.
It was small and run at one hospital. With 84 women, very small benefits could have been missed.
It’s a secondary analysis, looking at 12-month results from a trial whose main 6-month results were published earlier, with the same conclusion.
It studied one group of women and one laser protocol. Results may differ for other patients or devices, though other sham-controlled trials have reached similar conclusions.
The laser appeared safe. There were no serious side effects, so the issue is not danger but lack of added benefit.
Improvement after treatment isn’t proof of the treatment
For women dealing with painful side effects after cancer, it’s understandable to want a high-tech solution. And it’s understandable to believe it worked when symptoms improve.
This study shows that in this case, the improvements came from simple, inexpensive care and from being well looked after, not from the laser.
Feeling better after a treatment isn’t the same as the treatment making you better.