Cervical Cancer: Light-Based Options for More Effective Prevention
Cervical cancer, or cancer of the cervix, is a common disease that poses a heavy burden to women’s health around the world. According to the International Agency for Research on Cancer (IARC), cervical cancer is the third most commonly diagnosed cancer and the fourth leading cause of cancer death in women worldwide. Rates are, on average, four to five times higher in Eastern compared with Western or Nordic countries.
The precancerous condition called cervical intraepithelial neoplasia (CIN) has been a major focus of research on photodynamic therapy (PDT) because more effective treatment for this condition will help women lower their risk of cervical cancer. Studies in Asian countries have found PDT is effective not only for improving various clinical measures when treating CIN, but also for eradicating cervical infections with Human Papilloma Virus, the number one risk factor for CIN and cervical cancer.
Researchers at The Affiliated Hospital of Nanchang University in Nanchang, China recently reviewed 14 studies of PDT as a treatment for CIN. The studies included two randomized clinical trials, one case-control study, and 11 case-series studies. All 14 studies included a clinical assessment of the CIN lesions’ response to PDT; some studies also reported lesion recurrences.
The complete response rate for PDT ranged from 0 to 100%; additionally, the eradication of Human Papilloma Virus was reported in seven studies, with rates ranging from 53% to 80%. Unfortunately, it was impossible to derive average or median estimates of PDT’s effectiveness due to the great variation in study designs.
The researchers concluded that PDT is a safe and tolerable treatment for CIN, and emphasized that more randomized trials are needed to assess the true efficacy of this approach, as reported in the June 2014 issue of Photodiagnosis Photodynamic Therapy.
In 2014, a randomized double-blind clinical trial was reported out of Hannover Medical School in Hannover, Germany. In this study, the intervention group was treated with PDT using a photosensitizer called hexaminolevulinate (HAL). The researchers randomly assigned 70 patients with CIN to three groups: (1) HAL-PDT vaginal suppository, (2) placebo vaginal suppository, or (3) follow-up only.
Patients in the first two groups received HAL or placebo suppositories five hours before light treatment using red coherent light. All patients had a follow-up that included colposcopy, cytology, and testing for Human Papilloma Virus at three and six months, along with an additional biopsy six months after completing their photodynamic treatments.
After six months, CIN lesions had cleared in 57% of patients in the HAL-PDT group compared to only 25% in the combined control group—a statistically significant difference. The most common side effect was local discomfort that included mild pain and cramping. The German researchers concluded that HAL-PDT has favorable efficacy and safety, and that it represents a promising alternative to conventional surgical procedures for patients with grade 1 CIN, as reported in the 6 May 2014 issue of Lasers in Surgery and Medicine.
Given the tremendous suffering that is caused by cervical cancer, particularly in populations that have inadequate access to screening programs, the photodynamic treatment of CIN offers some very real hope for a more effective preventive strategy.
The main advantage of PDT is that it can help preserve the healthy functioning of the cervix and thus ensure long-term reproductive health as well as playing an pivotal role in the prevention of cervical cancer. Future studies should focus on making PDT more available and cost-effective in countries with populations at high risk for cervical cancer.
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Sources
Hillemanns P1, Petry KU, Soergel P, Collinet P, Ardaens K, Gallwas J, Luyten A, Dannecker C. Efficacy and safety of hexaminolevulinate photodynamic therapy in patients with low-grade cervical intraepithelial neoplasia. Lasers Surg Med. 2014 May 6. [Epub ahead of print]
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