272 The Korean Journal of Internal Medicine Vol. 27, No. 3, September 2012 achieved a mean dysphagia-free interval of 81 days. Although the study was a non-randomized, single-arm study, the results are very promising. Improvement of the dysphagia score in 90% of patients indicates that a better quality of life was achieved by most of the patients who received PDT as part of the multimodal treatment. Other recent studies have stated that PDT can be used as an ef- fective treatment modality in combination with other tech- niques, such as stents and radiation therapy for palliation of obstructive esophageal cancer, alleviating dysphagia [8- 10]. These results, including those in the current article, show that PDT is becoming established as a treatment of lumen-obstructing advanced esophageal cancer. In terms of treating difficult lesions, PDT has a sig- nificant advantage, compared with stents, in treating advanced esophageal cancer. When the lesion is located at the cervical esophagus, which can cause a foreign body sensation and pain, or at the gastroesophageal junction, when stent migration and symptoms due to reflux can fre- quently occur, PDT can be an appropriate solution. Indeed, PDT is more expensive than other treatment modalities. In the future, studies comparing the cost-effectiveness of PDT with other techniques such as stents are warranted. To achieve a better effect and gain more ground in terms of treatment indications, new photosensitizers with fewer side effects and light delivery systems allowing for deeper penetration are needed. With improvement in procedure equipment and further larger, randomized trials, the status of PDT, as an established therapeutic choice in the treatment of cancer, will be confirmed. Confilct of interest No potential conflict of interest relevant to this article is reported. REFERENCES 1. Wang KK, Lutzke L, Borkenhagen L, et al. Photodynamic therapy for Barrett’s esophagus: does light still have a role? Endoscopy 2008;40:1021-1025. 2. Wilson BC, Patterson MS. The physics, biophysics and technolog y of photody namic therapy. Phys Med Biol 2008;53:R61-R109. 3. Barr H, Tralau CJ, Boulos PB, MacRobert AJ, Tilly R, Bown SG. The contrasting mechanisms of colonic collagen damage between photodynamic therapy and thermal injury. Photo- chem Photobiol 1987;46:795-800. 4. McCaughan JS Jr, Guy JT, Hawley P, et al. Hematoporphy- rin-derivative and photoradiation therapy of malignant tu- mors. Lasers Surg Med 1983;3:199-209. 5. Sharpe DA, Moghissi K. Resectional surgery in carcinoma of the oesophagus and cardia: what influences long-term sur- vival? Eur J Cardiothorac Surg 1996;10:359-363. 6. Knyrim K, Wagner HJ, Bethge N, Keymling M, Vakil N. A controlled trial of an expansile metal stent for palliation of esophageal obstruction due to inoperable cancer. N Engl J Med 1993;329:1302-1307. 7. Yoon HY, Cheon YK, Choi HJ, Shim CS. Role of photodynam- ic therapy in the palliation of obstructing esophageal cancer. Korean J Intern Med 2012;27:278-284. 8. Lightdale CJ, Heier SK, Marcon NE, et al. Photodynamic therapy with porfimer sodium versus thermal ablation therapy with Nd:YAG laser for palliation of esophageal can- cer: a multicenter randomized trial. Gastrointest Endosc 1995;42:507-512. 9. Maier A, Tomaselli F, Gebhard F, Rehak P, Smolle J, Smolle- Juttner FM. Palliation of advanced esophageal carcinoma by photodynamic therapy and irradiation. Ann Thorac Surg 2000;69:1006-1009. 10. Luketich JD, Christie NA, Buenaventura PO, Weigel TL, Keenan RJ, Nguyen NT. Endoscopic photodynamic therapy for obstructing esophageal cancer: 77 cas s over a 2-year pe- riod. Surg Endosc 2000;14:653-657. http://dx.doi.org/10.3904/kjim.2012.27.3.271 http://www.kjim.or.kr