HPD and cancer: In 1966, hematoporphyrin derivative (HpD), the first-generation PSs, was reported to use in breast cancer treatment.120 After that, Kelly and Snell reported HpD in bladder cancer treatment in 1976.121 Until 1993, Photofrin (porfimer sodium), a purified component of HpD, was first approved for bladder cancer treatment in Canada.13 From then on, the curtain was raised for the application of PDT in cancer treatment.