Photodynamic Therapy Triggers Cytotoxic Drug Retained to Greater Degree by Cancer Cells

Eric Bernicker
JAMA. 1989;262(18):2500. doi:10.1001/jama.1989.03430180018003.
Text Size: A A A
Published online


RESEARCHERS ARE hoping that the triple threat of light, oxygen, and light-sensitive drugs will usher in a new age in cancer treatment. The new weapon, called photodynamic therapy, uses laser light to activate a cytotoxic drug selectively in tumor cells.

The drugs involved, hematoporphyrin and its more potent derivative, dihematoporphyrin ether (DHE, Photofrin) (Quadra Logic Technologies, Vancouver, Canada), have been known to be light activated since early in this century. But it was not until the 1970s that the first systemic use of photodynamic therapy was pioneered by Thomas Dougherty, PhD, and his group at Roswell Park Memorial Institute, the New York State facility in Buffalo.

The drug enters both normal and malignant cells. However, it is retained to a greater degree by neoplastic cells.

Thus, 48 to 72 hours after administration, there is a gradient between the normal cells and the tumor. Photodynamic therapy seeks to exploit this.



Sign In to Access Full Content

Don't have Access?

Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more

Subscribe for full-text access to content from 1998 forward and a host of useful features

Activate your current subscription (AMA members and current subscribers)

Purchase Online Access to this article for 24 hours




Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).


Some tools below are only available to our subscribers or users with an online account.

Sign In to Access Full Content

Related Content

Customize your page view by dragging & repositioning the boxes below.