Laser photochemotherapy: A less invasive approach for treatment of cancer

Abstract

The effectiveness of combining surgery with chemo- and radiation therapy in treatment of human cancer provides a useful model for further development of new multimodality approaches including laser photochemotherapy. Laser endoscopy often is a useful treatment for obstructive tumors in airways, but interstitial laser fiberoptics is becoming a more precise, minimally invasive alternative for ablation of unresectable or recurrent neoplasms. Combining intratumor chemotherapy with laser energy delivery via interstitial fiberoptics should be most effective using drugs activated by photothermal energy. A number of investigators have shown that anthracyclines and cis-platinum are likely candidates for light or heat activation in cancer cells. An advantage of anthracyclines is their dual role as antitumor drugs and as photosensitizers. Because they are effective chemotherapy agents without photoactivation, two approaches are possible to increase tumor responses. Maximum tolerated dose followed by photoillumination via laser fiberoptics can be used to obtain better tumor palliation. Improved treatment response to lower intratumor drug levels after laser activation also should reduce systemic toxicity. Preclinical studies and recent case reports from several groups suggest photochemotherapy with currently approved drugs and lasers may soon become an attractive alternative for treatment of recurrent tumors in cancer patients.

Improved photochemotherapy of malignant cells with daunomycin and the KTP laser

“…The current studies corroborate and extend previous in vitro experiments that demonstrate that anthracyclines have dual properties as photodynamic agents and as cytostatic anticancer drugs [1,8,[16][17][18][19]. For example, a recent in vitro study with Adriamycin using explanted human squamous-cell carcinoma showed that exposure to the argon laser at 514 nm led to over 50% increased cytotoxicity at drug levels equal to or above 5 g/ml compared to chemotherapy alone in the dark [19].…”

“…Although interstitial laser therapy (ILT) is less invasive than surgical resection, it appears that ILT as a single treatment modality will fail in those cases in which tumors encroach upon heat-sensitive vital structures [7]. An alternative approach is to deliver laser photothermal emissions to tumors after uptake of light-and heat-sensitive anti-cancer drugs, allowing therapy at reduced thermal energy and elevated intratumor drug levels [8][9][10].…”

Modulation of Tumor Cell Metabolism by Laser Photochemotherapy with Cisplatin or Zoledronic Acid In Vitro

“…Further in vivo research demonstrated that the antitumor effect of a local cisplatin application can be boosted by laser thermal therapy (9) or by interstitial laser therapy (38). Taken together, LLLT was able to raise the cytotoxicity of the applied drug at nearly every concentration tested, which is known as laser photochemotherapy (39). There is evidence (6 h) that chemotherapeutic agents such as cisplatin are potential candidates for light or heat activation in tumor cells (40).…”

Laser Photo Chemotherapy: An Alternative Treatment for Cancer

“…In addition to the advantage of photo-activation, several of these light sensitive chemotherapeutic agents have been reported to exhibit enhanced toxicity in tumor cells after photo-thermal-activation (Chung et al, 2003;Graeber et al, 1999;Graeber et al, 1998;Paiva et al, 1995;Saxton et al, 1996). As a result, a potentially useful and less invasive approach for treatment of malignancies is to combine imaging guided interstitial laser surgery with conventional chemotherapy (Paiva et al, 2005b;Saxton et al, 1995). Several FDA approved anti-cancer drugs are highly photosensitive or heat-responsive, including anthracycline derivatives and cisplatin Graeber et al, 1999).…”