Photodynamic therapy of neoplastic disease

We conducted a trial of photoradiation therapy of cancer at the University of California at Irvine. The basis of this technique is a photochemical reaction between an i.v.-injected material, hematoporphyrin derivative, and red light (wavelength, 630 nm). Hematoporphyrin derivative localized in malignant tissue, resulting in selective destruction of cancer cells upon illumination with red light. One hundred twenty-eight sites of recurrent cancer or premalignant lesions were treated in 37 patients. Of this group, 35 patients had recurrent cancer refractory to conventional therapy, and two had premalignant lesions. Favorable responses were achieved in 67% of the sites treated. The dose of hematoporphyrin derivative used in this study ranged from 2 to 5 mg/kg with the majority of patients receiving 3 mg/kg. Total light dose administered appeared to be the most critical parameter evaluated. Light doses in excess of 20 J/sq cm generally resulted in blistering and necrosis of intact skin, while no appreciable increase in response was observed. Photoradiation therapy has demonstrable efficacy in cancer therapy and avoids much of the morbidity of current conventional techniques.

Laser photoradiation therapy of cancer

In preparing this document the Authors aimed to pool current information on canine and feline mast cell disease. The information was gathered from international studies and a emphasis was placed on material and opinion with a strong evidence base. We intend it to form the basis of our understanding in this disease at the current time and we anticipate that it will be particularly useful for the general practitioner. It should be emphasized that the authors are presenting this work from a European perspective.

/pdf/european-consensus-document-on-mast-cell-tumours-in-dogs-and-4ksvzt7rh3.pdf

European consensus document on mast cell tumours in dogs and cats.

Background and Objective

Photodynamic therapy has been shown to be an effective treatment modality for surface-oriented neoplasms of the skin, respiratory, gastrointestinal, and urogenital systems. The purpose of this study was to assess the safety and efficacy of photodynamic therapy using a new photosensitizer in the treatment of squamous cell carcinomas of the feline facial skin.



Study Design/Materials and Methods

Cats with naturally occurring squamous cell carcinomas of the facial skin were entered into the study. Tumors were staged using a modification of the World Health Organization (WHO) system for classification of feline tumors of epidermal origin. Photodynamic therapy was delivered to the tumors using an argon-pumped dye laser 24 hours after the administration of the photosensitizer pyropheophorbide-alpha-hexyl-ether (HPPH-23). Following treatment, tumors were evaluated for complete response rates and local control durations.



Results

Fifteen tumors were staged T1a ( 1.5 cm, invasive). Complete response rates as well as local control durations were significantly (P < 0.05) related to stage. Complete response was achieved in 100% of T1a tumors, 56% of T1b tumors, and 18% of T2b tumors. One-year local control rates were 100% for T1a tumors and 53% for T1b tumors; overall 1-year local control rate for all treated tumors was 62%. Clinical, hematological, and biochemical evidence of toxicity was not seen in any cat following drug administration. However, morbidity was observed following treatment of large, invasive tumors of the nasal plane.



Conclusion

Photodynamic therapy with the photosensitizer HPPH-23 was safe and effective in treating early stage squamous cell carcinomas of the feline nasal plane and facial skin. However, toxicity was encountered following treatment of large neoplasms. Lasers Surg. Med. 20:202–209, 1997. © 1997 Wiley-Liss, Inc.

Photodynamic therapy of facial squamous cell carcinoma in cats using a new photosensitizer

5-Ethylamino-9-diethylaminobenzo[a]phenothiazinium chloride (EtNBS) is a novel photodynamic therapy (PDT) photosensitizer with efficacy against experimental murine tumors. In this preliminary study, dogs and cats with naturally occurring tumors were treated with EtNBS-PDT to determine safety and efficacy. Fifteen treatments were performed on 13 animals (9 treatments in 8 cats and 6 treatments in 5 dogs), generally using 400 J of 652 nm light. Two feline sublingual squamous cell carcinomas (SCCs) responded briefly (minor response). Six feline facial SCCs were treated, resulting in two partial responses and four long-term complete responses (CR). Two canine intraoral SCCs were treated; one responded minimally for 2 weeks (minor response), and one achieved long-term CR. One canine cutaneous mast cell tumor achieved CR, and one canine ocular mast cell tumor responded briefly. One canine ocular melanoma did not respond to treatment. Systemic reactions included nausea associated with photosensitizer injection in two cats and two dogs, elevated body temperatures during treatment in two dogs, elevated body temperature 2 days after PDT in one cat, and inappetance for 2 weeks in one cat. A peripheral neuropathy of undetermined cause occurred in one cat 2 weeks after PDT and resolved without treatment. Local reaction was well tolerated in 13 of 15 treatments. All animals were exposed to normal daylight after less than 5 days (mean, 3.5 days) without residual photosensitization. EtNBS-PDT is safe for dogs and cats and has activity against selected naturally occurring tumors, with an overall objective response rate (partial response + CR) of 61.5%.

/pdf/photodynamic-therapy-of-naturally-occurring-tumors-in-slbtvflfgf.pdf

Photodynamic therapy of naturally occurring tumors in animals using a novel benzophenothiazine photosensitizer

Photodynamic therapy of spontaneous animal tumors using the active component of hematoporphyrin derivative (DHE) as photosensitizing drug: Clincal results

Hematoporphyrin derivative photochemotherapy of spontaneous animal tumors: Clinical results with optimized drug dose

Phototherapy with Hematoporphyrin Derivative (HpD) was performed in 26 clinical cases on 11 types of spontaneous tumors in dog and in cat, in most cases untreatable by conventional means. The tumors consisted in 7 squamous cell carcinomas of the mouth and tonsils, 5 mastocytomas of the skin, 4 eosinophilic granulomas of the lip and the skin, 2 adenocarcinomas of the nasal glands, 2 reticulum cell carcinomas of the lip, 1 osteolytic sarcoma of the radius, 1 carcinoma of circumanal glands and in the oral cavity 1 hemangiopericytoma, 1 liposarcoma, 1 melanoma, and 1 fibrosarcoma.

Renato Cheli

Papers

Photodynamic therapy of spontaneous animal tumors using the active component of hematoporphyrin derivative (DHE) as photosensitizing drug: Clincal results

Hematoporphyrin derivative photochemotherapy of spontaneous animal tumors: Clinical results with optimized drug dose

HpD Phototherapy on Spontaneous Tumors in Dog and Cat