Photodynamic therapy to the oral cavity, tongue and larynx: a canine normal tissue tolerance study

PHOTOFRIN-mediated photodynamic therapy for treatment of early stage oral cavity and laryngeal malignancies

BACKGROUND AND OBJECTIVE

To determine the efficacy of PHOTOFRIN-mediated photodynamic therapy (PDT) for treatment of diffuse "field cancerization" of the oral cavity and Cis-T2N0M0 squamous cell carcinoma (SqCCa) of the larynx in patients not amenable or that have failed conventional head and neck treatment.

STUDY DESIGN/MATERIALS AND METHODS

Over the past 15 years 10 patients with early stage Tis-T2N0M0 SqCCa of the oral cavity and oropharynx and 10 patients with Tis-T2N0M0 SqCCa of the larynx were treated. Intravenous PHOTOFRIN (porfimer sodium) (dose 2.0 mg/kg) was administered outpatient, followed 48-60 hours later by intraoperative light photoactivation at 630 nm via fiberoptic microlens (ML) delivery (surgical light dose, 50-100 J/cm(2)) and/or cylindrical diffuser (CD) delivery (80-100 J/cm).

RESULTS

Complete responses (CRs) (follow up 6 months-9 years) were achieved in eight of 10 patients with diffuse field cancerization of the oral cavity. CRs (follow up 6 months-8 years) were achieved in eight of 10 patients with superficial laryngeal cancer obviating the need for total laryngectomy in previously treated radiation therapy patients.

CONCLUSION

PHOTOFRIN-mediated PDT provides a surgical oncologic modality for potentially curative treatment of early stage oral cavity and laryngeal malignancies with minimal side effects, absence of systemic toxicity, preservation of oral function and voice quality, with multiple drug administration, and laser light retreatment capability.

Effect of photodynamic therapy on revascularization of fasciocutaneous flaps

OBJECTIVE

Photodynamic therapy (PDT) may be used as an adjuvant intraoperative treatment to improve locoregional control. PDT has been shown both to delay wound healing and to have a deleterious effect on flap survival after a primary ischemic insult. This delay in wound healing may make the flap dependent on its pedicled blood supply for a prolonged period. Long-term flap loss may be experienced. The effect of PDT on flap revascularization, with subsequent dependence on its vascular pedicle, is evaluated.

STUDY DESIGN

Randomized controlled trial using a rodent model.

METHODS

A rat fasciocutaneous flap was used. Study groups were as follows: group I received no treatment; group II received treatment with 630-nm light; groups IH and IV were given Photofrin (in group III, loupes without a fiberoptic light source were used for flap elevation, and in group IV, light source was employed); and group V was given Photofrin and 630-nm light. Primary ischemic times of 2 or 4 hours were used. Vascular pedicles were ligated on postoperative day (POD) 5, 6, or 7, and percentage of flap survival was evaluated 7 days later.

RESULTS

With 2 hours of ischemia, revascularization was decreased in the PDT group on POD 6 (P < .05) and on day 7 (P < .005) when compared with the other groups. With 4 hours of ischemia, revascularization was decreased in the PDT group on PODs 5 (P < .001), 6 (P < .01), and 7 (P < .005).

CONCLUSION

Intraoperative PDT decreases revascularization of a rat fasciocutaneous flap.

Effect of photodynamic therapy on the critical primary ischemic time of fasciocutaneous flaps

BACKGROUND

Photodynamic therapy (PDT) may be used as an adjuvant intraoperative therapy to improve locoregional control. PDT has been shown to delay wound healing. This raises concern about PDTs effect on survival of fasciocutaneous flaps.

OBJECTIVE

Evaluate the effect of 1) PDT on the critical ischemic time in a rat fasciocutaneous flap model and 2) photosensitizer activation by the surgical light source.

DESIGN

A fasciocutaneous flap, based on the left inferior epigastric vessels, was used. Ischemic times of 2, 4, 6, 8, 10, and 12 hours were induced by clamping the vascular pedicle. Animals were randomly divided into five groups: ischemia only, group I; light treatment to wound bed, group II; Photofrin before surgery with the flap elevated without a fiber optic head light, group III, or with a headlight, group IV; Photofrin prior to surgery with light treatment to the wound bed, group V. Flap survival was assessed on postoperative day 7.

RESULTS

The critical primary ischemic time of group V (PDT) was significantly less (P < .05) than groups I, II, III, and IV. There was no statistical difference in the critical primary ischemic time when a fiber optic headlight was used (group III vs. group IV).

CONCLUSION

Intraoperative PDT significantly reduces the critical primary ischemic time of the rat fasciocutaneous flap. White light illumination of the operative field does not result in photosensitizer activation and has no effect on the critical primary ischemic time.

Photodynamic therapy and the treatment of head and neck neoplasia

OBJECTIVE

To present the theory, technique, and results of photodynamic therapy for the treatment of oral, laryngeal, and head and neck cancers.

STUDY DESIGN

Retrospective review of the literature of more than 500 patients with head and neck cancer treated with photodynamic therapy, as well as a retrospective review of the author's 107 patients treated with photodynamic therapy for head and neck neoplasia between 1990 and 1997.

METHODS

The literature was retrospectively reviewed, as were patient records, and tabulated for age, sex, site, and staging of lesions, with special focus on post-photodynamic therapy treatment outcome, long-term disease-free survival, and complications.

RESULTS

Twenty-five patients with carcinoma in situ and T1 squamous cell carcinoma of the true vocal cord who underwent photodynamic therapy treatment for cure obtained a complete response after a single photodynamic therapy treatment. Only one patient has had recurrence to date, with a cure rate to 79-month follow-up of 95%. Twenty-nine patients with carcinoma in situ and T1 recurrent squamous cell carcinomas of the oral cavity and tongue were treated. All obtained a complete response after a single photodynamic therapy treatment; however, five patients developed local recurrence with follow-up to 70 months, for an 80% cure rate. A review of 217 patients with early squamous cell carcinomas of the head and neck treated with photodynamic therapy in the literature demonstrated an 89.5% complete response rate. The most common complication in these patients was limited prolonged skin photosensitivity without any permanent sequelae.

CONCLUSIONS

Photodynamic therapy is effective for treating carcinoma in situ and T1 squamous cell carcinoma of the larynx and oral cavity and may be of benefit as an adjuvant intraoperative treatment of stages III and IV tumors of the head and neck in conjunction with surgery and radiation therapy to improve cure rates. Further controlled studies need to be performed to further demonstrate the effectiveness of photodynamic therapy and the treatment of head and neck cancers.