Local laser therapy

Analysis of the literature reveals no significant differences between electrocoagulation and (very expensive) laser treatment procedures in terms of primary or definitive haemostasis. With laser therapy, the complication rate (0—4%) lies above that of electrocoagulation (0%). Heat and bipolar probes may be regarded as the most tissue-friendly , an inference supported by the results of animal experiments, while laser and monopolar probe methods are more aggressive . The electrohydrothermal probe offers a compromise. An additional consideration is that electrocoagulation and EHT procedures are technically uncomplicated, locally applicable and lower in cost compared to laser methods. 

Tumors not suitable for local ablative therapy such as radiofrequency and laser ablation... 

The development of so-called photodynamic therapy uses lasers for treatment of cancer. The patient is injected with a substance called hematoporphyrin derivative [68335-15-9] which is preferentially localized in cancerous tissues. The patient is later irradiated with laser light, often with a dye laser at a wavelength around 630 nm. The light energy catalyticaHy photooxidizes the hematoporphyrin derivative, releasing materials which kill the nearby cancerous tissue. Normal tissue which did not retain the chemical is not harmed. Photodynamic therapy offers promise as a new form of cancer treatment. 

Adili E Statius van Eps RG, Flotte TJ, et al. Photodynamic therapy with local photosensitizer delivery inhibits experimental intimal hyperplasia, Lasers Surg Med 1998 23 263-273. 

Combination therapy The use of local-interventional procedures is restricted to a maximum tumour size of 5 cm in diameter. Therefore, a combination of two local techniques is seen as promising. The joint application of PEI and TAB has proved its efficacy for some time. (177) Similarly, there have been reports about the successful use of TACE following laser thermal ablation. (136) Further encouraging options include a combination of TACE and RFTA, TACE with microwave coagulation (149) or TACE with cryotherapy. Using TACE, the size of the HCC can be reduced in some cases, making it possible to carry out subsequent ablation with better results. 

To perform photodynamic therapy (PDT) in skin tumors, the most often used substance is ALA. The porphyrin precursor is topically applied under occlusive foil as described above. Irradiation should be performed when the optimal ratio of photosensitizer levels between tumor and normal tissue is reached (in the case of ALA 2-6 h after application Figures 2, 5, 7) [16]. The type of light source (laser or incoherent light) and the required fluence depend on the photosensitizer used as well as on the type and localization of the lesion. 

Unresectable and chemorefractory malignant tumors in the liver are a major cause of death in solid tumors. Potentially curative surgery is uncommon for these patients. A number of liver-directed therapies are now available and are making important contributions to quality of life, prolonged time to liver progression, and overall survival. Limited surgery involving laparoscopy and percutaneous access approaches enables local tumor resection, cryotherapy, laser-induced interstitial thermotherapy, and radiofrequency ablation. 

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