Photodynamic therapy of cancer

PDT represents another modality for the treatment of human malignancy. Photoactivated hematoporphyrins have definite antitumor activity in both in vitro and in vivo experimental systems. Much of the early clinical work involved treatment of patients with advanced, recurrent disease who had not responded to conventional therapy. Because good responses with acceptable toxicity have been obtained in these patients, active investigation continued and is aimed at defining the most appropriate sites and applications for the technique. Because of the limited depth of light penetration in tissue, the most promising sites may be those where there is limited thickness of tumor, such as in superficial skin lesions or carcinomas in situ involving the aerodigestive tract, bronchial tree, or genitourinary tract. Other potential uses include those where PDT could be combined with surgical or chemotherapeutic debulking, such as pleural mesothelioma or advanced stage ovarian cancer. Whether PDT can be of benefit in surgical cases where the margins of resection are close is an interesting but speculative notion at the present time. Clinical trials with hematoporphyrin derivative PDT in the sites mentioned are in progress. Laboratory work to better understand HpD also continues, as well as investigations into alternative photosensitizers with improved tumor localization, less cutaneous photosensitivity, and absorption peaks at deeper penetrating wavelengths of light. Attempts at measuring singlet oxygen, if successful, will permit the development of more meaningful dosimetry in order to correlate response with actual tissue levels of the purported cytotoxic agent. Hopefully, these and other developments in the field of PDT will improve the treatment for patients with cancer.     

Photodynamic therapy of cholangiocarcinoma cancer

Prognosis of nonresectable cholangiocarcinoma is not good, and in Bismuth type III and IV tumors relief of jaundice is seldom achieved, despite successful endoprosthesis insertion. Additional photodynamic therapy seems to be a promising new approach to these tumors. First pilot studies show relief of jaundice, mainly because of opening of the intrahepatic ducts and improvements in quality of life indices. Survival time seems to be long; however, randomized studies are necessary to confirm these results.     

Photodynamic therapy of gastric cancer

Photodynamic therapy is a fascinating concept that will continue to occupy many research groups around the world in coming years. Although a widespread clinical application for the method has not yet emerged, there are good prospects that photodynamic therapy will establish itself at major gastroenterologic centers as an endoscopic procedure with few or no side effects in the treatment of Barrett's esophagus (sever dysplasia and early carcinoma) and, in selected cases, for the treatment of early gastric carcinoma.     

Cardiac cell therapy: a treatment option for cardiomyopathy

Cardiomyopathy is a common clinical disorder affecting the heart muscle. This disease process frequently leads to congestive heart failure and will often progress to end-stage heart failure. Present standard of care treatment options for cardiomyopathy include medical management, lifestyle changes, and surgical procedures including left ventricular assist devices as a destiny therapy or bridging to heart transplantation. Even despite advances in drug therapy, mechanical assist devices, and organ transplantation, more than half of the persons with cardiomyopathy will die within 5 years of diagnosis. Small uncontrolled clinical trials have demonstrated cardiac stem cells as a treatment option for cardiomyopathy. The theory for the individual or combined mechanism of action for stem cells includes (1) transdifferentiation to blood vessels or myocardium, (2) fusion with the native dysfunctional myocytes to augment function, and (3) homing that may be a systemic or panacrine response for recruiting other cells, and growth factors to help improve oxygen delivery and myocardial function. The field of cardiac cell therapy is rapidly progressing to gather more data with intermediate-size, double-blinded trials that will demonstrate the safety and efficacy of cell therapy.     

Therapeutic cancer vaccines: an emerging treatment option

Therapeutic cancer vaccines treat disease by stimulating the body's immune system. They are a form of active immunotherapy with the goal of producing an immune response that involves the cellular and humoral components of the immune system. These two components appear to be complementary and work together to induce tumor regression and long-lasting immunity to the disease being treated. This article reviews the history of cancer vaccine development, autologous and allogeneic vaccines, vaccine targets, carrier proteins, adjuvants, and clinical trial data of studies evaluating cancer vaccines. Knowledge of this emerging cancer treatment option will enable oncology nurses to be informed about cancer vaccines and accurately provide information about them to patients.     

Photodynamic therapy for head and neck cancer

Photodynamic therapy (PDT) is a recently developed treatment involving the use of a photosensitizer and low power light, usually from a laser, to selectively destroy tumor cells. At present, we perform PDT for head and neck cancer using argon or excimer dye lasers with hematoporphyrin derivative as a photosensitizer. This study attempted to assess the utility and safety of PDT and to investigate the long-term outcome. All 24 patients had squamous cell carcinoma: 15 with laryngeal, 5 with lingual or oral, and 4 with pharyngeal cancer and were treated by PDT. Data were obtained from records from February 1988 through April 1995. After PDT, 12 of 15 laryngeal cancer patients were classified as having a complete remission (CR), as were 2 of the 5 lingual or oral and one of the 4 pharyngeal cancer patients. The patients were followed for 8 to 153 months. The longest duration of CR in patients treated by PDT alone was 148 months. Photosensitivity was experienced by all patients, but required no treatment. Liver, kidneys, and bone marrow showed no abnormal values. There were no clinically relevant adverse reactions, and patients with severe complications due to other types of treatment and elderly patients were also treated safely with this therapy.     

Photodynamic therapy

Photodynamic therapy (PDT) is a photochemical process that uses?a photosensitizer drug activated by laser light to produce mucosal ablation. Porfimer sodium PDT has proved long-term efficacy and durability in the treatment of Barrett's esophagus and high-grade dysplasia and early esophageal adenocarcinoma. Its use has been limited by serious side effects including prolonged cutaneous photosensitivity and stricture formation. Other photosensitizers with a better safety profile have been used mostly in Europe with limited experience. The future of PDT lies on a better understanding of dosimetry, tissue properties, and host genetic factors.     

Photodynamic therapy

Photodynamic therapy (PDT) is an alternative treatment option for tumours of the head and neck. The principle of PDT is based on a photochemical reaction, which is initiated by light activation of a photosensitising drug causing tumour cell death. Light is mainly applied by superficial illumination of the tumour and the surrounding tissue causing drug activation followed by tumour cell death. New techniques use glass fibres, which are stabbed into the tumour, leading the light directly into the tumour tissue. Also, the intra-operative application of PDT to treat and “mop-up” the tumour bed of any remaining tumour cells has been reported.PDT damage heals mainly by regeneration rather than scarring. Due to the organ preserving principle of PDT, important structures are maintained with good functional and cosmetic outcome.This article will review the principle of PDT and the different indications for PDT of tumours of the head and neck.

Zusammenfassung

Die Photodynamische Therapie (PDT) stellt eine alternative Behandlungsmöglichkeit für Tumoren im Kopf- und Halsbereich dar. Das Prinzip der PDT basiert auf einer photochemischen Reaktion, die durch die Lichtaktivierung einer photosensiblen Substanz vermittelt wird, welche die Tumorzellen abtötet. Das Licht wird meist oberflächlich auf den Tumor und das umgebende Gewebe gestrahlt, sodass der Photosensibilisator aktiviert und die Tumorzellen abgetötet werden. Neue Techniken verwenden Glasfasern, die in den Tumor implantiert werden und so das Licht direkt in den Tumor hineinleiten. Auch die intra-operative Anwendung der PDT zur Behandlung und Beseitigung von zurückgebliebenen Tumorzellen im Bereich der Tumorresektionsränder wurde beschrieben.Nach Durchführung der PDT heilen die Läsionen meist via Regeneration mit nur geringer Narbenbildung ab. Auf Grund dieses organerhaltenden Prinzips werden wichtige Strukturen erhalten und sind gute funktionelle und kosmetische Ergebnisse zu erwarten.Dieser Artikel befasst sich mit dem Prinzip der PDT sowie den verschiedenen Indikationen für die PDT im Kopf-Halsbereich.     

Photodynamic therapy: a novel treatment for primary brain malignancy.

Providing therapy that conserves healthy brain tissue while effectively killing cancerous tissue remains a major challenge in the treatment of primary malignant brain tumors. The most common primary brain malignancies tend to recur despite intensive therapy, and the side effects of radiotherapy and chemotherapy can have considerable influence on health and quality of life. Photodynamic therapy (PDT) is a new technology being investigated to fulfill the need for a targeted cancer treatment that may reduce tumor recurrence and extend survival with few adverse effects. An investigational treatment, PDT employs wavelength-specific light in combination with a photosensitizing agent. The photosensitizing agent accumulates in tumor cells and is activated by nonthermal light, producing radical oxygen species that locally kill tumor cells. The selectivity of the process makes PDT appealing in the brain, where conservation of healthy tissue is vital. The most widely studied photosensitizer causes several weeks of ocular and cutaneous photosensitivity. Nursing care of the PDT patient includes intracranial pressure monitoring, neurological assessment, and intensive patient and family education. Many new photosensitizing compounds and varying methods of light delivery are being studied. This technology shows promise for the treatment of primary brain malignancies.     

5-氨基乙酰丙酸光动力治疗胰腺癌裸鼠移植瘤的实验研究

目的：探讨以5-氨基乙酰丙酸（5-ALA）作为光敏剂对胰腺癌裸鼠移植瘤进行光动力治疗的疗效。方法：将18只裸鼠随机分为3组，每组6只。A组为荷瘤对照组，不给任何治疗；B组行单纯激光照射，不予任何光敏剂；C组在瘤内注射5-ALA，剂量为30mg／kg，2h后进行肿瘤局部光动力治疗。结果：光动力治疗组（C组）肿瘤体积与对照组（A、B组）相比明显缩小。差异有显著性（P〈0．05）。结论：5-ALA作为光敏剂对胰腺癌裸鼠移植瘤进行光动力治疗，能使肿瘤组织坏死，生长速度明显减慢。     

Laparoscopic prostatectomy: a promising option in the treatment of prostate cancer

It is still too soon to know if a laparoscopic approach is as good or even better than open surgical radical prostatectomy, the gold standard. Early data seem to suggest lower intraoperative bleeding rates, less postoperative pain, shorter hospital stay, and similar rates of oncologic cure, return to potency, and urinary continence.     

Photodynamic therapy: The nurse's role

Patients with neovascular (wet) age-related macular degeneration, the leading cause of blindness in persons older than 50 years in developed countries, experience severe visual loss due to choroidal neovascularization, the growth of abnormal vessels under the retina. Photodynamic therapy is a new treatment modality that combines an intravenous injection of a photosensitizing drug, such as verteporfin, and nonthermal laser light application, which destroys choroidal neovascularization without damaging normal surrounding tissue. It has led to new challenges for nurses working in the ambulatory laser setting, including medication preparation, drug administration, and education regarding precautions and potential systemic side effects of photodynamic therapy. (Insight 2001;26:44-8.)     

Photodynamic therapy decreases cancer colonic cell adhesiveness and metastatic potential

Plasma membrane damage induced in various cell targets by hematoporphyrin (HPD) photodynamic therapy (PDT) could modify cancer cell adhesiveness, an important parameter in cancer metastasis. We investigated the effect of HPD or HPD incubation followed by argon laser light on the adhesiveness of progressive (PROb) or regressive (REGb) cancer cells of the same colonic origin but with a different in vivo metastatic potential. Adhesiveness was studied on plastic or endothelial cell monolayers (ECM). In the absence of treatment, both PROb and REGb cells adhered better on plastic than on ECM. HPD alone or HPD-PDT induced toxicity proportional to the HPD dose. HPD-PDT increased the adhesiveness rate of both cell lines on plastic and decreased it on ECM. HPD-PDT of ECM increased adhesiveness, but only at HPD doses causing at least 50% cell death. With HPD treatment alone or HPD-PDT of culture media, there was no significant decrease in cell adhesiveness to ECM. We also studied the effect of HPD or HPD incubation followed by argon laser light on the metastatic potential of cancer cells, which was decreased for PROb with HPD alone or HPD-PDT. Decreased adhesiveness of colonic cancer cells to ECM after HPD-PDT was thus correlated with decreased metastatic potential. REGb cells did not acquire a progressive phenotype either in vitro or in vivo after HPD-PDT. This work was supported by grants (No. 6727 and 6405) from the Association pour la Recherche sur le Cancer     

Photodynamic therapy in Barrett's esophagus

Photodynamic therapy (PDT) was one of the earliest ablative techniques applied to Barrett's esophagus. The rationale for this use was the ability to treat large amounts of esophageal mucosa in a single rapid application. Additionally, PDT has the ability to treat early carcinoma and dysplastic tissue. Because a small carcinoma in dysplastic Barrett's esophagus cannot not be excluded, PDT therapy is a reasonable treatment in this setting. The treatment involves the use of a light and drug combination that must be administered with close attention to dosimetry, since tissue effects of the therapy are delayed and cannot be observed at the time of treatment. Drug administration of sodium porfimer should precede photoradiation by 48 hours. Overall results with this treatment have been good. Case series have established a success rate of 88% to 100% in elimination of high-grade dysplasia. The only randomized multi-center prospective trial in the treatment of Barrett's esophagus with high-grade dysplasia has established that the treatment eliminates high-grade dysplasia better than administration of proton pump inhibitors alone. Unfortunately, there are significant adverse events, including cutaneous photosensitivity, odynophagia, stricture formation, and lack of response.     

Photodynamic therapy as salvage therapy for residual microscopic cancer after ultra-low anterior resection: A case report

BACKGROUND The rate of positive resection margins(R1) in patients with low rectal cancer is substantial. Recommended remedies such as extended resection or chemoradiotherapy have their own serious drawbacks. It has been reported that photodynamic therapy(PDT) as a remedial treatment for esophageal cancer.Colorectal cancer and esophageal cancer has many similarities,however,PDT as a salvage therapy for rectal cancer is rare.CASE SUMMARY Here,we describe a 56-year-old man who was admitted to the hospital due to a 6-mo history of hemafecia,which had been aggravated for 1 mo. Colonoscopy revealed a 3 × 4 cm ulcerated mass in the rectum 4 cm from the anus.Preoperative pathological examination showed villous adenoma,moderate-tohigh-grade dysplasia,good differentiation,and invasion of the mucosal muscle.The patient had R1 after ultra-low anterior resection,but he refused extended resection and experienced severe liver function impairment after 3 cycles of chemotherapy. Ultimately,the patient underwent PDT to remove R1. After five years of follow-up,there was no liver function impairment,recurrence,metastasis,sexual dysfunction,or abnormal defecation function.CONCLUSION This is the first case worldwide in which R1 of rectal cancer were successfully treated by PDT.