Intraoperative photodynamic therapy for retroperitoneal sarcomas

Advanced Nanotechnology Leading the Way to Multimodal Imaging-Guided Precision Surgical Therapy

Surgical resection is the primary and most effective treatment for most patients with solid tumors. However, patients suffer from postoperative recurrence and metastasis. In the past years, emerging nanotechnology has led the way to minimally invasive, precision and intelligent oncological surgery after the rapid development of minimally invasive surgical technology. Advanced nanotechnology in the construction of nanomaterials (NMs) for precision imaging-guided surgery (IGS) as well as surgery-assisted synergistic therapy is summarized, thereby unlocking the advantages of nanotechnology in multimodal IGS-assisted precision synergistic cancer therapy. First, mechanisms and principles of NMs to surgical targets are briefly introduced. Multimodal imaging based on molecular imaging technologies provides a practical method to achieve intraoperative visualization with high resolution and deep tissue penetration. Moreover, multifunctional NMs synergize surgery with adjuvant therapy (e.g., chemotherapy, immunotherapy, phototherapy) to eliminate residual lesions. Finally, key issues in the development of ideal theranostic NMs associated with surgical applications and challenges of clinical transformation are discussed to push forward further development of NMs for multimodal IGS-assisted precision synergistic cancer therapy.

Primary and recurrent retroperitoneal soft tissue sarcoma: prognostic factors affecting survival

BACKGROUND AND OBJECTIVES

To analyze treatment and survival in 34 patients (28 resected) with primary or recurrent retroperitoneal sarcoma (RPS).

METHODS

Between July 1994 and January 2001, 34 patients (15M, 19F; mean age: 56 years, range: 25-77) were evaluated. Complete resection was defined as removal of gross tumor with histologically confirmed clear resection margins.

RESULTS

Twenty-eight out of 34 patients (82%) (15 were affected by primary RPS, and 13 by recurrent RPS), underwent surgical exploration. Twenty-three patients had a grossly and microscopically complete resection, (3 having a grossly incomplete resection and 2 patients with a grossly complete resection having histologically involved resection margins). Twenty-one out of 28 patients (75%) underwent removal of contiguous intra-abdominal organs. Preoperative mortality was nil, and morbidity occurred in six cases only (21%). High tumor grade results a significant variable for a worse survival in all 28 patients (100% 5 years survival for low grade vs. 0% for high grade; P = 0.0004). Amongst completely resected patients, only histologic grade and peroperative blood transfusions affected disease-free survival (P = 0.04 and P = 0.05, respectively).

CONCLUSIONS

An aggressive surgical approach in both primary and recurrent RPS is associated with long-term survival.

Specific intensity imaging for glioblastoma and neural cell cultures with 5-aminolevulinic acid-derived protoporphyrin IX

The fluorescence of protophorphyrin IX (PpIX) synthesized after incubation with 5-aminolevulinic acid (5-Ala) is used for the intraoperative visualisation of glioma cells in vivo. Such fluorescence may also be useful for the photodynamic therapy (PTD) of gliomas. A significant difference of fluorescence intensity in tumor cells compared to neurons is required for this application. To explore this, eight human glioma cell lines (LN-18, LN-428, U87MG, U373MG, D247MG, U251MG, LN-308, T98G) were compared with human astrocytes (SV-FHAS) and rat neurons after incubation for different periods of time in vitro with 5-Ala (1 mg/ml). Fluorescence intensity profiles were measured by a digital camera comparing glioma cell lines with control cells. All glioma cell lines could be discriminated from neural cells by their intensity of fluorescence by post-hoc tests for pairwise comparisons using Tukey's honestly significant difference test, at the global significance level of 5%. The glioma cell lines showed significant variation in this possibly limiting clinical use of fluorescence as a guide for resection.

Preliminary report of photodynamic therapy for intraperitoneal sarcomatosis

INTRODUCTION

Sarcomatosis is the disseminated intraperitoneal spread of sarcoma. It is a condition for which there is no effective treatment. Photodynamic therapy (PDT) is a cancer treatment modality that uses a photosensitizing agent and laser light to kill cells. We report our preliminary Phase II clinical trial experience using PDT for the treatment of intraperitoneal sarcomatosis.

METHODS

From May 1997 to December 1998 eleven patients received twelve PDT treatments for intraperitoneal sarcomatosis. Photofrin (PF) 2.5 mg/kg was administered intravenously 48 hours before surgical debulking to a maximum residual tumor size of less than 5 mm. Light therapy was administered at a fluence of 2.5 J/cm2 of 532 nm green light to the mesentery and serosa of the small bowel and colon; 5 J/cm2 of 630 nm red light to the stomach and duodenum; 7.5 J/cm2 of red light to the surface of the liver, spleen, and diaphragms; and 10 J/cm2 of red light to the retroperitoneal gutters and pelvis. Light fluence was measured with an on-line light dosimetry system. Response to treatment was evaluated by abdominal CT scan at 3 and 6 months, diagnostic laparoscopy at 3 to 6 months, and clinical examination every 3 months.

RESULTS

Adequate tumor debulking required an omentectomy in eight patients (73%), small bowel resection in seven patients (64%), colon resection in four patients (36%), splenectomy in one patient (9%), and a left spermatic cord resection in one patient. Five patients (45%) have no evidence of disease at follow-up (range, 1.7-17.3 months), including patients at 13.8 and 17.3 months examined by CT. Two patients (18%) died from disease progression. Four patients (36%) are alive with disease progression. Toxicities related to PDT included substantial postoperative fluid shifts with volume overload, transient thrombocytopenia, and elevated liver function tests. One patient suffered a postoperative pulmonary embolism complicated by adult respiratory distress syndrome (ARDS).

CONCLUSIONS

Debulking surgery with intraperitoneal PDT for sarcomatosis is feasible. Preliminary response data suggest prolonged relapse-free survival in some patients. Additional follow-up with more patients will be necessary for full evaluation of the added benefit of PDT and aggressive surgical debulking in these patients.

Photodynamic therapy in dermatology

The combination of light and chemicals to treat skin diseases is widely practiced in dermatology. Within this broad use of light and drugs, in recent years the concept of photodynamic therapy (PDT) has emerged. PDT is a promising modality for the management of various tumors and nonmalignant diseases, based on the combination of a photosensitizer that is selectively localized in the target tissue and illumination of the lesion with visible light, resulting in photodamage and subsequent cell death. Moreover, the fluorescence of photosensitizing compounds is also utilized as a helpful diagnostic tool for the detection of neoplastic tissue. Intensive basic and clinical research culminated in the worldwide approval of PDT for bladder, esophageal, and lung cancer. The expanding use of this relatively new therapeutic modality in dermatology at many centers around the world has revealed its efficacy for the treatment of cutaneous precancer and cancer, as well as selected benign skin disorders. The following article summarizes the main principles of PDT considering the most recent developments and provides a comprehensive synopsis of the present status of the use of PDT in dermatology. (J Am Acad Dermatol 2000;42:389-413.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should be able to describe the basic concepts of PDT, including fundamental knowledge of the most relevant photosensitizers, the light sources, the mechanisms involved in PDT-mediated cell destruction, as well as the indications and limitations of photodynamic treatment of skin diseases.

Current concepts in gastrointestinal photodynamic therapy

OBJECTIVE

To review current concepts of photodynamic therapy (PDT) applied to the treatment of tumors of the gastrointestinal tract.

SUMMARY BACKGROUND DATA

PDT initially involves the uptake or production of a photosensitive compound by tumor cells. Subsequent activation of the photoreactive compound by a specific wavelength of light results in cell death, either directly or as a result of vascular compromise and/or apoptosis.

METHODS

The authors selectively review current concepts relating to photosensitization, photoactivation, time of PDT application, tissue selectivity, sites of photodynamic action, PDT effects on normal tissue, limitations of PDT, toxicity of photosensitizers, application of principles of PDT to tumor detection, and current applications of PDT to tumors of the gastrointestinal tract.

RESULTS

PDT is clearly effective for small cancers, but it is not yet clear in which cases such treatment is more effective than other currently acceptable approaches. The major side effect of PDT is cutaneous photosensitization. The major limitation of PDT is depth of tumor kill. As data from current and future clinical trials become available, a clearer perspective of where PDT fits in the treatment of cancers will be gained. Many issues regarding pharmacokinetic data of photosensitizers, newer technology involved in light sources, optimal treatment regimens that take advantage of the pharmacophysiology of photoablation, and light dosimetry still require solution. One can foresee application of differing sensitizers and light sources depending on the specific clinical situation. As technologic advances occur, interstitial PDT may have significant application.

CONCLUSIONS

PDT has a potentially important role either as a primary or adjuvant mode of treatment of tumors of the gastrointestinal tract.

Foscan-mediated photodynamic therapy for a peritoneal-cancer model: drug distribution and efficacy studies

Distribution of the photosensitizer Foscan (meta-tetrahydroxyphenylchlorin, mTHPC), after i.v. or i.p. injection, was investigated in Wag/Rij rats bearing i.p. tumours. These results were compared with the efficacy of mTHPC-mediated photodynamic therapy for illumination intervals of 4 hr to 3 days. For the distribution experiments a single tumour (CC53I colon carcinoma) was implanted intra-abdominally in a fat pad, or a cell suspension (1 x 10(6) CC531 cells) was injected into the peritoneal cavity, which results in a dissemination of tumour nodules on the peritoneum. 14C-mTHPC was not selectively taken up in the single-tumour model after i.v. or i.p. injection, but higher concentrations were achieved for i.p. administration. For this tumour model the concentration ratios between tumour and normal tissue never exceeded a value of 3. In the disseminated-tumour model, an uptake of up to 40% of the injected dose was found per gram tumour at 4 hr after an i.p. injection and this resulted in very high (> 14) concentration ratios of tumour to normal tissues. Low uptake was found after the i.v. injection route (1% of the injected dose per gram tumour) with lower tumour/normal tissue ratios (<8). The efficacy of i.p. photodynamic therapy (IPPDT) was evaluated using the single-tumour model only. The lower abdomen was illuminated at 4 hr to 3 days after mTHPC, and tumour size was repeatedly measured via a small laparoscopy. Significant delay in tumour regrowth was achieved for 6 J x cm-2 at 1 day after i.v., or at 4 hr after i.p. mTHPC (p values 0.019 and 0.045 respectively). Response to PDT, of tumours implanted in the fat pad, was not greater for i.p. administration of the photosensitizer and there was a poor correlation between times of maximum drug uptake in tumours and optimal illumination times for PDT efficacy.

Intraoperative photodynamic therapy with m-tetrahydroxyphenylchlorin for chest malignancies

BACKGROUND AND OBJECTIVE

Since there is no satisfactory treatment modality for diffuse malignant mesothelioma of the chest, we assessed surgical tumor resection followed by intraoperative photodynamic therapy with mTHPC in a phase I study.

STUDY DESIGN/MATERIALS AND METHODS

Since 1990, eight patients have undergone intraoperative photodynamic therapy with m-tetrahydroxyphenylchlorin (mTHPC-PDT) following thoracotomy and surgical tumor resection.

RESULTS

mTHPC-PDT-mediated tumor necrosis was characterized by tumor infarction due to tumor vessel necrosis and thrombosis, and its extent depended on drug-light conditions; 650 nm light delivered at 0.1 W/cm2 for 10 J/cm2 48 h after iv administration of 0.3 mg mTHPC/kg resulted in a 10-mm-deep complete tumor necrosis. Skin photosensitivity was related to the drug dose applied and occurred up to 17 days after iv administration of 0.3 mg mTHPC/kg, mTHPC-PDT of brachial plexus infiltrated by mesothelioma resulted in pain relief without deterioration of nerve function.

CONCLUSION

Tumor resection and intraoperative mTHPC-PDT of the chest cavity is feasible under clinical conditions and offers local tumor control of sites involved. However, distant tumor spread was not prevented by this combined treatment modality and optimization of mTHPC-PDT is warranted for further intraoperative application.

Photodynamic therapy for obstructing esophageal cancer: light dosimetry and randomized comparison with Nd:YAG laser therapy

BACKGROUND & AIMS

Light dosimetry analysis to achieve predictable tumor necrosis has not been performed for photodynamic therapy (PDT) in the gastrointestinal tract. We evaluated dihematoporphyrin ethers for sensitizing esophageal carcinomas to 630 nm light and compared PDT with neodymium:yttrium-aluminum-garnet (Nd:YAG) laser therapy in a randomized trial.

METHODS

Of 52 patients with dysphagia, 32 received palliative PDT. Ten patients treated with PDT participated in a preliminary trial using various doses of 630-nm light, and 22 patients treated with PDT participated in a randomized trial using a derived standardized light dose for comparison with 20 patients treated with the Nd:YAG laser.

RESULTS

Light dosimetry correlated with depth of tumor necrosis (r = 0.664; P < 0.001). PDT activity was similar for squamous cell and adenocarcinoma. Among randomized patients, both PDT and Nd:YAG therapy relieved dysphagia, but PDT resulted in improved Karnofsky performance status at 1 month (+7 vs. -7; P < 0.001) and longer duration of response (84 vs. 57 days; P = 0.008). Skin photoreactions were unique to PDT.

CONCLUSIONS

The extent of PDT tumor ablation correlates with light dosimetry, enabling selection of a standardized light dose. PDT can relieve esophageal obstruction from squamous cell and adenocarcinoma and is an alternative to Nd:YAG thermal necrosis with a longer duration of response. However, PDT requires patient precautions to minimize skin photoreactions.

Adjuvant intraoperative photodynamic therapy diminishes the rate of local recurrence in a rat mammary tumour model

The use of photodynamic therapy (PDT) as an adjunct to curative tumour resection was investigated in a tumour recurrence model, using rat mammary adenocarcinoma BN472. Tumours were inoculated subcutaneously in 60 animals and resected after 21 days of growth. Immediately after removal, the operation site was exposed to 320-450 nm light of 0.1 W cm-2 and 60 J cm-2 after photosensitisation with either Photofrin (5 mg kg-1 i.v. 48 h before illumination) or 5-aminolaevulinic acid (ALA) (2 mg ml-1 in drinking water for 9 days). Porphyrin concentrations were measured in tissue samples. After 28 days, animals treated with adjunctive PDT had a significantly longer tumour-free interval than controls (P < 0.01); median 25 days (Photofrin), 18 days (ALA), 14 days (controls). Moreover, in the PDT groups significantly fewer rats had lymph node metastasis. A prophyrin concentration ratio between tumour and mammary tissue of 2:1 was found after Photofrin and 4:1 after ALA. The results indicate that adjuvant intraoperative PDT may be a safe and effective method of destroying residual tumour, thereby preventing locoregional tumour recurrence.

Laser-induced fluorescence studies of meso-tetra(hydroxyphenyl)chlorin in malignant and normal tissues in rats

meso-Tetra(hydroxyphenyl)chlorin (mTHPC) is an attractive second-generation dihydroporphyrin photosensitiser for use in photodynamic therapy. In this study, 1.3 mg kg-1 body weight mTHPC was administered intravenously, and laser-induced fluorescence was used to characterise and compare its localisation and retention in different rat tissues, including an induced experimental adenocarcinoma, 24 h and 48 h post injection. These studies were performed in an attempt to predict the anatomical locations where mTHPC PDT might be most effective and suggest suitable injection--irradiation intervals in each case. Of particular interest were the intra-abdominal and intrathoracic tissues. The fluorescence was induced at 405 nm and the fluorescence spectrum in the region 450-750 nm was analysed. All collected spectra were dominated by the fluorescence signature of mTHPC with its peak at 652 nm, and all values in this study are in terms of background-free drug-specific fluorescence intensity at that wavelength. The photosensitiser accumulated in high concentrations in the tumour and the reticuloendothelial system. Muscular organs, such as the heart and the abdominal wall, were characterised by a low drug fluorescence signature.

Photodynamic therapy with m-tetrahydroxyphenylchlorin in vivo: optimization of the therapeutic index

The therapeutic index of meta-tetrahydroxyphenylchlorin-mediated photodynamic therapy (mTHPC-PDT) was assessed in BALB/c nude mice bearing human malignant mesothelioma xenografts. Equal doses of 650 nm laser light were delivered to the tumour and to an equal-sized area of the hind leg (control site) after i.p. administration of mTHPC. Twenty-one groups of 6 animals each were treated under various drug-light conditions and at drug-light intervals ranging from 4 hr to 6 days. After light delivery the extent of tumour necrosis and the depth of alterations in normal tissue were assessed by light microscopy of standardized histological sections. A therapeutic index (TI) of mTHPC-PDT was defined as the cross-sectional area of tumour necrosis per depth of visible tissue injury at the control site. This TI was strongly related to the conditions of treatment. In particular, it was increased by prolonging the drug-light interval up to 5 days and by increasing the dose of light for any dose of drug. The most profound increase of TI was obtained by increasing the intensity of light administered at the chosen interval while reducing the dose of drug. Our findings suggest that threshold conditions operate in PDT and have important implications for clinical application of the treatment.

In vitro photodynamic therapy of musculoskeletal neoplasms

Photodynamic therapy is a tumoricidal modality that utilizes an inactive pharmacologic agent that becomes activated on exposure to visible light. Neoplasms selectively retain and accumulate photosensitizers at levels generally higher than surrounding non-neoplastic tissues. The purpose of this study was to establish a testing method for in vitro investigation of the effects of photodynamic therapy on human musculoskeletal neoplasms by examination of the sensitivity of these tumors to photoactivation. Three human musculoskeletal neoplasms were cultured, exposed to the photosensitizer Photofrin, and then studied for their response to photodynamic therapy after laser activation. Giant-cell tumor, dedifferentiated chondrosarcoma, and osteosarcoma were examined with use of strict experimental controls. The photoradiation conditions during photodynamic therapy were kept constant. Cell viability was determined as a function of energy dose. We concluded that the three musculoskeletal tumors were susceptible to in vitro photodynamic therapy and the test system was reproducible. The optimal in vitro nontoxic incubation concentration of Photofrin was 3 micrograms/ml. A differential cytotoxic response to photodynamic therapy was exhibited by the musculoskeletal neoplasms as a function of increased dosages of energy.

Intra-abdominal photodynamic therapy: from theory to feasibility

Photodynamic therapy is a new anticancer technique, directed at the selective destruction of neoplastic tissue, which has been used in the treatment of superficial or intraluminal lesions. The technique has now reached the stage where it can be considered in the peroperative management of gastrointestinal tumours, for example in an attempt to eradicate micrometastases in the tissue around the primary tumour or in residual lymph nodes after curative resection. Many practical problems remain to be solved, such as the pharmacokinetics of photosensitizers, the dosimetry of illumination and the sensitivity of intra-abdominal organs. An experimental and clinical evaluation is in progress to assess the feasibility of photodynamic therapy in surgical practice.

Effect of drug-light interval on photodynamic therapy with meta-tetrahydroxyphenylchlorin in malignant mesothelioma

The influence of the time interval (TI) between drug administration and laser activation on selectivity of meta-tetrahydroxyphenylchlorin(mTHPC)-mediated photodynamic therapy (PDT) for tumour tissue was assessed in BALB/c nude mice bearing human malignant mesothelioma xenografts. Following i.p. administration of 0.3 mg/kg mTHPC, a light dose of 10 J/cm2 and 0.1 W/cm2 was delivered at 650 nm on the tumour and an equal-sized area of the hind leg after 4, 12, 24 and 36 hr and 2, 3, 4, 5 and 6 days to groups of 6 animals (surface irradiance). Then, 72 hr after light delivery, the depth of necrosis was measured in the tumour and in the skin and underlying muscle of the hind leg. Photosensitized necrosis occurred in normal tissue at TI from 4 hr to 3 days and in the tumour at TI from 12 hr to 4 days. The therapeutic ratio of mTHPC-PDT varied significantly with the time interval between drug administration and laser activation and was greatest at an interval of 3 days. mTHPC concentration was measured in 3 control unirradiated animals at all time points in normal tissues and in tumour tissue, and found to be the same in both tissues. Thus the tissue concentration of mTHPC was of limited use as regards the prediction of photosensitizing effects in the tumour model.

Experimental photodynamic therapy with a copper metal vapor laser in colorectal cancer

In an attempt to define the best conditions for an adjunctive treatment of residual colonic microtumors by photodynamic therapy (PDT), an experimental model has been defined. S.c. HT29 colonic-cancer-cell tumors grown in nude mice were used and, 48 hr after i.p. administration of 30 mg/kg Photofrin (PH), laser illumination was performed with 75 or 150 Joules/cm2. The efficiencies of 2 lasers, the classically used rhodamine laser (RL) and a copper metal vapor laser (CMVL), were compared. The effects of PDT were assessed by histological and immunocytochemical (detection of a digestive enzyme, dipeptidyl-peptidase IV, as a marker of cell viability) follow-up and by the growth curve of the tumors after illumination. We conclude that, although the depth of necrosis resulting from PDT was nearly 3 mm at 75 J/cm2 and nearly 4-5 mm at 150 J/cm2 with both lasers, complete necrosis was obtained only with the CMVL at 150 J/cm2 (in 50% of the tumors). Under the other conditions, a layer of unaffected cells persisted at the pole opposite to laser illumination, resulting in growth curves lower than but parallel to those of the controls. Analysis of drug concentrations in the tumors and various organs, 48 hr after injection, i.e., at the time of laser illumination, revealed the presence of 21 micrograms/g dry weight PH in the tumors. The tumor vs. host-organ ratios were equal to or higher than 1 for the small bowel, colon, stomach, lung, skin and muscle. In contrast, the ratios were below 1 for the spleen, pancreas, kidney and liver.

Laser and photodynamic therapy of esophageal cancer

With proper selection of patients with non-operative esophageal cancer, palliative therapy with Nd:YAG laser enhances the quality of life by improving the patient's ability to swallow soft or solid food. Also, the use of non-thermal laser light to initiate the process of photodynamic therapy (PDT) is an additional laser technique that appears effective, not just in palliative treatment, but also in the cure of early esophageal cancer. For PDT, considerable work will be necessary to provide standard techniques in tumor staging, light and drug delivery and in light dosimetry. Ultimately, palliative and curative therapy of esophageal cancer will most likely incorporate multiple modalities, including surgery, radiation, chemotherapy, stents, laser and other thermal modalities, photodynamic therapy, and combinations of these methods.

Photodynamic therapy

Photodynamic therapy (PDT) has been developed over the past decade into a useful treatment for several types of solid cancers in man. This unique therapy requires a photosensitiser accumulated in tumours and local activation by visible light generally delivered from lasers and delivered to the patient through various types of fibers and endoscopes. PDT appears to be most effective in treating certain superficial, difficult to treat cancers such as carcinoma in situ of the urinary bladder (here complete control is the intent), but also is effectively used in bulkier tumours obstructing bronchi or the oesophagus where palliation can be achieved. The primary mechanism of action is the in situ generation of an active form of molecular oxygen (singlet oxygen) which causes the rapid, local onset of vascular stasis and eventual vascular haemorrhage and tumour wall destruction. This process appears to be mediated through various cytokines such as prostaglandin, lymphokines and thromboxanes. The ultimate clinical value of PDT will be seen over the next few years following health agency approval worldwide.

Photodynamic therapy with chlorins for diffuse malignant mesothelioma: initial clinical results

Four patients underwent intraoperative photodynamic therapy after surgery with meso-tetra-(hydroxyphenyl)-chlorin (mTHPC-PDT) for diffuse malignant mesothelioma. Preliminary procedures were performed in two patients in order to establish the efficacy of mTHPC-PDT and to optimise its tumoricidal effect. The tumoricidal effect was related to the mTHPC dose, light dose and the time interval between sensitation and activation. 0.3 mg kg-1 mTHPC activated after 48 h with 10 Joules cm-2 of non-thermal laser light at 650 nm resulted in a 10 mm deep tumour infarction, due to tumour vessel necrosis and thrombosis. The mTHPC tissue concentration was up to 14 times higher in the tumour than in normal tissues. Skin photosensitivity was mild, dose dependent and occurred 3 to 10 days after administration of mTHPC. According to the results obtained, intraoperative mTHPC-PDT was performed following pleuropneumonectomy in two, pleurectomy and lobectomy in one and pleurectomy in one patient. Ten Joules cm-2 were delivered to the diaphragm and the costophrenic sulcus and 5 Joules cm-2 to the remaining thoracic cavity. The postoperative course was marked by loss of appetite, fluid retention, hypoproteinemia and severe chest pain. One patient succumbed from aspiration pneumonia. The remaining patients developed no neural or vascular alterations and no bronchial stump insufficiency during follow-up. mTHPC-PDT following surgical tumour resection deserves further evaluation in good risk patients with diffuse malignant mesothelioma.

Intravenous vs intraperitoneal sensitizer: implications for intraperitoneal photodynamic therapy

Photodynamic therapy (PDT) is a potential treatment for peritoneal carcinomatosis. However, little data is available regarding the relative distribution of sensitizer to tumor and intra-abdominal organs, optimal route of sensitizer administration, and maximal tolerated light dose. Tumor and normal tissue sensitizer levels were measured by tissue extraction 3, 24, 48 and 72 h after 10 mg/kg of Photofrin II was given intraperitoneally (IP) or intravenously (IV) in a mouse peritoneal tumor model, and the maximal tolerated PDT light dose determined. Equivalent tumor sensitizer levels were obtained regardless of the route of sensitizer administration. Route of administration, however, did affect the kinetics of tumor sensitizer elimination, with the half-time for elimination (T1/2) 113.6 h for IP drug and 60.6 h for IV drug. Route of administration also affected sensitizer levels in several intra-abdominal organs, resulting in somewhat higher tumor to liver and kidney levels at 24 and 72 h after IP sensitizer administration. Despite these tissue distribution differences, route of sensitizer administration did not significantly affect PDT toxicity or mortality when mice were treated with 630 nm light. The maximum tolerated light dose was 1.04 J/cm2. These parameters will prove helpful in designing large scale animal trials assessing the efficacy and safety of intra-abdominal PDT.

Management of primary and recurrent soft-tissue sarcoma of the retroperitoneum

From 1982 to 1987, 114 patients underwent operation at Memorial Sloan-Kettering Cancer Center for soft-tissue sarcoma of the retroperitoneum. A retrospective analysis of these patients defines the biologic behavior, surgical management of primary and recurrent disease, predictive factors for outcome, and impact of multimodality therapy. Complete resection was possible in 65% of primary retroperitoneal sarcomas and strongly predicts outcome (p less than 0.001). The rate of complete resection was not altered by histologic type, size, or grade of tumor. These patients had a median survival of 60 months compared to 24 months for those undergoing partial resection and 12 months for those with unresectable tumors. Forty-nine per cent of completely resected patients have had local recurrence. This is the site of first recurrence in 75% of patients. These patients undergo reoperation when feasible. Complete resection of recurrent disease was performed in 39 of 88 (44%) operations, with a 41-month median survival time after reoperation. Tumor grade was a significant predictor of outcome (p less than 0.001). High-grade tumors (n = 65) were associated with a 20-month median survival time compared to 80 months for low-grade tumors (n = 49). Gender, histologic type, size, previous biopsy, and partial resection versus unresectable tumors did not predict outcome by univariate analysis. Adjuvant radiation therapy and chemotherapy could not be shown to have significant impact on survival. Concerted attempt at complete resection of both primary and recurrent retroperitoneal soft-tissue sarcoma is indicated.

Potentiation of phototherapy cytotoxicity with light scattering media

Lung cancer cells are susceptible to photodynamic therapy (PDT) using 630 nm light and dihematoporphyrin ether (DHE). A light scattering media, intralipid (IL), was compared to balanced salt solution (PBS) for PDT of A549 human lung cancer cells. Differences in cellular DHE content after IL or PBS exposure were determined. Cells were incubated in 25 micrograms/ml DHE for 2 hr and then incubated in various concentrations of IL or PBS at room temperature for 2.5 to 10.0 min. Significant amounts of DHE were lost from IL-incubated cells compared to cells incubated in PBS. After 5 min in 1% IL, cellular DHE content was 0.32 +/- 0.04 microgram DHE/10(6) cells compared to 0.56 +/- 0.11 microgram DHE/10(6) cells in PBS-incubated cells (P less than 0.05). Despite this, superior PDT cytotoxicity was noted when cells were treated in IL with energy densities greater than or equal to 105 mJ/cm2. At an energy density of 210 mJ/cm2, the survival fraction (SF) of cells treated in 1% IL was 0.004 +/- 0.001 compared to 0.071 +/- 0.022 in PBS-treated cells (P less than 0.05). SF was dependent upon the IL concentration with the greatest cell killing noted with 1% IL. An apparent loss of cellular DHE ("DHE washout") was confirmed by demonstration of a higher SF of cells incubated in IL, rinsed, and subsequently PDT-treated in PBS with 157.5 mJ/cm2 (SF = 0.85 +/- 0.11) compared to cells incubated and treated in PBS (SF = 0.50 +/- 0.03, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)