Treatment of early stage non-small cell lung cancer

Myt1 overexpression mediates resistance to cell cycle and DNA damage checkpoint kinase inhibitors

Cell cycle checkpoint kinases serve as important therapeutic targets for various cancers. When they are inhibited by small molecules, checkpoint abrogation can induce cell death or further sensitize cancer cells to other genotoxic therapies. Particularly aberrant Cdk1 activation at the G2/M checkpoint by kinase inhibitors causing unscheduled mitotic entry and mitotic arrest was found to lead to DNA damage and cell death selectively in cancer cells. Promising drugs inhibiting kinases like Wee1 (Adavosertib), Wee1+Myt1 (PD166285), ATR (AZD6738) and Chk1 (UCN-01) have been developed, but clinical data has shown variable efficacy for them with poorly understood mechanisms of resistance. Our lab recently identified Myt1 as a predictive biomarker of acquired resistance to the Wee1 kinase inhibitor, Adavosertib. Here, we investigate the role of Myt1 overexpression in promoting resistance to inhibitors (PD166285, UCN-01 and AZD6738) of other kinases regulating cell cycle progression. We demonstrate that Myt1 confers resistance by compensating Cdk1 inhibition in the presence of these different kinase inhibitors. Myt1 overexpression leads to reduced premature mitotic entry and decreased length of mitosis eventually leading to increased survival rates in Adavosertib treated cells. Elevated Myt1 levels also conferred resistance to inhibitors of ATR or Chk1 inhibitor. Our data supports that Myt1 overexpression is a common mechanism by which cancer cells can acquire resistance to a variety of drugs entering the clinic that aim to induce mitotic catastrophe by abrogating the G2/M checkpoint.

Bronchoscopic treatment of inoperable nonsmall cell lung cancer

Patients with unresectable lung cancer range from those with early-stage or pre-invasive disease with comorbidities that preclude surgery to those with advanced stage disease in whom surgery is contraindicated. In such cases, a multidisciplinary approach to treatment is warranted, and may involve medical specialties including medical oncology, radiation oncology and interventional pulmonology. In this article we review bronchoscopic approaches to surgically unresectable lung cancer, including photodynamic therapy, brachytherapy, endoscopic ablation techniques and airway stenting. Current and past literature is reviewed to provide an overview of the topic, including a highlight of potential emerging approaches.

Role of bronchoscopy in management of central squamous cell lung carcinoma in situ

Squamous cell carcinoma in situ (SCIS) is the pre-invasive stage of squamous cell carcinoma. Early detection and management of SCIS can prevent further progression. Although surgery and external beam radiation therapy are treatment options for SCIS, smaller lesions can be easily managed by bronchoscopic modalities like photodynamic therapy (PDT), cryotherapy, mechanical debulking with biopsy forceps, electrocautery and argon plasma coagulation (APC). Endobronchial brachytherapy (EBBT) and lasers may be judiciously utilized in selected cases. Although, previous studies of treatment modalities may have inadvertently included cases of invasive carcinomas, the advent of new technologies like radial probe endobronchial ultrasound (RP-EBUS) and optical coherence tomography (OCT) can help accurately determine the of depth of invasion. Superficial extent can also be better demarcated with techniques like auto-fluorescence bronchoscopy and narrow band imaging (NBI). New drugs for PDT with deeper penetration and less phototoxicity are being developed. These advances hopefully will allow us to perform superior clinical trials in future and improve our understanding of diagnosis and management of SCIS.

LiGa5O8:Cr-based theranostic nanoparticles for imaging-guided X-ray induced photodynamic therapy of deep-seated tumors

Using X-ray as the irradiation source, a photodynamic therapy process can be initiated from under deep tissues. This technology, referred to as X-ray induced PDT, or X-PDT, holds great potential to treat tumors at internal organs. To this end, one question is how to navigate the treatment to tumors with accuracy with external irradiation. Herein we address the issue with a novel, LiGa₅O₈: Cr (LGO:Cr)-based nanoscintillator, which emits persistent, near-infrared X-ray luminescence. This permits deep-tissue optical imaging that can be employed to guide irradiation. Specifically, we encapsulated LGO:Cr nanoparticles and a photosensitizer, 2,3-naphthalocyanine, into mesoporous silica nanoparticles. The nanoparticles were conjugated with cetuximab and systemically injected into H1299 orthotopic non-small cell lung cancer tumor models. The nanoconjugates can efficiently home to tumors in the lung, confirmed by monitoring X-ray luminescence from LGO:Cr. Guided by the imaging, external irradiation was applied, leading to efficient tumor suppression while minimally affecting normal tissues. To the best of our knowledge, the present study is the first to demonstrate, with systematically injected nanoparticles, that X-PDT can suppress growth of deep-seated tumors. The imaging guidance is also new to X-PDT, and is significant to the further transformation of the technology.

Successful treatment of limited-stage small-cell lung cancer in the right mainstem bronchus by a combination of chemotherapy and argon plasma coagulation

The current standard-of-care treatment for patients with limited-stage small-cell lung cancer (SCLC) is concurrent chemoradiotherapy for local and systemic control. However, standard-of-care treatment strategies have not been established for those with limited-stage SCLC who have a history of thoracic radiotherapy due to concerns with complications associated with radiation overdose. A 37-year-old male developed an aspergilloma in the postoperative left thoracic space after he was treated with concurrent chemoradiotherapy for mediastinal type lung adenocarcionoma and subsequent left upper lobectomy for heterochronous dual adenocarcinoma. Fiberoptic bronchoscopy was performed to examine the status of the suspected bronchopleural fistula when a polypoid mass was observed in the right mainstem bronchus. A histological examination showed that the mass was SCLC at a clinical stage of cTisN0M0, stageIA, without local invasion. Since thoracic radiotherapy was not an option due to a previous history of thoracic irradiation, a combination treatment of carboplatin and etoposide was administered for 4 cycles and resulted in good partial response. In addition, argon plasma coagulation (APC) was performed as an alternative to curative radiotherapy on day 22 of the 4th cycle. The 5th cycle was administered 7 days after APC at which the anticancer therapy was completed. The patient remains disease-free 60 months after the completion of treatment, which suggests that this combination therapy may resolve very early-stage SCLC.

Minimally Invasive but Maximally Obstructive: Carcinoma In Situ Obstructing a Mainstem Bronchus

Here we report a case of mainstem bronchus obstruction due to a carcinoma in situ. Preinvasive lesions, such as carcinoma in situ, are usually small and limited to the bronchial wall. This exceptional presentation shows a tumor growth large enough to completely occlude the right mainstem bronchus. The endoluminal lesion was removed using rigid bronchoscopy. The patient, not eligible for a local treatment, has been treated with surgery.

Photodynamic Therapy in Non-Gastrointestinal Thoracic Malignancies

Photodynamic therapy has a role in the management of early and late thoracic malignancies. It can be used to facilitate minimally-invasive treatment of early endobronchial tumours and also to palliate obstructive and bleeding effects of advanced endobronchial tumours. Photodynamic therapy has been used as a means of downsizing tumours to allow for resection, as well as reducing the extent of resection necessary. It has also been used successfully for minimally-invasive management of local recurrences, which is especially valuable for patients who are not eligible for radiation therapy. Photodynamic therapy has also shown promising results in mesothelioma and pleural-based metastatic disease. As new generation photosensitizers are being developed and tested and methodological issues continue to be addressed, the role of photodynamic therapy in thoracic malignancies continues to evolve.

Terminology and reporting criteria for radiofrequency ablation of tumors in the scientific literature: systematic review of compliance with reporting standards

OBJECTIVE

To perform a systematic review of compliance with standardized terminology and reporting criteria for radiofrequency (RF) tumor ablation, proposed by the International Working Group on Image-Guided Tumor Ablation in 2003, in the published reports.

MATERIALS AND METHODS

Literature search in the PubMed database was performed using index keywords, PubMed limit system, and eligibility criteria. The entire content of each article was reviewed to assess the terminology used for procedure terms, imaging findings, therapeutic efficacy, follow-up, and complications. Accuracy of the terminology and the use of alternative terms instead of standard terminology were analyzed. In addition, disparities in accuracy of terminology in articles according to the medical specialty and the type of radiology journal were evaluated.

RESULTS

Among the articles (n = 308) included in this study, the accuracy of the terms 'procedure or session', 'treatment', 'index tumor', 'ablation zone', 'technical success', 'primary technique effectiveness rate', 'secondary technique effectiveness rate', 'local tumor progression', 'major complication', and 'minor complication' was 97% (298/307), 97% (291/300), 8% (25/307), 65% (103/159), 55% (52/94), 33% (42/129), 94% (17/18), 45% (88/195), 99% (79/80), and 100% (77/77), respectively. The overall accuracy of each term showed a tendency to improve over the years. The most commonly used alternative terms for 'technical success' and 'local tumor progression' were 'complete ablation' and 'local (tumor) recurrence', respectively. The accuracy of terminology in articles published in radiology journals was significantly greater than that of terminology in articles published in non-radiology journals, especially in Radiology and The Journal of Vascular and Interventional Radiology.

CONCLUSION

The proposal for standardization of terminology and reporting criteria for RF tumor ablation has been gaining support according to the recently published scientific reports, especially in the field of radiology. However, more work is still needed for the complete standardization of terminology.

Future of oncologic photodynamic therapy

Photodynamic therapy (PDT) is a tumor-ablative and function-sparing oncologic intervention. The relative simplicity of photosensitizer application followed by light activation resulting in the cytotoxic and vasculartoxic photodynamic reaction has allowed PDT to reach a worldwide audience. With several commercially available photosensitizing agents now on the market, numerous well designed clinical trials have demonstrated the efficacy of PDT on various cutaneous and deep tissue tumors. However, current photosensitizers and light sources still have a number of limitations. Future PDT will build on those findings to allow development and refinement of more optimal therapeutic agents and illumination devices. This article reviews the current state of the art and limitations of PDT, and highlight the progress being made towards the future of oncologic PDT.

Autofluorescence bronchoscopy, a novel modality for the early detection of bronchial premalignant and malignant lesions

Lung cancer is the leading cause of cancer deaths in developed countries. Recently, autofluorescence bronchoscopy has been reported to improve the early detection of lung cancer in high-risk individuals. In the present study, we evaluated the efficacy of autofluorescence bronchoscopy for the early detection of bronchial premalignant and malignant lesions. From November 2000 through March 2004, 123 high-risk individuals (114 men and 9 women with a mean age of 68 years) were enrolled. Among 282 biopsy specimens, 93 (33.0%) were premalignant or malignant lesions. The sensitivity and negative predictive value for the detection of bronchial premalignant and malignant lesions were significantly higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone. Moreover, the sensitivity for the detection of bronchial premalignant lesions was extremely higher with the addition of autofluorescence bronchoscopy than white light bronchoscopy alone, whereas there was no significant difference between autofluorescence bronchoscopy and white light bronchoscopy alone for the detection of non-malignant and malignant lesions. Autofluorescence bronchoscopy is a novel modality for the early detection of bronchial abnormality, especially for bronchial premalignant lesions.

Long-term survival of patients treated with photodynamic therapy for carcinoma in situ and early non-small-cell lung carcinoma

PURPOSE

The role of photodynamic therapy (PDT) in the treatment of small cancers has been established in several clinical studies. Here, we report on the efficacy of PDT for early inoperable or recurrent non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

From June 1989 to November 2004, 40 patients with 50 NSCLC were treated with PDT. Twelve cases were inoperable for medical reasons and were staged as T1N0M0, and 28 had recurrent in situ carcinoma. Patients with residual disease after PDT received definitive radiotherapy and/or brachytherapy. Follow-up ranged from 6 to 167 months (median 43.59). Twenty of the 40 patients received i.v. injections of hematoporphyrin derivative (5 mg/kg), the other 20 had injections of porfimer sodium (Photofrin, 2 mg/kg). An argon dye laser (630 nm wavelength, 200-300 J/cm2) was used for light irradiation in 24 of the 40 patients, a diode laser (Diomed, 630 nm wavelength, 100-200 J/cm2) in the other 16.

RESULTS

PDT obtained a 72% complete response (CR) rate (36/50 treated lesions), that is 27 CR among the 37 Tis carcinomas and 9 among the 13 T1 cases. Kaplan-Meier curves showed a mean overall survival (OS) of 75.59 months (median 91.4 months). Two- and 5-year OS rates were 72.78% and 59.55%. The mean and median survival rates for patients with Tis stage were 86.5 and 120.4 months, respectively (standard error 9.50) and for patients with T1 disease they were 45.78 and 35.71 months, respectively; the difference was statistically significant (P = 0.03). No severe early or late PDT-related adverse events were recorded.

CONCLUSIONS

PDT is effective in early primary or recurrent NSCLC, resulting in a CR rate of 72%. The incorporation of PDT in standard clinical practice, in combination with radiotherapy, warrants further investigation.

Photodynamic therapy for lung cancers based on novel photodynamic diagnosis using talaporfin sodium (NPe6) and autofluorescence bronchoscopy

BACKGROUND

We had previously developed the possibility of use of a photodynamic diagnosis (PDD) system using a tumor-selective photosensitizer and laser irradiation for the early detection and photodynamic therapy (PDT) for centrally located early lung cancers. Recently, we established the autofluorescence diagnosis system integrated into a videoendoscope (SAFE-3000) as a very useful technique for the early diagnosis of lung cancer.

PATIENTS AND METHODS

Twenty-nine patients (38 lesions) with centrally located early lung cancer received PDD and PDT using the second-generation photosensitizer, talaporfin sodium (NPe6). Just before the PDT, we defined the tumor margin accurately using the novel PDD system SAFE-3000 with NPe6 and a diode laser (408nm).

RESULTS

Red fluorescence emitted from the tumor by excitation of the photosensitizer by the diode laser (408nm) from SAFE-3000 allowed accurate determination of the tumor margin just before the PDT. The complete remission (CR) rate following NPe6-PDT in the cases with early lung cancer was 92.1% (35/38 lesions). We also confirmed the loss of red fluorescence from the tumors immediately after the PDT using SAFE-3000. We confirmed that all the NPe6 in the tumor had been excited and photobleached by the laser irradiation (664nm) and that no additional laser irradiation was needed for curative treatment.

CONCLUSIONS

This novel PDD system using SAFE-3000 and NPe6 improved the quality and efficacy of PDT and avoided misjudgement of the dose of the photosensitizer or laser irradiation in PDT. PDT using NPe6 will become a standard option of treatments for centrally located early lung cancer.

Initial bronchoscopic treatment for patients with intraluminal bronchial carcinoids

OBJECTIVE

Carcinoid of the lung is considered low-grade malignancy, and less invasive treatment may therefore be considered. We analyzed the long-term outcome of initial bronchoscopic treatment in patients with intraluminal bronchial carcinoids.

METHODS

Initial bronchoscopic treatment was applied to improve presurgical condition, to obtain tissue samples for proper histologic classification, and to enable less extensive parenchymal resection. For intraluminal bronchial carcinoid, complete tumor eradication with initial bronchoscopic treatment was attempted. High-resolution computed tomography in addition to bronchoscopy was used to determine intraluminal versus extraluminal tumor growth. Surgery followed in cases of atypical carcinoid, residue, or recurrence.

RESULTS

Seventy-two patients, 43 of them female, have been treated (median age 47 years, range 16-80 years). Median follow-up has been 65 months (range 2-180 months). Fifty-seven (79%) had typical carcinoids and 15 (21%) had atypical carcinoids. Initial bronchoscopic treatment resulted in complete tumor eradication in 33 of 72 cases (46%), 30 typical and 3 atypical. Thirty-seven of 72 cases (51%), 11 atypical, required surgery (2 for late detected recurrences). Two patients had metastatic atypical carcinoid, 1 already at referral. Of the 6 deaths, 1 was tumor related.

CONCLUSIONS

Initial bronchoscopic treatment is a potentially more tissue-sparing alternative than immediate surgical resection in patients with intraluminal bronchial carcinoids. For successful tumor eradication with initial bronchoscopic treatment in central carcinoids, assessment of intraluminal versus extraluminal growth may be of much more importance than histologic division between typical and atypical carcinoid. Disease-specific mortality is low, and long-term outcome has been excellent. Implementation of initial bronchoscopic treatment had no negative impact on surgical treatment outcome.

Tumor ablation with photodynamic therapy: introduction to mechanism and clinical applications

Photodynamic therapy (PDT) has been used to treat cancer for more than 25 years. Although the focus has been primarily on surface or superficial lesions, there has been a rapid growth in its application to the treatment of deeper parenchymal malignancies. The photochemical reaction consists of a photosensitizer, which, when irradiated by light at a specific wavelength, generates a cytotoxic oxygen singlet. The end result is an efficient induction of cell death, primarily through apoptosis, microvascular damage, and an antitumor immune response. PDT is currently being used in the treatment of many cancers including lung cancer, head and neck cancers, liver metastases, cholangiocarcinoma, and prostate cancer. The growing body of evidence concerning its efficacy, the increasing use of imaging to guide PDT, and the innate minimally invasive characteristics of PDT suggest that it should become an important addition to the growing array of techniques in interventional oncology.

Photodynamic therapy (PDT) in early central lung cancer: a treatment option for patients ineligible for surgical resection

OBJECTIVES

To review the Yorkshire Laser Centre experience with bronchoscopic photodynamic therapy (PDT) in early central lung cancer in subjects not eligible for surgery and to discuss diagnostic problems and the indications for PDT in such cases.

METHODS

Of 200 patients undergoing bronchoscopic PDT, 21 had early central lung cancer and were entered into a prospective study. Patients underwent standard investigations including white light bronchoscopy in all and autofluorescence bronchoscopy in 12 of the most recent cases. Indications for bronchoscopic PDT were recurrence/metachronous endobronchial lesions following previous treatment with curative intent in 10 patients (11 lesions), ineligibility for surgery because of poor cardiorespiratory function in 8 patients (9 lesions) and declined consent to operation in 3 patients. PDT consisted of intravenous administration of Photofrin 2 mg/kg followed by bronchoscopic illumination 24-48 h later.

RESULTS

29 treatments were performed in 21 patients (23 lesions). There was no procedure-related or 30 day mortality. One patient developed mild skin photosensitivity. All patients expressed satisfaction with the treatment and had a complete response of variable duration. Six patients died at 3-103 months (mean 39.3), three of which were not as a result of cancer. Fifteen patients were alive at 12-82 months.

CONCLUSION

Bronchoscopic PDT in early central lung cancer can achieve long disease-free survival and should be considered as a treatment option in those ineligible for resection. Autofluorescence bronchoscopy is a valuable complementary investigation for identification of synchronous lesions and accurate illumination in bronchoscopic PDT.

Bronchoscopic Cryotherapy Treatment of Isolated Endoluminal Typical Carcinoid Tumor

BACKGROUND

Bronchial typical carcinoid tumors are rare. The "gold standard" treatment is surgery, but there is literature to support bronchoscopic therapy with curative intent. Based on the efficacy of cryotherapy for in situ lung cancer, we studied the safety and efficacy of rigid bronchoscopic treatment with cryotherapy on isolated endoluminal typical carcinoid tumors.

METHODS

All the patients from the Department of Pulmonary Diseases and Thoracic Oncology of St. Etienne University Hospital (France), and of Hôpital Notre Dame, University Hospital of Montreal referred with typical carcinoid were screened. Inclusion criteria included the following: proven typical carcinoid, strictly endoluminal disease amenable to bronchoscopic therapy, and no evidence of lymph node invasion. All patients had a complete removal of the tumor, and all patients received cryotherapy to the implantation base.

RESULTS

Twenty-nine patients were screened, and 18 were included. Mean age was 47 years, and study population included 11 women. Median follow-up was 55 months. There was a single recurrence 7 years after the initial bronchoscopic treatment.

CONCLUSIONS

Cryotherapy is a safe and effective adjunct to endobronchial mechanical resection of typical carcinoids. Unlike other adjuncts that have been proposed, cryotherapy is not associated with long-term complications including bronchial stenosis.

A review of progress in clinical photodynamic therapy

Photodynamic therapy (PDT) has received increased attention since the regulatory approvals have been granted to several photosensitizing drugs and light applicators worldwide. Much progress has been seen in basic sciences and clinical photodynamics in recent years. This review will focus on new developments of clinical investigation and discuss the usefulness of various forms of PDT techniques for curative or palliative treatment of malignant and non-malignant diseases.

Role of bronchoscopic photodynamic therapy in lung cancer management

PURPOSE OF REVIEW

At present there is universal awareness of the role of photodynamic therapy in oncology. There is also a widespread acceptance of its safety and efficacy in its bronchoscopic application for bronchopulmonary malignant neoplasia. It, is therefore, both timely and relevant to present here the current status of bronchoscopic photodynamic therapy in lung cancer based on a critical review highlighting its indications and results.

RECENT FINDINGS

Bronchoscopic photodynamic therapy has emerged as an important treatment in lung cancer. In advanced disease with focus on quality of life, it offers palliation to all patients and survival benefit to a defined subset. In early cases it provides long survival (potential cure). In patients with intraepithelial stage disease, when it can be accurately diagnosed by the use of fluorescence bronchoscopy and endoscopic ultrasonography, the results can match those of surgical resection.

SUMMARY

In bronchoscopic photodynamic therapy, the endobronchial tumor is presensitized by systemic administration of a sensitizing photochemical. After a time interval, bronchoscopic illumination (exposure to laser light) is performed to achieve cancer necrosis. The prerequisite for bronchoscopic photodynamic therapy is identification and histologic evidence of cancer within the airway. Photodynamic therapy is indicated in both early and advanced stage cancer. In patients with advanced disease and important exophytic tumors, the aim is palliation; in those with early central disease, treatment is done with curative intent. A large body of published evidence now suggests that these objectives are achievable.

What is early lung cancer? A review of the literature

The dismal cure rate of patients with lung cancer and the stage shift hypothesis have propelled the interest to perform screening at large, despite that previous randomized clinical trials failed to show any mortality benefit and the controversial issue of overdiagnosis. Due to early detection programs, a larger number of individuals at risk will be found to harbor small and potentially malignant early stage lesions. The application of non- and minimal invasive techniques for early detection, staging and treatment will become increasingly important. This review deals with the available clinical, surgical and pathological data focusing on early lung cancer lesions < or =1 cm. Literature data from both centrally located and parenchymal lesions < or =3 cm. have been analyzed. For all sub-centimeter lesions, minimal invasive staging and treatment approaches must still be considered inappropriate. Less invasive and less extensive treatment methods may be considered in high risk individuals with < or =1 cm. peripheral lesion showing > or =50 ground glass opacity on high resolution CT scan and those with superficial lesion in their central airways without deeper tumor invasion in the bronchial wall. Caution is necessary, however, as clinical staging remains inferior to pathological staging which is based on tissue samples collected after complete tumor removal and mediastinal lymph nodes dissection have been performed.

Primary and Secondary Lung Malignancies Treated with Percutaneous Radiofrequency Ablation: Evaluation with Follow-Up Helical CT

OBJECTIVE

We sought to describe the appearance of primary and secondary lung malignancies treated with radiofrequency ablation on follow-up helical CT and to identify the important CT findings for evaluating therapeutic efficacy and response on follow-up CT.

MATERIALS AND METHODS

Among the 21 patients in our study population, 17 had lung cancer and four had metastatic nodules. All patients underwent follow-up helical CT immediately after undergoing percutaneous radiofrequency ablation, 1 month later, and then every 3 months. Two reviewers interpreted the CT findings and reached a consensus opinion. Patients were divided into two groups on the basis of the posttreatment contrast-enhanced CT findings-those with a complete ablation and those with a partial ablation. The serial changes in the enhancement pattern, size, peripheral ground-glass opacities, and other findings in the treated area in the two groups were assessed on follow-up CT.

RESULTS

In the complete ablation group (n = 9 patients), the ablated lesions were completely without contrast enhancement on follow-up CT, and the mean percentage of decrease in the size of the ablated lesions at 3, 6, 9, 12, and 15 months was 5.7%, 11.4%, 14.3%, 40%, and 40%, respectively, compared with the lesion size on the follow-up CT scans obtained immediately after treatment. In the partial ablation group (n = 12 patients), the ablated lesions had various degrees of enhancement, and the mean percentage of ablated lesion size gradually increased after the 6-month follow-up CT examination. Enveloped ground-glass opacity surrounding tumor was seen in five (23.8%) of 21 lesions on the immediate follow-up CT scans.

CONCLUSION

Of the CT findings of lung malignancy after radiofrequency ablation therapy, the enhancement pattern and the size of the change in the ablated lesion are the most important factors for determining whether a complete ablation has been achieved.

The present and future role of photodynamic therapy in cancer treatment

It is more than 25 years since photodynamic therapy (PDT) was proposed as a useful tool in oncology, but the approach is only now being used more widely in the clinic. The understanding of the biology of PDT has advanced, and efficient, convenient, and inexpensive systems of light delivery are now available. Results from well-controlled, randomised phase III trials are also becoming available, especially for treatment of non-melanoma skin cancer and Barrett's oesophagus, and improved photosensitising drugs are in development. PDT has several potential advantages over surgery and radiotherapy: it is comparatively non-invasive, it can be targeted accurately, repeated doses can be given without the total-dose limitations associated with radiotherapy, and the healing process results in little or no scarring. PDT can usually be done in an outpatient or day-case setting, is convenient for the patient, and has no side-effects. Two photosensitising drugs, porfirmer sodium and temoporfin, have now been approved for systemic administration, and aminolevulinic acid and methyl aminolevulinate have been approved for topical use. Here, we review current use of PDT in oncology and look at its future potential as more selective photosensitising drugs become available.

Future generation CT imaging

X-ray CT technology has been available for more than 30 years, yet continued technological advances have kept CT imaging at the forefront of medical imaging innovation. Consequently, the number of clinical CT applications has increased steadily. Other imaging modalities might be superior to CT imaging for some specific applications, but no other single modality is more often used in chest imaging today. Future technological developments in the area of high-resolution detectors, high-capacity x-ray tubes, advanced reconstruction algorithms, and improved visualization techniques will continue to expand the imaging capability. Future CT imaging technology will combine improved imaging capability with advanced and specific computer-assisted tools, which will expand the usefulness of CT imaging in many areas.