Response to topotecan of symptomatic brain metastases of small-cell lung cancer also after whole-brain irradiation. a multicentre phase II study

[Small cell lung cancer--state of the art and future perspectives]

Lung cancer is the leading cause of cancer-related death in Portugal. Almost 3500 Portuguese are expected to be diagnosed with lung cancer in 2006; approximately 20% will have small cell lung cancer (SCLC). At presentation, 25% to 30% of patients will have local or regional disease, classified as limited stage disease. The concurrent chemovalidation therapy is the best choice. Once daily thoracic radiation therapy to doses in the range of 50 Gy to 60 Gy would reflect an accepted standard of care in daily practice. Because of the increase toxicity associated with hyper fractionated radiation, this approach is often limited to select patients. Etoposide plus cisplatin are synergistic, well tolerated and result in equal or superior survival compared with other regimens. This is the standard regimen for concomitant therapy in limited stage and for extensive disease SCLC. Despite good chemo sensitivity and radio sensitivity, the prognosis of SCLC is very poor because of the early development of resistance and the associated high tendency to recurrence, making second line treatment of SCLC a problem of real medical relevance. Topotecan now offers an effective and well tolerated monosubstance for second line therapy of recurrent SCLC. There has been a significant increase in median survival for patients with SCLC receiving topotecan plus symptomatic therapy versus symptomatic therapy. The efficacy of this drug is comparable to the efficacy of the three-drug combination CAV. The tolerability can be improved by means of toxicity-adapted dosing. In elderly and in patients with performance status 2, topotecan is also well tolerated and has good efficacy. Initial studies into weekly administration also demonstrate good efficacy. The combination of topotecan with cranial radiotherapy is well tolerated and effective in the treatment of cerebral metastases of SCLC. New classes of agents, such as antiangiogenic agents including bevacizumab, small molecule tyrosine kinase inhibitors and thalidomide are being evaluated with chemotherapy for patients with extensive stage SCLC.

Topotecan for the treatment of small-cell lung cancer

Lung cancer is the most prevalent and yet the most preventable malignancy worldwide. Owing to the propensity of small-cell lung cancer to early relapse and its relative resistance to subsequent treatment there is a need to improve currently available therapies. Topotecan has provided an efficacious and tolerable therapeutic option for patients with recurrent small-cell lung cancer, and the oral formulation has also been shown to be beneficial, even in elderly patients of poor performance status. Herein we review the role of topotecan in the treatment of small-cell lung cancer.

The blood-brain barrier and cancer: transporters, treatment, and Trojan horses

Despite scientific advances in understanding the causes and treatment of human malignancy, a persistent challenge facing basic and clinical investigators is how to adequately treat primary and metastatic brain tumors. The blood-brain barrier is a physiologic obstruction to the delivery of systemic chemotherapy to the brain parenchyma and central nervous system (CNS). A number of physiologic properties make the endothelium in the CNS distinct from the vasculature found in the periphery. Recent evidence has shown that a critical aspect of this barrier is composed of xenobiotic transporters which extrude substrates from the brain into the cerebrospinal fluid and systemic circulation. These transporters also extrude drugs and toxins if they gain entry into the cytoplasm of brain endothelial cells before they enter the brain. This review highlights the properties of the blood-brain barrier, including the location, function, and relative importance of the drug transporters that maintain this barrier. Primary and metastatic brain malignancy can compromise this barrier, allowing some access of chemotherapy treatment to reach the tumor. The responsiveness of brain tumors to systemic treatment found in past clinical research is discussed, as are possible explanations as to why CNS tumors are nonetheless able to evade therapy. Finally, strategies to overcome this barrier and better deliver chemotherapy into CNS tumors are presented.

Increased permeability of the blood-brain barrier to chemotherapy in metastatic brain tumors: establishing a treatment paradigm

There is no accepted standard of care for the chemotherapy treatment of metastatic brain tumors, which has been generally limited to lipophilic alkylators, which may not have efficacy against the tumor that metastasized to the brain. More than 50% of chemotherapy agents are natural product drugs, which are rarely used in the treatment of metastatic brain tumors because they are thought to not cross the blood-brain barrier (BBB). A major protein constituent in the BBB is P-glycoprotein (P-gp), which pumps natural product chemotherapy drugs and toxins out of the CNS. However, P-gp expression in the neovasculature of metastatic brain tumors is similar to the P-gp expression in the neovasculature of the primary, extracranial tumor. In contrast, gliomas have higher P-gp expression in their neovasculature, similar to the greater intrinsic expression of P-gp in normal brain vasculature. This decreased immunohistochemical expression of P-gp in the neovasculature of metastatic tumors, as well as our recent pharmacologic demonstration of increased tissue concentrations of paclitaxel in metastatic brain tumors compared with gliomas, support the idea that the choice of chemotherapy agents should be based on the histologic origin of the metastatic brain tumor and not on the lipophilicity of the drug. Our hypothesis is that metastatic brain tumors from tumors with intrinsically low P-gp expression (eg, lung, melanoma, and untreated breast) may be more permeable to natural product chemotherapy drugs than gliomas. This information could lead to a paradigm shift in the use of natural product drugs for metastatic brain tumors.

A multi-center phase II study of weekly topotecan as second-line therapy for small cell lung cancer

PURPOSE

To determine the response rate, toxicity, failure free and overall survival of weekly topotecan in patients with relapsed small cell lung cancer who received one prior platinum based chemotherapy.

PATIENTS AND METHODS

Twenty two patients with relapsed disease after response to one prior chemotherapy with or without radiotherapy and patients with relapse more than 90 days after their last therapy received topotecan 4mg/m(2) intravenous over 30min on days 1,8,15; every 4 weeks (3 weeks on and 1 weeks off). Chemotherapy was given until disease progression or unacceptable toxicity.

RESULTS

Of 22 patients, none of the patients responded to weekly topotecan therapy. Four patients had stable disease. After a median follow up of 1 year, median time to progression was 6 weeks and median survival was 5 months. The common toxicities associated with this regimen were anemia, thrombocytopenia, fatigue, GI side effects and alopecia.

CONCLUSION

Weekly topotecan was well tolerated but ineffective in this trial. Although commonly used, weekly regimen of topotecan should be used with caution in relapsed SCLC.

A phase I/II trial of topotecan and radiation therapy for brain metastases in patients with solid tumors

PURPOSE

Outcomes in patients with brain metastases undergoing whole-brain radiotherapy (WBRT) are hardly encouraging, and an improvement in results is therefore needed. One possible approach is the addition of chemotherapeutics. However the data presented thus far are also disappointing. A promising substance in this setting could become topotecan, which is known to cross the blood-brain barrier and additionally offers radiosensitizing effects. Therefore we performed a phase I/II trial to evaluate the feasibility of a concurrent radiochemotherapy regimen.

METHODS AND MATERIALS

From January 1999 to July 2001, a total of 75 patients (10 in phase I and 65 in phase II) were included. The WBRT was applied with a fraction size of 2 Gy/day for a total of 40 Gy. Topotecan was administered as a 30-min infusion with 0.2 to 0.5 mg/m(2)/day for 5 days over 4 weeks within 2 h to radiation therapy.

RESULTS

Because of the higher toxic rates seen in patients receiving 0.5 mg/m(2)/day, the recommended dosage for phase II was 0.4 mg/m(2)/day. In this group Grade 3/4 hematologic and nonhematologic side effects occurred in 19% and 21% of the patients, respectively. The overall response rate was 72% with an overall survival of 17 weeks and 30 weeks among the responders.

CONCLUSIONS

Based on the moderate toxicity profile presented here we recommend to perform a phase III trial to confirm the promising phase I/II data.

Chemotherapy and cerebral metastases: misperception or reality?

Cerebral metastases remain a common complication among patients with cancer. Surgery and radiotherapy remain the principal therapeutic interventions. In contrast, the benefit of chemotherapy has long been viewed with skepticism. Nonetheless, as survival in cancer patients improves and the incidence of cerebral metastases increases, so does the demand for effective therapies. It is now recognized that the blood-brain barrier within metastases is permeable and thus allows entry of otherwise excluded drugs. Limited data have suggested that cerebral metastases have modest sensitivity to chemotherapy. Furthermore, novel agents and delivery strategies have been developed to facilitate central nervous system penetration. Nonetheless, data are limited by methodological flaws, including heterogeneous inclusion criteria, small sample sizes, lack of randomization, and inconsistencies in defined end points and response assessment criteria. Well-designed clinical trials are needed to address the effect of chemotherapy. Acceptable control arms must be established to measure the effect of chemotherapies. Standardized response criteria and disease-specific studies are essential.

Update in the treatment of brain metastases from lung cancer

Brain metastases from lung cancer represent a prevalent and challenging clinical dilemma. The brain is an extremely common site of failure for non-small-cell lung cancer and small-cell lung cancer, often as a solitary site of disease. Despite steady research developments during recent years, survival rates remain poor. Some research suggests that the outcomes and characteristics of brain metastases that result from lung cancer primary sites are perhaps different than those from other primary sites. Clinical treatment strategies should therefore be adjusted accordingly. This article reviews the clinical characteristics, prognostic factors, and treatment strategies of brain metastases from lung cancer with a particular emphasis on recent research developments in the field.

Resection versus radiosurgery for patients with brain metastases

Brain metastases occur in 20–40% of adult cancer patients and the incidence is apparently increasing. Despite advances in treatment, the prognosis of these patients is poor, with a median survival of approximately 4 months. Whole brain radiation therapy is the standard of care for most patients with brain metastases. Randomized trials have demonstrated that focal treatments, such as resection and radiosurgery, yield significant improvement in the survival of patients with a single metastasis. The utility of these strategies, specifically in terms of increased survival, is unclear in patients with more than one metastasis. In addition to focal treatments, future directions in the treatment of brain metastases include the development of intraoperative imaging capabilities, improved methods of identifying patients who are likely to benefit from treatment, systemic agents, such as chemotherapy and radiosensitizers, and the incorporation of targeted and antiangiogenic therapies.

Chemotherapy and targeted molecular therapies for brain metastases

As therapy for systemic cancers improves, an increasing number of patients are developing brain metastases. Although conventional therapy with surgery, radiation therapy and radiosurgery has improved the outcome of a significant number of patients, many develop multiple lesions that are not amenable to standard treatments. In this review, the current role of chemotherapy and targeted molecular agents for brain metastases is summarized and future directions are discussed.

Integration of chemotherapy into current treatment strategies for brain metastases from solid tumors

Patients with brain metastases represent a heterogeneous group where selection of the most appropriate treatment depends on many patient- and disease-related factors. Eventually, a considerable proportion of patients are treated with palliative approaches such as whole-brain radiotherapy. Whole-brain radiotherapy in combination with chemotherapy has recently gained increasing attention and is hoped to augment the palliative effect of whole-brain radiotherapy alone and to extend survival in certain subsets of patients with controlled extracranial disease and good performance status. The randomized trials of whole-brain radiotherapy vs. whole-brain radiotherapy plus chemotherapy suggest that this concept deserves further study, although they failed to improve survival. However, survival might not be the most relevant endpoint in a condition, where most patients die from extracranial progression. Sometimes, the question arises whether patients with newly detected brain metastases and the indication for systemic treatment of extracranial disease can undergo standard systemic chemotherapy with the option of deferred rather than immediate radiotherapy to the brain. The literature contains numerous small reports on this issue, mainly in malignant melanoma, breast cancer, lung cancer and ovarian cancer, but very few sufficiently powered randomized trials. With chemotherapy alone, response rates were mostly in the order of 20-40%. The choice of chemotherapy regimen is often complicated by previous systemic treatment and takes into account the activity of the drugs in extracranial metastatic disease. Because the blood-brain barrier is partially disrupted in most macroscopic metastases, systemically administered agents can gain access to such tumor sites. Our systematic literature review suggests that both chemotherapy and radiochemotherapy for newly diagnosed brain metastases need further critical evaluation before standard clinical implementation. A potential chemotherapy indication might exist as palliative option for patients who have progressive disease after radiotherapy.

Response of Asymptomatic Brain Metastases From Small-Cell Lung Cancer to Systemic First-Line Chemotherapy

Purpose

The purpose of this study was to investigate the radiologic response of asymptomatic brain metastases (BM) from small-cell lung cancer (SCLC) to first-line systemic chemotherapy.

Patients and Methods

From 1990 to 2003, 181 consecutive patients with SCLC were enrolled onto this study. Patients were examined by a neurologist on a regular basis. Magnetic resonance imaging (MRI) of the brain was performed routinely before (at diagnosis of SCLC) and after first-line systemic chemotherapy. Patients were treated with combination chemotherapy consisting of cyclophosphamide, doxorubicin, and etoposide. Clinically manifest BM were treated with whole-brain radiotherapy (WBRT). The response rate (RR) of BM was assessed by changes in the size or the number of enhanced lesions on MRI using standard criteria.

Results

Synchronous asymptomatic BM were found in 24 SCLC patients (13%). In six (27%) of the 22 assessable patients, the asymptomatic BM responded to systemic chemotherapy. A systemic response was found in 16 patients (73%). All patients became symptomatic during follow-up. The symptom-free survival did not differ between cranial responders and cranial nonresponders.

Conclusion

The RR of asymptomatic BM from SCLC to systemic chemotherapy is 27% and evidently lower than the systemic RR. Future studies should focus on the possible beneficial effect of WBRT for patients with asymptomatic synchronous BM.

Complete response of brain metastases to irinotecan-based chemotherapy

Brain metastases occur in 15-20% of patients with cancer and are generally associated with an overall poor prognosis. Currently, radiotherapy and surgery are the mainstay of palliative therapy for patients with brain metastases, while the role of systemic chemotherapy remains uncertain. In this article, we report complete responses to irinotecan-based chemotherapy in three patients with brain metastases from parotid adenocarcinoma, esophageal adenocarcinoma and small cell lung cancer. Irinotecan-based chemotherapy may hold promise in treating patients with brain metastases. Further studies are warranted to confirm our observations.

Treating brain metastases: current approaches and future directions

Brain metastases frequently present with neurologic signs or symptoms in a patient with a history of cancer. The finding of a brain metastasis is usually associated with terminal disease. However, patients with brain metastases are a heterogeneous group. Therefore, the treatment of brain metastases must be tailored to each individual patient. In this article, which patients with brain metastases benefit from surgical resection, radiosurgery and whole-brain radiation therapy are reviewed. Reports of treating patients with brain metastases with chemotherapy are also reviewed and data that supports prophylactic treatment of the brain for select patients is discussed. This review aims to provide a framework for treating patients with different presentations of brain metastases and to highlight important avenues for future research.

Prospective trial on topotecan salvage therapy in primary CNS lymphoma

BACKGROUND

Standard salvage therapy has not been established for recurrent primary central nervous system lymphoma (PCNSL). We report the final results of a prospective study on topotecan chemotherapy in relapsed or refractory PCNSL.

PATIENTS AND METHODS

The study included 27 patients with a median age of 51 years and an ECOG performance status of 2. Fourteen patients were refractory to the last therapy, and 13 relapsed after a median period of 6.0 months. Pretreatment with up to four regimens included chemotherapy in 26 patients and whole brain irradiation in 14. A 30-min daily topotecan infusion of 1.5 mg/m(2) for 5 days was repeated every 3 weeks.

RESULTS

The response rate was 33% with five complete (CR) and four partial remissions (PR). The median follow-up was 37.7 months. All complete responders had sustained remissions lasting for 9 to 28 months. The median event-free survival (EFS) was 2.0 months (9.1 months in responders), the overall survival (OAS) was 8.4 months. CTC grade 3-4 leukopenia occurred in 26% and thrombocytopenia in 11% of the patients. Eight of 12 patients alive without cerebral lymphoma > or = six months after topotecan exhibited deficits attributable to late neurotoxicity.

CONCLUSION

Topotecan as monotherapy is active in relapsed and refractory PCNSL with tolerable toxicity.

Chemotherapy in brain metastases

The use OF chemotherapy to treat patients with brain metastases has been viewed historically with skepticism. To date, a survival benefit has not been demonstrated with the use of systemic chemotherapy in patients with brain metastases. However, the introduction of novel agents and delivery techniques warrants a reexamination of the role of systemic chemotherapy in the management of brain metastases. Temozolomide has shown encouraging results in patients with nonsmall cell lung cancer, and implanted carmustine wafers have demonstrated excellent local tumor control rates. This review discusses clinical data from the past decade with emphasis on trial design, tumor histology, available agents, and multimodality strategies. In addition, delivery techniques that circumvent the blood-brain barrier are reviewed. Although chemotherapy is usually used as a salvage therapy, it may be considered for use in selected patients with newly diagnosed brain metastases. To better evaluate chemotherapy in brain metastases, future trials should evaluate novel agents in the preirradiation setting. Enhanced regional delivery methods warrant further investigation, and Phase III trials of current regimens stratified by histology and by prognostic factors will establish the role of specific chemotherapy regimens in the treatment of patients with brain metastases.

Sequential versus alternating administration of cisplatin/etoposide and topotecan as first-line treatment in extensive-stage small-cell lung cancer: preliminary results of a Phase III Trial of the Hellenic Oncology Research Group

BACKGROUND

This trial was designed to compare the efficacy and toxicity of sequential versus alternating administration of cisplatin/etoposide and topotecan in patients with previously untreated extensive-stage small-cell lung cancer (SCLC).

PATIENTS AND METHODS

Two hundred eighty-four chemotherapy-naive patients were randomized between the sequential therapy arm (n=142; 4 cycles of cisplatin 75 mg/m2 intravenously [I.V.] on day 1 with etoposide 100 mg/m2 per day I.V. on days 1-3 followed by 4 cycles of topotecan 1.5 mg/m2 per day I.V. on days 1-5) and the alternating arm (n=142; same doses of cisplatin/etoposide on cycles 1, 3, 5, and 7 and topotecan on cycles 2, 4, 6, and 8). Treatment cycles for both regimens were administered every 3 weeks.

RESULTS

At this preliminary analysis, no statistically significant difference in the overall response rate, duration of response, time to disease progression, or median survival was observed between the 2 arms. A total of 756 cycles of the sequential therapy and 830 cycles of the alternating therapy were administered, with a median numbers of 6 and 7 cycles per patient, respectively. Topotecan was administered in 85 patients on the sequential arm and 132 patients on the alternating arm. Dose reductions for toxicity were similar in both arms. Grade 3/4 toxicities in the sequential and alternating arms, respectively, included neutropenia (51% and 52%; P=NS), anemia (12% and 11%; P=NS), febrile neutropenia (7% and 9%; P=NS), thrombocytopenia (19% and 20%; P=NS), and asthenia (8% and 2%; P=0.02). There were 4 toxicity-related deaths in the sequential arm versus 3 in the alternating arm.

CONCLUSION

Our preliminary conclusion is that the sequential and alternating regimens resulted in comparable activity and tolerability in previously untreated patients with extensive-stage SCLC.

Radiotherapy and chemotherapy of brain metastases

The authors have reviewed the results, the indications and the controversies regarding radiotherapy and chemotherapy of patients with newly diagnosed and recurrent brain metastases. Whole-brain radiotherapy, radiosurgery, hypofractionated stereotactic radiotherapy, brachytherapy and chemotherapy are the available options. New radiosensitizers and cytotoxic or cytostatic agents are being investigated. Adjuvant whole brain radiotherapy, either after surgery or radiosurgery, and prophylactic cranial irradiation in small-cell lung cancer are discussed, taking into account local control, survival, and risk of late neurotoxicity. Increasingly, the different treatments are tailored to the different prognostic subgroups, as defined by Radiation Therapy Oncology Group RPA Classes.

Current Management of Brain Metastases, With a Focus on Systemic Options

Brain metastases are an important sequelae of many types of cancer, most commonly lung cancer. Current treatment options include whole-brain radiation therapy (WBRT), surgical resection, stereotactic radiosurgery, and chemotherapy. Corticosteroids and antiepileptic medications are commonly used for palliation of mass effect and seizures, respectively. The overall median survival is only 4 months after WBRT. Combined-modality strategies of WBRT with either chemotherapy or novel anticancer agents are under clinical investigation. Promising results have been obtained with several experimental agents and confirmatory phase III trials are underway. Although improvement in overall survival has not been seen universally, reduction in death due to progression of brain metastases and prolongation of the time to neurologic and neurocognitive progression have been reported in selected series. On the basis of these findings, it might be possible to identify new agents that may enhance the efficacy of WBRT.

Therapeutic management of brain metastasis

This review focuses on the management of brain metastases. The four main modes of therapy are discussed: whole brain radiation therapy (WBRT), surgery, radiosurgery, and chemotherapy. Young patients with limited extracranial disease may benefit from surgical resection of a single brain metastasis, and from radiosurgery (or stereotactic radiotherapy) if two to four brain metastases are present. Whether WBRT after surgery or radiosurgery is beneficial is uncertain. Therefore, two approaches can be justified in patients with a good prognosis: WBRT after surgery or radiosurgery, or alternatively, observation with MRI follow-up after surgery or radiosurgery. A hyperfractionated radiation scheme is then to be preferred to limit late toxicity of WBRT. Patients with extensive extracranial tumour activity or impaired quality of life may benefit from radiosurgery (one to four brain metastases), or from shorter WBRT schedules. We propose a decision tree on the various ways to treat brain metastasis.

Topotecan in the first-line treatment of small cell lung cancer

Small cell lung cancer (SCLC) is generally sensitive to first-line chemotherapy, but limited disease often recurs and extensive disease is rarely curable. The most common first-line therapy regimen is cisplatin (Platinol; Bristol-Myers Squibb; Princeton, NJ) plus etoposide (Etopophos; Bristol-Myers Squibb)--PE, which is associated with overall response rates >80% in patients with limited SCLC. Although it is associated with median survival times of approximately 18-20 months for limited disease, PE yields median survival times of only approximately 8-12 months in patients with extensive disease, and symptom palliation becomes the primary therapeutic goal. The toxicities of PE may undermine quality of life and leave patients more susceptible to adverse events during subsequent therapies. Topotecan (HYCAMTIN; GlaxoSmithKline; Philadelphia, PA), an established treatment for recurrent SCLC, is being investigated in the first-line setting because of its novel mechanism of action; predictable, noncumulative, and manageable toxicities; and potential synergy with other active agents. Several recent phase II trials have generated promising results for topotecan-based combination regimens, including topotecan/paclitaxel (TAXOL; Bristol-Myers Squibb) (overall response rates 45%-100%), topotecan/etoposide (overall response, 95%), and topotecan, paclitaxel, and platinum agent triplets (overall response rates 51%-93%). The most frequent serious toxicity associated with these regimens was reversible and noncumulative neutropenia, which was generally manageable with supportive care. Additional clinical trials to investigate topotecan-based combination regimens and confirm their role in the first-line treatment of SCLC are under way.

The pathogenesis and treatment of brain metastases: a comprehensive review

Brain metastases are the most common intracranial tumors and their incidence is increasing. Untreated brain metastases are associated with a poor prognosis and a poor performance status. The role of surgery in the management of multiple brain metastases is still controversial. As more than 70% of patients have multiple metastases at the time of diagnosis, whole brain radiotherapy is the treatment of choice in most cases. Brain metastases are an ideal target for stereotactic radiosurgery, as they are better circumscribed than primary brain tumors. Currently, chemotherapy has a limited role in the treatment of most brain metastases. Several new therapies, with a good penetration through the blood brain barrier, such as temozolomide, have been used in brain metastases with different results depending on the histology of the primary tumor. A better understanding of the complex processes underlying the development of brain metastasis will enable us to develop more satisfactory targeted treatments.

Brain Metastasis Responding to Gefitinib Alone

A woman with stage IIIb non-small cell lung cancer (NSCLC) developed disease progression with brain metastases during chemotherapy. Due to unusual circumstances, the patient received gefitinib alone, without the use of corticosteroid treatment or radiotherapy. There was a dramatic clinical improvement within 1 week. Follow-up magnetic resonance imaging of the brain 1 month later showed decreases in both the size and number of brain metastases. The patient remains well 9 months after initiation of gefitinib. It is proposed that gefitinib may have a role in treatment of brain metastases from NSCLC.

Progress in the therapy of small cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 14% of all cases of lung cancer. Combination chemotherapy is the most effective treatment modality for SCLC and recently, several new active drugs have emerged. Combinations of platinum agents with CPT-11 or gemcitabine have been successfully compared in phase III trials against the cisplatin/etoposide standard. Modest improvements in the outcome of patients with SCLC have been noted over the last two decades. Thoracic irradiation given concurrently with chemotherapy improves survival compared with sequential chemotherapy and radiation, but this approach is associated with more toxicity. Moreover, the optimal doses and fractionation of thoracic irradiation remain to be determined. Three-dimensional treatment planning is under investigation. Prophylactic cranial irradiation (PCI) has established a role in the management of patients who have achieved a complete response to the initial therapy. Novel molecular targeted therapies are among the strategies currently being investigated in SCLC.

Treatment of brain metastases from lung cancer: chemotherapy

Brain metastases are a frequent complication in patients suffering from Lung cancer, and a significant cause of morbidity and mortality. Brain metastases are found in about 10% of patients at the time of diagnosis, and approximately 40% of all patients with lung cancer develop brain metastases during the course of their disease. The prognosis of these patients is rather poor. The standard treatment for brain metastases, so far, has been whole-brain radiation therapy and surgery focussing on symptom palliation. The use of chemotherapy for the treatment of brain metastases has been limited because of a presumed lack of effectiveness due to the blood-brain barrier. However, the importance of the blood-brain barrier is probably overrated in the case of macroscopic metastases or relapsed disease as the blood-brain barrier has already been disrupted at this stage resulting from the newly developed blood vessels not provided with the physiological properties of the common blood-brain barrier. Chemotherapeutic agents initially lipid-insoluble or liquor-impermeable can also penetrate into the brain and, therefore, trigger action against tumour cells. A number of clinical trials have demonstrated that brain metastases resulting from both small-cell lung cancer and non-small-cell lung cancer are susceptible to systemic chemotherapy. In small-cell lung cancer, cerebral response rates up to 50% were observed even in the second-line situation and were comparable to the response rates observed in the primary tumour. In non-small-cell lung cancer, similar results were achieved. Therefore, it seems justified to further evaluate the significance of chemotherapy compared to whole-brain radiation therapy. Whether chemotherapy alone is superior to whole-brain radiation therapy, or whether the combination of both therapeutic modalities should be preferred for the management of brain metastases, has not yet been proven, and further randomised phase-III studies are clearly needed. Based on the current available data, and the promising response rates in patients with lung cancer, chemotherapy should be considered for the management of brain metastases as part of a multimodality (or "interdisciplinary") treatment concept.

The role of topotecan in the treatment of brain metastases

Despite advances in the treatment of systemic malignancies, the prognosis for patients with brain metastases continues to be dismal. Because the majority of cytotoxic agents seem to be unable to penetrate the blood-brain barrier, the role of chemotherapy in the treatment of brain metastases remains controversial. However, growing amounts of both laboratory and clinical data suggest that a few of the newly developed cytotoxic agents can cross the blood-brain barrier and may have a role in the treatment of patients with brain metastases. Topotecan, a novel topoisomerase I inhibitor, freely crosses the blood-brain barrier and may be clinically effective in both the therapeutic and prophylactic settings in patients with brain metastases. Recent studies have demonstrated the antitumor activity of topotecan against brain metastases, with objective response rates ranging from 33%-63% in patients with various solid tumors. The antitumor response in the central nervous system was often greater and occurred more quickly than the systemic antitumor response to topotecan treatment. This result may be explained by the lack of exposure of brain metastases to previous cytotoxic agents, suggesting a role for topotecan in patients with brain metastases. Early studies have also suggested that topotecan, an apparent radiosensitizer, may be particularly effective in combination with radiotherapy, the current standard of care for patients with brain metastases. In addition, preliminary data suggest that topotecan in combination with temozolomide (another cytotoxic agent that can cross the blood-brain barrier) may have synergistic antitumor activity against brain metastases. This review summarizes the available preclinical and clinical evidence for the role of topotecan in the treatment of brain metastases and concludes with three case studies.

Prophylactic cranial irradiation in lung cancer

Patients with locally advanced lung cancer (non-small cell lung cancer or small cell lung cancer ) are threatened by concurrent risks of local, regional, and distant failure. By improving locoregional and systemic control within multimodality protocols, the brain emerges as one of the major relapse sites; therefore, prevention of brain relapse has become a primary focus of attention. Prophylactic cranial irradiation (PCI) has a high potential to reduce the risk of brain metastases. Clear evidence exists from meta-analysis that PCI improves overall and disease-free survival rates for patients with SCLC in complete remission. Long-term toxicities, predominantly neurocognitive impairments, represent potential risks, but within large prospective trials, including adequate control groups, late complications of clinical significance rarely have been observed. PCI is the recommended standard of care for the patients with limited disease SCLC in complete remission. As long as the optimal dose and fractionation remain to be defined in this setting, conventional fractionation with moderate total doses of approximately 30 Gy is preferred. In patients with locally advanced stage III non-small cell lung cancer treated within multimodality protocols, comparable relative risks for cumulative brain relapse have been demonstrated in long-term survivors. Although not the standard of care in this situation, the scientific community should be encouraged to further investigate PCI in these patient subgroups within carefully designed clinical trials, including untreated control arms.

The role of chemotherapy in brain metastases

Despite the widely held belief of the resistance to chemotherapy of brain metastases, central nervous system metastases of a malignancy are equally sensitive to chemotherapy as its metastases elsewhere in the body. This is due to the fact that the blood-brain barrier is disrupted in contrast enhancing brain metastases, and does not limit the response to chemotherapy. Therefore, the response rate of the primary tumour. Up-front chemotherapeutic treatment instead of radiotherapy of brain metastases should therefore be based on the chemosensitivity of the primary tumor to the used regimen, and not on the question whether the used agent penetrates an intact blood-brain barrier. First-line chemotherapy for brain metastases or with only minor neurological signs and symptoms, and who have an indication for systematic chemotherapy for metastases elsewhere in the body. In contrast, central nervous system micrometastases may hide behind an intact barrier, and this may be clinically relevant in patients that can be cured with chemotherapy (like in small cell lung cancer). Cytochrome P450 3A4 inducing anti-epileptic drugs like phenytoin, carbamazepine and phenobarbital may significantly increase the metabolism of many chemotherapeutic agents like CPT11 and paclitaxel (but also of newer biological agents like many tyrosine kinase inhibitors). These anti-epileptic drugs should be avoided in patients requiring chemotherapy with agents metabolised through the cytochrome P450.

Topotecan as first-line therapy for small cell lung cancer

Although current treatments for small-cell lung cancer (SCLC) yield objective response rates exceeding 50%, most patients relapse. Hence, research into the identification of novel agents and combinations that may improve therapy is ongoing. Topotecan, an established treatment for patients with recurrent SCLC, is being investigated as first-line therapy for SCLC because of its novel mechanism of action, non-cumulative toxicity and in vitro synergy with other active agents. Several phase II studies of doublet and triplet combination therapy with other agents, including paclitaxel, cisplatin, carboplatin and etoposide, have reported promising results for first-line treatment of SCLC. For example, in combination with paclitaxel, complete and overall responses were 3-67% and 45-100%, respectively, in extensive-stage disease. Furthermore, two studies of the triplet combination of topotecan with paclitaxel plus carboplatin yielded impressive complete response rates of 37-51% in limited-stage SCLC. The most frequent adverse events associated with topotecan-based regimens have been reported as neutropenia and thrombocytopenia so growth factor support is often incorporated into treatments. Several ongoing phase III studies will help to clarify the role of topotecan in the first-line treatment of SCLC.

Treatment of relapsed small-cell lung cancer--a focus on the evolving role of topotecan

Despite the high response rates to chemotherapy, small-cell lung cancer (SCLC) is among the most lethal malignancies. Long-term survival is anecdotal for patients with extensive disease; 5-years survival is < or =5% for those with limited disease. All patients with extensive disease and most patients with limited disease will experience disease progression and become candidates for second-line therapy. Although a number of agents have demonstrated antitumor activity in relapsed SCLC, including paclitaxel, docetaxel, etoposide, cisplatin, and carboplatin, topotecan is the only single agent currently approved in the United States for the treatment of recurrent disease. Topotecan is a novel topoisomerase I inhibitor with established antitumor activity in recurrent SCLC and has a predictable, noncumulative toxicity profile. Furthermore, topotecan has been shown to provide symptom improvement in this predominantly palliative setting. Evidence also suggests that topotecan readily penetrates the blood-brain barrier and might be active in the relatively large subset of SCLC patients who experience brain metastases. This article reviews the clinical utility of topotecan in recurrent SCLC, including its efficacy, tolerability, and quality-of-life effect, when used as monotherapy and in novel combination regimens.

Emerging Role of Topotecan in First-Line Therapy of Small-Cell Lung Cancer

Topotecan, a novel topoisomerase I inhibitor, is an established treatment for patients with recurrent small-cell lung cancer (SCLC), with antitumor response rates of approximately 20% and median survival of approximately 32 weeks in patients with extensive-stage disease. Topotecan's comparable activity relative to other agents used in SCLC and its novel mechanism of action, noncumulative toxicity, and in vitro synergy with other active agents have provided the rationale for investigating topotecan in first-line therapy. Furthermore, topotecan penetrates the blood-brain barrier and is potentially useful for the relatively large subset of patients with SCLC and brain metastases. In early studies of topotecan in brain metastases, encouraging antitumor activity has been observed. In several feasibility and phase II studies of topotecan as single-agent therapy in patients with extensive- and limited-stage tumors and as part of novel first-line combination regimens, overall response rates have ranged from 42% to 100%. Complete responses of 3%-67% and partial responses of 33%-80% have been observed in first-line therapy. Furthermore, the median overall survival in patients receiving topotecan in first-line therapy has ranged from approximately 8 months (extensive-stage disease) to 20 months (limited-stage disease). The most frequent adverse events associated with topotecan-based regimens include grade 3/4 neutropenia and thrombocytopenia that often require the incorporation of growth factor support into the treatment regimen. Nonhematologic adverse events associated with topotecan-based combination regimens have been mild or primarily attributed to other agents in the combination. Alternative doses and schedules (3 consecutive days and weekly) are being explored because they appear to be associated with considerably less myelosuppression. Although several trials have established the feasibility and activity of topotecan in first-line therapy of patients with SCLC, randomized phase III studies with comparison to standard therapy will be required to confirm a potential role for this active agent and to determine the optimal dosing regimen.

Chemotherapy versus best supportive care for extensive small cell lung cancer

BACKGROUND

Combination chemotherapy has been the mainstay of treatment for extensive stage small cell lung cancer (SCLC) over the last 25 years even though it only gives a short prolongation in median survival time. The main goal for these patients, if their survival prognosis is limited, should be adequate palliation with the aim of improving their quality of life.

OBJECTIVES

To evaluate the effectiveness of chemotherapy in extensive SCLC compared with best supportive care (BSC) or placebo treatment.

SEARCH STRATEGY

Medline (1966-Jan 2003), Embase (1974-Jan 2003), Cancerlit (1993-Jan 2003) and the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 4, 2002) were searched. In addition experts in the field were contacted to identify further studies not found by electronic searches.

SELECTION CRITERIA

Randomised controlled trials in which any chemotherapy treatment was compared with a placebo group or best supportive care in patients with extensive stage SCLC.

DATA COLLECTION AND ANALYSIS

Data extraction and quality assessment were undertaken independently by two reviewers and disagreements were resolved by a third author. Additional information on the included studies was obtained from the author of the original studies.

MAIN RESULTS

Only two studies (the first published in 1977 and the second in 1982) met the inclusion criteria of the review. A total of 65 patients with extensive disease (33 in the first study and 32 in the second) were randomised to received either placebo treatment or ifosfamide. In the second study a third arm of comparison included ifosfamide plus CCNU. Ifosfamide gave an extra 78.5 days survival (mean survival time) compared with the placebo group. Partial tumour response was greater with the active treatment. Toxicity was only seen in the chemotherapy group. Pooled analysis was not possible because only mean survival time was reported in both studies for patients with extensive disease.

REVIEWER'S CONCLUSIONS

Chemotherapeutic treatment prolongs survival in comparison with placebo in patients with advanced SCLC. Nevertheless the impact of chemotherapy on quality of life and in patients with poor prognosis is unknown. Well-designed, controlled trials are needed to further evaluate the risks and benefits of different chemotherapeutic schedules in patients with advanced small cell lung cancer.