Topotecan concomitant with primary brachytherapy radiation in patients with cervical carcinoma: a phase I trial

Pharmacotherapy options for locally advanced and advanced cervical cancer

Cervical cancer continues to be a significant health burden worldwide. Globally, the majority of cancers are locally advanced at diagnosis; hence, radiation remains the most frequently used therapeutic modality. Currently, the value of adding cisplatin or cisplatin-based chemotherapy to radiation for the treatment of locally advanced cervical cancer is strongly supported by randomized studies and meta-analyses. Nevertheless, despite these significant achievements, therapeutic results are far from optimal; thus, novel therapies need to be investigated. A recent, randomized, phase III trial has shown for the first time that combination chemotherapy with cisplatin and gemcitabine concurrently with radiation improves parameters of survival over cisplatin alone and establishes a new standard for the management of locally advanced cervical cancer. On the other hand, advanced disease, presenting either as an International Federation of Gynecology and Obstetrics (FIGO) stage IVB or as persistent or recurrent to primary therapy without local curative options, remains a devastating group of diseases with no options other than palliative chemotherapy. Recent results from the GOG (Gynecologic and Oncologic Group)-204 study demonstrate that cisplatin-doublets with paclitaxel, vinorelbine, gemcitabine or topotecan only produce small improvements in survival, although with different toxicity patterns; hence, patient-related factors are important when choosing any one of these regimens. The role of targeted therapies both in locally advanced and advanced disease is promising, but still at an investigational stage.

A review of topotecan in combination chemotherapy for advanced cervical cancer

Treatment of advanced, recurrent or persistent cervical cancer includes radiotherapy and chemotherapy. Radiation has been the primary treatment modality for locoregionally advanced cervical cancer. Concomitant systemic cisplatin chemotherapy and radiation have shown high response rates with improvements in durable remissions and overall survival. Cisplatin has been the standard medication for the treatment of advanced cervical cancer. Combinations with other chemotherapeutic agents have been the subject of clinical trials with varying results. The toxicity of combination chemotherapy and tolerability of patients are other factors that should be considered in the management of patients with advanced disease. Recently topotecan, in combination with cisplatin, achieved increased response and overall survival rates without further compromising the patients' quality of life. This review focuses on the mechanism of action and toxicities of topotecan, as well as its role as a radio-sensitizer and chemotherapeutic agent in the management of advanced, recurrent, or persistent cervical cancer. Other combination modalities and dosages are also discussed.

Topotecan in cervical cancer

Recurrent and advanced cervical cancers are associated with high mortality and a lack of effective treatment options, especially for women who are poor candidates for surgery or radiation therapy. The broad clinical effectiveness and manageable toxicity of topotecan in other human malignancies as well as promising recent study results suggest that it is highly effective in treating cervical tumors. We therefore conducted a systematic review on the studies using topotecan in cervical cancer. Seven phase I-III clinical trials using topotecan, both as a single agent and in combination with cisplatin or paclitaxel, in patients with recurrent or advanced carcinoma of the cervix were reviewed. Data from two studies in which topotecan was used in combination with radiotherapy for induction therapy were also evaluated. Although single-agent cisplatin-based chemoradiotherapy is the standard of care for high-risk or locally advanced cervical cancer, topotecan, when used concurrently with cisplatin and/or radiation therapy, produces high objective response rates and prolonged survival. Gynecologic Oncology Group (GOG) Protocol 179 for the first time showed significantly improved overall survival and progression-free survival in a combination therapy for advanced cervical cancer compared to cisplatin alone. Recent data suggest that topotecan, when used concurrently with cisplatin, may be the new standard of care for the management of recurrent or advanced cervical cancer. Ongoing phase III studies (GOG-204, AGO-Zervix-1) will compare this combination with other cisplatin-containing and cisplatin-free combinations. Moreover, further evaluation of topotecan appears to be warranted in conjunction with radiotherapy and in the neoadjuvant setting as well as in combination with novel biologic agents.

Topotecan in the management of cervical cancer

Topotecan, a semisynthetic camptothecin, exerts its cytotoxic effect through inhibition of DNA topoisomerase I. Single-agent topotecan has demonstrated activity against persistent, metastatic and recurrent cancer of the uterine cervix. When combined with cisplatin in Phase II trials, further improved response rates have been reported. The cisplatin/topotecan doublet subsequently proved to be the first regimen in a series of multiple Phase III studies to demonstrate improved disease-free and overall survival in this setting compared with cisplatin alone, thus leading to its third indication by both the US FDA and the European Medicines Agency in 2006. This survival advantage was achieved at the expense of an increase in grade 3-4 hematologic toxicity; however, there was no difference in patient-reported quality of life between the cisplatin/topotecan doublet and single-agent cisplatin. This article reviews the pharmacology of topotecan and its evolution as an active agent in advanced and metastatic cervical cancer that is not amenable to cure with surgery or radiotherapy.

Radiosensitizers in cervical cancer. Cisplatin and beyond

Cervical cancer continues to be a significant health burden worldwide. Globally, the majority of cancers are locally advanced at diagnosis; hence, radiation remains the most frequently used therapeutical modality. Currently, the value of adding cisplatin or cisplatin-based chemotherapy to radiation for treatment of locally advanced cervical cancer is strongly supported by randomized studies and meta-analyses. Nevertheless, despite these significant achievements, therapeutic results are far from optimal; thus, novel therapies need to be assayed. A strategy currently being investigated is the use of newer radiosensitizers alone or in combination with platinum compounds. In the present work, we present preclinical information on known and newer cytotoxic agents as radiosensitizers on cervical cancer models, as well as the clinical information emanating from early phase trials that incorporate them to the cervical cancer management. In addition, we present the perspectives on the combined approach of radiation therapy and molecular target-based drugs with proven radiosensitizing capacity.

The role of topotecan in the treatment of advanced cervical cancer

Improvements in the early detection of cervical cancer have markedly reduced associated mortality rates over the past few decades; however, in patients diagnosed with cervical cancer the rates have remained unchanged for 25 years. Hysterectomy, alone or with radiotherapy, is effective in early-stage disease, with a high cure rate, but the treatment of advanced and recurrent cervical cancer (usually with radiotherapy and cisplatin) is suboptimal, with 5-year survival rates of 50.9 and 16.5% for patients with regional involvement or distant disease, respectively. There is therefore an unmet need for more effective treatments for patients with advanced disease, and a number of new chemotherapy agents and treatment strategies have been investigated in this setting. Promising results have been reported in phase II trials of the topoisomerase inhibitor I, topotecan. Response rates of up to 19% have been reported in patients treated with topotecan as a single agent and response rates of up to 54% have been achieved when this agent is used in combination chemotherapy regimens. Toxicity levels are similar to those observed in patients with relapsed ovarian cancer and are not significantly different from levels with other chemotherapy agents. This paper reviews the current management of advanced cervical cancer and summarizes the available data on the use of topotecan in this setting.

Update on the treatment of cervical and uterine carcinoma: focus on topotecan

Carcinomas of the uterine cervix and corpus are significant causes of morbidity and mortality among women in the U.S. and are expected to contribute 10,700 deaths in 2002. Despite the widespread use of cytologic screening and improvements in early diagnosis, mortality rates have changed little over the past 25 years, and the management of cervical and uterine cancers remains a significant unmet medical need. Currently available modalities, including radiotherapy and cisplatin-based chemotherapy, provide suboptimal control of disease, and there are no effective treatments for recurrent disease. The antitumor activity and tolerability of a number of novel agents, including topoisomerase I inhibitors, vinca alkaloids, taxanes, and gemcitabine, have been of considerable interest in treatment of these cancers. This review discusses current trends in the treatment of cervical and endometrial carcinomas, focusing on the potential role of topotecan in the treatment of non-ovarian gynecologic malignancies.

Phase I study of topotecan and radiation therapy in advanced cervical cancer

OBJECTIVE

The goal of this study was to determine the maximal tolerated dose (MTD) of topotecan given with external-beam radiotherapy in advanced cervical cancer.

METHODS

A prospective Phase I trial of topotecan given with standard external-beam radiotherapy was performed in patients with advanced squamous cell carcinoma of the cervix. Patients were treated with a starting dose of 0.5 mg/m(2) and escalated by 0.25 mg/m(2). Nine patients were treated. Hematologic and nonhematologic toxicity were measured.

RESULTS

Patients were treated with 1.0 mg/m(2) daily for 5 days on Days 1-5 and 22-26 concomitantly with radiotherapy without significant toxicity. Grade III anemia in one case and Grade II leukopenia in two cases were seen in the three patients at this dose level. Dose-limiting toxicity was not reached.

CONCLUSION

Topotecan can be safely administered at a dose of 1.0 mg/m(2) during external-beam radiotherapy for advanced cervical cancer.