Enhanced radiosensitization with interferon-alpha-2b and cisplatin in the treatment of locally advanced cervical carcinoma

Combining Radiation Therapy With Interferons: Back to the Future

Radiation therapy has been linked to the induction of an intratumoral type I interferon (IFN) response, which positively affects the response to treatment. This has spiked the interest to combine radiation therapy with IFN-based treatment. Interestingly, this combination treatment has been considered previously, since preclinical studies demonstrated a radiosensitizing effect of interferons. As a result, multiple clinical trials have been performed combining radiation therapy with interferons in different tumor types. Although potential benefit has been suggested, the outcomes of the trials are diverse and challenging to interpret. In addition, increased grade ≥3 toxicity frequently resulted in a negative recommendation regarding the combination therapy. The latter appears premature because many studies were small and several aspects of the combination treatment have not yet been sufficiently explored to justify such a definite conclusion. This review summarizes the available literature on this combination therapy, with a focus on IFN-α and IFN-β. Based on preclinical studies and clinical trials, we evaluated the potential opportunities and describe the current challenges. In addition, we identify several issues that should be addressed to fully exploit the potential benefit of this combinatorial treatment approach.

Toxicity of combined treatment of adjuvant irradiation and interferon alpha2b in high-risk melanoma patients

Surgically resected stage III melanoma patients commonly receive adjuvant therapy with interferon (IFN) alpha2b. For those patients with high-risk features of draining node recurrence, radiation therapy can also be considered as a treatment option. The purpose of this retrospective study was to assess the efficacy and radiation-related toxicity of this combined therapy. Eighteen patients receiving adjuvant IFNalpha2b therapy during radiation therapy, or within 1 month of its completion, were reviewed retrospectively and analysed for outcome. Radiation was delivered at 600 cGy dose per fraction, in 16 out of 18 patients, twice a week, and at 200 cGy dose per fraction in two patients five times a week. Total radiation dose and number of fractions were as follows: 30 Gy/5 fr (n=8), 36 Gy/6 fr (n=8) and 50 Gy/25 fr (n=2). The percentage of disease-free patients, with no local recurrence, at 3 years was 88%. In 10 patients, IFNalpha2b was administered concurrently with radiotherapy; in three, within 30 days before or after radiation; and in five, more than 30 days after radiation. All the patients experienced acute skin reactions, grade I on the Radiation Therapy Oncology Group (RTOG) scale. Late radiation-related toxicity was seen in one patient with grade III (RTOG) skin reaction and two with grade IV (RTOG) radiation-induced myelitis. Concurrent use of adjuvant radiotherapy and IFNalpha2b might enhance radiation-induced toxicity, and special care should be taken when the spinal cord is included in the radiation field.

Chemotherapy in the primary treatment of cervical carcinoma

Two major treatment modalities in cervical cancer include radiotherapy and surgery. In an attempt to improve the outcome, these modalities have been increasingly supplemented by chemotherapy. Chemotherapy can be combined with local therapies in various sequences. Of the two possible strategies using chemotherapy and radiotherapy (sequential or concomitant), the latter seems to be more effective. Platinum-based regimens applied concurrently with both definitive and post-operative radiation therapy were demonstrated to provide survival benefit in five of the six recently published randomised trials. The positive impact of chemotherapy added to radiotherapy has also been shown in a meta-analysis including 1894 patients in 19 randomised studies. This strategy, however, is accompanied by increased early toxicity. The benefit of chemotherapy applied prior to surgery remains debatable. The role of new cytotoxic and biological substances, as well as agents combating tumour hypoxia, warrants further clinical investigation.

Concurrent adjuvant radiotherapy and interferon-α2b for resected high risk stage III melanoma – a retrospective single centre study

Interferon-alpha2b (IFNalpha2b) is the only form of systemic adjuvant therapy for stage III melanoma with documented survival benefit. Radiotherapy can also be utilized in the adjuvant setting in patients at high risk of nodal basin recurrence. As IFNalpha2b is associated with substantial toxicity, we sought to determine both the systemic and radiation-related toxicities in patients treated with combined adjuvant IFNalpha2b and regional adjuvant radiotherapy delivered in the setting of a single institution. Eighteen consecutive patients who commenced adjuvant IFNalpha2b between November 1997 and August 2002 were analysed retrospectively for toxicities associated with the combination of IFNalpha2b and adjuvant radiotherapy (40-50 Gy in 15-25 fractions) to nodal basins delivered during the maintenance phase of IFNalpha2b therapy (median dose during radiotherapy of 6.5 MU/m three times per week). Seven out of 18 patients who received concurrent radiotherapy and IFNalpha2b displayed grade 3 skin reactions. Severe radiation-induced toxicity was seen in three further patients, one who developed radiation pneumonitis, one who developed severe oral mucositis, and one who developed wound dehiscence that took 10 months to resolve. Non-radiation-related toxicity to IFNalpha2b therapy was typical for this dose and schedule. We conclude that concurrent use of adjuvant radiotherapy and IFNalpha2b may enhance radiation-induced toxicity. However, overall we found concurrent radiation and IFNalpha2b could be safely delivered with appropriate clinical monitoring.

Potential of interferon-alpha in solid tumours: part 2

The second part of this review examines the use of recombinant interferon-alpha (rIFNalpha) in the following solid tumours: superficial bladder cancer, Kaposi's sarcoma, head and neck cancer, gastrointestinal cancers, lung cancer, mesothelioma and ovarian, breast and cervical malignancies. In superficial bladder cancer, intravesical rIFNalpha has a promising role as second-line therapy in patients resistant or intolerant to intravesical bacille Calmette-Guérin (BCG). In HIV-associated Kaposi's sarcoma, rIFNalpha is active as monotherapy and in combination with antiretroviral agents, especially in patients with CD4 counts >200/mm(3), no prior opportunistic infections and nonvisceral disease. rIFNalpha has shown encouraging results when used in combination with retinoids in the chemoprevention of head and neck squamous cell cancers. It is effective in the chemoprevention of hepatocellular cancer in hepatitis C-seropositive patients. In neuroendocrine tumours, including carcinoid tumour, low-dosage (</=3 MU) or intermediate-dosage (5 to 10 MU) rIFNalpha is indicated as second-line treatment, either with octreotide or alone in patients resistant to somatostatin analogues. Intracavitary IFNalpha may be useful in malignant pleural effusions from mesothelioma. Similarly, intraperitoneal IFNalpha may have a role in the treatment of minimal residual disease in ovarian cancer. In breast cancer, the only possible role for IFNalpha appears to be intralesional administration for resistant disease. IFNalpha may have a role as a radiosensitising agent for the treatment of cervical cancer; however, this requires confirmation in randomised trials. On the basis of current evidence, the routine use of rIFNalpha is not recommended in the therapy of head and neck squamous cell cancers, upper gastrointestinal tract, colorectal and lung cancers, or mesothelioma. Pegylated IFNalpha (peginterferon-alpha) is an exciting development that offers theoretical advantages of increased efficacy, reduced toxicity and improved compliance. Further data from randomised studies in solid tumours are needed where rIFNalpha has activity, such as neuroendocrine tumours, minimal residual disease in ovarian cancer, and cervical cancer. A better understanding of the biological mechanisms that determine response to rIFNalpha is needed. Studies of IFNalpha-stimulated gene expression, which are now feasible, should help to identify molecular predictors of response and allow us to target therapy more selectively to patients with solid tumours responsive to IFNalpha.

Phase III randomized pilot study comparing interferon alpha-2b in combination with radiation therapy versus radiation therapy alone in patients with stage III-B carcinoma of the cervix

This randomized pilot study was designed to determine whether the addition of interferon alpha-2b to standard radiation therapy offered an advantage in loco-regional control and survival over radiation therapy alone in a homogeneous group of patients with stage IIIB carcinoma of the cervix. Thirty-six patients were treated with a combination of interferon alpha-2b plus radiation therapy, and 38 patients were treated with radiation therapy alone. Patients with evidence of ureteral obstruction were excluded from the study. Evaluation of loco-regional response was determined by pelvic examination, cervical cytology, biopsies and CT scans when indicated. Survival time was measured from initiation of treatment to date of death or last follow-up. Patient characteristics were comparable between both study arms. The objective complete response rate was 67% in the combined therapy group and 55% in the radiation alone group (P = 0.454). With a median follow-up of 17 months for all patients and 31 months for live patients, 50% of the combined group survived vs. 39.5% of the radiation alone group (P = 0.424). We conclude that the addition of interferon alpha-2b to standard radiation therapy did not significantly improve loco-regional response or survival, although such a trend was noted. We encourage the design of a larger randomized study with sufficient power to detect meaningful differences to prove whether the tendency observed in the present investigation holds any promise to improve the outcome of these patients.