Therapeutic options in renal cell carcinoma

The management of renal cell carcinoma remains a therapeutic challenge. For patients with localized disease, surgery represents the only curative treatment modality. Neither postoperative radiotherapy nor systemic hormonal therapy is of additional benefit in this setting. There are ongoing studies evaluating the role of biologic response modifiers, such as interferon and interleukin-2, as adjuncts to surgery. Patients with recurrent or metastatic disease have a poor prognosis and are a natural target for clinical trials designed to evaluate potential therapeutic modalities. Cytotoxic drugs and hormonal therapies are usually ineffective. The advent of interferon, and more recently of interleukin-2, has resulted in a modest advance in therapy of metastatic renal cell carcinoma. Studies designed to evaluate mechanisms associated with intrinsic or acquired resistance to cytotoxic drugs, as well as to biologic response modifiers, will lead to a better understanding of the biology of the disease and, ultimately, to a more rational and effective use of various therapeutic agents.

The role of interferons in the treatment of malignant neoplasms

Interferons (IFNs) are proteins with a wide range of biological effects. IFNs have antiviral and antiproliferative properties. They modulate both the immune system and the expression of cell phenotype. In the past decade, the IFNs have received intense clinical scrutiny. Alpha IFN is the best studied and displays activity in many neoplastic diseases; it has shown the most promise in the hematological cancers although several solid tumors, including epidemic Kaposi's sarcoma, renal cell carcinoma, and melanoma, respond. No neoplastic disease, however, has been cured by the IFNs. IFN seems to be most active in the setting of minimal residual disease, and clinical studies evaluating its role in the adjuvant setting are under way. Other areas of research include trials combining IFN with cytotoxic drugs or other biological response modifiers, and maintenance IFN to prolong remissions following successful induction therapy.

Effect of dipyridamole on fluorodeoxyuridine cytotoxicity in vitro and in cancer patients

Dipyridamole (DP) has previously been studied both in vitro and in vivo in combination with various anti-metabolites, including methotrexate and 5-fluorouracil (5FU). We evaluated in vitro and clinically the effects of adding DP to fluorodeoxyuridine (FUDR) in colorectal cancer. Using a human colony-forming assay, we observed that 0.05 microM DP increased the cytotoxicity of FUDR by a median of 33.5-fold vs 1.5-fold for 5FU against human colon-cancer cell lines. The mechanism of the DP-enhanced antitumor activity of FUDR is not completely understood but appears to be related to a profound inhibition by DP of thymidine accumulation in and FUDR efflux from colon-cancer cell lines. On the basis of these in vitro results, 28 patients with metastatic colon cancer were entered in a clinical trial of monthly courses of 0.1 mg/kg FUDR daily for 14 days and 75 mg oral DP 5 times daily for 14 days starting on the 3rd day of continuous i.v. FUDR infusion. The pharmacokinetics of DP was studied in three patients; the results showed that 98% of total serum DP was protein-bound and that free DP levels were significantly lower than the concentrations necessary for the expected in vitro DP/FUDR modulation. Treatment was well tolerated, with only 12 patients developing mild to moderate toxicity. Of 27 evaluable patients, 4 achieved a partial response that lasted 2, 3, 5, and 6+ months. This relatively low response rate (15%), which is similar to that achieved with FUDR alone, may be explained by the low steady-state plasma concentrations of free DP achieved in our patients. Other means of DP administration, such as i.v., i.a., and i.p. injection, may be required to achieve free DP concentrations necessary for successful biochemical modulation of FUDR in patients.

Management of refractory myeloma: a review

Management of refractory myeloma represents a common and challenging clinical problem. Approximately 30% to 50% of patients with multiple myeloma do not respond to first-line therapy, and those who initially achieve a remission will eventually relapse. Surprisingly, there is no routinely accepted approach to patients with refractory disease. Therefore, we review the literature in an attempt to provide an overview of the published results and outline our treatment recommendations for such patients. We suggest the following: (1) for truly resistant patients (ie, those who clearly progress with initial therapy), administration of high-dose or pulsed glucocorticosteroids is the best treatment, with an expected response of 40% (defined as a greater than or equal to 50% reduction in monoclonal [M]-protein concentration); (2) for patients who relapse during therapy or relapse within 6 months of stopping the initial treatment, the VAD regimen (vincristine, doxorubicin, and dexamethasone) is one of the most effective salvage therapies, resulting in an approximately 75% response rate (greater than or equal to 50% reduction in M-protein concentration); (3) for patients who relapse within more than 6 months of stopping therapy (unmaintained remission), reinitiation of the initial therapy represents an excellent alternative, leading to recontrol in 60% to 70% of patients (greater than or equal to 50% reduction in M-protein concentration). If progression is observed or if there is response and then relapse in this setting, VAD chemotherapy can be administered again. (4) Patients who fail second-line salvage therapies should enter well-designed clinical trials to evaluate new treatment modalities. If this is not feasible, alpha-interferon or "systemic" radiotherapy are recommended in selected cases.

Danazol in the treatment of myelodysplastic syndromes

20 patients with myelodysplastic syndromes (MDS) were treated with danazol, 800 mg daily in 4 divided doses. 18 patients were evaluable for response. 3 patients (17%), whose principal problem was anemia, responded to treatment, but only with an increase in platelet count. Responses were short-lived and lacked clinical significance. No patients with anemia or leukopenia responded to treatment and none of the 7 patients with a platelet count less than 30 x 10(9)/l responded. Danazol appears to have limited clinical utility in the treatment of MDS. However, occasional patients with thrombocytopenia may benefit.

Salvage therapy of advanced Hodgkin's disease. Critical appraisal of curative potential

The therapeutic outcome in patients with advanced Hodgkin's disease has improved considerably since the advent of MOPP chemotherapy (mechlorethamine, vincristine, procarbazine, and prednisone) and MOPP-like regimens. Still, failure will eventually occur in approximately 50 percent of these patients. The optimal approach to treating these patients is not well established. Currently, the six major salvage approaches available are: (1) chemotherapy reinduction with the same initial regimen: (2) chemotherapy with ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine); (3) non-ABVD second-line regimens; (4) third-line chemotherapy regimens; (5) wide-field radiation therapy alone or combined with second-line chemotherapy; and (6) autologous and allogeneic bone marrow transplantation. This review provides a critical evaluation of the curative potential of each therapeutic modality and outlines recommendations for the best current therapeutic approach and for future clinical study.

Phase II study of interferon alfa-2a, recombinant (Roferon-A) in metastatic renal cell carcinoma

In an attempt to decrease toxicity without compromising efficacy, 22 patients with locally advanced or metastatic renal cell carcinoma (RCC) were treated with recombinant interferon alfa-2a (rIFN alpha 2a, Roferon-A; Hoffman-LaRoche, Nutley, NJ) intramuscularly (IM) beginning at a dose of 3 X 10(6) U/d with incremental dose escalations to the highest dose of 36 X 10(6) U/d if tolerated, for a total induction period of 10 weeks. Patients demonstrating complete (CR), partial (PR), or minor (MR) responses or stabilization were continued on a maintenance regimen of the highest tolerated dose administered three times weekly until disease progression. Doses administered during maintenance were individually determined as the maximum dose that resulted in only mild toxicity. No CRs were achieved. Partial responses were observed in 23% of the patients with a median duration of response of 8.0 months (range, 1 to 17+). The majority of interferon side effects were seen during the induction phase, which was also the period requiring the most frequent adjustments in dose. In comparison to another study using similar toxicity criteria, overall toxicity was reduced in severity, most probably due to the study design, which allowed individual tailoring of doses. The use of an initial induction phase employing rapid dose escalation followed by a well-tolerated maintenance phase appeared to be a reasonable strategy. The therapeutic results to date represent a modest advance. An optimal dosage, route, and schedule for interferon administration for metastatic renal cancer is not yet clearly established.

Cranial metastases from prostate cancer simulating meningioma: report of two cases and review of the literature

Two cases of prostatic carcinoma metastatic to the cranium that presented with clinical and radiographic features simulating meningioma are described. The literature was reviewed, and 13 similar cases were identified. From the data gathered, we conclude that metastatic prostate cancer should be considered in the differential diagnosis of elderly males who present with characteristic clinical and radiological features of meningioma and that the classical description of meningioma is not specific.

Management of myelodysplastic syndromes

The treatment of myelodysplastic syndromes is reviewed, with emphasis on recently published clinical trials. Pyridoxine is rarely effective, but a trial in patients with refractory anemia with ringed sideroblasts is justifiable. Corticosteroids do not appear indicated unless in vitro data suggest response. Androgens are generally not beneficial, although danazol merits further evaluation. Both 13-cis-retinoic acid and low-dose cytosine arabinoside have considerable toxicity and yield short-lived partial responses that may not have a significant impact on survival. Combination chemotherapy may be considered in selected patients with refractory anemia with excess of blasts, refractory anemia with excess of blasts in transformation, and chronic myelomonocytic leukemia; however, in general, its toxicity outweighs potential benefit. For unusual patients under 30 years old, bone marrow transplantation should be considered as first-line therapy. Until more effective and less toxic agents are available, supportive care may still be the most appropriate therapy for many of these generally elderly patients.