The cancer journal from Scientific American最新文献

Objectives: To determine the association of intratumoral thymidylate synthase (TS) gene expression with resistance to fluoropyrimidines and to study the association of TS gene expression with outcome in patients with liver metastases from colorectal cancer.

Methods: Intratumoral TS gene expression was measured by reverse transcriptase and polymerase chain reaction in 33 patients with liver metastases from colorectal carcinoma. Fifteen patients underwent resection, and 18 were treated with chemotherapy only. Patients with high levels of TS gene expression were compared to those with low levels of TS gene expression.

Results: All patients with a high level of TS gene expression were nonresponders to fluoropyrimidine chemotherapy. Median survival in patients with unresectable disease was shorter in those who had high levels of TS gene expression (7 months vs 15 months, P = 0.02). After hepatic resection, median disease-free interval was shorter in patients with high levels of TS gene expression (5 months vs 18 months; P = 0.004). Similarly, survival was shorter after resection in those with high TS gene expression (17 months vs 43 months, P = 0.0002).

Discussion: Increased TS gene expression is associated with a poor outcome in patients with liver metastases from colorectal carcinoma, whether resected or treated by chemotherapy only. This is related in part to reduced responsiveness to chemotherapeutic agents, but it also reflects inherently more aggressive behavior of metastases.

Background: Interferon alfa has modest but definite activity in the treatment of metastatic melanoma and is the only agent currently available for adjuvant therapy of high-risk resected disease. A variety of retinoic acid derivatives have been shown to be synergistic with interferon alfa in vitro and in vivo, with nonoverlapping toxicities. If promising combinations of interferon alfa and retinoids could be developed for melanoma patients, they would have clinical relevance for the treatment of advanced as well as localized disease.

Purpose: To determine the efficacy and toxicity of a combination of interferon alfa-2a and all-trans-retinoic acid in patients with measurable metastatic melanoma, the South-west Oncology Group conducted a phase II clinical trial.

Patients and methods: Fifty-seven patients with measurable metastatic melanoma (American Joint Committee on Cancer stage IV) were entered; five patients were unevaluable. Treatment consisted of oral all-trans-retinoic acid (37.5 to 75 mg/m2 orally twice daily for 21 days followed by 7 days' rest) plus subcutaneously administered interferon alfa-2a (6 MU/m2 three times a week).

Results: Two complete and three partial responses were observed among 52 evaluable patients, for an objective response rate of 10% (95% confidence interval 3% to 21%). Responses were seen only in patients with pulmonary, nodal, or subcutaneous metastases, and lasted from 4 to 23+ months. Median survival for the 52 patients was 8 months. Side effects were tolerable but significant, with one case of grade IV anemia and 92% of patients experiencing at least grade II toxicity. Flu-like symptoms were the most commonly reported side effects. There was one case of grade III hyperlipidemia.

Conclusion: The combination of recombinant human interferon alfa-2a with all-trans-retinoic acid did not result in a greater percentage of objective responses or a longer overall survival than that associated with interferon alfa alone. This combination cannot be recommended for further evaluation in melanoma in either the advanced disease or the adjuvant settings.

Purpose: Suicide gene therapy has proved to be successful in enhancing the therapeutic index by sensitizing genetically modified tumor cells to prodrugs. Two of the most widely studied suicide genes, herpes simplex virus type 1 thymidine kinase and Escherichia coli cytosine deaminase, have proved effective at selectively eliminating malignant tumor cells. We previously demonstrated that transduced 9L glioma cells expressing E. coli cytosine deaminase and herpes simplex virus type 1 thymidine kinase concomitantly as a fusion protein exhibited greater levels of targeted cytotoxicity and radiosensitization than could be achieved by single suicide gene therapy. The present in vivo studies were carried out to determine whether double suicide gene therapy would enhance the tumor control rate of orthotopically implanted malignant glioma growing in the brain when coupled with radiotherapy.

Materials and methods: Rat 9L gliosarcoma cells were transfected with retroviral vectors containing an E. coli cytosine deaminase and herpes simplex virus type 1 thymidine kinase fusion gene and maintained in Dulbecco's modified Eagle's medium. The antitumor response of 9L E. coli cytosine deaminase and herpes simplex virus type 1 thymidine kinase tumors growing in the brain of Fischer rats was evaluated with small tumors (6-day-old tumors) versus large tumors (14-day-old tumors) against single versus double prodrug treatments. In the large brain tumors, the therapeutic efficacy of the combined single and double prodrugs coupled with radiotherapy was evaluated.

Results: Double suicide gene therapy using two prodrugs, 5-fluorocytosine (500 mg/kg) and ganciclovir (30 mg/kg), was effective in achieving long-term tumor control (50% survival) against early-stage brain tumors (6 days after implantation) but was only marginally effective against advanced stage tumors (14 days old). However, when these prodrugs were combined with radiotherapy and double suicide gene therapy against advanced-stage tumors, more than 70% of the animals were cured, whereas radiotherapy alone (20 Gy) failed to achieve any cure at all. Combined radiotherapy and single prodrug therapy showed a moderate increase in the animal survival rate (17% and 40% for 5-fluorocytosine and ganciclovir, respectively) but was inferior to the combination therapy of radiation and double prodrugs.

Conclusion: The present in vivo results indicate that double suicide gene therapy combined with radiotherapy may represent a new, effective approach to achieve a high tumor cure rate without producing any excessive normal tissue damage.

Purpose: Regional lymph node involvement is the most important prognostic indicator in patients with solid tumors. Conventional lymph node dissection has not been shown to affect survival and is often associated with considerable morbidity. Intraoperative lymphatic mapping and sentinel lymph node dissection were therefore designed as a minimally invasive alternative to routine elective lymph node dissection in patients with primary cutaneous melanoma. This study examined whether introperative lymphatic mapping and sentinel lymph node dissection were accurate in staging patients with other solid malignancies.

Patients and methods: Between 1985 and 1998, 107 patients with breast cancer, 17 with thyroid tumors, 14 with gastrointestinal/gynecologic cancers, six with Merkel cell cancers, and five with squamous cell carcinomas of the head and neck have undergone mapping and sentinel lymph node dissection at the John Wayne Cancer Institute.

Results: The sentinel node was identified in 96% of patients (98% melanoma). In 36% of patients the sentinel node was the only tumor-positive node (71% melanoma). Eighteen percent of sentinel nodes were negative by hematoxylin and eosin staining but were positive by immunohistochemical staining (15% melanoma).

Conclusion: These data suggest that many solid neoplasms have a primary lymphatic channel and lymph node to which it drains. Although sentinel lymph node dissection has been popularized in melanoma therapy, we have found it feasible for treatment of other solid malignancies. This technique may ultimately replace conventional dissection with more accurate staging.

Background: Chest wall recurrence of breast cancer after mastectomy, radiation therapy, and chemotherapy poses a therapeutic dilemma. Further intervention with any or all of these modalities is often futile and morbid. Left untreated, severe pain, infection, and suffering occur.

Objective: To ascertain whether photodynamic therapy may present a palliative option for these individuals.

Methods: A total of 86 lesions (2.4-cm mean diameter) were treated on eight patients who had biopsy-proven chest wall recurrence despite surgery, chemotherapy, and radiation therapy. Each patient underwent a single photodynamic therapy session in which 1.2 mg/kg of the drug tin ethyl etiopurpurin (Purlytin) was injected and followed 24 hours later by laser light treatment at 660 +/- 3 nm (at 150 mW/cm2 for a total light dose of 200 J/cm2).

Results: With a minimum 6-month follow-up, the objective response rates after photodynamic therapy were complete response, 92%; partial response, 8%; and no response, 0%. Lesions less than 0.5 cm had a 100% complete response. Morbidity was minimal with no systemic toxicity. One patient had a wound infection that responded to oral antibiotics. No photosensitivity reactions were reported in this set of patients. Posttreatment pain was reported and could be treated with medication and application of cold compresses.

Conclusions: Photodynamic therapy offers an excellent local control rate of chest wall recurrence with minimal morbidity after multimodality treatment failure. The treatment is given in a single session and on an outpatient basis. In patients who may register a partial response or have recurrence or the incidence of further chest wall nodules after photodynamic therapy, the treatment is repeatable.