In vivo selection of human embryonic stem cell-derived cells expressing methotrexate-resistant dihydrofolate reductase

Human embryonic stem cells (hESCs) provide a novel source of hematopoietic and other cell populations suitable for gene therapy applications. Preclinical studies to evaluate engraftment of hESC-derived hematopoietic cells transplanted into immunodeficient mice demonstrate only limited repopulation. Expression of a drug resistance gene, such as Tyr22-dihydrofolate reductase (Tyr22-DHFR), coupled to methotrexate (MTX) chemotherapy has the potential to selectively increase engraftment of gene-modified hESC-derived cells in mouse xenografts. Here, we describe the generation of Tyr22-DHFR – GFP expressing hESCs that maintain pluripotency, produce teratomas and can differentiate into MTXr-hemato-endothelial cells. We demonstrate that MTX administered to nonobese diabetic/severe combined immunodeficient/IL-2Rγc^null (NSG) mice after injection of Tyr22-DHFR-derived cells significantly increases human CD34⁺ and CD45⁺ cell engraftment in the bone marrow (BM) and peripheral blood of transplanted MTX-treated mice. These results demonstrate that MTX treatment supports selective, long-term engraftment of Tyr22-DHFR-cells in vivo, and provides a novel approach for combined human cell and gene therapy.

Phase II study of sunitinib in men with advanced prostate cancer

BACKGROUND

This study explored the efficacy and tolerability of sunitinib, an inhibitor of tyrosine kinase receptors, in men with castration-resistant prostate cancer (CRPC).

METHODS

Men with no prior chemotherapy (group A) and men with docetaxel (Taxotere)-resistant prostate cancer (group B) were treated with sunitinib. The primary end point was confirmed 50% prostate-specific antigen (PSA) decline. Secondary end points included objective response rate and safety. Serum-soluble biomarkers were measured.

RESULTS

Seventeen men were enrolled in each group. One confirmed PSA response was observed in each group, and an additional eight men and seven men had stable PSA at week 12 in groups A and B, respectively. Improvements in imaging were observed in the absence of post-treatment PSA declines. Common adverse effects included fatigue, nausea, diarrhea, myelosuppression and transaminase elevation. Significant changes following sunitinib treatment were observed in serum-soluble biomarkers including soluble vascular endothelial growth factor receptor-2, platelet-derived growth factor aa, placental growth factor and leptin.

CONCLUSIONS

Sunitinib monotherapy resulted in few confirmed 50% post-treatment declines in PSA in men with CRPC. Serum markers of angiogenesis confirmed on-target effects of sunitinib. Assessments of radiographic disease status were often discordant with changes in PSA, indicating that alternate end points are important in future trials.

Challenges in the treatment of bladder cancer

Seventy to eighty percent of patients with newly-diagnosed bladder cancer will present with superficial tumors (Ta, Tis or T(1)). There is, however, a continuum between superficial and muscle-invasive cancer, with the advanced cases usually associated with less-differentiated histology and aneuploidy. Common sites of metastasis include regional lymph nodes, bone, lung, skin and liver. From the low cure rates achieved with radical cystectomy, there is strong evidence that bladder cancer, from the outset, is a systemic disease. The limitations of local treatment are well-documented: a local control rate of 30% with radiation treatment, and 50-70% with radical cystectomy; and no improvement in surgical cure was seen with the use of preoperative radiation. Over the past 30 years, since the initial reports of the effectiveness of cisplatin in the treatment of advanced bladder cancer, there has been a steady flow of chemotherapeutic agents, singly and in combination, shown to be effective in the treatment of this tumor. While response rates and CR rates have increased with the use of combination chemotherapy, this has not translated into survival in advanced disease of greater than 16 months. While the search for more effective agents and combinations continues, attention has also been given to the roles of neoadjuvant and adjuvant chemotherapy in an effort to improve the cure rate achieved with surgery alone. Although radical cystectomy, with continent diversion or neobladder construction in selected cases remains the standard of care in the United States for patients with muscle-invasive bladder cancer, several groups have explored therapeutic strategies that aim at bladder preservation. Early approaches with the goal of bladder preservation consisted of radiation treatment as monotherapy (largely abandoned) or aggressive TURBT for smaller tumors. Over the past 20 years, the Massachusetts General Hospital (MGH) and the Radiation Therapy Oncology Group (RTOG) have studied patients with muscle-invading bladder cancer utilizing tri-modality treatment: a visibly complete transurethral resection followed by radiation with concurrent radiosensitizing chemotherapy and, subsequently, adjuvant chemotherapy. Thus, chemotherapy has been used in two phases of treatment (1) as radiosensitizers, given concurrently with radiation treatment and (2) as adjuvant treatment, recognizing that survival will only be improved by the successful treatment of micrometastases. Based on preliminary information from reports of the effectiveness of gemcitabine/cisplatin in advanced disease, that combination was chosen as the adjuvant regimen in one of our earlier protocols, recently completed and reported. Our current protocol utilizes the Bellmunt regimen as our adjuvant program with the highest RR in advanced disease. This study is ongoing, with early reports of tolerance of the three-drug regimen encouraging. The treatment options for muscularis propria-invasive bladder tumors can broadly be divided into those that spare the bladder and those that involve removing it. In the United States, radical cystectomy with pelvic lymph node dissection is the standard method used to treat patients with this tumor.

Annual zoledronic acid to prevent gonadotropin-releasing hormone agonist-induced bone loss in men with prostate cancer: A randomized placebo-controlled trial

4515

Background: Gonadotropin-releasing hormone (GnRH) agonists decrease bone mineral density (BMD) and increase fracture risk in men with prostate cancer. Zoledronic acid (4 mg IV every 3 months) increases BMD in GnRH agonist treated men. Intermittent zoledronic acid (4 mg IV once annually) increases BMD in postmenopausal women with osteoporosis but the efficacy of the annual treatment schedule in hypogonadal men is unknown. Methods: In a 12-month open-label study, men with nonmetastatic prostate cancer (n = 44) who were receiving a GnRH agonist were assigned randomly to zoledronic acid (4 mg IV × 1) or placebo. BMD of the posteroanterior lumbar spine and total hip were measured by dual energy x-ray absorptiometry at baseline and month 12. Serum N-telopeptide, a marker of osteoclast activity, was measured every 3 months. Results: Mean (± SE) BMD of the posteroanterior lumbar spine increased by 4.0 ± 0.9 in men treated with zoledronic acid and decreased by 3.1 ± 0.9 percent in men who received placebo (P < 0.001 for between-group comparison). BMD of the total hip decreased by 0.7 ± 0.6 percent in men treated with zoledronic acid and decreased by 1.9 ± 0.7 percent in men who received placebo (P = 0.005). Compared to placebo, zoledronic acid significantly decreased serum N-telopeptide throughout the 12-month study (P < 0.05). Conclusions: In men receiving a GnRH agonist for prostate cancer, a single treatment of zoledronic acid significantly increased bone mineral density of the total hip and spine at 12 months. Annual zoledronic acid may provide a convenient and effective strategy to prevent bone loss in hypogonadal men. This study was supported in part by Novartis Oncology and by the Prostate Cancer Foundation.

[Table: see text]

Finasteride and bicalutamide as primary hormonal therapy in patients with advanced adenocarcinoma of the prostate

BACKGROUND

Medical or surgical castration is effective in advanced prostate cancer but with profound side-effects, particularly on sexual function. Effective, less toxic therapies are needed. This study examined whether the addition of finasteride to high-dose bicalutamide enhanced disease control, as measured by additional decreases in serum prostate-specific antigen (PSA).

PATIENTS AND METHODS

Forty-one patients with advanced prostate cancer received bicalutamide (150 mg/day). Finasteride (5 mg/day) was added at first PSA nadir. Serum PSA was measured every 2 weeks until disease progression. Questionnaires were administered to assess sexual function.

RESULTS

Median follow-up is 3.9 years. At the first PSA nadir, median decrease in PSA from baseline was 96.5%. Thirty of 41 patients (73%) achieved a second PSA nadir and median decrease of 98.5% from baseline. Median time to each nadir was 3.7 and 5.8 weeks, respectively. Median time to treatment failure was 21.3 months. Toxicities were minor, including gynecomastia. Seventeen of 29 (59%) and 12 of 24 (50%) men had normal sex drive at baseline and at second PSA nadir, respectively. One-third of men had spontaneous erection at both time points.

CONCLUSION

Finasteride provides additional intracellular androgen blockade when added to bicalutamide. Duration of control is comparable to castration, with preserved sexual function in some patients.

Selective bladder preservation for muscle-invasive transitional cell carcinoma of the urinary bladder

Invasive transitional cell carcinoma (TCC) of the urinary bladder is traditionally treated with radical cystectomy. This approach results in great morbidity and lifestyle changes, and approximately half of the patients treated in this way will experience recurrent TCC despite surgery. An alternative approach using selective bladder-preservation techniques incorporates transurethral resection of bladder tumours, radiation therapy, and chemotherapy. Over the past 20 years, international experience has demonstrated that this approach is feasible, safe, and well tolerated. Furthermore, the long-term outcomes of overall survival and disease-free survival compare favourably with the outcomes from radical cystectomy. The most important predictor of response is stage, with significantly higher long-term survival in patients with T2 disease. Another important positive predictor of complete response to therapy is the ability of the urologic oncologist to remove all visible tumour through a transurethral approach prior to initiation of radiation therapy. A negative predictive factor is the presence of hydronephrosis, and age and gender do not affect disease-free survival. The majority of patients who enjoy long-term survival do so with an intact native bladder. Quality of life studies have demonstrated that the retained bladder functions well in nearly all of these patients. Selective bladder preservation will not entirely take the place of radical cystectomy, but should be offered as an important alternative to patients newly diagnosed with muscle-invasive TCC.

Selective bladder preservation by combined modality protocol treatment: long-term outcomes of 190 patients with invasive bladder cancer

OBJECTIVES

To evaluate the outcomes of patients with muscle-invasive Stage T2-4a bladder carcinoma managed by transurethral surgery and concurrent chemoradiation.

METHODS

A total of 190 patients were treated on institutional prospective protocols using concurrent cisplatin-containing chemotherapy and radiotherapy after rigorous transurethral resection of the bladder tumor. Patients were re-evaluated by repeated biopsy and urine cytologic analysis after 40 Gy, with the initial tumor response guiding subsequent therapy. One hundred twenty-one patients with a complete response by cytologic and histologic examination and those medically unfit for cystectomy received boost chemoradiation to 64 to 65 Gy. Those patients without a complete response were advised to undergo radical cystectomy. A total of 66 patients (35%) ultimately underwent radical cystectomy; 41 for less than a complete response and an additional 25 for recurrent invasive tumors. The median follow-up was 6.7 years for all surviving patients.

RESULTS

The 5 and 10-year actuarial overall survival rate was 54% and 36%, respectively (Stage T2, 62% and 41%; Stage T3-T4a, 47% and 31%, respectively). The 5 and 10-year disease-specific survival rate was 63% and 59% (Stage T2, 74% and 66%; Stage T3-T4a, 53% and 52%), respectively. The 5 and 10-year disease-specific survival rate for patients with an intact bladder was 46% and 45% (Stage T2, 57% and 50%; Stage T3-T4a, 35% and 34%), respectively. The pelvic failure rate was 8.4%. No patient required cystectomy because of bladder morbidity.

CONCLUSIONS

The 10-year overall survival and disease-specific survival rates are comparable with the results reported for contemporary radical cystectomy for patients of similar clinical and pathologic stage. One third of patients treated on protocol with the goal of bladder sparing ultimately required a cystectomy. A trimodality approach with bladder preservation based on the initial tumor response is, therefore, safe, with most long-term survivors retaining functional bladders.

Human ES cells--haematopoiesis and transplantation strategies

Human embryonic stem (ES) cells provide a novel opportunity to study early developmental events in a human system. We have used human ES cell lines, including clonally derived lines, to evaluate haematopoiesis. Co-culture of the human ES cells with irradiated bone marrow stromal cell lines in the presence of fetal bovine serum (FBS), but without other exogenous cytokines, leads to differentiation of the human ES cells within a matter of days. A portion of these differentiated cells express CD34, the best-defined marker for early haematopoietic cells. Haematopoietic colony-forming cells (CFCs) are demonstrated by methylcellulose assay. Myeloid, erythroid, megakaryocyte and multipotential CFCs can all be derived under these conditions. Enrichment of CD34+ cells derived from the human ES cells markedly increases the yield of CFCs, as would be expected for cells derived from adult bone marrow or umbilical cord blood. Transcription factors are also expressed in a manner consistent with haematopoietic differentiation. This system now presents the potential to evaluate specific conditions needed to induce or support events in early human blood development. Human ES cells are also a novel source of cells for transplantation therapies. The immunogenicity of ES cell-derived cells is unknown. The unique properties of ES cells afford the opportunity to explore novel mechanisms to prevent immune-mediated rejection. Potential strategies to overcome rejection will be presented, including creation of haematopoietic chimerism as a means to successfully transplant cells and tissues derived from human ES cells.

Hematopoietic colony-forming cells derived from human embryonic stem cells

Human embryonic stem (ES) cells are undifferentiated, pluripotent cells that can be maintained indefinitely in culture. Here we demonstrate that human ES cells differentiate to hematopoietic precursor cells when cocultured with the murine bone marrow cell line S17 or the yolk sac endothelial cell line C166. This hematopoietic differentiation requires fetal bovine serum, but no other exogenous cytokines. ES cell-derived hematopoietic precursor cells express the cell surface antigen CD34 and the hematopoietic transcription factors TAL-1, LMO-2, and GATA-2. When cultured on semisolid media with hematopoietic growth factors, these hematopoietic precursor cells form characteristic myeloid, erythroid, and megakaryocyte colonies. Selection for CD34(+) cells derived from human ES cells enriches for hematopoietic colony-forming cells, similar to CD34 selection of primary hematopoietic tissue (bone marrow, umbilical cord blood). More terminally differentiated hematopoietic cells derived from human ES cells under these conditions also express normal surface antigens: glycophorin A on erythroid cells, CD15 on myeloid cells, and CD41 on megakaryocytes. The in vitro differentiation of human ES cells provides an opportunity to better understand human hematopoiesis and could lead to a novel source of cells for transfusion and transplantation therapies.

Selective bladder conservation using transurethral resection, chemotherapy, and radiation: management and consequences of Ta, T1, and Tis recurrence within the retained bladder

OBJECTIVES

Although radical cystectomy remains the standard of care for invasive bladder cancer in the United States, many groups are exploring the use of trimodality therapy using transurethral resection of the bladder tumor, radiation, and chemotherapy in an attempt to spare patients the need for cystectomy. As transitional cell carcinoma often arises from a urothelial field change, there is concern that the retained bladder is at risk of subsequent superficial (Ta, T1, Tis) tumors, some of which may have lethal potential. This study reports the outcomes of those patients with superficial relapse of transitional cell carcinoma after trimodality therapy.

METHODS

One hundred ninety patients were treated using a series of trimodality therapy protocols between 1986 and 1998. All patients received induction chemotherapy and radiation and were selected for bladder preservation on the basis of a cytologic and histologic complete response. One hundred twenty-one patients had a complete response and formed the subjects of this study.

RESULTS

With a median follow-up of 6.7 years for patients still alive, 32 experienced a superficial relapse (26%). The median time to this failure was 2.1 years. Sixty percent of the superficial failures were carcinoma in situ (Tis) and 67% arose at the site of the original invasive tumor. The risk of superficial failure was higher among those who had Tis associated with their original muscle-invasive tumor. Twenty-seven of these 32 cases were managed conservatively with transurethral resection and intravesical therapy. The irradiated bladder tolerated this therapy well and only 3 patients required treatment breaks. The 5 and 8-year survival was comparable for those who experienced superficial failure (68% and 54%, respectively) and those who had no failure at all (n = 74, 69% and 61%, respectively). However, a substantially lower chance of being alive with the native bladder owing to the need for late salvage cystectomies (61% versus 34%) was found. Cystectomy became necessary in 31% (10 of 32) either because of additional superficial recurrence (n = 7) or progression to invasive disease (n = 3).

CONCLUSIONS

A trimodality approach to transitional cell bladder cancer mandates lifelong cystoscopic surveillance. Although most completely responding patients retain their bladders free from invasive relapse, one quarter will develop superficial disease. This may be managed in the standard fashion with transurethral resection of the bladder tumor and intravesical therapies but carries an additional risk that late cystectomy will be required.

Neoadjuvant docetaxel followed by radical prostatectomy in patients with high-risk localized prostate cancer: a preliminary report

Effective treatment options for high-risk localized prostate cancer are limited. Patients at high risk for recurrence include those with biopsy Gleason scores of 8 to 10, prostate specific antigen (PSA) levels > 20 ng/mL, and clinical stage T3 disease. Docetaxel chemotherapy is active in hormone-refractory prostate cancer, either combined with estramustine or used as a single agent. To determine if systemic therapy can improve the outcome of radical prostatectomy in men with high-risk localized prostate cancer, we are undertaking a pilot phase II clinical trial of weekly docetaxel at 36 mg/m(2) for up to 6 months, followed by surgery. Patients are monitored with weekly visits, monthly digital rectal examinations, PSA measurement, and testosterone tests, and endorectal magnetic resonance imaging done at baseline, after two cycles, and again after six cycles. To date, 15 patients have been enrolled, and 70 cycles of chemotherapy have been administered. Toxicity has been mostly grade 1 in intensity, and fatigue has been the most common grade 2 toxicity reported. The primary endpoint of the trial is measurement of pathologic complete response rate, for which data are not yet available. Recruitment to the trial is ongoing.

Multilineage differentiation from human embryonic stem cell lines

Stem cells are unique cell populations with the ability to undergo both self-renewal and differentiation. A wide variety of adult mammalian tissues harbors stem cells, yet "adult" stem cells may be capable of developing into only a limited number of cell types. In contrast, embryonic stem (ES) cells, derived from blastocyst-stage early mammalian embryos, have the ability to form any fully differentiated cell of the body. Human ES cells have a normal karyotype, maintain high telomerase activity, and exhibit remarkable long-term proliferative potential, providing the possibility for unlimited expansion in culture. Furthermore, they can differentiate into derivatives of all three embryonic germ layers when transferred to an in vivo environment. Data are now emerging that demonstrate human ES cells can initiate lineage-specific differentiation programs of many tissue and cell types in vitro. Based on this property, it is likely that human ES cells will provide a useful differentiation culture system to study the mechanisms underlying many facets of human development. Because they have the dual ability to proliferate indefinitely and differentiate into multiple tissue types, human ES cells could potentially provide an unlimited supply of tissue for human transplantation. Though human ES cell-based transplantation therapy holds great promise to successfully treat a variety of diseases (e.g., Parkinson's disease, diabetes, and heart failure) many barriers remain in the way of successful clinical trials.

Multilineage differentiation from human embryonic stem cell lines

Stem cells are unique cell populations with the ability to undergo both self-renewal and differentiation. A wide variety of adult mammalian tissues harbors stem cells, yet "adult" stem cells may be capable of developing into only a limited number of cell types. In contrast, embryonic stem (ES) cells, derived from blastocyst-stage early mammalian embryos, have the ability to form any fully differentiated cell of the body. Human ES cells have a normal karyotype, maintain high telomerase activity, and exhibit remarkable long-term proliferative potential, providing the possibility for unlimited expansion in culture. Furthermore, they can differentiate into derivatives of all three embryonic germ layers when transferred to an in vivo environment. Data are now emerging that demonstrate human ES cells can initiate lineage-specific differentiation programs of many tissue and cell types in vitro. Based on this property, it is likely that human ES cells will provide a useful differentiation culture system to study the mechanisms underlying many facets of human development. Because they have the dual ability to proliferate indefinitely and differentiate into multiple tissue types, human ES cells could potentially provide an unlimited supply of tissue for human transplantation. Though human ES cell-based transplantation therapy holds great promise to successfully treat a variety of diseases (e.g., Parkinson's disease, diabetes, and heart failure) many barriers remain in the way of successful clinical trials.

AN ORGAN-PRESERVING APPROACH TO MUSCLE-INVADING TRANSITIONAL CELL CANCER OF THE BLADDER

Bladder-preserving treatment for muscle-invasive disease is based on the response of the tumor to induction combined modality therapy. In the future, an organ-conserving approach will be widely offered as a safe and reasonable alternative to radical cystectomy.

The initial results in muscle-invading bladder cancer of RTOG 95-06: phase I/II trial of transurethral surgery plus radiation therapy with concurrent cisplatin and 5-fluorouracil followed by selective bladder preservation or cystectomy depending on the initial response

PURPOSE

To assess the safety, tolerance, and efficacy of transurethral surgery plus concomitant cisplatin, 5-fluorouracil (5-FU), and radiation therapy in conjunction with selective bladder preservation in patients with muscle-invading bladder cancer. Patients and Methods. Thirty-four eligible patients with clinical stage T2-T4a, Nx M0 bladder cancer without hydronephrosis were entered into a protocol aimed at selective bladder preservation. Treatment began with as complete a transurethral resection as possible followed by induction chemoradiation. This consisted of cisplatin 15 mg/m(2) i.v. and 5-fluorouracil (5-FU) 400 mg/m(2) i.v. in the mornings on d 1, 2, 3, 15, 16, and 17. On d 1, 3, 15, and 17, radiation was given immediately following the chemotherapy using twice-a-day 3 Gy per fraction cores to the pelvis for a total radiation dose of 24 Gy. Response was evaluated by cystoscopy, cytology, and rebiopsy four weeks later. Patients with a complete response received consolidation therapy with the same drugs and doses on d 1, 2, 3, 15, 16, and 17 combined with twice-daily radiation therapy to the bladder and bladder tumor volume of 2.5 Gy per fraction for a total consolidation dose of 20 Gy and a total induction plus consolidation dose to the bladder and bladder tumor of 44 Gy. Patients who did not achieve a complete response were advised to undergo prompt cystectomy, as were those with a subsequent invasive recurrence. The median follow up is 29 months.

RESULTS

Of the 34 eligible patients, 26 had a visibly complete transurethral resection. One patient did not complete induction treatment due to acute hematologic toxicity. After induction treatment, 22 (67%) of the 33 patients had no tumor detectable on urine cytology or rebiopsy. Of the 11 patients who still had detectable tumor, six underwent radical cystectomy and five underwent consolidation chemoradiation (one because of refusal to have the recommended cystectomy and four because the treating institutions erroneously assigned them to receive consolidation chemoradiation rather than cystectomy). No patient has required a cystectomy for radiation toxicity. Six patients have died of bladder cancer. The actuarial overall survival at three years is 83%. The probability of surviving with an intact bladder is 66% at three years. A total of seven patients (21%) developed grade 3 or grade 4 hematologic toxicity in conjunction with this treatment.

CONCLUSION

This aggressive protocol comprising local surgery plus concurrent 5-FU, cisplatin, and high-dose hypofractionated radiation has been associated with moderately severe hematologic toxicity. Longer follow-up will be necessary to assess efficacy. Both the 67% complete response rate to induction therapy and the 66% three-year survival with an intact bladder are encouraging.

The National Bladder Cancer Group's experience: invasive and metastatic bladder cancer selected reports

The National Bladder Cancer Group, a multidisciplinary organization that was originally the therapeutic arm of the National Bladder Cancer Project, reported the results of trials using cisplatin with and without cyclophosphamide in patients with advanced bladder cancer. The objective response rate in both arms was 16% of 109 patients with no difference between the arms. Other studies included cisplatin and irradiation for patients who had comorbid conditions that prevented cystectomy (local response--cT2 11/13 patients; cT3 & cT4 2/4 patients). Seventy patients were treated on the same protocol, and 33 were alive 4 years later. Complete response versus local failure produced 57% versus 11% at 4 years. After cessation of funding, the clinicians at the Massachusetts General Hospital agreed to follow a potentially bladder-sparing multimodality protocol, which stipulated that visible tumor be resected following which the patient received methotrexate, vinblastine and cisplatin (MCV), small-volume irradiation, and more cisplatin with midcourse cystectomy if local tumor persisted. Overall survival was 45%. The Radiation Therapy Oncology Group conducted a similar study omitting MCV from one arm. The 5-year survival rate was 38% with no advantage for either arm.

Effects of ligand activation of peroxisome proliferator-activated receptor gamma in human prostate cancer

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a nuclear hormone receptor that plays a key role in the differentiation of adipocytes. Activation of this receptor in liposarcomas and breast and colon cancer cells also induces cell growth inhibition and differentiation. In the present study, we show that PPARgamma is expressed in human prostate adenocarcinomas and cell lines derived from these tumors. Activation of this receptor with specific ligands exerts an inhibitory effect on the growth of prostate cancer cell lines. Further, we show that prostate cancer and cell lines do not have intragenic mutations in the PPARgamma gene, although 40% of the informative tumors have hemizygous deletions of this gene. Based on our preclinical data, we conducted a phase II clinical study in patients with advanced prostate cancer using troglitazone, a PPARgamma ligand used for the treatment of type 2 diabetes. Forty-one men with histologically confirmed prostate cancer and no symptomatic metastatic disease were treated orally with troglitazone. An unexpectedly high incidence of prolonged stabilization of prostate-specific antigen was seen in patients treated with troglitazone. In addition, one patient had a dramatic decrease in serum prostate-specific antigen to nearly undetectable levels. These data suggest that PPARgamma may serve as a biological modifier in human prostate cancer and its therapeutic potential in this disease should be further investigated.

Organ-conserving approaches to muscle-invasive bladder cancer: future alternatives to radical cystectomy

In the USA radical surgery remains the golden standard for invasive bladder cancer. Yet in most other areas of surgical oncology the trend of the 1990s has been towards organ conservation with chemoradiation with or without limited local surgery. Patients with breast, oesophageal, anal, lung and larynx cancer are routinely offered conservative therapies as valid options in the management of their diseases but bladder stands apart from the crowd. Evidence is presented here to show that this need not be the case. Four older randomized trials failed to show a survival advantage when immediate cystectomy was compared with radiation followed by salvage cystectomy, if required. Five and 8-year survival rates for clinically staged patients treated by transurethral resection and chemoradiation (trimodality therapy) in several modern, large and mature series show survival rates comparable to those reported in contemporary radical cystectomy series. Eighty per cent of those alive 5 years after chemoradiation still retain their native bladder. Although superficial relapse occurs in 20% of cases, it remains responsive to BCG (Bacilles bilie de Calmette-Guerin) in the manner of de novo superficial disease. Quality-of-life studies show that the retained bladder functions well. At the Massachusetts General Hospital and in the multicentre prospective trials, less than 1% of patients needed cystectomy for bladder morbidity. It is of note that continent diversions may be performed as salvage after contemporary radiation therapy. Trimodality therapy is a novel and contemporary approach that owes little to the radiation treatment offered in the 1970s. While it will never entirely take the place of radical cystectomy, it should be offered as a reasonable alternative to patients with a new diagnosis of bladder cancer. This multidisciplinary approach will allow uro-oncology to keep in step with the oncological vanguard.

An update of combined modality therapy for patients with muscle invading bladder cancer using selective bladder preservation or cystectomy

PURPOSE

We update the results of tri-modality treatment for patients with muscle invading bladder tumors with selection for bladder preservation based on tumor response to induction therapy.

MATERIAL AND METHODS

We reviewed the literature on modern tri-modality bladder preserving approaches using transurethral resection, radiation and concurrent chemotherapy followed by either bladder conservation with careful surveillance for complete responding patients or prompt cystectomy in those whose tumors persist after induction therapy.

RESULTS

The published experiences from 3 centers and 2 prospective trials done by the Radiation Therapy Oncology Group were evaluated for 5-year overall survival of patients selected for bladder preservation or prompt cystectomy (49 to 63%) and for those with a conserved bladder (38 to 43%). The overall 5-year survival rates were comparable to other series of immediate cystectomy based approaches in patients of similar age and presenting with tumors of similar clinical stage. Of patients treated with the bladder preserving approach 20 to 30% cured of muscle invading cancer will subsequently have a new superficial tumor. The superficial tumors have responded well to intravesical drug therapy. Modern bladder preserving treatments usually result in a well functioning bladder without incontinence or significant hematuria. However, concurrent systemic chemotherapy and radiation have the potential for acute morbidity. Presently the ideal candidate for bladder preservation has primary clinical stage T2 tumor, no associated ureteral obstruction, visibly complete transurethral resection and complete response after induction chemoradiation based on endoscopic evaluation including re-biopsy and cytology.

CONCLUSIONS

It is recommended that tri-modality treatment be administered by dedicated multimodality teams. In this country this approach to treatment is available at many of the institutions participating in the Radiation Therapy Oncology Group study. This treatment may be considered a reasonable alternative in patients who are deemed medically unfit for cystectomy and for those who are seeking an alternative to radical cystectomy.

Does postoperative irradiation play a role in the adjuvant therapy of stage T4 colon cancer?

PURPOSE

This study analyzes the long-term outcome of patients with stage T4 colon cancer who receive postoperative irradiation. The purpose of the study is to define the potential role of this modality with current systemic therapies.

PATIENTS AND METHODS

A retrospective analysis was performed of 152 patients undergoing resection of T4 colon cancer followed by moderate- to high-dose postoperative tumor bed irradiation with and without 5-fluorouracil-based chemotherapy. Of the 152 patients, 110 patients (T4N0 or T4N+) were treated adjuvantly, whereas 42 patients received irradiation for the control of gross or microscopic residual local tumor.

RESULTS

For 79 adjuvantly treated patients with stage T4N0 or T4N+ cancer with one lymph node metastasis, the 10-year actuarial rates of local control and recurrence-free survival were 88% and 58%, respectively. Results were less satisfactory for patients with more extensive nodal involvement. The 10-year actuarial rates of local control and recurrence-free survival of 39 patients with T4 tumors complicated by perforation or fistulas were 81% and 53%, respectively. For 42 patients with incompletely resected tumors, the 10-year actuarial recurrence-free survival was 19%.

CONCLUSIONS

In comparison with historical controls, postoperative tumor bed irradiation improves local control for some subsets of patients. In addition to standard 5-fluorouracil-based chemotherapy, adjuvant tumor bed irradiation should be considered when colon cancers invade adjoining structures, when they are complicated by perforation or fistulas, or when they are incompletely excised at the primary site.

A phase I/II trial of transurethral surgery combined with concurrent cisplatin, 5-fluorouracil and twice daily radiation followed by selective bladder preservation in operable patients with muscle invading bladder cancer

PURPOSE

We describe a protocol designed to evaluate the use of twice daily radiation used together with cisplatin and 5 fluorouracil (5-FU) in the treatment of operable transitional cell carcinoma of the bladder with potential bladder preservation.

MATERIALS AND METHODS

A total of 18 consecutive patients with T2-T4a bladder tumors underwent as complete a transurethral resection as possible, which was visibly complete in 14 cases. They then received twice daily radiation and infusion cisplatin and 5-FU during an induction phase. No therapy was given for 3 weeks, following which patients were reevaluated cystoscopically. Cases of clinical complete response by biopsy and cytology were consolidated with further chemotherapy/radiation using the same chemotherapeutic agents and radiation schedule. Patients who had incomplete responses were advised to undergo an immediate radical cystectomy. Of the 18 patients 15 subsequently received 3 cycles of adjuvant chemotherapy, consisting of methotrexate, cisplatin and vinblastine. Median followup for the entire group is 32 months.

RESULTS

Of the 18 patients 14 had no detectable tumor after induction therapy. Of the 4 patients with persistent tumor 2 underwent radical cystectomy and 2 refused cystectomy, 1 of whom was treated with partial cystectomy and the other with consolidation chemotherapy/radiation. The actuarial overall survival at 3 years was 83%. The chance of a patient being alive at 3 years with a native bladder was 78%. No patient required cystectomy for hematuria or bladder shrinkage. Three patients in whom superficial tumors developed were treated successfully with bacillus Calmette-Guerin. Small bowel obstruction in 1 case was corrected surgically.

CONCLUSIONS

This pilot study demonstrates a high rate of response to this combined chemotherapy/radiation regimen in conjunction with a visibly complete transurethral resection. Reevaluation after a short induction phase allows for the early selection of patients with persistent disease for radical cystectomy.

Phase III trial of neoadjuvant chemotherapy in patients with invasive bladder cancer treated with selective bladder preservation by combined radiation therapy and chemotherapy: initial results of Radiation Therapy Oncology Group 89-03

PURPOSE

To assess the efficacy of neoadjuvant methotrexate, cisplatin, and vinblastine (MCV) chemotherapy in patients with muscle-invading bladder cancer treated with selective bladder preservation.

PATIENTS AND METHODS

One hundred twenty-three eligible patients with tumor, node, metastasis system clinical stage T2 to T4aNXMO bladder cancer were randomized to receive (arm 1, n=61 ) two cycles of MCV before 39.6-Gy pelvic irradiation with concurrent cisplatin 100 mg/m2 for two courses 3 weeks apart. Patients assigned to arm 2 (n=62) did not receive MCV before concurrent cisplatin and radiation therapy. Tumor response was scored as a clinical complete response (CR) when the cystoscopic tumor-site biopsy and urine cytology results were negative. The CR patients were treated with an additional 25.2 Gy to a total of 64.8 Gy and one additional dose of cisplatin. Those with less than a CR underwent cystectomy. The median follow-up of all patients who survived is 60 months.

RESULTS

Seventy-four percent of the patients completed the protocol with, at most, minor deviations; 67% on arm 1 and 81% on arm 2. The actuarial 5-year overall survival rate was 49%; 48% in arm 1 and 49% in arm 2. Thirty-five percent of the patients had evidence of distant metastases at 5 years; 33% in arm 1 and 39% in arm 2. The 5-year survival rate with a functioning bladder was 38%, 36% in arm 1 and 40% in arm 2. None of these differences are statistically significant.

CONCLUSION

Two cycles of MCV neoadjuvant chemotherapy were not shown to increase the rate of CR over that achieved with our standard induction therapy or to increase freedom from metastatic disease. There was no impact on 5-year overall survival.

The impact of 5-fluorouracil and intraoperative electron beam radiation therapy on the outcome of patients with locally advanced primary rectal and rectosigmoid cancer

OBJECTIVE

To analyze the effects of 5-fluorouracil (5-FU) chemotherapy combined with preoperative irradiation and the role of intraoperative electron beam irradiation (IOERT) on the outcome of patients with primary locally advanced rectal or rectosigmoid cancer.

METHODS

From 1978 to 1996, 145 patients with locally advanced rectal cancer underwent moderate- to high-dose preoperative irradiation followed by surgical resection. Ninety-three patients received 5-FU as a bolus for 3 days during the first and last weeks of radiation therapy (84 patients) or as a continuous infusion throughout irradiation (9 patients). At surgery, IOERT was administered to the surgical bed of 73 patients with persistent tumor adherence or residual disease in the pelvis.

RESULTS

No differences in sphincter preservation, pathologic downstaging, or resectability rates were observed by 5-FU use. However, there were statistically significant improvements in 5-year actuarial local control and disease-specific survival in patients receiving 5-FU during irradiation compared with patients undergoing irradiation without 5-FU. For the 73 patients selected to receive IOERT, local control and disease-specific survival correlated with resection extent. For the 45 patients undergoing complete resection and IOERT, the 5-year actuarial local control and disease-specific survival were 89% and 63%, respectively. These figures were 65% and 32%, respectively, for the 28 patients undergoing IOERT for residual disease. The overall 5-year actuarial complication rate was 11%.

CONCLUSIONS

Treatment strategies using 5-FU during irradiation and IOERT for patients with locally advanced rectal cancer are beneficial and well tolerated.

Invasive bladder cancer: treatment strategies using transurethral surgery, chemotherapy and radiation therapy with selection for bladder conservation

PURPOSE

Combined modality therapy has become the standard oncologic approach to achieve organ preservation in many malignancies.

METHODS AND MATERIALS

Although radical cystectomy has been considered as standard treatment for invasive bladder carcinoma in the United States, good results have been recently reported from several centers using multimodality treatment, particularly in patients with clinical T2 and T3a disease who do not have a ureter obstructed by tumor.

RESULTS

The components of the combined treatment are usually transurethral resection of the bladder tumor (TURBT) followed by concurrent chemotherapy and radiation therapy. Following an induction course of therapy a histologic response is evaluated by cystoscopy and rebiopsy. Clinical "complete responders" (tumor site rebiopsy negative and urine cytology with no tumor cells present) continue with a consolidation course of concurrent chemotherapy and radiation. Those patients not achieving a clinical complete response are recommended to have an immediate cystectomy. Individually the local monotherapies of radiation, TURBT, or multidrug chemotherapy each achieve a local control rate of the primary tumor of from 20 to 40%. When these are combined, clinical complete response rates of from 65 to 80% can be achieved. Seventy-five to 85% of the clinical complete responders will remain with bladders free of recurrence of an invasive tumor.

CONCLUSIONS

Bladder conservation trials using combined modality treatment approaches with selection for organ conservation by response of the tumor to initial treatment report overall 5-year survival rates of approximately 50%, and a 40-45% 5-year survival rate with the bladder intact. These modern multimodality bladder conservation approaches offer survival rates similar to radical cystectomy for patients of similar clinical stage and age. Bladder-conserving therapy should be offered to patients with invasive bladder carcinoma as a realistic alternative to radical cystectomy by experienced multimodality teams of urologic oncologists.

Time-dose considerations in the treatment of anal cancer

PURPOSE

To analyze the impact of patient and treatment parameters in concurrent chemoradiation treatment for anal carcinoma.

METHODS AND MATERIALS

Retrospective review of 50 MO anal cancer patients treated from 1984-1994. Most patients received concurrent 5-FU, mitomycin, and radiation. Local control and disease-free/overall survival were determined and analyzed according to patient and treatment parameters.

RESULTS

With 43 month median follow-up, projected overall survival is 66% at 5 and 8 years. Disease-free survival is 67% at 5 years and 59% at 8 years. Local control is 70% at 5 and 8 years. Doses of > or =54 Gy are associated with improved 5-year survival (84 vs. 47%, p = 0.02), disease-free survival (74 v. 56%, p = 0.09), and local control (77 vs. 61%, p = 0.04). Although local control, disease-free survival, and overall survival were improved in patients whose overall treatment time was <40 days, this was not statistically significant. Outcome in the four patients with pretreatment hemoglobin (Hgb) <10 appeared worse with 3-year overall survival 50 vs. 68% (p = 0.07), disease-free survival 0 vs. 67% (p = 0.11), and local control 0 vs. 74% (p = 0.05). Projected 5-year overall survival, relapse-free survival, and local control in 4 HIV(+) patients is 0, 75, and 75%. Multivariate analysis reveals that dose (p = 0.02) and Hgb (p = 0.05) independently affect local control, dose (p = 0.02) affects disease-free survival, and dose (p = 0.01), Hgb (p = 0.03), T-stage (p = 0.03), and HIV-status (0.07) independently influence overall survival.

CONCLUSION

Radiation doses of > or =54 Gy are associated with significantly improved survival and local control in anal cancer patients treated with chemoradiation. Overall treatment times of less than 40 days are associated with a trend towards improved outcome, but this is not significant. Pretreatment hemoglobin <10 is associated with worse treatment outcome. Survival of HIV (+) patient is poor, but the majority of such patients in this series died of intercurrent disease with their anal carcinomas controlled by chemoradiation.

Treatment strategies using transurethral surgery, chemotherapy, and radiation therapy with selection that safely allows bladder conservation for invasive bladder cancer

Combined modality therapy with the goal of effecting cure and achieving organ preservation has become the standard oncological approach in many malignancies. Although radical cystectomy has been considered the standard treatment for invasive carcinoma of the bladder, equivalent results have been achieved using combined modality treatment in selected patients, particularly those with T2 and T3a disease without obstructed ureters. Effective combined modality treatment consists of three treatment modalities: (1) transurethral resection of the bladder tumor (TURBT), followed by concurrent (2) chemotherapy, and (3) radiation. Following induction therapy, histologic response is evaluated by cystoscopy and biopsy. Clinical complete responders continue with concurrent chemotherapy and irradiation. Those patients not achieving a clinical complete response are advised to undergo cystectomy. Individually the local monotherapies of radiation, TURBT, or systemic chemotherapy each achieve a local control rate of 20% to 40%. When they are combined, complete response rates of 70-80% are achieved and 85% of these will remain free of invasive recurrence in the bladder. Bladder preservation trials using combined modality treatment approaches with selection for organ conservation by response to initial treatment report an overall 5-year survival rate of approximately 50%, and they have achieved a 40% to 45% 5-year survival rate with the bladder intact. Modern multi-modality bladder preservation approaches offer survival rates similar to radical cystectomy, for patients of similar clinical stage and age, and an improved quality of life by allowing a majority of patients to retain their own fully functional bladder. Bladder conservation therapy may be offered to selected patients with bladder cancer as one alternative to radical cystectomy, and its use should be by experienced multi-modality teams of urologic oncologists.

Bladder preservation by combined modality therapy for invasive bladder cancer

PURPOSE

To update the efficacy of a selective multimodality bladder-preserving approach by transurethral resection (TURBT), systemic chemotherapy, and radiation therapy.

PATIENTS AND METHODS

From 1986 through 1993, 106 patients with muscle-invading clinical stage T2 to T4a,Nx,M0 bladder cancer were treated with induction by maximal TURBT and two cycles of chemotherapy (methotrexate, cisplatin, vinblastine [MCV]) followed by 39.6-Gy pelvic irradiation with concomitant cisplatin. Patients with a negative postinduction therapy tumor site biopsy and cytology (a T0 response, 70 patients) plus those with less than a T0 response but medically unfit for cystectomy (six patients), received consolidative chemoradiation to a total of 64.8 Gy. Surgical candidates with less than a T0 response (13 patients) and patients who could not tolerate the chemoradiation (six patients) went to immediate cystectomy. The median follow-up duration is 4.4 years.

RESULTS

The 5-year actuarial overall survival and disease-specific survival rates of all patients are 52% and 60%, respectively. For clinical stage T2 patients, the actuarial overall survival rate is 63%, and for T3-4, 45%. Thirty-six patients (34%) underwent cystectomy, all with evidence of tumor activity, including 17 with an invasive recurrence. The 5-year overall survival rate with an intact functioning bladder is 43%. Among 76 patients who completed bladder-preserving therapy, the 5-year rate of freedom from an invasive bladder relapse is 79%. No patient required cystectomy for treatment-related bladder morbidity.

CONCLUSION

Combined modality therapy with TURBT, chemotherapy, radiation, and selection for organ-conservation by response has a 52% overall survival rate. This result is similar to cystectomy-based studies for patients of similar age and clinical stages. The majority of the long-term survivors retain fully functional bladders.

Organ-sparing treatment of bladder cancer: an innovative approach

Muscle-invasive carcinoma of the urinary bladder is a highly malignant disease with a rapid doubling time and a propensity for distant metastasis. Although radical cystectomy has been the treatment of choice in the United States, limited tumor resection followed by chemotherapy and radiation therapy, with preservation of a normally functioning bladder, is an alternative approach of significant usefulness. In carefully selected patients, such treatment offers a good chance of long-term cure and survival equal to that associated with cystectomy. This combined-modality approach remains investigational and requires a multidisciplinary team including a urologic surgeon, a radiation oncologist and a medical oncologist.

Opportunities with combined modality therapy for selective organ preservation in muscle-invasive bladder cancer

Combined-modality therapy for organ preservation represents an appropriate alternative to radical surgery in the management of several malignant diseases. The standard therapy for muscle-invasive bladder cancer in the United States has been radical cystectomy. Although the sequelae of radical surgery have been ameliorated somewhat by techniques for the construction of orthotopic bladders, the ideal therapy should both cure the patient of cancer and maintain a functioning natural bladder. Years of experience in Europe and Canada with bladder preservation using radiation therapy are documented. Advances in transurethral surgery technique and in the combination of radiation and chemotherapy have led to safe and effective regimens for patients with bladder cancer. Several recent trials with combined-modality therapy have established this treatment as a viable alternative to radical cystectomy in selected patients.

Conservative surgery, patient selection, and chemoradiation as organ-preserving treatment for muscle-invading bladder cancer

Multimodality organ-sparing treatment has, during the last decade, become the standard of care for many common malignancies. In appropriately selected patients with muscle-invading bladder cancer, bladder-preserving treatment combining surgical transurethral resection (TUR) with chemoradiation therapy offers a chance for long-term cure and survival equal to cystectomy, while also affording a 60% to 70% chance of maintaining a normally functioning bladder. Selection criteria helpful in determining appropriate patients for bladder preservation include such variables as small tumor size, that a visibly complete TUR is possible, the absence of hydronephrosis and that a complete response (CR) to induction chemoradiotherapy was achieved. Selecting patients based on response to induction therapy allows for prompt cystectomy if residual disease is found or for prompt consolidation chemoradiotherapy if a CR with induction therapy is achieved. Bladder-preserving treatment usually results in a normally functioning bladder without incontinence or hematuria for stage T2 and T3a patients. Stage T3b-T4 patients are locally controlled less frequently using these techniques. However, no data exist to suggest that patients with more advanced disease are in any way disadvantaged by preoperative chemoradiotherapy as an attempt at bladder conservation. Patients require close urological surveillance as do any patients with superficial bladder cancer who are being treated conservatively. As studies addressing the possibility of organ preservation continue to show positive results, more patients will become informed about and will be offered selective bladder-sparing approaches as one-treatment option.

The management and outcome of stage IAE nonHodgkin's lymphoma of the testis

PURPOSE

The initial management of stage I nonHodgkin's lymphoma of the testis is by orchiectomy but the role and efficacy of adjuvant strategies are uncertain. We reviewed cases of lymphoma at our institution to determine whether adjuvant treatment was beneficial.

MATERIALS AND METHODS

A retrospective review of outcome was conducted on 26 patients who presented to our institution. Median followup for the group was 54 months. Kaplan-Meier actuarial analyses were performed on the entire group and subsets. RESULTS; Actuarial 5 and 10-year overall survival rates were 79% and 63% and relapse-free survival rates were 61% and 46%, respectively. In patients who received adjuvant combination chemotherapy the 5-year relapse-free survival rate improved (75% versus 50%) but effect did not achieve statistical significance and was lost by 10 years. No relapse-free survival advantage was noted for patients receiving adjuvant irradiation to the pelvic and para-aortic nodes. Patients who did not receive irradiation remained free of isolated relapses in the pelvic or para-aortic regions.

CONCLUSIONS

These data lend support to the use of adjuvant chemotherapy but do not support a role for adjuvant nodal irradiation.

Combined modality treatment with selective bladder conservation for invasive bladder cancer: long-term tolerance in the female patient

PURPOSE

To assess the physical, psychological, social, and organ-specific long-term treatment sequelae occurring in women with muscle-invading bladder carcinoma treated with combined modality therapy that allowed for bladder conservation in 67% of patients.

PATIENTS AND METHODS

Patients with muscle-invading (T2-4a,Nx,M0) bladder cancer were treated with maximal transurethral resection followed by induction chemoradiotherapy (cisplatin x 2 plus 40 Gy pelvic irradiation or the same preceded by 2 cycles of methotrexate, cisplatin, and vinblastine) between the years 1986 and 1994. Women who had a complete response and all those who were not candidates for cystectomy received consolidation therapy of additional cisplatin and tumor boost to 64.8 Gy. Women who were incomplete responders and those who developed recurrent invasive tumor underwent immediate radical cystectomy. Forty-two women were treated with this approach, 21 of whom (median age, 69 years; median follow-up time, 56 months) were available for and underwent a structured interview of treatment and health-related issues using a quantitative symptom score.

RESULTS

All 21 patients have full urinary continence and no dysuria. Nineteen report unchanged or improved bladder capacity and function. No patient reported loss of bowel continence. Of the five women who were sexually active, two report an increase in intercourse frequency and one noted a decrease. There is no decrease in intercourse satisfaction or orgasm, and no dyspareunia or vaginal bleeding was noted. Eleven patients reported high levels of anxiety related to their bladder cancer before treatment. This was significantly reduced or absent in 9 of 11 after treatment. Actuarial overall survival for all 42 women was 58% at 5 years. Actuarial overall survival with an intact bladder was 47% at 5 years.

DISCUSSION

This study shows that overall survival is high when chemoradiation and transurethral resection are used in potential bladder-sparing protocols for muscle-invading transitional cell carcinoma of the bladder in women. Furthermore, 67% of the women, including most long-term survivors, retain their bladders. The functional quality of the conserved organ, the rectum, and the vagina, as reported by the patients, was excellent.

Inhibition of selective signaling events in natural killer cells recognizing major histocompatibility complex class I

Many studies have characterized the transmembrane signaling events initiated after T-cell antigen receptor recognition of major histocompatibility complex (MHC)-bound peptides. Yet, little is known about signal transduction from a set of MHC class I recognizing receptors on natural killer (NK) cells whose ligation dramatically inhibits NK cell-mediated killing. In this study we evaluated the influence of MHC recognition on the proximal signaling events in NK cells binding tumor targets. We utilized two experimental models where NK cell-mediated cytotoxicity was fully inhibited by the recognition of specific MHC class I molecules. NK cell binding to either class I-deficient or class I-transfected target cells initiated rapid protein tyrosine kinase activation. In contrast, whereas NK cell binding to class I-deficient targets led to inositol phosphate release and increased intracellular free calcium ([Ca2+]i), NK recognition of class I-bearing targets did not induce the activation of these phospholipase C-dependent signaling events. The recognition of class I by NK cells clearly had a negative regulatory effect since blocking this interaction using anti-class I F(ab')2 fragments increased inositol 1,4,5-trisphosphate release and [Ca2+]i and increased the lysis of the targets. These results suggest that one of the mechanisms by which NK cell recognition of specific MHC class I molecules can block the development of cell-mediated cytotoxicity is by inhibiting specific critical signaling events.

Selective bladder preservation by combination treatment of invasive bladder cancer

BACKGROUND

For patients with invasive bladder cancer the usual recommended treatment is radical cystectomy, although transurethral resection of the tumor, systemic chemotherapy, and radiotherapy are each effective in some patients. We sought to determine whether these treatments in combination might be as effective as radical cystectomy and thus might allow the bladder to be preserved and the cancer cured.

METHODS

We enrolled 53 consecutive patients with muscle-invading bladder cancer (stages T2 through T4, NXM0) in a trial of transurethral surgery, combination chemotherapy, and irradiation (4000 cGy) with concurrent cisplatin administration. Urologic evaluation of the tumor response directed further therapy: radical cystectomy in the 8 patients who had incomplete responses, additional chemotherapy and radiotherapy (6480 cGy) in the 34 patients who had complete responses or who were unsuited for cystectomy, and alternative care in the 11 patients who could not tolerate either irradiation or chemotherapy.

RESULTS

After a median follow-up of 48 months, 24 of the 53 patients (45 percent) were alive and free of detectable tumor. In 31 patients (58 percent) the bladder was free of invasive tumor and functioning well, even though in 9 (17 percent) a superficial tumor recurred and required further transurethral surgery and intravesical drug therapy. Of the 28 patients who had complete responses after initial treatment, 89 percent had functioning tumor-free bladders.

CONCLUSIONS

Conservative combination treatment may be an acceptable alternative to immediate cystectomy in selected patients with bladder cancer, although a randomized clinical trial that included a group for simultaneous comparison would be required to produce definitive results.

The combination of cis-platin based chemotherapy and radiation in the treatment of muscle-invading transitional cell cancer of the bladder

Radical cystectomy is the standard of care for patients with muscle-invading transitional cell carcinoma of the bladder. More limited surgery is only useful in highly selected patients and radiation therapy alone gives overall local-control rates under 40%. Phase II studies have shown that when radiation and trans-urethral surgery are combined with cis-platin based chemotherapy local-control rates increase such that the majority of patients preserve a tumor-free functional bladder. Up to 85% of patients selected for bladder sparing therapy on the basis of their initial response to chemo-radiation may keep their bladders. This figure could increase further when other powerful prognostic factors such as the presence of hydronephrosis, the presence of carcinoma in situ, and DNA ploidy are also taken into account in initial patient selection. The activity of cisplatin combinations in metastatic disease is not in doubt with up to 50% response rates generally reported. The hope that this will translate into the eradication of micrometastatic disease (known to be present in up to 40% of patients at diagnosis) has yet to be borne out. Those randomized trials so far reported have not shown any survival advantage when combined-modality therapy is compared to radiation alone. The addition of combination chemotherapy to radiation does not increase bladder morbidity but carries a considerable systemic penalty. Thus, despite promising Phase II studies, until local control and survival benefit is proven in a randomized trial it should continue to be regarded as experimental.

Postoperative radiation therapy for high-risk colon carcinoma

PURPOSE

This study examines the experience of patients treated with postoperative radiation therapy after resection of high-risk colon carcinoma in an effort to assess the potential role of this modality in combination with current systemic therapies.

PATIENTS AND METHODS

From 1976 to 1989, 203 patients received postoperative radiation therapy with and without concurrent fluorouracil (5-FU) chemotherapy following resection of modified Astler-Coller B2, B3, C2, and C3 colon tumors. Of the 203 patients, 30 (15%) were identified as having residual local tumor after subtotal resection, whereas 173 (85%) had no known residual disease. The 173 patients treated with adjuvant radiation therapy were compared with a historical control group of 395 patients undergoing surgery only.

RESULTS

Three groups of patients who appeared to benefit from postoperative radiation were identified. Improved local control and recurrence-free survival rates were seen for patients with stage B3 and C3 colon carcinoma treated with postoperative radiation therapy compared with a similarly staged group of patients undergoing surgery only. Irradiated patients whose tumors had an associated abscess or fistula formation had improved local control and recurrence-free survival rates compared with a similar group of patients undergoing surgery only. There appears to be a subset of patients with residual local disease after subtotal resection that may be salvaged by high-dose postoperative radiation therapy.

CONCLUSION

Selected groups of patients with colon carcinoma may benefit from postoperative radiation in addition to current systemic therapies. Integration of 5-FU and levamisole with postoperative radiation therapy should be considered for patients with (1) stage B3 and C3 lesions, (2) tumors associated with abscess or fistula formation, and (3) residual local disease after subtotal resection.

Perturbation of cell pH regulation by H2O2 in renal epithelial cells

The purpose of these studies was to define the effect of oxidant stress on intracellular pH in renal tubular epithelial cells. Cell pH was therefore quantitated from the fluorescence ratio of 2',7'-bis-(2-carboxyethyl)-5(6)-carboxyfluorescein in the BSC-1 and opossum kidney (OK) established cell lines, both of which are known to be susceptible to oxidant injury. Exposure to 1 mM H2O2 acidified cytosolic pH in both cell types, and this acidification reversed on withdrawal of the H2O2. Half-maximal acidification was seen at 10 microM H2O2. Effects on Na/H antiport were first measured as the recovery from an NH4Cl-pulse acid load: 1 mM H2O2 inhibited Na/H antiport-mediated pH recovery by approximately 40% in both cell types. H2O2 substantially increased the rate of passive Na-independent H+ flux in the OK cell but under the conditions used did not effect this flux in the BSC-1 cell. When both the Na/H antiport and Na-independent transport systems were blocked by perfusion with a 0-Na depolarizing buffer, the H2O2-induced acidification was totally abolished. Measured from the rate of H+ appearance in the medium, H2O2 decreased the rates of endogenous H+ production in both cell types. As measured from the fluorescence of endocytosed fluorescein isothiocyanate-dextran, H2O2 alkalinized lysosomes/late-endosomes, but at a rate much slower than the rate of cytosolic acidification. The results indicate that H2O2 acidifies cell pH in these cell lines by inhibiting Na/H antiport, by accelerating the passive influx of H+, and to some extent by releasing H+ from subcellular compartments. The acidification may have important effects in modulating the toxicity of H2O2.

MHC class I expression on tumor targets inhibits natural killer cell-mediated cytotoxicity without interfering with target recognition

NK cell-mediated killing is inversely proportional to the amount of MHC class I expression on certain tumor targets. Two hypotheses have been proposed to explain why class I-bearing targets are more resistant to NK cell-mediated lysis: 1) the presence of class I prevents NK cell recognition of a triggering molecule on the target cell surface, or 2) class I recognition transmits a separate inhibitory signal to the NK cell. To differentiate between these potential mechanisms, we have used cloned human CD16+/CD3- NK cells, the class I-deficient cell line C1R, and C1R cells expressing high levels of transfected HLA class I gene products. If class I expression blocks NK cell recognition of the targets, then proximal cell signaling events such as phospholipase C-mediated hydrolysis of membrane phosphoinositides should be decreased in the NK cells interacting with the class I transfectants. However, we found that increases in the level of target cell class I expressions did not decrease phosphoinositide turnover or calcium signaling in NK cells. We also examined the effect of treating HLA-transfected C1R cells with mAb specific for the transfected MHC class I gene product. If class I expression has a negative regulatory influence on NK cell activation, then treating the targets with anti-HLA mAb should block the transmission of this negative signal. Consistent with this notion, addition of anti-HLA mAb (either whole Ig or F(ab')2 fragments) led to increased lysis of the class I-transfected targets. In contrast, addition of isotype-matched mAb specific for other cell surface markers did not alter sensitivity to lysis. All of these results suggest that MHC class I expression on target cells can initiate inhibitory signals in NK cells without blocking access to target structures.

MHC class I expression on tumor targets inhibits natural killer cell-mediated cytotoxicity without interfering with target recognition

NK cell-mediated killing is inversely proportional to the amount of MHC class I expression on certain tumor targets. Two hypotheses have been proposed to explain why class I-bearing targets are more resistant to NK cell-mediated lysis: 1) the presence of class I prevents NK cell recognition of a triggering molecule on the target cell surface, or 2) class I recognition transmits a separate inhibitory signal to the NK cell. To differentiate between these potential mechanisms, we have used cloned human CD16+/CD3- NK cells, the class I-deficient cell line C1R, and C1R cells expressing high levels of transfected HLA class I gene products. If class I expression blocks NK cell recognition of the targets, then proximal cell signaling events such as phospholipase C-mediated hydrolysis of membrane phosphoinositides should be decreased in the NK cells interacting with the class I transfectants. However, we found that increases in the level of target cell class I expressions did not decrease phosphoinositide turnover or calcium signaling in NK cells. We also examined the effect of treating HLA-transfected C1R cells with mAb specific for the transfected MHC class I gene product. If class I expression has a negative regulatory influence on NK cell activation, then treating the targets with anti-HLA mAb should block the transmission of this negative signal. Consistent with this notion, addition of anti-HLA mAb (either whole Ig or F(ab')2 fragments) led to increased lysis of the class I-transfected targets. In contrast, addition of isotype-matched mAb specific for other cell surface markers did not alter sensitivity to lysis. All of these results suggest that MHC class I expression on target cells can initiate inhibitory signals in NK cells without blocking access to target structures.

Adjuvant postoperative radiation therapy for rectal adenocarcinoma

From October 1975 to August 1988, 261 patients at high risk for local recurrence after curative resection of rectal carcinoma underwent high-dose postoperative irradiation. Patients received 45 Gy by a 4-field box usually followed by a boost to 50.4 Gy or higher when small bowel could be excluded from the reduced field. Since January 1986, patients also received 5-fluorouracil (5-FU) for 3 consecutive days during the first and last week of radiotherapy. Five-year actuarial local control and disease-free survival decreased with increasing stage of disease; patients with Stage B2 and B3 disease had local control rates of 83% and 87% and disease-free survivals of 55% and 74%, respectively. In patients with Stage C1 through C3 tumors, local control rates ranged from 76% to 23%, and disease-free survivals ranged from 62% to 10%, respectively. For patients with Stage C disease, disease-free survival decreased progressively with increasing lymph node involvement, but local control was independent of the extent of lymph node involvement. For each stage of disease, local control and disease-free survival did not correlate with the dose of pelvic irradiation. Preliminary data from this study suggest a trend toward improved local control for patients with Stage B2, C1, and C2 tumors who receive 5-FU for 3 consecutive days during the first and last weeks of irradiation compared with patients who do not receive 5-FU. Current prospective randomized studies are addressing questions regarding the optimum administration of chemotherapy with pelvic irradiation for patients following resection of rectal carcinoma.

Role for major histocompatibility complex class I in regulating natural killer cell-mediated killing of virus-infected cells

Target structures important for natural killer (NK) cell recognition of virally infected cells are not well defined. Since major histocompatibility complex (MHC) class I molecules bind viral peptides during acute infection, we evaluated whether an interaction between MHC and virus might influence the susceptibility of infected cells to NK cell-mediated lysis. To control for MHC class I expression on target cells, we used either HLA class I-deficient C1R cells or C1R sublines expressing transfected HLA class I gene products. Human NK cells were unable to preferentially lyse class I-deficient C1R cells after infection with herpes simplex virus (HSV). In contrast, HLA class I transfectants were significantly more susceptible to NK cell-mediated cytotoxicity after HSV infection. This occurred for HSV-infected C1R cells expressing any of the three HLA class I gene products tested (i.e., HLA-B27, HLA-A3, or HLA-Aw68), indicating that NK cell recognition in this system does not require "self" MHC and is not unique for a single haplotype. Productive HSV infection is required for the increased killing, since inoculation with UV-inactivated virus did not lead to increased lysis. In addition, since HSV infection of the transfectants did not significantly alter the level of class I expression, the change in susceptibility appears to be due to qualitative changes in the target structures on HSV-infected, HLA class I+ targets. These results demonstrate a role for MHC class I in regulating NK cell-mediated killing of virus-infected cells.

Deoxyribonucleic acid flow cytometry in invasive bladder carcinoma: a possible predictor for successful bladder preservation following transurethral surgery and chemotherapy-radiotherapy

Tumor deoxyribonucleic acid (DNA) ploidy was evaluated as an objective parameter that may correlate better with the responsiveness of bladder cancer to chemotherapy plus radiotherapy than do clinical features or histopathological subtypes. A total of 40 patients with localized muscle-invading bladder cancer (clinical stages T2 to T4) underwent prospective treatment on a potential bladder preserving protocol. Tumors of 37 of the 40 patients were analyzed by DNA flow cytometry of multiple paraffin embedded specimens. Transurethral resection, neoadjuvant chemotherapy and 40 Gy. radiotherapy plus cisplatin were followed by urological reevaluation of the tumor (a complete response required a negative biopsy and a negative urine cytology study). A total of 7 noncomplete response patients underwent immediate radical cystectomy whereas the full bladder sparing treatment (radiotherapy to 64.80 Gy. plus cisplatin) was given to 23 complete response patients and 7 noncomplete response patients who were unsuited for surgery. Of the tumors 22 (59%) were purely aneuploid and 10 (27%) were purely diploid. Five tumors contained aneuploid and diploid patterns in different tumor specimens (partly diploid). Current status with a 30-month median followup in surviving patients includes an 82% overall survival rate in the aneuploid group versus 47% in the diploid/partly diploid group. Of all the patients 68% are free of invasive tumor: 82% in the aneuploid group versus 47% in the diploid/partly diploid group. By multivariate analysis pure aneuploidy was significantly (p = 0.05) correlated with freedom from invasive tumor in the bladder (either as persistence or as recurrence) and approached significance (p = 0.08) in correlation with overall patient survival. A longer observation time will be required to confirm this unexpectedly good outcome for patients with pure aneuploid tumors. We hypothesize that pretreatment DNA ploidy status may become a clinically useful prognostic factor in selecting patients for successful treatment with transurethral surgery and neoadjuvant chemotherapy plus radiotherapy.