D. Robert Siemens

Active Surveillance of Small Renal Masses: Progression Patterns of Early Stage Kidney Cancer ☆

BACKGROUND Most early stage kidney cancers are renal cell carcinomas (RCCs), and most are diagnosed incidentally by imaging as small renal masses (SRMs). Indirect evidence suggests that most small RCCs grow slowly and rarely metastasize. OBJECTIVE To determine the progression and growth rates for newly diagnosed SRMs stratified by needle core biopsy pathology. DESIGN, SETTING, AND PARTICIPANTS A multicenter prospective phase 2 clinical trial of active surveillance of 209 SRMs in 178 elderly and/or infirm patients was conducted from 2004 until 2009 with treatment delayed until progression. INTERVENTION Patients underwent serial imaging and needle core biopsies. MEASUREMENTS We measured rates of change in tumor diameter (growth measured by imaging) and progression to ≥ 4 cm, doubling of tumor volume, or metastasis with histology on biopsy. RESULTS AND LIMITATIONS Local progression occurred in 25 patients (12%), plus 2 progressed with metastases (1.1%). Of the 178 subjects with 209 SRMs, 127 with 151 SRMs had>12 mo of follow-up with two or more images, with a mean follow-up of 28 mo. Their tumor diameters increased by an average of 0.13 cm/yr. Needle core biopsy in 101 SRMs demonstrated that the presence of RCC did not significantly change growth rate. Limitations included no central review of imaging and pathology and a short follow-up. CONCLUSIONS This is the first SRM active surveillance study to correlate growth with histology prospectively. In the first 2 yr, the rate of local progression to higher stage is low, and metastases are rare. SRMs appear to grow very slowly, even if biopsy proven to be RCC. Many patients with SRMs can therefore be initially managed conservatively with serial imaging, avoiding the morbidity of surgical or ablative treatment.

A survey on the attitudes towards research in medical school.

BackgroundAn observed decrease of physician scientists in medical practice has generated much recent interest in increasing the exposure of research programs in medical school. The aim of this study was to review the experience and attitudes regarding research by medical students in Canada.MethodsAn anonymous, cross-sectional, self-report questionnaire was administered to second and fourth year students in three medical schools in Ontario between February and May of 2005. Questions were primarily closed-ended and consisted of Likert scales. Descriptive and correlative statistics were used to analyze the responses between students of different years and previous research experience.ResultsThere was a 47% (327/699) overall response rate to the questionnaire. Despite 87% of respondents reporting that they had been involved in some degree of research prior to medical school, 43% report that they have not been significantly involved in research activity during medical school and 24% had no interest in any participation. There were significant differences in the attitudes towards research endeavors during medical school between students in their fourth year compared to second year. The greatest barriers to involvement in research in medical school appear to be time, availability of research mentors, formal teaching of research methodology and the perception that the student would not receive appropriate acknowledgement for work put towards a research project.ConclusionThe results of this self-report survey outline the significant differences in attitudes towards mandatory research as a component of critical inquiry and scholarship in the undergraduate curriculum in Ontario medical schools.

Chemosensitization of Cancer In vitro and In vivo by Nitric Oxide Signaling

Purpose: Hypoxia contributes to drug resistance in solid cancers, and studies have revealed that low concentrations of nitric oxide (NO) mimetics attenuate hypoxia-induced drug resistance in tumor cells in vitro. Classic NO signaling involves activation of soluble guanylyl cyclase, generation of cyclic GMP (cGMP), and activation of cGMP-dependent protein kinase. Here, we determined whether chemosensitization by NO mimetics requires cGMP-dependent signaling and whether low concentrations of NO mimetics can chemosensitize tumors in vivo. Experimental Design: Survival of human prostate and breast cancer cells was assessed by clonogenic assays following exposure to chemotherapeutic agents. The effect of NO mimetics on tumor chemosensitivity in vivo was determined using a mouse xenograft model of human prostate cancer. Drug efflux in vitro was assessed by measuring intracellular doxorubicin-associated fluorescence. Results: Low concentrations of the NO mimetics glyceryl trinitrate (GTN) and isosorbide dinitrate attenuated hypoxia-induced resistance to doxorubicin and paclitaxel. Similar to hypoxia-induced drug resistance, inhibition of various components of the NO signaling pathway increased resistance to doxorubicin, whereas activation of the pathway with 8-bromo-cGMP attenuated hypoxia-induced resistance. Drug efflux was unaffected by hypoxia and inhibitors of drug efflux did not significantly attenuate hypoxia-induced chemoresistance. Compared with mice treated with doxorubicin alone, tumor growth was decreased in mice treated with doxorubicin and a transdermal GTN patch. The presence of GTN and GTN metabolites in plasma samples was confirmed by gas chromatography. Conclusion: Tumor hypoxia induces resistance to anticancer drugs by interfering with endogenous NO signaling and reactivation of NO signaling represents a novel approach to enhance chemotherapy.

Immunization with type 5 adenovirus recombinant for a tumor antigen in combination with recombinant canarypox virus (alvac) cytokine gene delivery induces destruction of established prostate tumors

Prostate‐specific antigen (PSA) is expressed by prostate epithelial cells and has a highly restricted tissue distribution. Prostatic malignancies in 95% of patients continue to express PSA, making this antigen a good candidate for targeted immunotherapy. The goals of our studies are to generate a recombinant PSA adenovirus type 5 (Ad5‐PSA) that is safe and effectively activates a PSA‐specific T‐cell response capable of eliminating prostate cancer cells, and to characterize the immunologic basis for this rejection. Here we show that immunization of mice with Ad5‐PSA induced PSA‐specific cellular and humoral immunity that was protective against a subcutaneous challenge with RM11 prostate cancer cells expressing PSA (RM11psa), but not mock‐transfected RM11 tumor cells (RM11neo). Mice immunized with recombinant adenovirus type 5 encoding β‐galactosidase (Ad5‐lacZ) did not generate protective immunity. Antitumor activity was predominantly mediated by CD8+ T lymphocytes. Although Ad5‐PSA immunization prior to RM11psa challenge was protective, Ad5‐PSA immunization alone was not able to control the growth of existing RM11psa tumors. In contrast, established RM11psa tumors ranging in size from 500 to 1,000 mm3 were efficiently eliminated if Ad5‐PSA priming was followed 7 days later by intratumoral injection of recombinant canarypox viruses (ALVAC) encoding interleukin‐12 (IL‐12), IL‐2, and tumor necrosis factor‐α. In this case, antitumor immunity was still dominated by CD8+ T lymphocytes, but natural killer cells became necessary for a maximal response. These data provide information on the effector cell populations in a protective immune response to prostate cancer and demonstrate the utility of an Ad5‐PSA vaccine combined with cytokine gene delivery to eliminate large established tumors that are refractory to other interventional methods.

Efficacy and safety of enzalutamide versus bicalutamide for patients with metastatic prostate cancer (TERRAIN): a randomised, double-blind, phase 2 study

BACKGROUND Enzalutamide is an oral androgen-receptor inhibitor that has been shown to improve survival in two placebo-controlled phase 3 trials, and is approved for patients with metastatic castration-resistant prostate cancer. The objective of the TERRAIN study was to compare the efficacy and safety of enzalutamide with bicalutamide in patients with metastatic castration-resistant prostate cancer. METHODS TERRAIN was a double-blind, randomised phase 2 study, that recruited asymptomatic or minimally symptomatic men with prostate cancer progression on androgen-deprivation therapy (ADT) from academic, community, and private health-care provision sites across North America and Europe. Eligible patients were randomly assigned (1:1) via an interactive voice response system to receive enzalutamide 160 mg/day or bicalutamide 50 mg/day, both taken orally, in addition to ADT, until disease progression. Patients were stratified by a permutated block method (block size of four), by whether bilateral orchiectomy or receipt of luteinising hormone-releasing hormone agonist or antagonist therapy started before or after the diagnosis of metastases, and by study site. Participants, investigators, and those assessing outcomes were masked to group assignment. The primary endpoint was progression-free survival, analysed in all randomised patients. Safety outcomes were analysed in all patients who received at least one dose of study drug. The open-label period of the trial is in progress, wherein patients still on treatment at the end of the double-blind treatment period were offered open-label enzalutamide at the discretion of the patient and study investigator. This trial is registered with ClinicalTrials.gov, number NCT01288911. FINDINGS Between March 22, 2011, and July 11, 2013, 375 patients were randomly assigned, 184 to enzalutamide and 191 to bicalutamide. 126 (68%) and 168 (88%) patients, respectively, discontinued their assigned treatment before study end, mainly due to progressive disease. Median follow-up time was 20·0 months (IQR 15·0-25·6) in the enzalutamide group and 16·7 months (10·2-21·9) in the bicalutamide group. Patients in the enzalutamide group had significantly improved median progression-free survival (15·7 months [95% CI 11·5-19·4]) compared with patients in the bicalutamide group (5·8 months [4·8-8·1]; hazard ratio 0·44 [95% CI 0·34-0·57]; p<0·0001). Of the most common adverse events, those occurring more frequently with enzalutamide than with bicalutamide were fatigue (51 [28%] of 183 patients in the enzalutamide group vs 38 [20%] of 189 in the bicalutamide group), back pain (35 [19%] vs 34 [18%]), and hot flush (27 [15%] vs 21 [11%]); those occurring more frequently with bicalutamide were nausea (26 [14%] vs 33 [17%]), constipation (23 [13%] vs 25 [13%]), and arthralgia (18 [10%] vs 30 [16%]). The most common grade 3 or worse adverse events in the enzalutamide or bicalutamide treatment groups, respectively, were hypertension (13 [7%] vs eight [4%]), hydronephrosis (three [2%] vs seven [4%]), back pain (five [3%] vs three [2%]), pathological fracture (five [3%] vs two [1%]), dyspnoea (four [2%] vs one [1%]), bone pain (one [1%] vs four [2%]), congestive cardiac failure (four [2%] vs two [1%]), myocardial infarction (five [3%] vs none), and anaemia (four [2%] vs none]). Serious adverse events were reported by 57 (31%) of 183 patients and 44 (23%) of 189 patients in the enzalutamide and bicalutamide groups, respectively. One of the nine deaths in the enzalutamide group was thought to be possibly related to treatment (due to systemic inflammatory response syndrome) compared with none of the three deaths in the bicalutamide group. INTERPRETATION The data from the TERRAIN trial support the use of enzalutamide rather than bicalutamide in patients with asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer. FUNDING Astellas Pharma, Inc and Medivation, Inc.

Hypoxia induces escape from innate immunity in cancer cells via increased expression of ADAM10: role of nitric oxide

One key to malignant progression is the acquired ability of tumor cells to escape immune-mediated lysis. Whereas tumor hypoxia is known to play a causal role in cancer metastasis and resistance to therapy, the link between hypoxia and immune escape in cancer remains poorly understood. Here, we show that hypoxia induces tumor cell resistance to lysis mediated by immune effectors and that this resistance to lysis occurs via a hypoxia-inducible factor-1 (HIF-1)-dependent pathway linked to increased expression of the metalloproteinase ADAM10. This enzyme is required for the hypoxia-induced shedding of MHC class I chain-related molecule A (MICA), a ligand that triggers the cytolytic action of immune effectors, from the surface of tumor cells. Indeed, our findings show a mechanistic link between hypoxia-induced accumulation of the α-subunit of HIF-1 (HIF-1α), increased expression of ADAM10, and decreased surface MICA levels leading to tumor cell resistance to lysis mediated by innate immune effectors. Nitric oxide mimetic agents interfered with the hypoxia-induced accumulation of HIF-1α and with the hypoxia-induced upregulation of ADAM10 expression required for decreased surface MICA expression and resistance to lysis. Furthermore, treatment of tumor-bearing mice with nitroglycerin, a nitric oxide mimetic, attenuated tumor growth by a mechanism that relied upon innate immune effector cells. Together, these findings reveal a novel mechanism by which the hypoxic tumor microenvironment contributes to immune escape in cancer, lending support to potential immunotherapeutic strategies involving the use of nitric oxide mimetics.

Phase II study of nitric oxide donor for men with increasing prostate-specific antigen level after surgery or radiotherapy for prostate cancer.

OBJECTIVES To evaluate the effect of low-dose glyceryl trinitrate (GTN) on men with biochemical recurrence of prostate cancer after primary therapy. Preclinical, proof-of-principle studies have demonstrated that nitric oxide signaling plays a significant role in the hypoxia-induced progression of prostate cancer. METHODS A prospective, open-label clinical trial of men with an increasing prostate-specific antigen (PSA) level after surgery or radiotherapy was conducted. Men with PSA recurrence were enrolled in a 24-month trial investigating the effect of a low-dose, slow-release transdermal GTN patch. The PSA doubling time (PSADT) was compared before and after treatment initiation, as well as with a matched control group that received no immediate treatment for their PSA recurrence. RESULTS A total of 29 patients were enrolled in the study. Of the 29 patients, 62% completed the 24-month protocol, with 10% experiencing clinical disease progression. The calculated PSADT of the treatment group before initiating GTN was 13.3 months, not significantly different from that of the matched control group at 12.8 months. In an intention-to-treat analysis, the end-of-study PSADT for the treatment group was significantly different at 31.8 months (P < .001). CONCLUSIONS We report the first clinical trial of a GTN patch in patients with prostate cancer. The prolongation of the PSADT and the safety of the drug, coupled with the corresponding preclinical in vitro and in vivo data documenting the ability of nitric oxide to attenuate hypoxia-induced progression of prostate cancer, warrant further testing in a placebo-controlled study.

Predictive validity of five comorbidity indices in prostate carcinoma patients treated with curative intent.

Comorbidity is important to consider in clinical research on curative prostate carcinoma because of the role of competing risks. Five chart‐based comorbidity indices were assessed for their ability to predict survival.

Cutting Edge: Restoration of the Ability to Generate CTL in Mice Immune to Adenovirus by Delivery of Virus in a Collagen-Based Matrix

Viruses are commonly used for the delivery of genes coding for tumor-associated Ags to elicit tumor-specific immune responses. The success of viral vectors has been limited in preclinical and clinical trials in part because of antiviral immunity. We investigated the ability of a collagen-based matrix (Gelfoam; Pharmacia and Upjohn, Kalamazoo, MI) to improve CTL activation by recombinant adenovirus. The data show that coinjection of Gelfoam with type 5 adenovirus recombinant for prostate-specific Ag (Ad5-PSA) enhanced CTL activation. Ad5-PSA priming in Gelfoam also abrogated the inhibitory effects of adenoviral immunity on CTL activation in mice naive to PSA but immune to adenovirus. Finally, Gelfoam enhanced immunization in a self-Ag model using type 5 adenovirus recombinant for membrane-bound OVA (Ad5-mOVA) in rat insulin promoter (RIP)-mOVA-transgenic mice. Thus, Gelfoam enhances CTL activation by recombinant viral vectors in a setting where preformed Ab to the virus is present and also in a tolerant self-Ag model.

Perioperative chemotherapy for muscle-invasive bladder cancer: A population-based outcomes study.

Practice guidelines recommend neoadjuvant chemotherapy (NACT) for bladder cancer. However, the evidence in support of adjuvant chemotherapy (ACT) is less robust. Here we describe whether the evidence of efficacy for NACT/ACT was sufficient to change clinical practice and whether the efficacy demonstrated in clinical trials was translated into effectiveness in the general population.