Consensus Statement on Proton Therapy for Prostate Cancer.

Proton therapy is a promising but controversial treatment in the management of prostate cancer. Despite its dosimetric advantages when compared with photon radiation therapy, its increased cost to patients and insurers has raised questions regarding its value. Multiple prospective and retrospective studies have been published documenting the efficacy and safety of proton therapy for patients with localized prostate cancer and for patients requiring adjuvant or salvage pelvic radiation after surgery. The Particle Therapy Co-Operative Group (PTCOG) Genitourinary Subcommittee intends to address current proton therapy indications, advantages, disadvantages, and cost effectiveness. We will also discuss the current landscape of clinical trials. This consensus report can be used to guide clinical practice and research directions.

Stereotactic body radiation therapy for low and intermediate risk prostate cancer-Results from a multi-institutional clinical trial.

BACKGROUND: We report the outcome of a phase I/II clinical trial of stereotactic body radiation therapy (SBRT) for low (LR) and select intermediate risk (IR) prostate cancer (PCa) patients. PATIENTS AND METHODS: Eligible patients included men with prostate adenocarcinoma with Gleason score 6 with PSA ≤ 20 or Gleason 7 with PSA ≤ 15 and clinical stage ≤ T2b. For the phase I portion of the study patients in cohorts of 15 received 45, 47.5, or 50 Gray (Gy) in five fractions. Since the maximally tolerated dose was not met in the phase I study, an additional 47 patients received 50 Gy in five fractions in the phase II study. Toxicity using Common Toxicity Criteria for Adverse Events v. 3.0, quality of life, and outcome data was collected. RESULTS: A total of 91 patients are included for analysis; 63.7% had NCCN IR and 36.3% had LR PCa. At a median follow up of 54 months the actuarial freedom from biochemical failure was 100% at 3 years and 98.6% at 5 years. Actuarial distant metastasis free survival was 100% at 3 and 5 years. Overall survival was 94% at 3 years and 89.7% at 5 years with no deaths attributed to PCa. Acute and late urinary grade ≥ III toxicity occurred in 0% and 5.5% of patients, respectively. Gastrointestinal (GI) acute and late toxicity of grade ≥ III occurred in 2% and 7% of patients, respectively. A total of four men experienced grade IV toxicity (three GI, one genitourinary). CONCLUSION: SBRT treatment results in excellent biochemical control rates at 5 years for LR and IR PCa patients although doses greater than 47.5 Gy in five fractions led to increased severe late toxicity.

Whole Pelvis Versus Prostate-Only Radiotherapy With or Without Short-Course Androgen Deprivation Therapy and Mortality Risk.

BACKGROUND: The purpose of the study was to determine whether the extent of prostate radiotherapy (ie, whole-pelvic radiotherapy [WPRT] vs. prostate and seminal vesicle radiotherapy [PSVRT]) is associated with all-cause mortality (ACM) in men treated with or without androgen deprivation therapy (ADT). PATIENTS AND METHODS: A multiple-institution cohort of 3709 prostate cancer patients was prospectively assembled from 1991 to 2006. The median age was 72 years and all patients had T1c-T3N0M0 adenocarcinoma of the prostate. Patients were treated with WPRT or PSVRT followed by a brachytherapy boost, with or without neoadjuvant ADT (median duration, 4.2 months). Seventy percent of patients had unfavorable-risk disease (Gleason score ≥ 7; prostate-specific antigen ≥ 10 ng/mL; or stage ≥ T2b). Cox regression was applied to determine whether the radiation treatment volume affected the risk of ACM. The interaction between radiation volume and ADT use was assessed. RESULTS: After a median follow-up of 3.3 years, 561 deaths were observed. A decreased risk of ACM was noted with the use of WPRT versus PSVRT (adjusted hazard ratio [AHR], 0.58; 95% confidence interval [CI], 0.38-0.89; P = .01), or with ADT use (AHR, 0.71; 95% CI, 0.58-0.90; P = .004). However, a combination of WPRT and ADT did not further improve ACM compared with either WPRT alone or PSVRT with ADT. Moreover, there was a significant interaction between the radiotherapeutic treatment volume and ADT (AHR, 1.61; 95% CI, 1.004-2.58; P = .048). CONCLUSION: Treatment with WPRT or short-course ADT is associated with a decreased risk of ACM, although a combination of the two does not yield greater benefit. This observation suggests a shared mechanism for this risk reduction, which we hypothesize to be via the treatment of micrometastatic disease within the pelvic lymph nodes.

Predictors of rectal tolerance observed in a dose-escalated phase 1-2 trial of stereotactic body radiation therapy for prostate cancer.

PURPOSE: To convey the occurrence of isolated cases of severe rectal toxicity at the highest dose level tested in 5-fraction stereotactic body radiation therapy (SBRT) for localized prostate cancer; and to rationally test potential causal mechanisms to guide future studies and experiments to aid in mitigating or altogether avoiding such severe bowel injury. METHODS AND MATERIALS: Clinical and treatment planning data were analyzed from 91 patients enrolled from 2006 to 2011 on a dose-escalation (45, 47.5, and 50 Gy in 5 fractions) phase 1/2 clinical study of SBRT for localized prostate cancer. RESULTS: At the highest dose level, 6.6% of patients treated (6 of 91) developed high-grade rectal toxicity, 5 of whom required colostomy. Grade 3+ delayed rectal toxicity was strongly correlated with volume of rectal wall receiving 50 Gy >3 cm(3) (P<.0001), and treatment of >35% circumference of rectal wall to 39 Gy (P=.003). Grade 2+ acute rectal toxicity was significantly correlated with treatment of >50% circumference of rectal wall to 24 Gy (P=.010). CONCLUSION: Caution is advised when considering high-dose SBRT for treatment of tumors near bowel structures, including prostate cancer. Threshold dose constraints developed from physiologic principles are defined, and if respected can minimize risk of severe rectal toxicity.

Neoadjuvant hormonal therapy use and the risk of death in men with prostate cancer treated with brachytherapy who have no or at least a single risk factor for coronary artery disease.

BACKGROUND: Neoadjuvant hormone therapy (NHT) use is associated with an increased risk of all-cause mortality (ACM) in men with a history of coronary artery disease (CAD)-induced congestive heart failure (CHF) or myocardial infarction (MI). However, its effect in men with no or at least a single risk factor for CAD stratified by prostate cancer (PCa) aggressiveness is unknown. OBJECTIVE: To assess whether NHT use affects the risk of ACM in men with low-, intermediate-, and high-risk PCa treated with brachytherapy who have no or at least a single risk factor for CAD. DESIGN, SETTING, AND PARTICIPANTS: This retrospective study cohort consisted of 5411 men with low-risk PCa (prostate-specific antigen [PSA] <10 ng/ml, Gleason score 6, and clinical stage T1-T2a); 4365 men with intermediate-risk PCa (PSA 10-20 ng/ml or Gleason score <8 or clinical stage

Cardiovascular comorbidity and mortality in men with prostate cancer treated with brachytherapy-based radiation with or without hormonal therapy.

PURPOSE: To assess the impact of coronary artery disease (CAD) risk factors and sequelae on the risk of all-cause mortality (ACM) in men treated for prostate cancer (PC). METHODS AND MATERIALS: The study cohort comprised 5077 men with PC consecutively treated with curative intent between 1997 and 2006 at the Chicago Prostate Cancer Center. Cox and Fine and Gray's competing risks regression multivariable analyses were performed, assessing whether cardiovascular comorbidity impacted the risk of ACM and PC-specific mortality, respectively, adjusting for CAD risk factors (diabetes mellitus, hypercholesterolemia, or hypertension) and sequelae (congestive heart failure or myocardial infarction), age, year and type of treatment, and known PC prognostic factors. RESULTS: When compared with men with no comorbidity there was a significantly increased risk of ACM in men with congestive heart failure or myocardial infarction (adjusted hazard ratio [AHR] 1.96, P<.001) and in men with diabetes mellitus (AHR 1.60, P=.03) and hypertension (AHR 1.25, P=.04). In contrast, men with hypercholesterolemia had a similar risk of ACM (AHR 0.68, P=.17) when compared with men with no comorbidity. Other factors associated with a significantly increased risk of ACM included age (AHR 1.09, P<.001), prostate-specific antigen level (AHR 1.25, P=.008), and Gleason score 8-10 disease (AHR 1.71, P=.003). Cardiovascular comorbidity did not impact the risk of PC-specific mortality. CONCLUSIONS: In addition to age and unfavorable PC prognostic factors, select CAD risk factors and sequelae are associated with an increased risk of ACM in men treated for PC. These comorbidity prognostic factors predict time courses of mortality from competing causes, which may be factored into the decision-making process when considering management options for PC in a given individual.

EGF receptor inhibition radiosensitizes NSCLC cells by inducing senescence in cells sustaining DNA double-strand breaks.

The mechanisms by which inhibition of the epidermal growth factor receptor (EGFR) sensitizes non-small cell lung cancer (NSCLC) cells to ionizing radiation remain poorly understood. We set out to characterize the radiosensitizing effects of the tyrosine kinase inhibitor erlotinib and the monoclonal antibody cetuximab in NSCLC cells that contain wild-type p53. Unexpectedly, EGFR inhibition led to pronounced cellular senescence but not apoptosis of irradiated cells, both in vitro and in vivo. Senescence was completely dependent on wild-type p53 and associated with a reduction in cell number as well as impaired clonogenic radiation survival. Study of ten additional NSCLC cell lines revealed that senescence is a prominent mechanism of radiosensitization in 45% of cell lines and occurs not only in cells with wild-type p53 but also in cells with mutant p53, where it is associated with an induction of p16. Interestingly, senescence and radiosensitization were linked to an increase in residual radiation-induced DNA double-strand breaks irrespective of p53/p16 status. This effect of EGFR inhibition was at least partially mediated by disruption of the MEK-ERK pathway. Thus, our data indicate a common mechanism of radiosensitization by erlotinib or cetuximab across diverse genetic backgrounds. Our findings also suggest that assays that are able to capture the initial proliferative delay that is associated with senescence should be useful for screening large cell line panels to identify genomic biomarkers of EGFR inhibitor-mediated radiosensitization.

Predictors of prostate cancer-specific mortality in elderly men with intermediate-risk prostate cancer treated with brachytherapy with or without external beam radiation therapy.

PURPOSE: To identify clinical factors associated with prostate cancer-specific mortality (PCSM), adjusting for comorbidity, in elderly men with intermediate-risk prostate cancer treated with brachytherapy alone or in conjunction with external beam radiation therapy. METHODS AND MATERIALS: The study cohort comprised 1,978 men of median age 71 (interquartile range, 66-75) years with intermediate-risk disease (Gleason score 7, prostate-specific antigen (PSA) 20 ng/mL or less, tumor category T2c or less). Fine and Gray's multivariable competing risks regression was used to assess whether prevalent cardiovascular disease (CVD), age, treatment, year of brachytherapy, PSA level, or tumor category was associated with the risk of PCSM. RESULTS: After a median follow-up of 3.2 (interquartile range, 1.7-5.4) years, the presence of CVD was significantly associated with a decreased risk of PCSM (adjusted hazard ratio, 0.20; 95% CI 0.04-0.99; p = 0.05), whereas an increasing PSA level was significantly associated with an increased risk of PCSM (adjusted hazard ratio 1.14; 95% CI 1.02-1.27; p = 0.02). In the absence of CVD, cumulative incidence estimates of PCSM were higher (p = 0.03) in men with PSA levels above as compared with the median PSA level (7.3 ng/mL) or less; however, in the setting of CVD there was no difference (p = 0.27) in these estimates stratified by the median PSA level (6.9 ng/mL). CONCLUSIONS: In elderly men with intermediate-risk prostate cancer, CVD status is a negative predictor of PCSM and affects the prognostic capacity of pretreatment PSA level. These observations support the potential utility of prerandomization stratification by comorbidity to more accurately assess prognostic factors and treatment effects within this population.

Total androgen blockade versus a luteinizing hormone-releasing hormone agonist alone in men with high-risk prostate cancer treated with radiotherapy.

PURPOSE: To assess whether short-course total androgen blockade vs. a luteinizing hormone-releasing hormone (LHRH) agonist alone affects the risk of prostate cancer-specific mortality (PCSM) in men with localized but high-risk disease treated with radiotherapy. METHODS AND MATERIALS: The study cohort comprised 628 men with T1-T4, N0, M0 prostate cancer with high-risk disease (prostate-specific antigen level >20 ng/mL, Gleason score >or=8, or clinical category >or=T3) treated with 45 Gy of external beam radiotherapy followed by a brachytherapy boost in addition to receiving a median of 4.3 (interquartile range [IQR], 3.6-6.4) months of hormonal blockade with an LHRH agonist plus an antiandrogen or monotherapy with an LHRH agonist. Fine and Gray's multivariable regression analysis was used to determine whether combination androgen suppression therapy (AST) vs. monotherapy affected the risk of PCSM, adjusting for treatment year, duration of AST, age, and known prognostic factors. RESULTS: After a median follow-up of 4.9 (IQR, 3.5-6.5) years, men receiving combination AST had a lower risk of PCSM than those treated with monotherapy (adjusted hazard ratio [AHR], 0.18; 95% confidence interval [CI], 0.04-0.90; p = 0.04). An increasing prostate-specific antigen level (AHR, 2.70; 95% CI, 1.64-4.45; p < 0.001) and clinical category T3/4 disease (AHR, 29.6; 95% CI, 2.88-303.5; p = 0.004) were also associated with an increased risk of PCSM. CONCLUSIONS: In men with localized but high-risk prostate cancer treated with external beam radiotherapy and brachytherapy, short-course AST with an LHRH agonist plus an antiandrogen is associated with a decreased risk of PCSM when compared with monotherapy with an LHRH agonist.

Hormonal therapy use for prostate cancer and mortality in men with coronary artery disease-induced congestive heart failure or myocardial infarction.

CONTEXT: Hormonal therapy (HT) when added to radiation therapy (RT) for treating unfavorable-risk prostate cancer leads to an increase in survival except possibly in men with moderate to severe comorbidity. However, it is unknown which comorbid conditions eliminate this survival benefit. OBJECTIVE: To assess whether neoadjuvant HT use affects the risk of all-cause mortality in men with prostate cancer and coronary artery disease (CAD)-induced congestive heart failure (CHF) or myocardial infarction (MI), CAD risk factors, or no comorbidity. DESIGN, SETTING, AND PATIENTS: A total of 5077 men (median age, 69.5 years) with localized or locally advanced prostate cancer were consecutively treated with or without a median of 4 months of neoadjuvant HT followed by RT at a suburban cancer center between 1997 and 2006 and were followed up until July 1, 2008. Cox regression multivariable analyses were performed assessing whether neoadjuvant HT use affected the risk of all-cause mortality, adjusting for age, year and type of RT, treatment propensity score, and known prostate cancer prognostic factors in each comorbidity group. MAIN OUTCOME MEASURE: Risk of all-cause mortality. RESULTS: Neoadjuvant HT use was not associated with an increased risk of all-cause mortality in men with no comorbidity (9.6% vs 6.7%, adjusted hazard ratio [HR], 0.97; 95% confidence interval [CI], 0.72-1.32; P = .86) or a single CAD risk factor (10.7% vs 7.0%, adjusted HR, 1.04; 95% CI, 0.75-1.43; P = .82) after median follow-ups of 5.0 and 4.4 years, respectively. However, for men with CAD-induced CHF or MI, after a median follow-up of 5.1 years, neoadjuvant HT use was significantly associated with an increased risk of all-cause mortality (26.3% vs 11.2%, adjusted HR, 1.96; 95% CI, 1.04-3.71; P = .04). CONCLUSION: Neoadjuvant HT use is significantly associated with an increased risk of all-cause mortality among men with a history of CAD-induced CHF or MI but not among men with no comorbidity or a single CAD risk factor.

Gleason Pattern 5 prostate cancer: further stratification of patients with high-risk disease and implications for future randomized trials.

PURPOSE: To compare prostate-specific antigen (PSA) outcomes in a cohort of men with high-risk prostate cancer based on the presence or absence of any Gleason Grade 5 component (primary, secondary, or tertiary). METHODS AND MATERIALS: Our study cohort consisted of 312 men with T1c-T3N0M0 prostate cancer with Gleason Scores of 7 with tertiary Grade 5, 8, or 9-10 who underwent radical prostatectomy or external beam radiotherapy with or without androgen suppression therapy. Cox regression multivariable analysis was used to assess whether a difference existed in risk of PSA recurrence in men with Gleason Score of 9-10 compared with those with Gleason Score of 8 and 7 with tertiary Grade 5, adjusting for treatment, age, and known prostate cancer prognostic factors. RESULTS: After a median follow-up of 5.7 years, men with a Gleason Score of 8 had a lower risk of PSA recurrence than those with a Gleason Score of 9-10 (hazard ratio, 0.74; 95% confidence interval, 0.52-1.05; p = 0.09). Conversely, men with a Gleason Score of 7 with tertiary Grade 5 had a similar risk of PSA recurrence compared with men with a Gleason Score of 9-10 (hazard ratio, 1.08; 95% confidence interval, 0.60-1.94; p = 0.81). Median times to PSA failure for men with Gleason Scores of 9-10, 7 with tertiary Grade 5, and 8 were 4.5, 5.0, and 5.4 years, respectively. CONCLUSIONS: Our results highlight the importance of further substratification of the high-risk Gleason Score category of 8-10 into 8 vs. 9, 10, and 7 with tertiary Grade 5.

Unusual tumor response and toxicity from radiation and concurrent erlotinib for non-small-cell lung cancer.

We report a case of a never-smoker female with non-small-cell lung cancer (NSCLC) who experienced a striking tumor response to combined low-dose radiation and the epidermal growth factor receptor inhibitor erlotinib, even though erlotinib alone was not effective in preventing tumor progression. Furthermore, the patient developed symptomatic pneumonitis, which is unusual for the small volume of lung that was exposed to a significant dose of radiation. This case demonstrates that combination therapy with radiation and erlotinib has the potential to significantly benefit a subset of patients with NSCLC in addition to those approximately 10% who have tumors which respond to erlotinib alone. It also highlights the potential risks of molecular targeted radiation therapy.

Tumor endothelial marker 1 (Tem1) functions in the growth and progression of abdominal tumors.

Tumor endothelial marker 1 (Tem1; endosialin) is the prototypical member of a family of genes expressed in the stroma of tumors. To assess the functional role of Tem1, we disrupted the Tem1 gene in mice by targeted homologous recombination. Tem1(-/-) mice were healthy, their wound healing was normal, and tumors grew normally when implanted in s.c. sites. However, there was a striking reduction in tumor growth, invasiveness, and metastasis after transplantation of tumors to abdominal sites in mice without functional Tem1 genes. These data indicate that the stroma can control tumor aggressiveness and that this control varies with anatomic site. Therefore, they have significant implications for the mechanisms underlying tumor invasiveness and for models that evaluate this process.

Identification of a binding partner for the endothelial cell surface proteins TEM7 and TEM7R.

Tumor endothelial marker 7 (TEM7) was recently identified as an mRNA transcript overexpressed in the blood vessels of human solid tumors. Here, we identify several new variants of TEM7, derived by alternative splicing, that are predicted to be intracellular (TEM7-I), secreted (TEM7-S), or on the cell surface membrane (TEM7-M) of tumor endothelium. Using new antibodies against the TEM7 protein, we confirmed the predicted expression of TEM7 on the cell surface and demonstrated that TEM7-M protein, like its mRNA, is overexpressed on the endothelium of various tumor types. We then used an affinity purification strategy to search for TEM7-binding proteins and identified cortactin as a protein capable of binding to the extracellular region of both TEM7 and its closest homologue, TEM7-related (TEM7R), which is also expressed in tumor endothelium. The binding domain of cortactin was mapped to a unique nine-amino acid region in its plexin-like domain. These studies establish the overexpression of TEM7 protein in tumor endothelium and provide new opportunities for the delivery of therapeutic and imaging agents to the vessels of solid tumors.