Bladder carcinoma and other second malignancies after radiotherapy for prostate carcinoma

Poor Prognosis among Radiation-Associated Bladder Cancer Is Defined by Clinicogenomic Features

Radiotherapy (RT) for prostate cancer has been associated with an increased risk for the development of bladder cancer. We aimed to integrate clinical and genomic data to better understand the development of RT-associated bladder cancer. A retrospective analysis was performed to identify control patients (CTRL; n = 41) and patients with RT-associated bladder cancer (n = 41). RT- and CTRL-specific features were then identified through integration and analysis of the genomic sequencing data and clinical variables. RT-associated bladder tumors were significantly enriched for alterations in KDM6A and ATM, whereas CTRL tumors were enriched for CDKN2A mutation. Globally, there were an increased number of variants within RT tumors, albeit at a lower variant allele frequency. Mutational signature analysis revealed three predominate motif patterns, with similarity to SBS2/13 (APOBEC3A), SBS5 (ERCC2/smoking), and SBS6/15 (MMR). Poor prognostic factors in the RT cohort include a short tumor latency, smoking status, the presence of the smoking and X-ray therapy mutational signatures, and CDKN2A copy number loss. Based on the clinical and genomic findings, we suggest at least two potential pathways leading to RT-associated bladder cancer: The first occurs in the setting of field cancerization related to smoking or preexisting genetic alterations and leads to the development of more aggressive bladder tumors, and the second involves RT initiating the oncogenic process in otherwise healthy urothelium, leading to a longer latency and less aggressive disease.

SIGNIFICANCE

Clinicogenomic analysis of radiation-associated bladder cancer uncovered mutational signatures that, in addition to a short tumor latency, smoking, and CDKN2A loss, are associated with a poor outcome. These clinical and genomic features provide a potential method to identify patients with prostate cancer who are at an increased risk for the development of aggressive bladder cancer following prostate RT.

Does intensity-modulated radiation therapy by helical tomotherapy for prostate cancer increase the subsequent risk of bladder cancer? A propensity score-matched analysis

OBJECTIVES

This study aimed to evaluate the risk of bladder cancer after intensity-modulated radiation therapy (IMRT) using helical tomotherapy for prostate cancer in comparison to the risk post-radical prostatectomy (RP) using propensity score-matched analysis and to assess the risk factors for bladder cancer.

METHODS

This retrospective study included 2067 patients with non-metastatic prostate cancer treated at our institution between June 2007 and December 2016. Of these, 1547 patients were treated with IMRT and 520 underwent RP. The propensity scores were calculated using age, National Comprehensive Cancer Network risk classification, prostate volume, Brinkman index, and follow-up time as matched covariates. A propensity score-matched patient cohort (n = 718; IMRT: 359, RP: 359) was created, and the risk of bladder cancer after treatment was compared.

RESULTS

In total, bladder cancer was detected in 33 patients. Five patients in the IMRT group and one in the RP group died of bladder cancer. In the propensity score-matched analysis, the 5-year bladder cancer-free survival rate was significantly lower in the IMRT group than in the RP group (91.7% and 96.2%, respectively; p < 0.001). Multivariate analysis revealed that IMRT and the Brinkman index were the risk factors for bladder cancer in this cohort (odds ratio = 5.085, 95% confidence interval = 1.436-18.008, p = 0.012 and odds ratio = 1.001, 95% confidence interval = 1.000-1.001, p = 0.010, respectively).

CONCLUSIONS

IMRT for prostate cancer using helical tomotherapy increases the subsequent risk of bladder cancer compared with RP and is an independent risk factor for bladder cancer similar to smoking.

Rectal Cancer after Prostate Radiation: A Complex and Controversial Disease

A small proportion of rectal adenocarcinomas develop in patients many years after the treatment of a previous cancer using pelvic radiation, and the incidence of these rectal cancers depends on the length of follow-up from the end of radiotherapy. The risk of radiation-associated rectal cancer (RARC) is higher in patients treated with prostate external beam radiotherapy than it is in patients treated with brachytherapy. The molecular features of RARC have not been fully investigated, and survival is lower compared to non-irradiated rectal cancer patients. Ultimately, it is unclear whether the worse outcomes are related to differences in patient characteristics, treatment-related factors, or tumor biology. Radiation is widely used in the management of rectal adenocarcinoma; however, pelvic re-irradiation of RARC is challenging and carries a higher risk of treatment complications. Although RARC can develop in patients treated for a variety of malignancies, it is most common in patients treated for prostate cancer. This study will review the incidence, molecular characteristics, clinical course, and treatment outcomes of rectal adenocarcinoma in patients previously treated with radiation for prostate cancer. For clarity, we will distinguish between rectal cancer not associated with prostate cancer (RCNAPC), rectal cancer in non-irradiated prostate cancer patients (RCNRPC), and rectal cancer in irradiated prostate cancer patients (RCRPC). RARC represents a unique but understudied subset of rectal cancer, and thus requires a more comprehensive investigation in order to improve its treatment and prognosis.

Assessment of Second Primary Cancer Risk Among Men Receiving Primary Radiotherapy vs Surgery for the Treatment of Prostate Cancer

IMPORTANCE

Shared decision-making is an important part of the treatment selection process among patients with prostate cancer. Updated information is needed regarding the long-term incidence and risk of second primary cancer after radiotherapy vs nonradiotherapy treatments, which may help to inform discussions of risks and benefits for men diagnosed with prostate cancer.

OBJECTIVE

To assess the current incidence and risk of developing a second primary cancer after receipt of radiotherapy vs nonradiotherapy treatments for prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study used the Veterans Affairs Corporate Data Warehouse to identify 154 514 male veterans 18 years and older who had localized prostate cancer (tumor stages T1-T3) diagnosed between January 1, 2000, and December 31, 2015, and no cancer history. A total of 10 628 patients were excluded because of (1) incomplete treatment information for the year after diagnosis, (2) receipt of both radiotherapy and a surgical procedure in the year after diagnosis, (3) receipt of radiotherapy more than 1 year after diagnosis, (4) occurrence of second primary cancer or death within 1 year or less after diagnosis, (5) prostate-specific antigen value greater than 99 ng/mL within 6 months before diagnosis, or (6) no recorded Veterans Health Administration service after diagnosis. The remaining 143 886 patients included in the study had a median (IQR) follow-up of 9 (6-13) years. Data were analyzed from May 1, 2021, to May 22, 2022.

MAIN OUTCOMES AND MEASURES

Diagnosis of a second primary cancer more than 1 year after prostate cancer diagnosis.

RESULTS

Among 143 886 male veterans (median [IQR] age, 65 [60-71] years) with localized prostate cancer, 750 (0.5%) were American Indian or Alaska Native, 389 (0.3%) were Asian, 37 796 (26.3%) were Black or African American, 933 (0.6%) were Native Hawaiian or other Pacific Islander, 91 091 (63.3%) were White, and 12 927 (9.0%) were of unknown race; 7299 patients (5.1%) were Hispanic or Latino, 128 796 (89.5%) were not Hispanic or Latino, and 7791 (5.4%) were of unknown ethnicity. A total of 52 886 patients (36.8%) received primary radiotherapy, and 91 000 (63.2%) did not. A second primary cancer more than 1 year after prostate cancer diagnosis was present in 4257 patients (3.0%), comprising 1955 patients (3.7%) in the radiotherapy cohort and 2302 patients (2.5%) in the nonradiotherapy cohort. In the multivariable analyses, patients in the radiotherapy cohort had a higher risk of second primary cancer compared with those in the nonradiotherapy cohort at years 1 to 5 after diagnosis (hazard ratio [HR], 1.24; 95% CI, 1.13-1.37; P < .001), with higher adjusted HRs in the subsequent 15 years (years 5-10: 1.50 [95% CI, 1.36-1.65; P < .001]; years 10-15: 1.59 [95% CI, 1.37-1.84; P < .001]; years 15-20: 1.47 [95% CI, 1.08-2.01; P = .02).

CONCLUSIONS AND RELEVANCE

In this cohort study, patients with prostate cancer who received radiotherapy were more likely to develop a second primary cancer than patients who did not receive radiotherapy, with increased risk over time. Although the incidence and risk of developing a second primary cancer were low, it is important to discuss the risk with patients during shared decision-making about prostate cancer treatment options.

Prostate radiotherapy and the risk of secondary rectal cancer-a meta-analysis

PURPOSE

Radiotherapy is being used increasingly in the treatment of prostate cancer. However, ionising radiation may confer a small risk of a radiation-induced secondary malignancy. We aim to assess the risk of rectal cancer following pelvic radiotherapy for prostate cancer.

METHODS

A search was conducted of the PubMed/MEDLINE, EMBASE and Web of Science databases identifying studies reporting on the risk of rectal cancer following prostatic radiotherapy. Studies must have included an appropriate control group of non-irradiated prostate cancer patients. A meta-analysis was performed to assess the risk of prostatic radiotherapy on subsequent rectal cancer diagnosis.

RESULTS

In total, 4757 articles were screened with eight studies meeting the predetermined criteria. A total of 796,386 patients were included in this meta-analysis which showed an increased odds ratio (OR) for subsequent rectal cancer in prostate cancer patients treated with radiotherapy compared to those treated by non-radiotherapy means (OR 1.45, 1.07-1.97, p = 0.02).

CONCLUSION

These findings confirm that prostate radiotherapy significantly increases the risk of subsequent rectal cancer. This risk has implications for treatment selection, surveillance and patient counselling. However, it is crucial that this information is presented in a rational and comprehensible manner that does not disproportionately frighten or deter patients from what might be their most suitable treatment modality.

Genomic Features of Muscle-invasive Bladder Cancer Arising After Prostate Radiotherapy

BACKGROUND

Muscle-invasive bladder cancer (MIBC) is a rare but serious event following definitive radiation for prostate cancer. Radiation-associated MIBC (RA-MIBC) can be difficult to manage given the challenges of delivering definitive therapy to a previously irradiated pelvis. The genomic landscape of RA-MIBC and whether it is distinct from non-RA-MIBC are unknown.

OBJECTIVE

To define mutational features of RA-MIBC and compare the genomic landscape of RA-MIBC with that of non-RA-MIBC.

DESIGN, SETTING, AND PARTICIPANTS

We identified patients from our institution who received radiotherapy for prostate cancer and subsequently developed MIBC.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We performed whole exome sequencing of bladder tumors from RA-MIBC patients. Tumor genetic alterations including mutations, copy number alterations, and mutational signatures were identified and were compared with genetic features of non-RA-MIBC. We used the Kaplan-Meier method to estimate recurrence-free (RFS) and overall (OS) survival.

RESULTS AND LIMITATIONS

We identified 19 RA-MIBC patients with available tumor tissue (n = 22 tumors) and clinical data. The median age was 76 yr, and the median time from prostate cancer radiation to RA-MIBC was 12 yr. The median RFS was 14.5 mo and the median OS was 22.0 mo. Compared with a cohort of non-RA-MIBC analyzed in parallel, there was no difference in tumor mutational burden, but RA-MIBCs had a significantly increased number of short insertions and deletions (indels) consistent with previous radiation exposure. We identified mutation signatures characteristic of APOBEC-mediated mutagenesis, aging, and homologous recombination deficiency. The frequency of mutations in many known bladder cancer genes, including TP53, KDM6A, and RB1, as well as copy number alterations such as CDKN2A loss was similar in RA-MIBC and non-RA-MIBC.

CONCLUSIONS

We identified unique mutational properties that likely contribute to the distinct biological and clinical features of RA-MIBC.

PATIENT SUMMARY

Bladder cancer is a rare but serious diagnosis following radiation for prostate cancer. We characterized genetic features of bladder tumors arising after prostate radiotherapy, and identify similarities with and differences from bladder tumors from patients without previous radiation.

Racial differences in the risk of second primary bladder cancer following radiation therapy among localized prostate cancer patients

OBJECTIVES

To investigate the race-specific second primary bladder cancer (SPBC) risk following prostatic irradiation.

METHODS

Louisiana residents who were diagnosed with localized prostate cancer (PCa) in 1996-2013 and received surgery or radiation were included. Patients were followed until SPBC diagnosis, death, or Dec. 2018. The exposure variable was type of treatment (radiation only vs. surgery only). The outcome was time from PCa diagnosis to SPBC diagnosis, stratified by race. Fine and Gray's competing risk model was applied with death as a competing event and adjustment of sociodemographic and tumor characteristics. We used 5 years and 10 years as lag time in the analyses.

RESULTS

A total of 26,277 PCa patients with a median follow-up of 10.7 years were analyzed, including 18,598 white and 7679 black patients. About 42.9 % of whites and 45.7 % of blacks received radiation. SPBC counted for 1.84 % in the radiation group and 0.90 % in the surgery group among white patients and for 0.91 % and 0.58 %, respectively, among black patients. The adjusted subdistribution hazard ratio of SPBC was 1.80 (95 % CI: 1.30-2.48) for radiation recipients compared to surgery recipients among white patients; 1.93 (95 % CI: 1.36-2.74) if restricted to external beam radiation therapy (EBRT). The SPBC risk was not significantly different between irradiated and surgically treated among blacks.

CONCLUSIONS

The SPBC risk is almost two-fold among white irradiated PCa patients compared to their counterparts treated surgically. Our findings highlight the need for enhanced surveillance for white PCa survivors receiving radiotherapy, especially those received EBRT.

Urinary bladder cancer as a late sequela of traumatic spinal cord injury

BACKGROUND

Traumatic spinal cord injury (SCI) is also a combat-related injury that is increasing in modern warfare. The aim of this work is to inform medical experts regarding the different course of bladder cancer in able-bodied patients compared with SCI patients based on the latest medical scientific knowledge, and to present decision-making aids for the assessment of bladder cancer as a late sequela of traumatic SCI.

METHODS

A study conducted between January 1998 and December 2019 in the BG Trauma Hospital Hamburg formed the basis for the decision-making aids. Urinary bladder cancer was diagnosed in 40 out of 7396 treated outpatient and inpatient SCI patients. General patient information, latency period, age at initial diagnosis, type of bladder management and survival of SCI patients with bladder cancer were collected and analysed. T category, grading and tumour entity in these patients were compared with those in the general population. Relevant bladder cancer risk factors in SCI patients were analysed. Furthermore, relevant published literature was taken into consideration.

RESULTS

Initial diagnosis of urinary bladder cancer in SCI patients occurs at a mean age of 56.4 years (SD ± 10.7 years), i.e., approximately 20 years earlier as compared with the general population. These bladder cancers are significantly more frequently muscle invasive (i.e., T category ≥ T2) and present a higher grade at initial diagnosis. Furthermore, SCI patients show a significantly higher proportion of the more aggressive squamous cell carcinoma than that of the general population in areas not endemic for the tropical disease schistosomiasis. Consequently, the survival time is extremely unfavourable. A very important finding, for practical reasons is that, in the Hamburg study as well as in the literature, urinary bladder cancer is more frequently observed after 10 years or more of SCI. Based on these findings, a matrix was compiled where the various influencing factors, either for or against the recognition of an association between SCI and urinary bladder cancer, were weighted according to their relevance.

CONCLUSIONS

The results showed that urinary bladder cancer in SCI patients differs considerably from that in able-bodied patients. The presented algorithm is an important aid in everyday clinical practice for assessing the correlation between SCI and bladder cancer.

Secondary malignancy risk for patients with localized prostate cancer after intensity-modulated radiotherapy with and without flattening filter

Men treated for localized prostate cancer by radiotherapy have often a remaining life span of 10 yr or more. Therefore, the risk for secondary malignancies should be taken into account. Plans for ten patients were evaluated which had been performed on an Oncentra® treatment planning system for a treatment with an Elekta Synergy™ linac with Agility™ head. The investigated techniques involved IMRT and VMTA with and without flattening filter. Different dose response models were applied for secondary carcinoma and sarcoma risk in the treated region and also in the periphery. As organs at risk we regarded for carcinoma risk urinary bladder, rectum, colon, esophagus, thyroid, and for sarcoma risk bone and soft tissue. The excess absolute risk (EAR) was found very similar in the treated region for both techniques (IMRT and VMAT) and also for both with and without flattening filter. The secondary sarcoma risk resulted about one magnitude smaller than the secondary carcinoma risk. The EAR to the peripheral organs was statistically significant reduced by application of the flattening filter free mode concerning the flattening filter as main source of scattered dose. Application of flattening filter free mode can thus support to reduce second malignancy risk for patients with localized prostate cancer.

Clinical Characteristics, Treatment Strategy, and Outcomes of Primary Large Cell Neuroendocrine Carcinoma of the Bladder: A Case Report and Systematic Review of the Literature

Purpose: The aim of this study was to review the clinicopathologic characteristics, treatments, and outcomes of patients with primary large cell neuroendocrine carcinoma of the bladder (LCNEC).

Patients and Methods: We report one patient diagnosed with primary pure LCNEC of the bladder in Sun Yat-sen Memorial Hospital. In addition, we performed a systematic literature review, in April 2020, on case report and case series of LCNEC of the bladder. The clinicopathologic characteristics, treatments and outcomes of this rare disease were analyzed.

Results: A total of 39 patients were included in our analysis (1 case from our institution and 38 cases from the literature). Most patients (79.5%) were male. The average age at the surgery for the patients is 61.5 years (range 19–85 years). The most common symptom was hematuria (n = 20, 76.9%). Almost all patients (38, 97.4%) underwent surgery, with 26 (66.7%) receiving multimodality therapy. Out of 24 patients with available data, regional or distant recurrences developed in 14 patients (58.3%). The median overall survival of the patients was 11.5 months, with 1- and 3-year survival rates of 54.0 and 21.4%, respectively. In the survival analysis, theT1–2 tumors (P = 0.025), no distant metastases at diagnosis (P = 0.001), and multimodality therapy (P = 0.017) were associated with better overall survival (OS).

Conclusions: LCNEC of the bladder is an extremely rare neoplasm. The available data suggest that the disease has an aggressive natural history with poor prognosis. Early pathologic stage and multimodality treatment may be important factors in determining prognosis.

Clinicopathological characteristics and outcomes of metachronous rectal cancer in patients with a history of cervical cancer with and without remote radiotherapy: Reports of 45 cases

The purpose of this study was to report the clinicopathological characteristics and treatment outcomes of 45 rectal cancer patients who have a history of cervical cancer with or without remote radiotherapy. Twenty-nine patients (64.4%) with a history of cervical cancer treated with pelvic radiotherapy were classified as group A, 16 (35.6%) patients with a history of cervical cancer not treated with radiotherapy were classified as group B. The median duration between radiotherapy for cervical cancer and rectal adenocarcinoma diagnosis was 18 years. At the time of rectal cancer diagnosis, 5 (17.2%) patients presented stage I disease, 15 (51.7%) had stage II, 1 (3.4%) had stage III, and 8 (27.6%) had stage IV. The patients in group A had older age, higher rates of gross ulcerative lesions, low hemoglobin levels, and a lower rate of lymph node metastases. The patients with secondary rectal cancer developed after radiotherapy for cervical cancer usually presented with abnormal abdominal symptoms, such as proctitis, cystitis, or rectal fistula. Higher colostomy rate was found in this group of patients due to severe pelvic fibrosis or proctitis.

[Urinary bladder cancer as a late sequela of spinal cord injury : Decision-making aids for assessment of this causal association]

BACKGROUND

There is to date no convincing literature that has assessed the association between traumatic spinal cord injury (SCI) and the later development of urinary bladder cancer. The aim of this work is to present medical experts as well as the national accident insurance and the social courts decision-making aids based on the latest medical scientific knowledge, for assessment of this causal association.

MATERIALS AND METHODS

A study conducted between April 1998 and March 2017 in the BG Trauma Hospital Hamburg forms the basis for the decision-making aids. Urinary bladder cancer was diagnosed in 32 out of 6432 treated outpatient and inpatient SCI patients. Furthermore, relevant published literature was taken into consideration for the decision-making aids.

RESULTS

It was found that urinary bladder cancer in SCI patients occurs at a considerably younger age as compared to the general population, more frequently shows muscle invasive carcinoma with a higher grade at first diagnosis and a higher proportion of the more aggressive squamous cell carcinoma than that of the general population. Correspondingly, the survival time is extremely unfavorable. For medical experts a matrix was compiled where the various influencing factors, either for or against the recognition of an association between SCI and urinary bladder cancer, were weighted according to their relevance.

CONCLUSION

The results showed that urinary bladder cancer in SCI patients differs considerably from that of able-bodied patients. These differences drastically shorten the survival time. A study on patients with spina bifida, i.e., a congenital spinal cord disorder, corroborates these observations. They indicate histopathological differences that have so far been intangible.

Overall survival and second primary malignancies in men with metastatic prostate cancer

Background

Among prostate cancer (PC) patients, over 90% of distant metastases occur in the bone. PC treatments may be associated with side effects, including second primary malignancies (SPM). There is limited information on the incidence of SPM among men with bone metastatic PC (mPC) and among men with bone metastatic castration-resistant PC (mCRPC). We estimated overall survival and the incidence of SPM in men with mPC and mCRPC.

Methods

In the Prostate Cancer data Base Sweden, the National Prostate Cancer Register was linked to other national health care registers, 15,953 men with mPC in 1999–2011 were identified. Further, 693 men with mCRPC were identified. Outcomes were evaluated using stratified incidence rates, Kaplan-Meier estimators and Cox models.

Results

The mean age among men with mPC was 73.9 years and in men with mCRPC 70.0 years. The median respective survivals were 1.5 (13,965 deaths) and 1.14 years (599 deaths), and average times since PC diagnosis 1.8 and 4.7 years. We observed 2,669 SPMs in men with mPC and 100 SPMs in men with mCRPC. The incidence rate of SPM per 1,000 person-years was 81.8 (78.8–85.0) for mPC and 115.6 (95.1–140.7) for mCRPC. High age, prior neoplasms, urinary tract infection, congestive heart failure, diabetes and renal disease were most strongly associated with increased mortality risk. Prior neoplasms and prior use of antineoplastic agents were most strongly associated with increased SPM risk. Several factors associated with increased mortality and SPM risks were more prevalent in the mCRPC cohort.

Conclusions

Our results on mortality for men with mPC and mCRPC are in line with previous studies from the same time period. Investigation of factors associated with mortality and SPM in men with mPC and mCRPC can help to further understand these outcomes in the era prior to several new treatments have come available.

Does radiotherapy increase the risk of colorectal cancer among prostate cancer patients? A large population-based study

Objective: The survival of prostate cancer (PC) patients after radiotherapy (RT) has improved over time, but it raises the debate of increased risk of secondary colorectal cancer (SCRC). This study aimed to assess whether RT for PC treatment increases the risk of SCRC in comparison with radical prostatectomy (RP). Methods: A population-based cohort of PC patients treated only with RT or only with RP between January 2007 and December 2015 was identified from the Taiwan Cancer Registry. The incidence rate of SCRC development was estimated using Cox regression model. Results: In this study, total 8,797 PC patients treated with either RT (n = 3,219) or RP (n =5,578). Patients subjected to RT were elder (higher percentage of 70≧years, p < 0.0001) and more advanced clinically (stage III: 22.90% vs. 11.87%; stage IV: 22.15% vs. 13.80%, p < 0.0001), compared to those subjected to RP. More patients subjected to RT had a much higher percentage of autoimmune disease (22.34% vs. 18.75%, p < 0.0001) and osteoarthritis and allied disorders (16.31% vs. 12.98%, p < 0.0001). Besides, RT patients had a higher percentage of underlying Crohn's disease (0.25% vs. 0.05%, p = 0.0230). Although almost all selected factors were not statistically significant, they presented the positive risk of SCRC for those under RP compared with those among RT. Besides, for PC patients in clinical stage I and II, patients with RP may have borderline significantly protective effects of SCRC compared with those under RT (stage I, HR: 0.14; 95% C.I.:0.01-1.39; p = 0.0929; stage II, HR: 1.92; 95% C.I.:0.93-3.95; p = 0.0775). Kaplan-Meier curves for a 3-year-period, which demonstrated no statistical difference in the risk of SCRC free between PC patients undergoing RT and RP (p = 0.9766). Conclusion: Whether or not pelvic RT for PC is associated with an increased risk for SCRC on a population-based level remains a matter of considerable debate. From a clinical perspective, these PC survivors should be counseled accordingly and received continued cancer surveillance with regular colonoscopy follow-up.

Long-Term Management of Incidental Bladder Cancer Detected in Patients Undergoing Prostatectomy for Prostate Cancer

INTRODUCTION

At our institution, screening for incidental bladder cancer is routinely performed to avoid tumor cell dissemination caused by surgery in patients undergoing prostatectomy for prostate cancer (PCa). Here, we report the long-term clinical results in patients with incidental bladder cancer detected by routine screening prior to prostatectomy.

MATERIALS AND METHODS

Between January 2003 and December 2013, 430 patients undergoing prostatectomy for resection of PCa were enrolled in this cohort study. All patients underwent screening with cystoscopy, urinary sediment analysis, and urinary cytology to detect incidental bladder cancer. The clinical outcomes of cases with incidental bladder cancer were evaluated.

RESULTS

The incidence of incidental bladder cancer was 2.1% (9/430). All tumors were single papillary tumors located around the urinary orifice or lateral side and were diagnosed as urothelial cancer (UC). No significant findings were detected by urinary sediment analysis or urinary cytology. Pathological results of transurethral resections revealed 5 cases of pTa with Grade 1 UC and 4 cases of pTa with Grade 2 UC. Androgen-deprivation therapy was administered to 8/9 patients. During the observation period (average of 7.2 years), UC recurrence was detected in 2 cases (2 and 7.3 years). However, transurethral resection successfully removed the tumor completely. After an average of 19.6 months (12-25 months) without UC recurrence, 7 patients (77.8%) underwent prostatectomy, and 2 patients received radiation or androgen-deprivation therapy. Prostatectomy was carried out without dissemination of UC during the observation period.

CONCLUSION

Incidental UC was detected in 2.1% of prostatectomy candidates. Preoperative routine screening with flexible cystoscopy was useful to detect early incidental UC.

Second cancers in radically treated Norwegian prostate cancer patients

Introduction: The aim of this registry-based cohort study was to estimate second cancer (SC) risk following radical prostate cancer (PC) treatment and evaluate if the risk was influenced by radiotherapy. Materials and methods: We collected data from the Cancer Registry of Norway on all patients with PC as first cancer diagnosis, from 1997 to 2014. Standardized incidence ratios (SIRs) for SC were calculated by comparing our cohort to the standard male population. Subdistribution hazard ratios were estimated in treatment groups, using patients treated with radical prostatectomy (RP) as reference. Results: We analyzed 24,592 radically treated PC patients. The median follow-up was 7.75 and 6.25 years in the external beam radiotherapy (EBRT) and RP-groups, respectively. SIR for SC was indifferent from the reference population in 24,592 radically treated patients, higher following EBRT, SIR 1.12 (1.07-1.17), and lower following RP, SIR 0.93 (0.87-0.99). EBRT treated patients had higher rectal and urinary bladder cancer incidences, SIR 1.38 (1.16-1.64) and 1.49 (1.31-1.69), respectively. The EBRT patients and the patients treated with radiation after RP (RT after RP) had 38 and 27% higher risk of any SC. We found higher risk of bladder cancer for all treatment groups as compared to RP patients. Only EBRT treated patients showed higher risk of rectal and lung cancer. Discussion/conclusions: In our study, we found that PC patients treated with EBRT had an increased incidence of SC compared to the general population. Patients treated with EBRT and RT after RP were found to have increased risk of SCs, using RP patients as reference. The risks of rectal and urinary bladder cancer in patients receiving EBRT were higher compared to both the general population and to patients treated with radical prostatectomy. The risk of SC should be taken into account when discussing treatment for patients and designing follow-up.

The impact of age at the time of radiotherapy for localized prostate cancer on the development of second primary malignancies

PURPOSE

There is a known increased risk of second primary malignancy (SPM) in patients with prostate cancer (CaP) treated with radiotherapy (RT). It is unclear how age at diagnosis influences the risk of SPMs.

MATERIALS AND METHODS

Using the 1973 to 2013 Surveillance, Epidemiology, and End Results Program, we studied the impact of age on SPMs (defined as a bladder or rectal tumor) after localized CaP treatment with radical prostatectomy (RP) or RT. SPM risk was compared using inverse probability of treatment weighting (IPTW)-adjusted cumulative incidence function and competing-risk proportional hazard models. Overall survival (OS) in patients with SPM was compared using Kaplan Meier and Cox regression analyses.

RESULTS

A total of 579,608 patients met inclusion criteria, and 51.8% of the cohort was treated with RT. The 10- and 20-year cumulative incidences of competing risk (IPTW adjusted) of SPMs were 1.9% (95%CI = 1.8-1.9%) and 3.6% (95%CI = 3.4-3.7%) after RP vs. 2.7% (95%CI = 2.6-2.8%) and 5.4%(95%CI = 5.3-5.6%) after RT. IPTW-adjusted competing risk hazard ratio (HR) of SPM after RT compared to RP was increased in the entire cohort (HR 1.46; 95%CI = 1.39-1.53, P < 0.001) and was highest in the youngest patients: Age <55 HR = 1.83 (95% confidence interval [CI] = 1.49-2.24, P<0.001), Age 55 to 64 HR = 1.66 (95%CI = 1.54-1.79, P < 0.001), Age 65-74 HR = 1.41 (95%CI = 1.33-1.48, P < 0.001), Age ≥75 HR = 1.14 (95%CI = 0.97-1.35, P = 0.112). At 10 years, SPM-specific mortality occurred in 28.9% of patients treated with RT, though OS with SPM was worse in the youngest patients: Age <55 HR = 1.88 (95%CI = 1.25-2.81, P = 0.002), Age 55-64 HR = 1.60 (95%CI = 1.42-1.81, P < 0.001), Age 65-74 HR = 1.40 (95%CI = 1.30-1.52, P < 0.001), Age ≥ 75 HR = 1.27 (95%CI = 1.06-1.53, P = 0.009). All of the age categories had similar median follow-up times.

CONCLUSION

At 10 years there is a 1.8% increased incidence of SPM after RT compared to RP, of which <30% of RT-treated patients with an SPM die as a result of a SPM. However, the risk of SPMs was greatest among younger men treated with RT for localized CaP, and this relationship could not be explained solely by follow-up time, latency time, or life expectancy. An improved understanding of those at the highest risk of SPMs may help tailor treatment and surveillance strategies.

Risk of secondary rectal cancer and colon cancer after radiotherapy for prostate cancer: a meta-analysis

PURPOSE

To investigate whether radiotherapy for prostate cancer increases the risk of therapy-related rectal cancer and colon cancer.

METHODS

A systematic literature search was carried out using the Medline (PubMed), EMBASE, and the Cochrane Library to identify studies examining the association between radiotherapy for prostate cancer and secondary colorectal cancer (rectal cancer and colon cancer) published before March 19, 2018. The risk of second colorectal cancer after radiotherapy was summarized using unadjusted odds ratio (OR) and adjusted hazard ratio (HR) with their 95% confidence interval (CI). Subgroup and sensitivity analyses were conducted to detect potential bias and heterogeneity.

RESULTS

After study selection, 16 reports were retrieved for analysis. When patients received radiotherapy compared with those unexposed to radiation, there was an increased risk of the rectal cancer (OR 1.37, 95%CI 1.01 to 1.85), but not colon cancer. According to adjusted HR, there was an increased risk of the rectal cancer (HR 1.64, 95%CI 1.39 to 1.94), and colon cancer (HR 1.33, 95%CI 1.02 to 1.76). The OR for rectal cancer showed an increased risk with longer latent period (5 years lag time versus 10 years lag time, OR: 1.56 versus 2.22). Brachytherapy had no association with second cancer across all analyses.

CONCLUSIONS

Radiotherapy was associated with an increased risk of subsequent rectal cancer compared with patients unexposed to radiation. Colon may be free from the damage of radiation. Brachytherapy had no association with second rectal cancer or colon cancer.

Multicenter Trial of Stereotactic Body Radiation Therapy for Low- and Intermediate-Risk Prostate Cancer: Survival and Toxicity Endpoints

PURPOSE

The radiobiology of prostate cancer may favor the extreme hypofractionation inherent in stereotactic body radiation therapy (SBRT); however, data from a large multicenter study are lacking. We therefore examined the hypothesis that dose-escalated SBRT can be safely administered across multiple institutions, with favorable 5-year disease-free survival (DFS) rates compared with historical controls.

METHODS AND MATERIALS

Twenty-one centers enrolled 309 patients with prostate adenocarcinoma: 172 with low-risk (LR) and 137 with intermediate-risk (IR) disease. All were treated with a non-coplanar robotic SBRT platform using real-time tracking of implanted fiducials. The prostate was prescribed 40 Gy in 5 fractions of 8 Gy. We assessed toxicities using Common Terminology Criteria for Adverse Events (CTCAE) version 3 and biochemical failure using the "nadir + 2" definition. The study population yielded 90% power to identify excessive (>10%) rates of grade ≥3 genitourinary (GU) or gastrointestinal toxicities and, in the LR group, 80% power to show superiority in DFS over a 93% historical comparison rate.

RESULTS

At a median follow-up of 61 months, 2 LR patients (1.2%) and 2 IR patients (1.5%) experienced grade 3 GU toxicities, far below the 10% toxicity rate deemed excessive (upper limits of 95% confidence interval, 3.5% and 4.3%, respectively). No grade 4 or 5 toxicities occurred. All grade 3 toxicities were GU, occurring 11 to 51 months after treatment. For the entire group, the actuarial 5-year overall survival rate was 95.6% and the DFS rate was 97.1%. The 5-year DFS rate was 97.3% for LR patients (superior to the 93% DFS rate for historical controls; P = .0008; lower limit of 95% confidence interval, 94.6%) and 97.1% for IR patients.

CONCLUSIONS

Dose-escalated prostate SBRT was administered with minimal toxicity in this multi-institutional study. Relapse rates compared favorably with historical controls. SBRT is a suitable option for LR and IR prostate cancer.

Metachronous Malignancies in Men with Previous Prostate Cancer in Umbria, Italy, 1994–2003

Data about second primary tumors after prostate carcinoma are controversial. Some authors emphasize an increased incidence of some cancer sites, others an overall diminution. With the aim to provide further information to define the issue, we have analyzed the frequency of second metachronous primary malignancies in patients with diagnosed prostate cancer in the Umbria region of Italy. A total of 410 metachronous cancers among 4528 prostate cancer patients were abstracted from incident cases of the RTUP, over the period 1994–2003. This cohort was compared with all cases (except prostate cancers) recorded in the RTUP archive. The expected number of cases was obtained from indirect standardization with regional incidence rates of several sites. The significance of the observed/expected ratios and the corresponding 95% confidence intervals were based on the Poisson distribution. A significant standardized incidence ratio was found for all sites but prostate, with 410/351 observed/expected cases. The significance disappears considering all sites except prostate and skin non-melanomas. Among several sites, significant standardized incidence ratios were found for skin non-melanomas, for bladder, for rectum, but not for colon cancers. Kidney, ureter and urethra showed a nonsignificant standardized incidence ratio. Nasopharynx showed a significant standardized incidence ratio, but the result was based on a very small number of cases. In our data, the increase in urinary bladder and rectal cancers, after prostate cancer diagnosis, seems to be real: it is plausible that the number of second cancers may be due to increased urologist surveillance, which, in our Region, does not seem to be reduced in elderly men.

Hospital burden of long-term genitourinary and gastrointestinal toxicity after radical radiotherapy for prostate cancer

INTRODUCTION

Treatment options for prostate cancer (PCa) include radical radiotherapy (RT) and radical prostatectomy, both of which have comparable oncological outcomes. The aim of this study was to investigate the hospital burden of long-term genitourinary and gastrointestinal toxicity among patients with PCa who were treated with radiotherapy at our institution.

METHODS

The radiotherapy department database was used retrospectively to identify all patients who underwent radiotherapy for PCa from January 2006 to January 2008. The patient administration system from each public hospital in the region was interrogated and all patient points of contact were recorded. Minimum follow up was 5 years. Individual patient charts were reviewed and factors that might influence outcomes were documented.

RESULTS

We identified 112 patients. The mean age at diagnosis was 66 (44-76) and the median PSA was 12.1 (3.2-38). The mean duration of follow-up was 7.8 yrs. Twenty-three patients (20%) presented to the Emergency Department (ED) with late onset toxicity. Nine patients had more than 2 ED attendances. Twenty-five patients (22%) were investigated for genitourinary toxicity. Forty-seven patients (42%) underwent investigation for gastrointestinal side-effects and 45% of these required argon therapy (21/47).

CONCLUSION

We found a significant hospital burden related to the management of gastrointestinal and genitourinary toxicity post radical radiotherapy for prostate cancer. As health care reforms gain momentum, policy makers must take into account the considerable longitudinal health care cost related to radiotherapy. It is also important that patients are counselled carefully in relation to potential long-term side-effects.

Secondary Urethral Malignancies Following Prostate Brachytherapy

OBJECTIVE

To understand urethral secondary malignancies among patients treated with brachytherapy (BRT) for primary prostate cancer.

PATIENTS AND METHODS

Institutional retrospective review identified 13 patients evaluated from 2003 to 2014 with urethral cancer and history of BRT monotherapy for prostate cancer. All patients were biochemically free of their primary disease and radiation-associated secondary malignancies (RASMs) were confirmed pathologically to be histologically distinct from primary tumor. BRT characteristics, patient age, presentation, staging workup, and clinical course were evaluated.

RESULTS

The mean time from BRT to presenting symptoms of hematuria, urinary retention, and/or renal failure was 71 months. Symptom onset to RASM diagnosis interval was 24 months. Mean time from BRT to RASM diagnosis was 95 months. Eighty-five percent of patients had an undetectable prostate-specific antigen level (<0.2 ng/mL) at last follow-up. Types of RASM included sarcomatoid carcinoma (6), small cell carcinoma (2), urothelial carcinoma with squamous differentiation (2), squamous cell carcinoma (1), rhabdomyosarcoma (1), and urothelial carcinoma (1). A majority of patients were diagnosed with advanced disease with either distant metastases (54%) or local progression (23%). Ten patients died during this study period with median time to death after RASM diagnosis of 6 months.

CONCLUSION

RASMs localized to the posterior urethra displayed advanced disease and high mortality rates. Refractory lower urinary tract symptoms, hematuria, and history of prostate BRT should raise suspicion for urethral RASMs. Further studies are warranted to determine patient and disease characteristics that correlate with disease-specific mortality of secondary urethral malignancies.

Myelodysplastic Syndromes and Acute Myeloid Leukemia After Radiotherapy for Prostate Cancer: A Population-Based Study

BACKGROUND

To understand the impact of radiotherapy on the development of myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) among elderly prostate cancer patients.

METHODS

We performed a retrospective cohort study of elderly prostate cancer patients diagnosed during 1999-2011 by using the National Cancer Institute's Surveillance, Epidemiology and End Results-Medicare linked database. Competing risk analyses adjusting for patient characteristics were conducted to assess the impact of radiotherapy on the development of subsequent MDS/AML, compared with surgery.

RESULTS

Of 32,112 prostate cancer patients, 14,672 underwent radiotherapy, and 17,440 received surgery only. The median follow-up was 4.68 years. A total of 157 (0.47%) prostate cancer patients developed subsequent MDS or AML, and the median time to develop MDS/AML was 3.30 (range: 0.16-9.48) years. Compared with prostate cancer patients who received surgery only, patients who underwent radiotherapy had a significantly increased risk of developing MDS/AML (hazard ratio [HR] =1.51, 95% confidence interval [CI]: 1.07-2.13). When radiotherapy was further categorized by modalities (brachytherapy, conventional conformal radiotherapy, and intensity-modulated radiotherapy [IMRT]), increased risk of second MDS/AML was only observed in the IMRT group (HR = 1.66, 95% CI: 1.09-2.54).

CONCLUSIONS

Our findings suggest that radiotherapy for prostate cancer increases the risk of MDS/AML, and the impact may differ by modality. Additional studies with longer follow-up are needed to further clarify the role of radiotherapy in the development of subsequent myeloid malignancies. A better understanding may help patients, physicians, and other stakeholders make more informed treatment decisions. Prostate 77:437-445, 2017. © 2016 Wiley Periodicals, Inc.

Secondary malignancies after rectal cancer resection with and without radiation therapy: A propensity-adjusted, population-based SEER analysis

BACKGROUND

The relationship between radiation therapy for rectal cancer and secondary malignancies is debated. The present study is the first population-based analysis using conventional multivariable analyses as well as propensity score matching to assess this relationship.

METHODS

Overall, 77,484 patients after resection of localized or locally advanced rectal adenocarcinoma diagnosed between 1973 and 2012 were identified in the Surveillance, Epidemiology, and End Results (SEER) registry. The occurrence of secondary malignancies diagnosed at least 1 (median follow up 5.8years [1-39.9years]) year after rectal cancer diagnosis was compared in patients who did and did not undergo radiation using stratified and propensity score matched Cox regression analysis.

RESULTS

Of 77,484 patients, 34,114 underwent radiation and 43,370 did not. Ignoring gender and entity, radiation therapy was not associated with secondary malignancies (hazard ratio [HR]=0.97 (95%CI: 0.92-1.02, P=0.269). The risk for prostate cancer was decreased and (HR=0.42, 95%CI: 0.36-0.48, P<0.001) and increased risk for endometrial cancer (HR=1.95, 95%CI: 1.49-2.56, P<0.001). Overall, patients undergoing radiation had higher risks for lung cancer (HR=1.18, 95%CI: 1.06-1.30, P<0.001), bladder cancer (HR=1.54, 95%CI: 1.31-1.80, P<0.001) and lymphomas (HR=1.27, 95%CI: 1.03-1.58, P=0.026).

CONCLUSIONS

The present analysis describes the occurence of secondary malignancies after pelvic radiation in patients undergoing rectal cancer surgery. Indeed, radiation for rectal cancer is associated with a significantly decreased risk of prostate cancer, however, an increased risk of endometrial, lung, and bladder cancer as well as lymphomas was observed. Overall, the risk of secondary malignancies was slightly decreased with radiation in patients undergoing rectal cancer resection, this was attributable to lower rates in prostate cancer.

Pattern of solid and hematopoietic second malignancy after local therapy for prostate cancer

BACKGROUND AND PURPOSE

Second malignancies (SM) after external beam radiotherapy (EBRT) or brachytherapy (BT) for prostate cancer (PCa) are rare but serious sequelae.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was used to identify men diagnosed with cT1-2N0M0 PCa between 1999 and 2005, who underwent EBRT, BT or radical prostatectomy (RP). Patients with time interval to second malignancy or follow-up shorter than five and two years were excluded for solid and hematopoietic SM analyses respectively. Risks for solid and hematopoietic SM were evaluated via the multivariate Fine and Gray proportional hazards model.

RESULTS

EBRT and BT resulted in similar increases in solid and hematopoietic SM compared to RP. In subgroup analysis stratified by treatment modality, only the EBRT cohort demonstrated significantly decreased solid and hematopoietic SM in years 2002-2005 compared to years 1999-2001, with adjusted-hazard ratios of 0.752 (p=0.001) and 0.815 (p=0.018) respectively.

CONCLUSIONS

EBRT and BT resulted in statistically equivalent increase in both solid and hematopoietic SM compared to RP. EBRT in more recent years resulted in significantly decreased solid and hematopoietic SM, coinciding with increased utilization of IMRT.

Secondary Cancers After Radiation Therapy for Primary Prostate or Rectal Cancer

Literature about the risk of secondary cancer after radiation therapy (RT) of prostate and rectal cancer reveals contradictory results. We conducted a meta-analysis to examine whether the RT induces secondary rectal or prostate cancer in patients, respectively, with prostate or rectal cancer. All studies published in Medline or Pubmed up to March 3, 2015, containing RT of primary rectal or prostate cancer, and providing risk estimates of secondary prostate or rectal cancer were considered as eligible. Relative risk (RR) and standardized incidence ratios (SIR) were calculated using the random-effects model. Twenty studies met the inclusion criteria. 12 of them were from the Surveillance, Epidemiology, and End Results (SEER) database. For prostate cancer patients, pooled adjusted RRs or SIRs did not show an effect on the risk of secondary rectal cancer. However, notwithstanding the limitations of SEER-based studies, the subgroup of prostate cancer patients receiving external beam radiation therapy (EBRT) showed an increased risk of rectal cancer. For rectal cancer patients, pooled adjusted RR of prostate cancer was 1.12 (95 % CI, 0.44-2.8) and SIR was 0.40 (95 % CI, 0.29-0.55). All studies included in the SIR analysis of rectal cancer were derived from the SEER data source. Based on current evidence, RT for prostate cancer patients had no effect on rectal cancer incidence, except for patients who received EBRT therapy. However, compared with the general population, RT for rectal cancer is associated with a decreased prostate cancer risk as found in SEER-based studies.

Incidence of bladder cancer after radiation for prostate cancer as a function of time and radiation modality

OBJECTIVES

To evaluate the risk of BlCa developing after radiation for PCa, stratified by ethnicity and follow-up duration.

METHODS

The 1973-2011 surveillance, epidemiology and end results database was used to determine the observed and expected number of BlCa after PCa radiation. The adjusted relative risks (RRs) of developing BlCa were calculated for the various radiation modalities relative to no radiation, stratified by ethnicity and follow-up duration. BlCa characteristics were compared between patients with a history of prostate radiation and those without PCa.

RESULTS

PCa was radiated in 346,429 men, 6401 of whom developed BlCa versus 2464 expected cases [SIR (95 % CI) of 2.60 (2.53-2.66)]. All radiation modalities were found to have an increased RR of developing BlCa after 10 years, with brachytherapy having a significantly higher RR than external beam radiation (EBRT) or combined EBRT and brachytherapy in Caucasian men and a significantly higher RR than EBRT in men of other/unknown ethnicity. Post-radiation BlCa, in particular that after brachytherapy, had higher grade (P = 0.0001) and lower stage (P = 0.0001) versus the general population.

CONCLUSIONS

The increased risk of BlCa after prostate radiation occurs predominantly after 10 years, regardless of ethnicity. The RR of developing BlCa after 10 years is significantly higher following brachytherapy than after EBRT or EBRT and brachytherapy. Bladder cancers after prostate radiation, especially after brachytherapy, are generally lower stage but higher grade than those in patients without PCa.

The risk of second malignancies after 125I prostate brachytherapy as monotherapy in a single Australian institution

PURPOSE

To report the incidence of second primary cancer (SPC) after ¹²⁵I brachytherapy (BT) for early prostate cancer in an Australian institution.

METHODS AND MATERIALS

All the patients in our cohort had a cystoscopy before the implant. Data were prospectively collected on all subsequent SPC diagnoses. Standardized incidence ratios (SIRs) were calculated to compare data with the Australian population. Kaplan-Meier analysis was used to determine the actuarial second malignancy and pelvic malignancy rates and the death from SPC and from any cause.

RESULTS

A total of 889 patients were followed up for a median of 4.16 (0-13) years with 370 (42%) patients having ≥5 years of followup. Sixty patients subsequently developed an SPC of which 11 were pelvic malignancies. The 5- and 10-year cumulative incidences were 1.3% (95% confidence interval [CI]: 0.6-3) and 3.3% (95% CI: 1-7) for any pelvic malignancy and 1% (95% CI: 0.4-2) and 2.6% (1-6) for bladder cancer, respectively. The SIR was significantly higher than expected for all bladder cancers at 2.9 (95% CI: 1-6) and close to significance (SIR, 3.0; 95% CI: 0.97-7) for bladder cancers within the first 5 years of followup in the subgroup analysis. On multivariate analysis, older age was associated with increased SPC risk and older age and positive smoking status were associated with increased overall mortality, mortality due to SPC, and mortality from second malignancy (p < 0.05).

CONCLUSIONS

There may be a small increased risk of bladder SPC after prostate BT. A tendency toward a higher risk of bladder SPC after BT was found within the first 5 years of followup probably reflecting screening bias.

Secondary bladder cancer after anticancer therapy for prostate cancer: reduced comorbidity after androgen-deprivation therapy

Radiotherapy for prostate cancer is associated with an increased incidence of secondary bladder cancer (BC). We investigated the incidence, clinicopathological characteristics, and prognosis of BC after radiotherapy, surgical therapy, and primary androgen-deprivation therapy (ADT) for prostate cancer. This study included 1,334 Japanese patients with prostate cancer treated with radiotherapy (n=631), surgical therapy (n=437), and primary ADT (n=266). During the median follow-up period of 51.2, 44.8, and 45.5 months, secondary BC occurred in 14 (2.2%), 5 (1.1%), and 0 (0%) of patients with prostate cancer treated with radiotherapy, surgical therapy, and primary ADT, respectively. The 10-year BC-free survival rate was 91.3% in the radiotherapy group, 97.4% in the surgical therapy group, and 100% in the primary ADT group. The rates of intravesical recurrence, progression to muscle-invasive BC, and BC-specific death might be higher in secondary BC after radiotherapy compared with after surgical therapy. There was a significant difference in the incidence of secondary BC among different therapeutic modalities for prostate cancer in Japanese men, indicating significantly lower comorbidity rates of secondary BC after primary ADT for prostate cancer compared with radiotherapy.

Risk of colorectal cancer after the diagnosis of prostate cancer: A population-based study

BACKGROUND

A rigorous assessment of the risk of colorectal cancer (CRC) among prostate cancer (PC) survivors that controls for important confounding factors and competing risks is necessary to determine the risk of CRC in this population and to inform screening guidelines.

METHODS

With data from Manitoba, Canada, subjects diagnosed with PC as their first cancer between 1987 and 2009 were age-matched with up to 5 men with no history of invasive cancer on the PC diagnosis date. Subjects were followed to the date of diagnosis of CRC or another cancer, death, emigration, or the study endpoint (December 31, 2009). Competing risk proportional hazards models were used to compare the CRC incidence between those with PC and those without PC with the following model covariates: history of lower gastrointestinal endoscopy, frequency of health care visits, diabetes, and socioeconomic status. Mutually exclusive competing outcomes included CRC, another primary cancer, and death.

RESULTS

For a total of 559,081 person-years, 14,164 men with PC and 69,051 men without PC were followed. Men diagnosed with PC had an increased risk of a subsequent diagnosis of CRC (all CRC: hazard ratio [HR], 1.14; 95% confidence interval [CI], 1.02-1.27; rectal cancer: HR, 1.36; 95% CI, 1.09-1.71). The treatment of PC with radiation was associated with an increased risk for rectal cancer (HR, 2.06; 95% CI, 1.42-2.99) in comparison with PC cases not treated with radiation.

CONCLUSIONS

The risk of CRC is increased after a diagnosis of PC and is highest for rectal cancer among those treated with radiation. CRC screening should be considered soon after the diagnosis of PC, especially for men planning for radiotherapy.

The Prognostic Value of Previous Irradiation on Survival of Bladder Cancer Patients

Background: Radiation exposure is an established risk factor for bladder cancer, however consensus is lacking on the survival characteristics of bladder cancer patients with a history of radiation therapy (RT). Confounding patient comorbidities and baseline characteristics hinders prior attempts at developing such a consensus.

Objective: To compare the survival characteristics of patients with suspected radiation-induced second primary cancer (RISPC) of the bladder to those with de novo bladder cancer, taking into account the patient comorbidities and baseline characteristics predictive of survival.

Methods: Retrospective analysis of patients with muscle-invasive (≥T2a) or BCG-refractory stage Tis-T1 urothelial bladder cancer. Patients were excluded if prior RT exposure was used as treatment for bladder cancer or if cause of death was due to post-operative complications. A digit matching propensity score algorithm was used to match patients with prior radiation treatment to those without prior treatment. Cox regression analysis for time until death was performed following creation of the propensity score matched sample.

Results: 29 patients with history of RT were matched with two controls each, resulting in a dataset of 87 observations in the event model. Results from the Cox model indicate a significantly increased hazard ratio for death at 2.22 (p = 0.047, 95% CI: 1.015–4.860) given a history of prior radiation therapy.

Conclusions: In a small cohort, bladder cancer patients who underwent cystectomy had a significantly higher risk of death in the face of prior pelvic RT. This effect was found to be independent of surgical complications, numerous established patient characteristics and comorbidities traditionally predictive of survival.

Risk of Second Primary Cancer among Prostate Cancer Patients in Korea: A Population-Based Cohort Study

As patients with prostate cancer have a long life expectancy, there is increasing interest in predicting the risk of development of a second primary cancer (SPC), and we therefore designed this study to estimate the overall risk of developing SPCs among Korean prostate cancer patients. We used a population-based cohort from the Korean Central Cancer Registry composed of 55,378 men diagnosed with a first primary prostate cancer between 1993 and 2011. Standardized incidence ratios (SIRs) of SPCs were analyzed by age at diagnosis, latency period, period of diagnosis, and type of initial treatment. Survival analysis was stratified by development of SPC. Men with primary prostate cancer had an overall lower risk of developing an SPC [SIR = 0.75; 95% CI, 0.72-0.78], which was significant for SPCs of the esophagus, stomach, rectum, liver, gallbladder, bile duct, pancreas, larynx, lung, and bronchus. In contrast, there were significant increases in the risk of bladder and thyroid cancers, which tended to decrease after longer follow-up. Patients who received initial radiation therapy had an increased risk of subsequent rectal cancer, although this was still lower than that of the general male population. Other urinary tract cancers including those of the kidney, renal pelvis, and ureter tended to be associated with a higher risk of developing an SPC, but this difference did not reach statistical significance. The patients with prostate cancer and SPC had lower overall survival rates than those with one primary prostate cancer. Our findings suggest that men with prostate cancer have a 25% lower risk of developing an SPC in Korea, but a higher risk of developing subsequent bladder and thyroid cancers, which suggests the need for continued cancer surveillance among prostate cancer survivors.

Risk of Second Primary Cancer among Prostate Cancer Patients in Korea: A Population-Based Cohort Study

As patients with prostate cancer have a long life expectancy, there is increasing interest in predicting the risk of development of a second primary cancer (SPC), and we therefore designed this study to estimate the overall risk of developing SPCs among Korean prostate cancer patients. We used a population-based cohort from the Korean Central Cancer Registry composed of 55,378 men diagnosed with a first primary prostate cancer between 1993 and 2011. Standardized incidence ratios (SIRs) of SPCs were analyzed by age at diagnosis, latency period, period of diagnosis, and type of initial treatment. Survival analysis was stratified by development of SPC. Men with primary prostate cancer had an overall lower risk of developing an SPC [SIR = 0.75; 95% CI, 0.72-0.78], which was significant for SPCs of the esophagus, stomach, rectum, liver, gallbladder, bile duct, pancreas, larynx, lung, and bronchus. In contrast, there were significant increases in the risk of bladder and thyroid cancers, which tended to decrease after longer follow-up. Patients who received initial radiation therapy had an increased risk of subsequent rectal cancer, although this was still lower than that of the general male population. Other urinary tract cancers including those of the kidney, renal pelvis, and ureter tended to be associated with a higher risk of developing an SPC, but this difference did not reach statistical significance. The patients with prostate cancer and SPC had lower overall survival rates than those with one primary prostate cancer. Our findings suggest that men with prostate cancer have a 25% lower risk of developing an SPC in Korea, but a higher risk of developing subsequent bladder and thyroid cancers, which suggests the need for continued cancer surveillance among prostate cancer survivors.

Evolved Cellular Mechanisms to Respond to Genotoxic Insults: Implications for Radiation-Induced Hematologic Malignancies

Human exposure to ionizing radiation is highly associated with adverse health effects, including reduced hematopoietic cell function and increased risk of carcinogenesis. The hematopoietic deficits manifest across blood cell types and persist for years after radiation exposure, suggesting a long-lived and multi-potent cellular reservoir for radiation-induced effects. As such, research has focused on identifying both the immediate and latent hematopoietic stem cell responses to radiation exposure. Radiation-associated effects on hematopoietic function and malignancy development have generally been attributed to the direct induction of mutations resulting from radiation-induced DNA damage. Other studies have illuminated the role of cellular programs that both limit and enhance radiation-induced tissue phenotypes and carcinogenesis. In this review, distinct but collaborative cellular responses to genotoxic insults are highlighted, with an emphasis on how these programmed responses impact hematopoietic cellular fitness and competition. These radiation-induced cellular programs include apoptosis, senescence and impaired self-renewal within the hematopoietic stem cell (HSC) pool. In the context of sporadic DNA damage to a cell, these cellular responses act in concert to restore tissue function and prevent selection for adaptive oncogenic mutations. But in the contexts of whole-tissue exposure or whole-body exposure to genotoxins, such as radiotherapy or chemotherapy, we propose that these programs can contribute to long-lasting tissue impairment and increased carcinogenesis.

Management of post-radiation therapy complications among prostate cancer patients: A case series

INTRODUCTION

Treating prostate cancer with radiation therapy (RT) is a viable option, albeit with its own profile of complications. We describe a unique Canadian report of a single surgeon (RJB) experience in the management of complex post-prostate cancer RT complications.

METHODS

We retrospectively analyzed patients who had previously received external beam radiation (XRT) or brachytherapy (BT) for prostate cancer referred to a single surgeon for persistent urologic related difficulties between 2005 and 2010. We used the Radiation Therapy Oncology Group (RTOG) morbidity grading system to assign each patient a 1 to 5 grade for their greatest complication.

RESULTS

In total, 15 patients were identified with a total of 43 RT-related complications. Of these 43 complications, 19 presented with obstruction, 8 with radiation failure or new bladder cancer, 6 with hematuria, 5 with intractable incontinence, and 5 with urinary tract infections. These patients required several investigations prior to treatment. Treatment of these complications used surgical, local and medical approaches. In the end, 1 patient had total incontinence, 3 improved their incontinence, 3 had self-catheterization and dilation, 1 voided well, 3 underwent cystectomy with ileo-conduits, 2 had chronic hematuria, and 2 passed away.

CONCLUSION

These patients are heavily investigated and require significant resources, including patient visits, diagnostics and treatment modalities to optimize their condition. Cure is not always possible, but the aim to improve quality of life should guide management.

Risk of second primary tumors in men diagnosed with prostate cancer: a population-based cohort study

BACKGROUND

The survival of men diagnosed with prostate cancer has improved over time, and the current 10-year relative survival rate is 99.7%. The long survival of patients with this common cancer raises questions about the risk of a second primary cancer and the need for continued surveillance.

METHODS

A population-based cohort of 441,504 men who were diagnosed with prostate cancer between 1992 and 2010 was identified from Surveillance, Epidemiology and End Results Program (SEER) data (SEER13). The standardized incidence ratio (SIR) was calculated as an estimate of the risk of a second primary malignancy based on the incidence in the general population.

RESULTS

Prostate cancer survivors had a lower risk of being diagnosed with another cancer overall compared with the US population (SIR = 0.60; 95% confidence interval, 0.60-0.61). The risks of leukemia and cancers of the oral cavity and pharynx, esophagus, stomach, colon and rectum, liver, gallbladder, pancreas, lung and bronchus, and larynx were significantly lower. Conversely, these patients had a greater risk of bladder, kidney, and endocrine and soft tissue cancers. Men who received treatment with radiation therapy (external-beam radiation therapy) had long-term increases in their risk of bladder cancer (SIR = 1.42) and rectal cancer (SIR = 1.70) risk compared with who did not receive radiation (SIRbladder  = 0.76; SIRrectal  = 0.74). There were significant racial differences in the risk of being diagnosed with a second primary cancer, and the magnitude and direction of these risks depended on tumor type.

CONCLUSIONS

Prostate cancer survivors remain at risk of subsequent malignancies, and race and treatment choice important determinants of long-term risk.

Radiation-induced secondary malignancy in prostate cancer: a systematic review and meta-analysis

OBJECTIVE

To investigate the risk of radiation-induced secondary malignancy in patients with prostate cancer.

METHODS

We identified 690 references from PubMed, Embase and the Cochrane Library before August 1, 2012, that reported secondary malignancy in patients with prostate cancer after receiving radiation therapy (RT), and finally four studies were included. We calculated summary estimates using random-effects meta-analysis.

RESULTS

The overall standardized incidence ratio (SIR) of secondary malignancy in patients with prostate cancer receiving RT to the general population was 1.14 (95% CI 1.04-1.32). In the subgroup analysis, no increment in radiation-induced secondary malignancy risk was detected. In terms of SIR with different follow-up intervals, there was no difference in SIR (>6 months; <5 years) (SIR = 1.19, 95% CI 0.75-1.89) and SIR (>5 years; <10 years) (SIR = 1.39, 95% CI 0.87-2.23). When the follow-up extended to >10 years, a significantly increased secondary malignancy risk was observed (SIR = 1.45, 95% CI 1.23-1.72). There is no significantly increased secondary malignancy risk in patients receiving no RT.

CONCLUSION

RT is associated with increased secondary malignancy in patients with prostate cancer; this effect only become conspicuous more than 10 years after treatment.

Risk for developing myelodysplastic syndromes in prostate cancer patients definitively treated with radiation

BACKGROUND

Exposure to ionizing radiation has been linked to myelodysplastic syndromes (MDS); it is not clear whether therapeutic radiation doses used for prostate cancer pose an increased MDS risk.

METHODS

We performed a retrospective cohort study of prostate cancer patients diagnosed between 1986 and 2011 at Cleveland Clinic, comparing those who underwent definitive treatment with radical prostatectomy (RP) to radiotherapy either external beam radiotherapy (EBRT) or prostate interstitial brachytherapy (PI) and to population-based registries. Competing risk regression analyses were used to determine the cumulative risk of developing MDS. All statistical tests were two-sided.

RESULTS

Of 10924 patients, 5119 (47%) received radiation (n = 2183 [43%] in EBRT group and n = 2936 [57%] in PI group) and 5805 (53%) were treated with RP. Overall, 31 cases of MDS were observed, with age-adjusted incidence rates no higher than in population-based registries. In univariate analyses, advancing age (hazard ratio [HR] = 1.14; 95% confidence interval [CI] = 1.09 to 1.20; P < .001) and radiotherapy exposure (HR = 3.44; 95% CI = 1.41 to 8.37; P = .007) were statistically significantly associated with development of MDS. In multivariable analyses, although advanced age (HR = 1.13; 95% CI = 1.06 to 1.19; P < .001) remained statistically associated with MDS, radiation did not, although a small non-statistically significant trend existed for PI-treated patients. MDS rates were no higher than in population-based registries.

CONCLUSIONS

With relatively short follow-up, prostate cancer patients definitively treated with radiation did not appear to have a statistically increased risk of subsequent MDS.

[The issue of low doses in radiation therapy and impact on radiation-induced secondary malignancies]

Several studies have well documented that the risk of secondary neoplasms is increasing among patients having received radiation therapy as part of their primary anticancer treatment. Most frequently, radiation-induced neoplasms occur in volume exposed to high doses. However, the impact of "low" doses (<5 Gy) in radiation-induced carcinogenesis should be clinically considered because modern techniques of intensity-modulated radiation therapy (IMRT) or stereotactic irradiation significantly increase tissue volumes receiving low doses. The risk inherent to these technologies remains uncertain and estimates closely depend on the chosen risk model. According to the (debated) linear no-threshold model, the risk of secondary neoplasms could be twice higher with IMRT, as compared to conformal radiation therapy. It seems that only proton therapy could decrease both high and low doses delivered to non-target volumes. Except for pediatric tumors, for which the unequivocal risk of second malignancies (much higher than in adults) should be taken into account, epidemiological data suggest that the risk of secondary cancer related to low doses could be very low, even negligible in some cases. However, clinical follow-up remains insufficient and a marginal increase in secondary tumors could counterbalance the benefit of a highly sophisticated irradiation technique. It therefore remains necessary to integrate the potential risk of new irradiation modalities in a risk-adapted strategy taking into account therapeutic objectives but also associated risk factors, such as age (essentially), chemotherapy, or life style.