A nested case-control study on radiation dose-response for cardiac events in breast cancer patients in Germany

Background

Previous studies with the majority of breast cancer (BC) patients treated up to 2000 provided evidence that radiation dose to the heart from radiotherapy (RT) was linearly associated with increasing risk for long-term cardiac disease. RT techniques changed substantially over time. This study aimed to investigate the dose-dependent cardiac risk in German BC patients treated with more contemporary RT.

Methods

In a cohort of 11,982 BC patients diagnosed in 1998–2008, we identified 494 women treated with 3D-conformal RT who subsequently developed a cardiac event. Within a nested case-control approach, these cases were matched to 988 controls. Controls were patients without a cardiac event after RT until the index date of the corresponding case. Separate multivariable conditional logistic regression models were used to assess the association of radiation to the complete heart and to the left anterior heart wall (LAHW) with cardiac events.

Results

Mean dose to the heart for cases with left-sided BC was 4.27 Gy and 1.64 Gy for cases with right-sided BC. For controls, corresponding values were 4.31 Gy and 1.66 Gy, respectively. The odds ratio (OR) per 1 Gy increase in dose to the complete heart was 0.99 (95% confidence interval (CI): 0.94–1.05, P = .72). The OR per 1 Gy increase in LAHW dose was 1.00 (95% CI: 0.98–1.01, P = .68).

Conclusions

Contrary to previous studies, our study provided no evidence that radiation dose to the heart from 3D-conformal RT for BC patients treated between 1998 and 2008 was associated with risk of cardiac events.

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Dose-response analysis on cardiac late effects in irradiated breast cancer patients.

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Nested case-control study with individual retrospective heart dosimetry.

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Included 494 cases and 988 controls treated in 1998–2008 in Germany.

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No association for cardiac late effects of 3D-conformal radiotherapy observed.

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No association for the complete heart and left anterior heart wall observed.

Heart atlas for retrospective cardiac dosimetry: a multi-institutional study on interobserver contouring variations and their dosimetric impact

PURPOSE

Cardiac effects after breast cancer radiation therapy potentially affect more patients as survival improves. The heart's heterogeneous radiation exposure and composition of functional structures call for establishing individual relationships between structure dose and specific late effects. However, valid dosimetry requires reliable contouring which is challenging for small volumes based on older, lower-quality computed tomography imaging. We developed a heart atlas for robust heart contouring in retrospective epidemiologic studies.

METHODS AND MATERIALS

The atlas defined the complete heart and geometric surrogate volumes for six cardiac structures: aortic valve, pulmonary valve, all deeper structures combined, myocardium, left anterior myocardium, and right anterior myocardium. We collected treatment planning records from 16 patients from 4 hospitals including dose calculations for 3D conformal tangential field radiation therapy for left-sided breast cancer. Six observers each contoured all patients. We assessed spatial contouring agreement and corresponding dosimetric variability.

RESULTS

Contouring agreement for the complete heart was high with a mean Jaccard similarity coefficient (JSC) of 89%, a volume coefficient of variation (CV) of 5.2%, and a mean dose CV of 4.2%. The left (right) anterior myocardium had acceptable agreement with 63% (58%) JSC, 9.8% (11.5%) volume CV, and 11.9% (8.0%) mean dose CV. Dosimetric agreement for the deep structures and aortic valve was good despite higher spatial variation. Low spatial agreement for the pulmonary valve translated to poor dosimetric agreement.

CONCLUSIONS

For the purpose of retrospective dosimetry based on older imaging, geometric surrogate volumes for cardiac organs at risk can yield better contouring agreement than anatomical definitions, but retain limitations for small structures like the pulmonary valve.

Changes of Radiation Treatment Concept Based on 68Ga-PSMA-11-PET/CT in Early PSA-Recurrences After Radical Prostatectomy

Background and Purpose

Salvage radiotherapy (SRT) is the main potentially curative treatment option for prostate cancer patients with post-prostatectomy PSA progression. Improved diagnostics by positron emission tomography/computed tomography (PET/CT) can lead to adjustments in treatment procedures (e.g. target volume of radiotherapy, androgen deprivation therapy). We analyzed the impact of ⁶⁸Ga-PSMA-11-PET/CT on the target volume in early biochemical recurrence (PSA up to 0.5 ng/ml).

Patients and Methods

We retrospectively analyzed 76 patients with biochemical recurrence after radical prostatectomy in whom SRT was planned after ⁶⁸Ga-PSMA-11-PET/CT. All patients had a PSA ≤0.5 ng/ml. An experienced radiation oncologist determined the radiotherapy concept, first with consideration of the PET/CT, second hypothetically based on the clinical and pathological features excluding PET/CT results.

Results

Without considering the PET/CT, all 76 patients would have been assigned to RT, 60 (79%) to the bed of the prostate and seminal vesicles alone, and 16 (21%) also to the pelvic lymph nodes because of histopathologic risk factors. Uptake indicative for tumor recurrence in ⁶⁸Ga-PSMA-11-PET/CT was found in 54% of the patients. The median pre-PET/CT PSA level was 0.245 ng/ml (range 0.07-0.5 ng/ml). The results of the PET/CT led to a change in the radiotherapeutic target volume in 21 patients (28%). There were major changes in the target volume including the additional irradiation of lymph nodes or the additional or exclusive irradiation of bone metastases in 13 patients (17%). Minor changes including the additional irradiation of original seminal vesicle (base) position resulted in eight patients (11%).

Conclusion

Using ⁶⁸Ga-PSMA-11-PET/CT for radiation planning, a change in the treatment concept was indicated in 28% of patients. With PET/CT, the actual extent of the tumor can be precisely determined even with PSA values of ≤0.5 ng/ml. Thus, the treatment concept can be improved and individualized. This may have a positive impact on progression free survival. Our results warrant further prospective studies.

Lead-time bias does not falsify the efficacy of early salvage radiotherapy for recurrent prostate cancer

BACKGROUND

In prostate cancer (PCa) recurring after radical prostatectomy (RP), salvage radiotherapy (SRT) is recommended to be given at PSA <0.5 ng/ml. It has been speculated, that the advantage from early SRT is mainly caused by lead-time bias: Calculating from time of SRT, earlier treatment would per-se result in longer time to event/censoring compared with later treatment, but not extend the interval from RP to post-SRT failure.

METHODS

In 603 consecutive PCa patients receiving SRT between 1997 and 2017, we compared outcomes, calculating from time of irradiation vs. time of surgery.

RESULTS

In multivariable analysis, tumor stage pT3-4, pathological Gleason score GS ≤6 vs. GS 7 vs. GS ≥8, post-RP PSA persistence (nadir ≥0.1 ng/ml), and the pre-SRT PSA (continuous or with cutoff 0.4 ng/ml) were significant risk-factors for biochemical progression (BCR) and progression-free survival (PFS) post-SRT and post-RP. A pre-SRT PSA <0.4 ng/ml was a significant discriminator for Kaplan-Meier rates of BCR and PFS. The Cox model for overall survival (OS) included age at RP (continuous), pT2 vs. pT3-4, and pre-SRT PSA (continuous) as significant predictors. However, no significant cutoff for the pre-SRT PSA could be identified to differentiate Kaplan-Meier estimates of OS, possibly because there were too few events, as 88% of the patients were still alive at last follow-up.

CONCLUSIONS

The pre-SRT PSA has a significant impact on BCR, PFS and potentially on OS, calculating either from RP or from SRT to event/censoring, respectively. This contradicts the hypothesis of lead-time bias falsifying the advantage from early SRT.

Interobserver variability, detection rate, and lesion patterns of 68Ga-PSMA-11-PET/CT in early-stage biochemical recurrence of prostate cancer after radical prostatectomy

PURPOSE

⁶⁸Ga-PSMA-11-PET/CT is increasingly used in early-stage biochemical recurrence of prostate cancer to detect potential lesions for an individualized radiotherapy concept. However, subtle findings especially concerning small local recurrences can still be challenging to interpret and are prone to variability between different readers. Thus, we analyzed interobserver variability, detection rate, and lesion patterns systematically in a homogeneous patient population with low-level biochemical recurrence.

METHODS

We analyzed ⁶⁸Ga-PSMA-11-PET/CTs in 116 patients with status post-prostatectomy and PSA levels up to 0.6 ng/ml. None of them received ADT or radiotherapy beforehand. Images were interpreted and blinded by two nuclear medicine physicians (R1 and R2). Findings were rated using a 5-point scale concerning local recurrence, lymph nodes, bone lesions, and other findings (1: definitely benign, 2: probably benign, 3: equivocal, 4: probably malignant, 5: definitely malignant). In findings with substantial discrepancies of 2 or more categories and/or potentially leading to differences in further patient management, a consensus reading was done with a third reader (R3). Interobserver agreement was measured by Cohens Kappa analysis after sub-categorizing our classification system to benign (1 + 2), equivocal (3), and malignant (4 + 5). Time course of PSA levels after salvage treatment of patients rated as positive (4 + 5) was analyzed.

RESULTS

The overall detection rate (categories 4 and 5) was 50% (R1/R2, 49%/51%) and in the PSA subgroups 0-0.2 ng/ml, 0.21-0.3 ng/ml, and 0.31-0.6 ng/ml 24%/27%, 57%/57%, and 65%/68%, respectively. Local recurrence was the most common lesion manifestation followed by lymphatic and bone metastases. The overall agreement in the Cohens Kappa analysis was 0.74 between R1 and R2. For local, lymphatic, and bone sites, the agreement was 0.76, 0.73, and 0.58, respectively. PSA levels of PSMA PET/CT-positive patients after salvage treatment decreased in 75% (27/36) and increased in 25% (9/36). A decrease of PSA, although more frequent in patients with imaging suggesting only local tumor recurrence (86%, 18/21), was also observed in 67% (10/15) of patients with findings of metastatic disease.

CONCLUSIONS

In a highly homogeneous group of prostate cancer patients with early-stage biochemical recurrence after radical prostatectomy, we could show that ⁶⁸Ga-PSMA-11-PET/CT has a good detection rate of 50% which is in accordance with literature, with clinically relevant findings even in patients with PSA < 0.21 ng/ml. The interobserver variability is low, particularly concerning assessment of local recurrences and lymph nodes. Therefore, PSMA-PET/CT is a robust diagnostic modality in this patient group for therapy planning.

Defining the Most Informative Intermediate Clinical Endpoints for Patients Treated with Salvage Radiotherapy for Prostate-specific Antigen Rise After Radical Prostatectomy

Intermediate clinical endpoints (ICEs) might aid in trial design and potentially expedite study results. However, little is known about the most informative ICE for patients receiving salvage radiation therapy (sRT) after radical prostatectomy. To investigate the most informative ICE for patients receiving sRT, we used a multi-institutional database encompassing patients treated at eight tertiary centers. Overall, 1301 men with node-negative disease who had not received any form of androgen deprivation therapy were identified. Associations of biochemical (BCR) and clinical recurrence (CR) within 1, 3, 5, and 7yr after surgery with the risk of overall mortality were evaluated using multivariable Cox regression analyses fitted at the landmark points of 1, 3, 5, and 7yr after sRT. The discriminative ability of each model for predicting overall survival (OS) was assessed using Harrell's c index. Median follow-up for survivors was 5.6yr (interquartile range 2.0-8.8). On multivariable analysis, progression to CR within 3yr from sRT (hazard ratio 4.19, 95% confidence interval 1.44-11.2; p= 0.008) was the most informative ICE for predicting OS (c index 0.78) compared to CR within 1, 5, and 7yr (c index 0.72, 0.75, and 0.71). In conclusion, progression to CR within 3yr after sRT, irrespective of the time of surgery, was the most informative ICE for prediction of OS. Our study is hypothesis-generating. If these results are confirmed in future prospective studies and surrogacy is met, this information could be applied for study design and could potentially expedite earlier release of results from ongoing randomized controlled trials. PATIENT SUMMARY: Clinical recurrence of prostate cancer within 3yr after salvage radiation therapy, irrespective of the time of radical prostatectomy, represents the most informative intermediate clinical endpoint for the prediction of overall survival. This information could be applied in the design of future studies and could potentially expedite earlier release of results from ongoing randomized controlled trials.

The impact of prostate-specific antigen persistence after radical prostatectomy on the efficacy of salvage radiotherapy in patients with primary N0 prostate cancer

OBJECTIVE

To test whether salvage radiotherapy (SRT) in patients with lymph node negative (N0) prostate cancer is equally effective with persistent prostate-specific antigen (PSA) and PSA rising from the undetectable range (<0.1 ng/mL) after radical prostatectomy (RP).

PATIENTS AND METHODS

We assessed post-SRT PSA progression-free survival (PFS) in 555 patients with prostate cancer. The entire cohort was compared with a risk-adjusted subgroup of 112 patient pairs with matching pre-RP PSA level (±10 ng/mL), Gleason score (≤6 vs 7 vs ≥8), and pre-SRT PSA level (±0.5 ng/mL).

RESULTS

The median follow-up was 6.1 years. After RP, PSA was undetectable in 422 and persistent in 133 patients. PSA persistence and a pre-SRT PSA level of ≥0.5 ng/mL reduced Kaplan-Meier rates of PFS significantly. In multivariate analysis of the entire cohort and after risk adjustment, the pre-SRT PSA level but not post-RP PSA persistence was a significant parameter. In the matched cohort's subgroup with early SRT at a PSA level of <0.5 ng/mL, a trend towards a worse outcome with post-RP PSA persistence was observed. Delayed SRT with a PSA level ≥0.5 ng/mL led to a PFS of <30%, irrespective of the post-RP PSA level.

CONCLUSION

In patients with N0 prostate cancer with post-RP PSA persistence, early SRT at a PSA level <0.5 ng/mL seems to be less effective than in recurrent patients with post-RP undetectable PSA. They might benefit from intensified therapy, but larger case numbers are required to substantiate this conclusion. In patients with a PSA level ≥0.5 ng/mL and higher-risk features associated with post-RP PSA persistence, SRT alone is unlikely to provide long-term freedom from further progression.

Effect of early salvage radiotherapy at PSA < 0.5 ng/ml and impact of post-SRT PSA nadir in post-prostatectomy recurrent prostate cancer

BACKGROUND

For patients with recurrent prostate cancer after radical prostatectomy (RP), salvage radiotherapy (SRT) offers a second chance of cure. European guidelines (EAU) recommend SRT at a PSA < 0.5 ng/ml. We analyze the efficacy of SRT given according to this recommendation and investigate the predictive power of the post-SRT PSA nadir.

METHODS

Between 1998 and 2013, 301 patients of two university hospitals received SRT at a PSA < 0.5 ng/ml (median 0.192 ng/ml, IQR 0.110-0.300). Patients, who previously received androgen deprivation therapy, were excluded. All patients had 3D-conformal RT or intensity-modulated radiotherapy (IMRT, n = 59) (median 66.6 Gy). The median follow-up was 5.9 years. Progression and overall survival were the endpoints.

RESULTS

After SRT, 252 patients re-achieved an undetectable PSA. In univariate analysis, pre-RP PSA ≥ 10 ng/ml, pT3-4, Gleason score (GS) 7-10 or 8-10, negative surgical margins, post-RP PSA ≥ 0.1 ng/ml, pre-SRT PSA ≥ 0.2 ng/ml and post-SRT PSA nadir ≥ 0.1 ng/ml correlated unfavorably with post-SRT progression. In a multivariable Cox model, pT3-4, GS 7-10, negative margins and a pre-SRT PSA ≥ 0.2 ng/ml were significant risk factors. If the post-SRT PSA was added to the analysis, it dominated the outcome (HR = 9.00). Of the patients with a pre-SRT PSA < 0.2 ng/ml, only 9% failed re-achieving an undetectable PSA. Overall survival in these patients was 98% after 5.9 years compared to 91% in patients with higher pre-SRT PSA (Logrank p = 0.004).

CONCLUSIONS

SRT at a PSA < 0.2 ng/ml correlates significantly with achieving a post-SRT undetectable PSA (<0.1 ng/ml) and subsequently with improved freedom from progression. Given these overall favorable outcomes, whether additional androgen deprivation therapy is required for these men requires further study.

Prostate-specific antigen after salvage radiotherapy for postprostatectomy biochemical recurrence predicts long-term outcome including overall survival

BACKGROUND

For patients with recurrent prostate cancer after radical prostatectomy (RP), salvage radiotherapy (SRT) is a second chance of cure. However, depending on risk factors, 40-70% of the patients experience further progression. With a focus on the pre- and post-SRT serum level of the prostate-specific antigen (PSA), we assessed the determinants of the long-term outcome after SRT.

PATIENT AND METHODS

Between 1997 and 2011, 464 patients received 3D-conformal SRT with median 66.6 Gy. The median PSA level before SRT was 0.31 ng/ml. In our retrospective analysis, post-SRT progression was defined as either a rising PSA >0.2 ng/ml above the nadir, or the application of anti-androgens or clinical recurrence. A PSA <0.1 ng/ml was termed undetectable. We analyzed the data with the Kaplan-Meier method (Logrank test) and multivariable Cox regression.

RESULTS

The median follow-up was 5.9 years. Overall, 178 patients had recurrence, 13 developed distant metastases and 30 died. Univariate, a pre-RP PSA <10 ng/ml, pathological stage pT <3, Gleason score <8, positive surgical margins, a pre-SRT PSA <0.2 ng/ml and a post-SRT PSA nadir <0.1 ng/ml correlated with fewer and later second recurrences. In a multivariable Cox model, pT, Gleason score, margin status and pre-SRT PSA were significant covariates of progression. If the post-SRT PSA response was included in the regression analysis, then a nadir ≥0.1 ng/ml was the strongest risk factor. Initiating SRT at a PSA <0.2 ng/ml correlated with a post-SRT PSA <0.1 ng/ml. Men who achieved an undetectable post-SRT PSA nadir also had lower rates of metastases and a better overall survival. However, there were too few events for Cox regression analysis of these two endpoints.

CONCLUSIONS

Early SRT at a PSA <0.2 ng/ml correlates with re-achieving an undetectable PSA, which predicts improved freedom from progression and metastases and better overall survival.

Defining biochemical recurrence after radical prostatectomy and timing of early salvage radiotherapy : Informing the debate

BACKGROUND

The optimal prostate-specific antigen (PSA) level after radical prostatectomy (RP) for defining biochemical recurrence and initiating salvage radiation therapy (SRT) is still debatable. Whereas adjuvant or extremely early SRT irrespective of PSA progression might be overtreatment for some patients, SRT at PSA >0.2 ng/ml might be undertreatment for others. The current study addresses the optimal timing of radiation therapy after RP.

PATIENTS AND METHODS

Cohort 1 comprised 293 men with PSA 0.1-0.19 ng/ml after RP. Cohort 2 comprised 198 men with SRT. PSA progression and metastases were assessed in cohort 1. In cohort 2, we compared freedom from progression according to pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml). Multivariable Cox regression analyses predicted progression after SRT.

RESULTS

In cohort 1, 281 (95.9%) men had further PSA progression ≥0.2 ng/ml and 27 (9.2%) men developed metastases within a median follow-up of 74.3 months. In cohort 2, we recorded improved freedom from progression according to lower pre-SRT PSA (0.03-0.19 vs. 0.2-0.499 ng/ml: 69 vs. 53%; log-rank p = 0.051). Patients with higher pre-SRT PSA ≥0.2 ng/ml were at a higher risk of progression after SRT (hazard ratio: 1.8; p < 0.05).

CONCLUSION

The vast majority of patients with PSA ≥0.1 ng/ml after RP will progress to PSA ≥0.2 ng/ml. Additionally, early administration of SRT at post-RP PSA level <0.2 ng/ml might improve freedom from progression. Consequently, we suggest a PSA threshold of 0.1 ng/ml to define biochemical recurrence after RP.

Predicting Heart Dose in Breast Cancer Patients Who Received 3D Conformal Radiation Therapy

Cardiac late effects are a major health concern for long-term survivors after radiotherapy for breast cancer. Large cohort studies to better understand the exact dose-response relationship require individual estimates of radiation dose to the heart. To predict individual cardiac dose from information that is typically available for all members of a retrospective epidemiological cohort study, 774 female breast cancer patients treated with megavoltage tangential field radiotherapy in 1998-2008 were examined. All dose distributions were calculated using Eclipse with the anisotropic analytical algorithm (AAA) for photon fields and the electron Monte Carlo algorithm for electron boost fields. Based on individual dose volume histograms, the authors calculated absorbed dose in the complete heart as well as in six functional substructures. Statistical models were developed to predict absorbed dose using only covariate information from patients' clinical records on tumor location, patient anatomy and radiotherapy prescription. The out-of-sample prediction error for mean heart dose was 54% (coefficient of variation). The prediction error in functional substructures ranged from 49-68% for mean dose and from 52-86% for extreme dose. The authors conclude that based on a patient sample with exact heart dosimetry, it is possible to use clinical information alone to predict absorbed heart dose in the remaining cohort with a quantified error suitable for dose-response analyses of cardiac late effects.

[Radiotherapy in node-positive prostate cancer]

BACKGROUND

There are numerous randomized trials to guide the management of patients with localized (and metastatic) prostate cancer, but only a few (mostly retrospective) studies have specifically addressed node-positive patients. Therefore, there is uncertainty regarding optimal treatment in this situation. Current guidelines recommend long-term androgen deprivation therapy (ADT) alone or radiotherapy plus long-term ADT as treatment options.

OBJECTIVES

This overview summarizes the existing literature on the use of radiotherapy for node-positive prostate cancer as definitive treatment and as adjuvant or salvage therapy after radical prostatectomy. In this context, we also discuss several PET tracers in the imaging evaluation of patients with biochemical recurrence of prostate cancer after radical prostatectomy. As for definitive treatment, retrospective studies suggest that ADT plus radiotherapy improves overall survival compared with ADT alone. These studies also consistently demonstrated that many patients with node-positive prostate cancer can achieve long-term survival - and are likely curable - with aggressive therapy.

RESULTS

The beneficial impact of adjuvant radiotherapy on survival in patients with pN1 prostate cancer seems to be highly influenced by tumor characteristics. Men with ≤ 2 positive lymph nodes in the presence of intermediate- to high-grade disease, or positive margins, and those with 3 or 4 positive lymph nodes are the ideal candidates for adjuvant radiotherapy (plus long-term ADT) after surgery.

CONCLUSION

There is a need for randomized trials to further examine the potential role of radiotherapy as either definitive or adjuvant treatment, for patients with node-positive prostate cancer.

Porous MgF2-over-gold nanoparticles (MON) as plasmonic substrate for analytical applications

Porous MgF₂-over-nanoparticles (MON) surfaces are fabricated from immobilized gold nanoparticles of different sizes on a glass surface by coating them with a magnesium fluoride layer, resulting in favorable optical and mechanical properties.

Redefining postprostatectomy biochemical progression: The significance of a PSA cutoff below 0.2 ng/ml—Results from two retrospective series with and without salvage radiotherapy

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Background: Biochemical recurrence (BCR) after radical prostatectomy (RP) is usually defined at a PSA >0.2 ng/ml. BCR may precede clinical progression by years. Though salvage radiotherapy (SRT) is recommend to be initiated at PSA <0.5 ng/ml, its efficiency at PSA <0.2 ng/ml is not well documented. Methods: We relied on two independent post-RP cohorts. Cohort 1 (n=311, Hamburg) comprised men whose post-RP PSA levels had risen to 0.1-0.2 ng/ml. Further biochemical and clinical progression were recorded during follow-up. Cohort 2 (n=198, Berlin) were patients with BCR who received SRT (66/72 Gy) at a PSA <0.5 ng/ml. The median follow-up was 6.9 years. Post-SRT progression and overall survival were addressed by Kaplan-Meier analysis and Cox regression modelling. Results: In cohort 1, 299 (96%) men experienced further PSA progression (>0.2 ng/ml) within a median time of 7 months. Subsequent PSA rise to >0.3, >0.4, and >0.6 ng/ml was recorded in 174 (58%), 123 (41%), and 24 (8%) men, respectively. Twenty-four (8%) men developed metastases. In cohort 2, 112 men received SRT at PSA between 0.03 and 0.2 ng/ml, and 86 at 0.2-0.499 ng/ml. The latter group, had a poorer 10-years BCR-free Kaplan-Meier rate, 43% vs. 66% (p=0.051). Together with pT<3, Gleason Score <7, and post-RP PSA <0.03 ng/ml, SRT at PSA <0.2 ng/ml was an independent favorable predictor of freedom from BCR (OR=0.60, p<0.05). Ultimately, 14 patients died. However, overall survival did not significantly correlate with the pre-SRT PSA. Conclusions: The vast majority of patients with a PSA >0.1 ng/ml after RP will subsequently progress to PSA >0.2 ng/ml. Improved progression free survival can be achieved, if SRT is administered at a PSA <0.2 ng/ml. Therefore the contemporary PSA threshold for defining BCR after RP needs to be reconsidered and early sRT should be contemplated on a individual basis for optimizing oncological outcomes.

Prognostic significance of the PSA nadir after salvage radiotherapy following radical prostatectomy in prostate cancer

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Background: Salvage radiotherapy (SRT) is a curative approach in recurrent prostate cancer after radical prostatectomy. The outcome depends on various parameters. We report the long term results of SRT with special respect to the course of PSA after SRT. Methods: Between 1997 and 2007, 307 patients received SRT with 66.6 (N=240) or 70.2 Gy (N=67) using CT-based 3D planning. The median pre-SRT PSA was 0.297 ng/ml. Post-SRT progression was defined as either PSA rising >0.2 ng/ml above nadir, or hormone treatment, or clinical recurrence. Data were analyzed with the Kaplan-Meier method (Logrank-test) and with multivariate Cox regression. Results: Patients were followed up for median 7.2 (max. 14.4) years. Recurrence occurred in median 9.4 months post-RP. In 112 patients, SRT was administered before their PSA reached 0.2 ng/ml, 195 men were above that threshold. After SRT, 222 patients achieved a PSA nadir <0.1 ng/ml, 85 retained higher values. SRT given at a PSA <0.2 ng/ml correlated with achieving a post-SRT nadir <0.1 ng/ml (p<0.0001) and with improved freedom from progression (p=0.0133). Men with a post-SRT nadir <0.1 ng/ml (undetectable range) had significantly less recurrences (p<0.0001) and a better overall survival (p=0.0248). In multivariate analysis of pre-SRT parameters, pT≥3, Gleason Score ≥7, a post-RP PSA nadir ≥0.1 ng/ml and pre-SRT PSA ≥0.2 ng/ml increased the risk of progression. If failing the post-SRT nadir <0.1 ng/ml was included in the model, then this was the strongest risk factor (hazard ratio 7.93). Conclusions: Our data suggest early salvage RT at a PSA level below 0.2 ng/ml to be a favorable treatment option for post-RP PSA recurrence. It increases the chances of achieving a post-SRT PSA-nadir <0.1 ng/ml, which is associated with an improved outcome in terms of PSA progression and overall survival.

[Adjuvant vs. salvage radiotherapy after radical prostatectomy]

BACKGROUND

After radical prostatectomy (RP) the pre-RP PSA value, Gleason Score, pT-stage, state of seminal vesicles and state of surgical margins are key indicators for the risk of biochemical or clinical recurrence. Depending on the tumour stage, 50-70% of the high-risk patients suffer biochemical progression. The treatment options in these circumstances are adjuvant radiotherapy (ART, for an undetectable PSA) or salvage radiotherapy (SRT, for persisting PSA or PSA re-rising above detection limits). Data from ongoing randomised trials that compare ART and SRT directly have not yet been published.

METHOD

A search in PubMed for ART and SRT after RP for prostate cancer was undertaken to compare the results of the 2 treatment approaches.

RESULTS

3 randomised phase-III studies have shown a nearly 20% advantage in terms of biochemical progression after ART (60-64 Gy) compared with a wait-and-see strategy. The largest effect was seen in patients with pT3 prostate cancer with positive surgical margins. According to the German S3-guidelines, SRT with at least 66 Gy can be offered to patients with a post-RP persisting PSA or a PSA re-rising above detection limits. 30-70% of these patients re-achieve an undetectable PSA. Thus, there is a second option for curative treatment. Due to the lower total dose, ART seems to be connected with fewer late complications than SRT. SRT, on the other hand, reduces the risk of potential interactions with post-RP complications and of overtreatment. There is a controversial discussion about the inclusion of the pelvic lymph nodes in the treatment volume, the additional application of anti-androgens and the total dose of both ART and SRT.

CONCLUSIONS

The comparison of SRT after PSA progression with ART at a PSA below the detection limits cannot yet be judged conclusively. The indication for ART depends on the associated risk factors. However, regarding freedom from biochemical progression, it is backed up by high level evidence. If SRT is applied for biochemical progression, then it should be initiated early, i. e., at the lowest PSA possible.

Modelling the growth of plants with a uniform growth logistics

BACKGROUND AND AIMS

The increment model has previously been used to describe the growth of plants in general. Here, we examine how the same logistics enables the development of different superstructures.

METHODS

Data from the literature are analyzed with the increment model. Increments are growth-invariant molecular clusters, treated as heuristic particles. This approach formulates the law of mass action for multi-component systems, describing the general properties of superstructures which are optimized via relaxation processes.

RESULTS

The daily growth patterns of hypocotyls can be reproduced implying predetermined growth invariant model parameters. In various species, the coordinated formation and death of fine roots are modeled successfully. Their biphasic annual growth follows distinct morphological programs but both use the same logistics. In tropical forests, distributions of the diameter in breast height of trees of different species adhere to the same pattern. Beyond structural fluctuations, competition and cooperation within and between the species may drive optimization.

CONCLUSION

All superstructures of plants examined so far could be reproduced with our approach. With genetically encoded growth-invariant model parameters (interaction with the environment included) perfect morphological development runs embedded in the uniform logistics of the increment model.

Adjuvant radiotherapy versus wait-and-see after radical prostatectomy: 10-year follow-up of the ARO 96-02/AUO AP 09/95 trial

BACKGROUND

Local failure after radical prostatectomy (RP) is common in patients with cancer extending beyond the capsule. Three prospectively randomized trials demonstrated an advantage for adjuvant radiotherapy (ART) compared with a wait-and-see (WS) policy.

OBJECTIVE

To determine the efficiency of ART after a 10-yr follow-up in the ARO 96-02 study.

DESIGN, SETTING, AND PARTICIPANTS

After RP, 388 patients with pT3 pN0 prostate cancer (PCa) were randomized to WS or three-dimensional conformal ART with 60 Gy. The present analysis focuses on intent-to-treat patients who achieved an undetectable prostate-specific antigen after RP (ITT2 population)--that is, 159 WS plus 148 ART men.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary end point of the study was progression-free survival (PFS) (events: biochemical recurrence, clinical recurrence, or death). Outcomes were compared by log-rank test. Cox regression analysis served to identify variables influencing the course of disease.

RESULTS AND LIMITATIONS

The median follow-up was 111 mo for ART and 113 mo for WS. At 10 yr, PFS was 56% for ART and 35% for WS (p<0.0001). In pT3b and R1 patients, the rates for WS even dropped to 28% and 27%, respectively. Of all 307 ITT2 patients, 15 died from PCa, and 28 died for other or unknown reasons. Neither metastasis-free survival nor overall survival was significantly improved by ART. However, the study was underpowered for these end points. The worst late sequelae in the ART cohort were one grade 3 and three grade 2 cases of bladder toxicity and two grade 2 cases of rectum toxicity. No grade 4 events occurred.

CONCLUSIONS

Compared with WS, ART reduced the risk of (biochemical) progression with a hazard ratio of 0.51 in pT3 PCa. With only one grade 3 case of late toxicity, ART was safe.

PATIENT SUMMARY

Precautionary radiotherapy counteracts relapse after surgery for prostate cancer with specific risk factors.

Post-prostatectomy persisting PSA: Correlation with disease progression and survival in pT3 prostate cancer patients of the ARO 96-02 randomized phase III clinical trial—10 years' follow-up

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Background: In the ARO 96-02 trial, patients with pT3 prostate cancer were randomly assigned before achieving an undetectable prostate-specific antigen (PSA) after radical prostatectomy (RP) to receive a wait and see policy (arm A) or adjuvant radiotherapy (RT) (arm B). If the undetectable PSA level was not achieved, patients were excluded by protocol and received RT with 66 Gy (arm C). Methods: Three hundred eighty eight patients with pT3-4 pN0 prostate cancer with positive or negative surgical margins were recruited; 78 retained a detectable PSA (median 0.6 ng/mL, range 0.05-5.6 ng/mL) after RP; 74 of them were irradiated with 66 Gy to the prostatic fossa. Radiotherapy was applied in median 86 days post-RP. Results: Compared to patients in arm A and B, the patients with persisting PSA after RP had higher preoperative PSA values (p<0.0001), higher tumor stages (p=0.0057), higher grades (more G3 tumors), higher Gleason scores (p=0.0013) and more positive surgical margins (p=0.033). For the 74 patients, the 10 years clinical relapse-free survival rate was 63%. Forty three men had hormonal therapy, 12 developed distant metastases; 23 patients died. Compared to patients who did achieve an undetectable PSA (arms A+B), arm-C patients fared significantly worse with a 10 year overall survival of 68% versus 84% (p=0.0019). The rate of developing distant metastases within 10 year post-RP was 2.5 fold higher (14.6 vs. 5.8%) for men with a persisting PSA compared with the patients in arm A (p=0.0079). Metastasis-free survival after 10 years was 67% in arm C versus 81% in arm B (p=0.01). Conclusions: A persisting PSA after prostatectomy seems to be an important prognosticator of clinical progression for pT3 tumors which should then prompt aggressive treatment. It correlates with a higher rate of distant metastases and with worse overall survival. The results underline the significance of achieving an undetectable PSA after radical prostatectomy.