Adding intensity-modulated radiotherapy to the pelvis does not worsen the adverse effect profiles compared to limited field radiotherapy in men with prostate cancer at 12-month follow-up

Germline variants disrupting microRNAs predict long-term genitourinary toxicity after prostate cancer radiation

BACKGROUND AND PURPOSE

The purpose of this study was to determine whether single nucleotide polymorphisms disrupting microRNA targets (mirSNPs) can serve as predictive biomarkers for toxicity after radiotherapy for prostate cancer and whether these may be differentially predictive depending on radiation fractionation.

MATERIALS AND METHODS

We identified 201 men treated with two forms of definitive radiotherapy for prostate cancer at two institutions: 108 men received conventionally-fractionated radiotherapy (CF-RT) and 93 received stereotactic body radiotherapy (SBRT). Germline DNA was evaluated for the presence of functional mirSNPs. Random forest, boosted trees and elastic net models were developed to predict late grade ≥2 GU toxicity by the RTOG scale.

RESULTS

The crude incidence of late grade ≥2 GU toxicity was 16% after CF-RT and 15% after SBRT. An elastic net model based on 22 mirSNPs differentiated CF-RT patients at high risk (71.5%) versus low risk (7.5%) for toxicity, with an area under the curve (AUC) values of 0.76-0.81. An elastic net model based on 32 mirSNPs differentiated SBRT patients at high risk (64.7%) versus low risk (3.9%) for toxicity, with an area under the curve (AUC) values of 0.81-0.87. These models were specific to treatment type delivered. Prospective studies are warranted to further validate these results.

CONCLUSION

Predictive models using germline mirSNPs have high accuracy for predicting late grade ≥2 GU toxicity after either CF-RT or SBRT, and are unique for each treatment, suggesting that germline predictors of late radiation sensitivity are fractionation-dependent. Prospective studies are warranted to further validate these results.

Toxicity of Pelvic Lymph Node Irradiation With Intensity Modulated Radiation Therapy for High-Risk and Locally Advanced Prostate Cancer: A National Population-Based Study Using Patient-Reported Outcomes

PURPOSE

Little is known about the toxicity of additional pelvic lymph node irradiation in men receiving intensity modulated radiation therapy (IMRT) for prostate cancer. The aim of this study was to compare patient-reported outcomes after IMRT to the prostate only (PO-IMRT) versus the prostate and pelvic lymph nodes (PPLN-IMRT).

METHODS AND MATERIALS

Patients who received a diagnosis of high-risk or locally advanced prostate cancer in the English National Health Service between April 2014 and September 2016 who were treated with IMRT were mailed a questionnaire at least 18 months after diagnosis. Patient-reported urinary, sexual, bowel, and hormonal functional domains on a scale from 0 to 100, with higher scores indicating better outcomes, and generic health-related quality of life were collected using the Expanded Prostate Cancer Index Composite 26-item version and EQ-5D-5L. We used linear regression to compare PPLN-IMRT versus PO-IMRT with adjustment for patient, tumor, and treatment characteristics.

RESULTS

Of the 7017 men who received a questionnaire, 5468 (77.9%) responded; 4196 (76.7%) had received PO-IMRT and 1272 (23.3%) PPLN-IMRT. Adjusted differences in the Expanded Prostate Cancer Index Composite 26-item version domain scores were smaller than 1 (P always >.2), except for sexual function, with men who had PPNL-IMRT reporting a lower mean score (adjusted difference, 2.3; 95% confidence interval, 0.9-3.7; P = .002). This did not represent a clinically relevant difference. There was no significant difference in health-related quality of life (P = .5).

CONCLUSIONS

Additional pelvic lymph node irradiation does not lead to clinically meaningful increases in the toxicity of IMRT for prostate cancer according to patient-reported functional outcomes and health-related quality of life.

Treatment-Related Toxicity Using Prostate-Only Versus Prostate and Pelvic Lymph Node Intensity-Modulated Radiation Therapy: A National Population-Based Study

PURPOSE

There is a debate about the effectiveness and toxicity of pelvic lymph node (PLN) irradiation for the treatment of men with high-risk prostate cancer. This study compared the toxicity of intensity-modulated radiation therapy (IMRT) to the prostate and the pelvic lymph nodes (PPLN-IMRT) with prostate-only IMRT (PO-IMRT).

MATERIALS AND METHODS

Patients with high-risk localized or locally advanced prostate cancer treated with IMRT in the English National Health Service between 2010 and 2013 were identified by using data from the Cancer Registry, the National Radiotherapy Dataset, and Hospital Episode Statistics, an administrative database of all hospital admissions. Follow-up was available up to December 31, 2015. Validated indicators were used to identify patients with severe toxicity according to the presence of both a procedure code and diagnostic code in patient Hospital Episode Statistics records. A competing risks regression analysis, with adjustment for patient and tumor characteristics, estimated subdistribution hazard ratios (sHRs) by comparing GI and genitourinary (GU) complications for PPLN-IMRT versus PO-IMRT.

RESULTS

Three-year cumulative incidence in the PPLN-IMRT (n = 780) and PO-IMRT (n = 3,065) groups was 14% for both groups for GI toxicity, and 9% and 8% for GU toxicity, respectively. Patients receiving PPLN-IMRT and PO-IMRT had similar levels of severe GI (adjusted sHR, 1.00; 95% CI, 0.80 to 1.24; P = .97) and GU (adjusted sHR, 1.10; 95% CI, 0.83 to 1.46; P = .50) toxicity rates.

CONCLUSION

Including PLNs in radiation fields for high-risk or locally advanced prostate cancer is not associated with increased GI or GU toxicity at 3 years. Additional follow-up is required to answer questions about its impact on late GU toxicity. Results from ongoing trials will provide insight into the anticancer effectiveness of PLN irradiation.

Fatigue and other adverse effects in men treated by pelvic radiation and long-term androgen deprivation for locally advanced prostate cancer

Background We compared the development of adverse effects and psychosocial measures from baseline to 36-month follow-up in patients with prostate cancer (T1-3 M0) referred to our department for definitive radiotherapy encompassing the prostate and pelvic lymph nodes (RAD + IMRT) or radiotherapy to the prostatic gland only (RAD), applied with standard adjuvant androgen deprivation (AD) in all patients. Few studies have explored the impact of fatigue on patients' reported quality of life (QoL) after combined therapy for prostate cancer. Material and methods The 206 consecutive eligible men (RAD + IMRT = 64 and RAD = 142) completed the UCLA-PCI questionnaire for adverse effects at baseline, 12, 24, and 36 months. QoL, anxiety and depression, and fatigue were rated at the same time points. Between-group and longitudinal within-group changes at different time points were reported. At 36 months variables associated with fatigue were analyzed with regression analyses. Results Our main novel finding is the long-term high level of fatigue and high prevalence of chronic fatigue, affecting patients receiving radiotherapy combined with long-term AD. Except for urinary bother in the RAD + IMRT group all functions and the other bothers mean scores were significantly worse at 36 months compared to baseline. In multivariable analyses only physical QoL remained significantly associated with fatigue at 36-months follow-up. Conclusions Fatigue and impaired QoL in patients considered to curative irradiation with long-term AD should be addressed when counseling men to combined treatment.

No increase in toxicity of pelvic irradiation when intensity modulation is employed: clinical and dosimetric data of 208 patients treated with post-prostatectomy radiotherapy

OBJECTIVE

To compare the toxicity of image-guided intensity-modulated radiotherapy (IG-IMRT) to the pelvis or prostate bed (PB) only. To test the hypothesis that the potentially injurious effect of pelvic irradiation can be counterbalanced by reduced irradiated normal tissue volume using IG-IMRT.

METHODS

Between February 2010 and February 2012, 208 patients with prostate cancer were treated with adjuvant or salvage IG-IMRT to the PB (102 patients, Group PB) or the pelvis and prostate bed (P) (106 patients, Group P). The Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria were used to evaluate toxicity.

RESULTS

Median follow-up was 27 months. Toxicity G ≥ 2 in Group PB: in the bowel acute and late toxicities were 11.8% and 10%, respectively; urinary acute and late toxicities were 10.8% and 15%, respectively. Toxicity G ≥ 2 in Group P: in the bowel acute and late toxicities were both 13.2%; urinary acute and late toxicities were 13.2% and 15.1%, respectively. No statistical difference in acute or late toxicity between the groups was found (bowel: p = 0.23 and p = 0.89 for acute and late toxicity, respectively; urinary: p = 0.39 and p = 0.66 for acute and late toxicity, respectively). Of the clinical variables, only previous abdominal surgery was correlated with acute bowel toxicity. Dosimetric parameters that correlated with bowel toxicity were identified.

CONCLUSION

The toxicity rates were low and similar in both groups, suggesting that IG-IMRT allows for a safe post-operative irradiation of larger volumes. Further investigation is warranted to exclude bias owing to non-randomized character of the study.

ADVANCES IN KNOWLEDGE

Our report shows that modern radiotherapy technology and careful planning allow maintaining the toxicity of pelvic lymph node treatment at the acceptable level, as it is in the case of PB radiotherapy.

Comparison of dosimetric parameters and acute toxicity after whole-pelvic vs prostate-only volumetric-modulated arc therapy with daily image guidance for prostate cancer

OBJECTIVE

To compare dosimetric parameters and acute toxicity rates between whole-pelvic (WP) and prostate-only (PO) volumetric-modulated arc therapy (VMAT) in patients with localized prostate cancer.

METHODS

A total of 224 consecutive patients treated with definitive VMAT to 78 Gy in 39 fractions were enrolled. Of these, 119 patients received initial WP VMAT at 46.8 Gy in 26 fractions using a simultaneous integrated boost technique, and 105 patients received PO VMAT. Image-guided radiotherapy was practised with daily cone beam CT.

RESULTS

The mean rectal dose, the rectal volume receiving ≥30 Gy (V30Gy), rectal V50Gy, the mean bladder dose, bladder V30Gy and bladder V50Gy were significantly increased in the WP group (p < 0.05 each); however, the rectal V70Gy did not differ between groups (p = 0.101), and the bladder V70Gy was significantly lower in the WP group (p = 0.029). The WP group experienced a significantly increased frequency of acute grade 2 diarrhoea relative to the PO group (5.9% vs 0%; p = 0.015). No differences were seen between the WP and PO groups in terms of acute grade 2 proctitis (10.1% vs 6.7%; p = 0.360) and genitourinary (GU) toxicity (12.6% vs 10.5%; p = 0.620).

CONCLUSION

Despite larger rectum and bladder volumes at low- and medium-dose levels, WP VMAT resulted in no significant increase in acute proctitis or GU toxicity when compared with PO VMAT.

ADVANCES IN KNOWLEDGE

This study demonstrates that whole-pelvic radiotherapy has comparable acute toxicity to those observed with prostate-only radiotherapy when VMAT with daily image guidance is used.

Favorable outcomes in locally advanced and node positive prostate cancer patients treated with combined pelvic IMRT and androgen deprivation therapy

Background

The most appropriate treatment for men with prostate cancer and positive pelvic nodes, N+, is an area of active controversy. We report our 5-years outcomes in men with locally advanced prostate cancer (T1-T4N0-N1M0) treated with definitive radiotherapy encompassing the prostate and pelvic lymph nodes (intensity modulated radiotherapy, IMRT) and long-term androgen deprivation therapy (ADT).

Material and methods

Of the 138 consecutive eligible men all living patients have been followed up to almost 5 years. Survival endpoints for 5-year biochemical failure-free survival (BFFS), relapse-free survival (RFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were assessed by Kaplan-Meier analysis. Univariate and multivariate Cox regression proportional hazards models were constructed for all survival endpoints. The RTOG morbidity grading system for physician rated toxicity was applied.

Results

Patients with locally advanced T3-T4 tumors (35 %) and N1 (51 %) have favorable outcome when long-term ADT is combined with definitive radiotherapy encompassing pelvic lymph nodes. The 5-year BFFS, RFS, PCSS and OS were 71.4, 76.2, 94.5 and 89.0 %, respectively. High Gleason sum (9–10) had a strong independent prognostic impact on BFFS, RFS and OS (p = 0.001, <0.001, and 0.005 respectively). The duration of ADT (= > 28 months) showed a significant independent association with improved PCSS (p = 0.02) and OS (p = 0.001). Lymph node involvement was not associated with survival endpoints in the multivariate analysis. The radiotherapy induced toxicity seen in our study population was moderate with rare Grade 3 GI side effects and up to 11 % for Grade 3 GU consisting mainly of urgency and frequency.

Conclusion

Pelvic IMRT in combination with long-term ADT can achieve long-lasting disease control in men with N+ disease and unfavorable prognostic factors.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-015-0540-3) contains supplementary material, which is available to authorized users.