Single Dose vs. Fractionated High-Dose Rate Brachytherapy in Localized Prostate Cancer: Long Term Results

PURPOSE/OBJECTIVE(S)

To evaluate long-term freedom from biochemical relapse (FFbR) and overall survival (OS) after single-dose high-dose-rate brachytherapy (HDR-BT) compared with 2 or 3 fraction schedules.

MATERIALS/METHODS

HDR-BT, delivering 1 × 19 Gy or 1 × 20 Gy (A = 49), 2 × 13 Gy (B = 138) or 3 × 10.5 Gy (C = 106), was given to patients with intermediate or high-risk prostate cancer as their sole treatment. Patients were staged with pelvic MRI and isotope bone scan. Transperineal transrectal ultrasound guided implantation was followed by MRI based CTV definition based on GEC ESTRO guidelines. Biochemical relapse was assessed using the Phœnix definition (PSA nadir plus 2 µg/L). Patients were evaluated prospectively from 6 months after implant and bi-annually thereafter. Estimates of freedom from biochemical relapse, and overall survival (OS) were calculated using the Kaplan-Meier (K-M) method and the log-rank test to test for significance. Univariate and multivariate hazard ratios (HR) were obtained using Cox's proportional hazard model. For multivariate modelling a stepwise reduction method was used.

RESULTS

Median follow-up was 123, 116 and 120 months (p = 0.4), (A, B, C, respectively). Neo-adjuvant and adjuvant androgen deprivation treatment was given to 80% of all patients, median duration was 9 months for A and 6 months for B and C. K-M estimates of FFbR, at 8 and 10 years, were 67% and 64% (Group A), 78% and 72% (Group B), and 80% and 76% (Group C). Differences in FFbR between dose groups was not significant (p = 0.2). Similarly, no significant difference was seen in OS. Eight and 10-year estimates were 81% and 75% (A), 85% and 74% (B), and 90% and 83% (C); p = 0.5. Hazard Ratios for risk of biochemical recurrence were significant for ADT administration (yes/no) and overall risk category, in multivariate analyses. Only the latter was significant in univariate analysis for risk of death, Gleason risk (low, intermediate, high), MRI tumor stage risk and overall risk category were significant in univariate analyses. Only tumor stage and Gleason risk were significant in multivariate analyses.

CONCLUSION

Concerns around the efficacy of 19-20 Gy single dose HDR BT as monotherapy, based on early data, may have been unfounded. Long-term outcome data up to 10 years show no significant difference in PSA control and overall survival compared to 2 and 3 fractions of HDR-BT.

Acute Toxicity of Hypofractionated and Conventionally Fractionated (Chemo)Radiotherapy Regimens for Bladder Cancer: An Exploratory Analysis from the RAIDER Trial

AIMS

Adding concurrent (chemo)therapy to radiotherapy improves outcomes for muscle-invasive bladder cancer patients. A recent meta-analysis showed superior invasive locoregional disease control for a hypofractionated 55 Gy in 20 fractions schedule compared with 64 Gy in 32 fractions. In the RAIDER clinical trial, patients undergoing 20 or 32 fractions of radical radiotherapy were randomised (1:1:2) to standard radiotherapy or to standard-dose or escalated-dose adaptive radiotherapy. Neoadjuvant chemotherapy and concomitant therapy were permitted. We report exploratory analyses of acute toxicity by concomitant therapy-fractionation schedule combination.

MATERIALS AND METHODS

Participants had unifocal bladder urothelial carcinoma staged T2-T4a N0 M0. Acute toxicity was assessed (Common Terminology Criteria for Adverse Events) weekly during radiotherapy and at 10 weeks after the start of treatment. Within each fractionation cohort, non-randomised comparisons of the proportion of patients reporting treatment emergent grade 2 or worse genitourinary, gastrointestinal or other adverse events at any point in the acute period were carried out using Fisher's exact tests.

RESULTS

Between September 2015 and April 2020, 345 (163 receiving 20 fractions; 182 receiving 32 fractions) patients were recruited from 46 centres. The median age was 73 years; 49% received neoadjuvant chemotherapy; 71% received concomitant therapy, with 5-fluorouracil/mitomycin C most commonly used: 44/114 (39%) receiving 20 fractions; 94/130 (72%) receiving 32 fractions. The acute grade 2+ gastrointestinal toxicity rate was higher in those receiving concomitant therapy compared with radiotherapy alone in the 20-fraction cohort [54/111 (49%) versus 7/49 (14%), P < 0.001] but not in the 32-fraction cohort (P = 0.355). Grade 2+ gastrointestinal toxicity was highest for gemcitabine, with evidence of significant differences across therapies in the 32-fraction cohort (P = 0.006), with a similar pattern but no significant differences in the 20-fraction cohort (P = 0.099). There was no evidence of differences in grade 2+ genitourinary toxicity between concomitant therapies in either the 20- or 32-fraction cohorts.

CONCLUSION

Grade 2+ acute adverse events are common. The toxicity profile varied by type of concomitant therapy; the gastrointestinal toxicity rate seemed to be higher in patients receiving gemcitabine.

Clinical management and research priorities for high-risk prostate cancer in the UK: Meeting report of a multidisciplinary panel in conjunction with the NCRI Prostate Cancer Clinical Studies Localised Subgroup

The management of high-risk prostate cancer has become increasingly sophisticated, with refinements in radical therapy and the inclusion of adjuvant local and systemic therapies. Despite this, high-risk prostate cancer continues to have significant treatment failure rates, with progression to metastasis, castrate resistance and ultimately disease-specific death. In an effort to discuss the challenges in this field, the UK National Clinical Research Institute’s Prostate Cancer Clinical Studies localised subgroup convened a multidisciplinary national meeting in the autumn of 2014. The remit of the meeting was to debate and reach a consensus on the key clinical and research challenges in high-risk prostate cancer and to identify themes that the UK would be best placed to pursue to help improve outcomes. This report presents the outcome of those discussions and the key recommendations for future research in this highly heterogeneous disease entity.

Hypofractionated radiotherapy for localized prostate cancer using three-dimensional conformal radiotherapy technique: 3 years toxicity analysis

BACKGROUND

Hypofractionated radiotherapy in the radical treatment of localized prostate cancer has potential biological advantages relative to conventional fractionation. We report prospectively collected toxicity data from a cohort of patients treated with a 3D conformal technique (3DCRT).

MATERIALS AND METHODS

90 patients receiving curative intent hypofractionated radiotherapy with 57Gy in 19 daily fractions over 3.8 weeks were evaluated prospectively for the development of radiation related toxicity over a 3 year period.

RESULTS

All patients completed treatment. Maximal acute toxicity experienced was 58.6, 10 and 1.1% for grade 1, 2 and 3 genitourinary (GU) toxicity respectively and 75.6, 9 and 0% for gastrointestinal (GI) toxicity. For late toxicity the three year actuarial rates of grade 1, 2 and 3 GU and GI toxicity respectively were 47.3, 2.4 and 0%; and 40, 9.3 and 4.7%. There were no grade 4 or worse acute or late toxicities. 97.6% of evaluable patients remained free of biochemical failure 36 months post radiotherapy.

CONCLUSIONS

A 57Gy in 19 daily fraction radiotherapy schedule using 3D conformal radiotherapy for the definitive treatment of localized prostate cancer has acceptable early and late toxicity.

Functional Radiotherapy Targeting using Focused Dose Escalation

Various quantitative and semi-quantitative imaging biomarkers have been identified that may serve as valid surrogates for the risk of recurrence after radiotherapy. Tumour characteristics, such as hypoxia, vascularity, cellular proliferation and clonogen density, can be geographically mapped using biological imaging techniques. The potential gains in therapeutic ratio from the precision targeting of areas of intrinsic resistance makes focused dose escalation an exciting field of study. This overview will explore the issues surrounding biologically optimised radiotherapy, including its requirements, feasibility, technical considerations and potential applicability.

Using routinely collected data to stratify prostate cancer patients into phases of care in the United Kingdom: implications for resource allocation and the cancer survivorship programme

BACKGROUND

Prostate cancer is the most commonly diagnosed malignancy in British men. The increasing use of PSA screening test has resulted in many more patients being diagnosed with this condition. Advances in its treatment have improved the survival rate among these patients. By 2040, the prevalence of prostate cancer survivors is expected to reach 830 000. Many of them will require medical support for the management of their progressive disease or long-term toxicities from previous treatments. Successful implementation of the cancer survivorship programme among these patients depends on a good understanding of their demand on the health care system. The aim of this study is to segment the population of prostate cancer survivors into different needs groups and to quantify them with respect to their phase of care.

METHODS

Incidence, survival, prevalence and mortality data collected and reported by cancer registries across the United Kingdom have been used for the current study to provide indicative estimates as to the number of prostate cancer patients in each phase of the care pathway in a year.

RESULTS

The majority of prostate cancer patients are in the post-treatment monitoring phase. Around a fifth of the patients are either receiving treatment or in the recovery and readjustment phase having completed their treatment in the preceding year. Thirteen percent have not received any anticancer treatment, a further 12% (32 000) have developed metastatic disease and 4% are in the final stage of their lives.

CONCLUSION

On the basis of our estimates, patients undergoing post-treatment monitoring phase will constitute the biggest group among prostate cancer survivors. The pressure to provide adequate follow-up care to these patients will be a challenge. There is limited data available to definitively quantify the number of prostate cancer patients who follow different pathways of care, and we hope this study has highlighted the importance of collecting and reporting of such data to help future health care planning for these patients.

Imaging vascular function for early stage clinical trials using dynamic contrast-enhanced magnetic resonance imaging

Many therapeutic approaches to cancer affect the tumour vasculature, either indirectly or as a direct target. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important means of investigating this action, both pre-clinically and in early stage clinical trials. For such trials, it is essential that the measurement process (i.e. image acquisition and analysis) can be performed effectively and with consistency among contributing centres. As the technique continues to develop in order to provide potential improvements in sensitivity and physiological relevance, there is considerable scope for between-centre variation in techniques. A workshop was convened by the Imaging Committee of the Experimental Cancer Medicine Centres (ECMC) to review the current status of DCE-MRI and to provide recommendations on how the technique can best be used for early stage trials. This review and the consequent recommendations are summarised here. Key Points • Tumour vascular function is key to tumour development and treatment • Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) can assess tumour vascular function • Thus DCE-MRI with pharmacokinetic models can assess novel treatments • Many recent developments are advancing the accuracy of and information from DCE-MRI • Establishing common methodology across multiple centres is challenging and requires accepted guidelines.

Phase Ib trial of radiotherapy in combination with combretastatin-A4-phosphate in patients with non-small-cell lung cancer, prostate adenocarcinoma, and squamous cell carcinoma of the head and neck

BACKGROUND

The vascular disrupting agent combretastatin-A4-phosphate (CA4P) demonstrated antitumour activity in preclinical studies when combined with radiation.

METHODS

Patients with non-small-cell lung cancer (NSCLC), prostate adenocarcinoma, and squamous cell carcinoma of the head and neck (SCCHN) received 27 Gy in 6 fractions treating twice weekly over 3 weeks, 55 Gy in 20 fractions over 4 weeks, and 66 Gy in 33 fractions over 6 weeks respectively. CA4P was escalated from 50 mg/m2 to 63 mg/m2. CA4P exposure was further increased from one to three to six doses. Patients with SCCHN received cetuximab in addition.

RESULTS

Thirty-nine patients received 121 doses of CA4P. Dose-limiting toxic effects (DLTs) of reversible ataxia and oculomotor nerve palsy occurred in two patients with prostate cancer receiving weekly CA4P at 63 mg/m2. DLT of cardiac ischaemia occurred in two patients with SCCHN at a weekly dose of 50 mg/m2 in combination with cetuximab. Three patients developed grade 3 hypertension. Responses were seen in 7 of 18 patients with NSCLC. At 3 years, 3 of 18 patients with prostate cancer had prostate-specific antigen relapse.

CONCLUSIONS

Radiotherapy with CA4P appears well tolerated in most patients. The combination of CA4P, cetuximab, and radiotherapy needs further scrutiny before it can be recommended for clinical studies.

Functional imaging in clinical oncology: magnetic resonance imaging- and computerised tomography-based techniques

Over recent years, advances in cellular biology, molecular biology and genetics have led to a leap forward in our understanding of the biological basis of cancer. Some of these developments have revealed processes and targets that can be visualised and measured by new functional imaging techniques. The resulting images have the potential to improve cancer staging, prognosis and risk assessment, guide radiotherapy planning, direct treatment schedules, improve response assessment and provide new end points for clinical trials. In this review, we have outlined the magnetic resonance imaging- and computerised tomography-based functional techniques and provide evidence for their use.

Novel therapies in bladder cancer

The most effective non-surgical treatment for bladder cancer remains radiotherapy. The dramatic technical developments in radiotherapy have enabled greater accuracy and reliability based on three-dimensional imaging for both planning and verification. Particle therapy, in particular using protons, provides further opportunities for optimising radiation delivery and dose escalation. Novel fractionation schedules with both hyperfractionation and hypofractionation may have added benefits. Chemoradiation has been shown in one randomised-controlled trial to improve the results of radiotherapy alone, and requires further investigation. Hypoxia modification using carbogen and nicotinamide has also shown promising results in a phase II trial, and is now in phase III evaluation. Novel drug agents for bladder cancer are few, but the anti-EGFR agents and anti-angiogenic agents may have promise; the development of anti-apoptotic agents and antisense gene therapy may also become a component of the future multimodality management of this tumour.