10-Year efficacy and co-morbidity outcomes of a phase III randomised trial of conventional vs. hypofractionated high dose intensity modulated radiotherapy for prostate cancer (CHHiP; CRUK/06/016)

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Background: Five-year results from the CHHiP trial indicated that moderate hypofractionation of 60 Gray (Gy)/20 fractions (f) was non-inferior to 74Gy/37f (Lancet Oncology, 2016). Reporting of long-term efficacy and side effects is essential in a patient population that remain at risk of recurrence years after treatment. Here we report specific co-morbidity data collected at 10 years and an update of efficacy. Methods: Between October 2002 and June 2011, 3216 men with node negative T1b-T3a localised prostate cancer with risk of seminal vesical involvement ≤30% were randomised (1:1:1 ratio) to 74Gy/37f (control), 60Gy/20f or 57Gy/19f. Patients received 3-6 months of androgen deprivation prior to radiotherapy. The primary endpoint was time to biochemical failure (Phoenix consensus guidelines) or clinical failure (BCF). The non-inferiority design specified a critical hazard ratio (HR) of 1.208 for each hypofractionated schedule compared to control. Data on specific radiotherapy related co-morbidities were collected at 10-year follow-up and are presented as frequency and percentages. Analysis was by intention-to-treat; HRs quoted are unadjusted. Results: With a median follow up of 12.1 years, 10-year BCF-free rates (95% CI) were 74Gy: 76.0% (73.1%, 78.6%); 60Gy: 79.8% (77.1%, 82.3%) and 57Gy: 73.4% (70.5%, 76.1%). For 60Gy/20f, non-inferiority was confirmed: HR60=0.84 (90% CI 0.72, 0.97) with borderline significance for superiority (HR=0.84 (95% CI 0.70, 1.00). As in the primary analysis, for 57Gy/19f, non-inferiority could not be declared: HR57=1.13 (90% CI 0.98, 1.30). 10-year overall survival (95% CI) was 78.5% (75.9%, 81.0%), 82.9% (80.4%, 85.0%) and 79.9% (77.3%, 82.2%) in the 74Gy, 60Gy and 57Gy groups. Bone fractures were reported in 2% (15/700), 2% (19/771) and 3% (22/719) of patients in the 74Gy, 60Gy and 57Gy groups respectively at 10 years. The most common intervention reported was a sigmoidoscopy with 12% (79/681), 8% (60/739) and 9% (65/702) in the 74Gy, 60Gy and 57Gy groups respectively. Of those patients who underwent a sigmoidoscopy it was due to symptoms for 81% (63/78) 81% (48/59) and 85% (55/65) of patients in the 74Gy, 60Gy and 57Gy group respectively. Frequencies of all other pre-specified co-morbidities or related interventions (ureteric obstruction, bowel strictures, trans-urethral resection of prostate, urethrotomy, urethral dilatation or long term catheterisation or treatment of proctopathy with steroid, sucralfate, formalin, laser coagulation or rectal diversion) were <1% in all groups. Conclusions: With a median follow-up of 12 years, oncological outcomes following 60Gy/20f continue to be non-inferior to those with 74Gy/37f. Late co-morbidities were very low across all treatment groups. These data support the long-term safety of moderate hypofractionation. Clinical trial information: 97182923 .

Neurologically asymptomatic cerebral oligometastatic prostate carcinoma metastasis identified on [Ga]Ga-THP-PSMA PET/CT

Background

Brain metastases from prostate cancer are rare and usually only occur in the context of widespread systemic disease. This is the first case report of a solitary brain oligometastasis, in a neurologically intact prostate cancer patient with no other systemic disease, detected using [⁶⁸Ga]Ga-THP-PSMA PET/CT and only the second one using a PSMA-based radiopharmaceutical.

Case presentation

We report the case of a prostate cancer patient presenting 5 years after robot-assisted laparoscopic prostatectomy with biochemical recurrence, no neurological symptoms, and in the absence of metastatic lesions in the body on conventional imaging. A solitary cerebral metastasis was detected using [⁶⁸Ga]Ga-THP-PSMA PET/CT, surgically resected, leading to a drop in serum PSA and a good recovery.

Conclusion

In this case, [⁶⁸Ga]Ga-THP-PSMA PET/CT resulted in a major change in clinical management and avoided additional morbidity associated with delayed diagnosis and treatment. This report demonstrates the importance of considering the presence of metastatic disease outside the conventional locations of prostate cancer spread, as well as the importance of ensuring comprehensive [⁶⁸Ga]Ga-PSMA PET/CT coverage from vertex to upper thighs.

Eight-year outcomes of a phase III randomized trial of conventional versus hypofractionated high-dose intensity modulated radiotherapy for prostate cancer (CRUK/06/016): Update from the CHHiP Trial

325

Background: CHHiP is a non-inferiority trial to determine efficacy and safety of hypofractionated radiotherapy for localised prostate cancer (PCa). Five year results indicated that moderate hypofractionation of 60 Gray (Gy)/20 fractions (f) was non-inferior to 74Gy/37f (Lancet Oncology, 2016). Moderate hypofractionation is now an international standard of care but with patients remaining at risk of recurrence for many years, information on long-term outcomes is important. Here we report pre-planned analysis of 8 year outcomes. Methods: Between October 2002 and June 2011, 3216 men with node negative T1b-T3a localised PCa with risk of seminal vesical involvement ≤30% were randomised (1:1:1 ratio) to 74Gy/37f (control), 60Gy/20f or 57Gy/19f. Androgen deprivation began at least 3 months prior to radiotherapy (RT) and continued until end of RT. The primary endpoint was time to biochemical failure (Phoenix consensus guidelines) or clinical failure (BCF). The non-inferiority design specified a critical hazard ratio (HR) of 1.208 for each hypofractionated schedule compared to 74Gy/37f. Late toxicity was assessed at 5 years by RTOG and LENT-SOM scales. Analysis was by intention-to-treat. Results: With a median follow up of 9.2 years, 8 year BCF-free rates (95% CI) were 74Gy: 80.6% (77.9%, 83.0%); 60Gy: 83.7% (81.2%, 85.9%) and 57Gy: 78.5% (75.8%, 81.0%). For 60Gy/20f, non-inferiority was confirmed: HR60=0.84 (90% CI 0.71, 0.99). For 57Gy/19f, non-inferiority could not be declared: HR57=1.17 (90% CI 1.00, 1.37). Clinician assessments of late toxicity were similar across groups. At 5 years, RTOG grade≥2 (G2+) bowel toxicity was observed in 14/879 (1.6%), 18/908 (2.0%) and 17/904 (1.9%) of the 74Gy, 60Gy and 57Gy groups respectively. RTOG G2+ bladder toxicity was observed in 17/879 (1.9%), 14/908 (1.5%) and 17/904 (1.9%) of the 74Gy, 60Gy and 57Gy groups respectively. Conclusions: With BCF rates over 80%, long-term follow-up confirms that 60Gy/20f is non-inferior to 74Gy/37f. Late side effects were very low across all groups. These results support the continued use of 60Gy/20f as standard of care for men with localised PCa. Clinical trial information: 97182923.

Patterns of use of chemotherapy with radiotherapy in the treatment of muscle-invasive bladder cancer: Data from the RAIDER randomized trial of adaptive radiotherapy

503

Background: Level 1 evidence exists for the use of both neoadjuvant chemotherapy (NAC) and concomitant radiosensitization (CRS) to improve outcomes in patients receiving radical radiotherapy (RT) for muscle invasive bladder cancer, but uptake has been patchy. We report here the current patterns of usage in an ongoing trial of adaptive radiotherapy. Methods: RAIDER is an international randomized phase II trial recruiting patients with unifocal T2-T4a urothelial carcinoma of the bladder suitable for RT (ISCRTN:26779187). Patients are randomized in a 1:1:2 ratio to one of 3 arms: Standard whole bladder RT (control); Standard dose adaptive tumour focused RT; Dose escalated (DE) adaptive tumour boost RT. Standard dose patients are treated to either 64Gy/32f or 55Gy/20f and DE patients to 70Gy in 32f or 60Gy in 20f. Patients are encouraged to receive NAC and CRS. The primary endpoint is the rate of late toxicity 6-18 months post treatment in arm 3, with secondary endpoints of patient reported and disease related outcomes. Results: To August 2019, 285 patients had been recruited. Median age is 72 years (IQR 67-79). Stage of disease is T2 79%, T3 19%, T4 2%; 19% have hydronephrosis. Patients receiving NAC were more likely to be PS 0 at trial entry (70% v 45%). Variation in frequency of CRS use is seen across sites, with some offering to >90% of participants and some <50%. Data on NAC and CRS use is available for 249 patients recruited to date is shown in table. Conclusions: In this ongoing clinical trial the majority of patients are receiving NAC and/or CRS. However, uptake is not universal with ~30% of patients not receiving low dose CRS, including some who have received NAC. Clinical trial information: 26779187. [Table: see text]

Toxicity and Patient-Reported Outcomes of a Phase 2 Randomized Trial of Prostate and Pelvic Lymph Node Versus Prostate only Radiotherapy in Advanced Localised Prostate Cancer (PIVOTAL)

PURPOSE

To establish the toxicity profile of high-dose pelvic lymph node intensity-modulated radiation therapy (IMRT) and to assess whether it is safely deliverable at multiple centers.

METHODS AND MATERIALS

In this phase 2 noncomparative multicenter trial, 124 patients with locally advanced, high-risk prostate cancer were randomized between prostate-only IMRT (PO) (74 Gy/37 fractions) and prostate and pelvic lymph node IMRT (P&P; 74 Gy/37 fractions to prostate, 60 Gy/37 fractions to pelvis). The primary endpoint was acute lower gastrointestinal (GI) Radiation Therapy Oncology Group (RTOG) toxicity at week 18, aiming to exclude a grade 2 or greater (G2+) toxicity-free rate of 80% in the P&P group. Key secondary endpoints included patient-reported outcomes and late toxicity.

RESULTS

One hundred twenty-four participants were randomized (62 PO, 62 P&P) from May 2011 to March 2013. Median follow-up was 37.6 months (interquartile range [IQR], 35.4-38.9 months). Participants had a median age of 69 years (IQR, 64-74 years) and median diagnostic prostate-specific androgen level of 21.6 ng/mL (IQR, 11.8-35.1 ng/mL). At week 18, G2+ lower GI toxicity-free rates were 59 of 61 (96.7%; 90% confidence interval [CI], 90.0-99.4) for the PO group and 59 of 62 (95.2%; 90% CI, 88.0-98.7) for the P&P group. Patients in both groups reported similarly low Inflammatory Bowel Disease Questionnaire symptoms and Vaizey incontinence scores. The largest difference occurred at week 6 with 4 of 61 (7%) and 16 of 61 (26%) PO and P&P patients, respectively, experiencing G2+ toxicity. At 2 years, the cumulative proportion of RTOG G2+ GI toxicity was 16.9% (95% CI, 8.9%-30.9%) for the PO group and 24.0% (95% CI, 8.4%-57.9%) for the P&P group; in addition, RTOG G2+ bladder toxicity was 5.1% (95% CI, 1.7%-14.9%) for the PO group and 5.6% (95% CI, 1.8%-16.7%) for the P&P group.

CONCLUSIONS

PIVOTAL demonstrated that high-dose pelvic lymph node IMRT can be delivered at multiple centers with a modest side effect profile. Although safety data from the present study are encouraging, the impact of P&P IMRT on disease control remains to be established.

Results of a randomised phase II study of hypofractionated bladder radiotherapy (RT) with or without image guided adaptive planning (HYBRID - CRUK/12/055)

283

Background: Muscle invasive bladder cancer (MIBC) incidence increases with age, with many patients (pts) unfit for radical therapy. We aimed to demonstrate feasibility of delivery & acceptable rates of hypofractionated RT toxicity using image guided adaptive techniques for these pts in a multicentre trial. Methods: Pts with T2-T4aN0M0 MIBC had 36 Gray (Gy) in 6 fractions (fr) over 6 weeks & were randomised (1:1) to standard (SP) or adaptive planning (AP). For AP 3 RT plans (small, medium, large) were generated with preRT cone beam (CB) CT used to select best fitting ‘plan of the day’ at each fr. A QA programme aided standardised CBCT image interpretation. The SP group had RT with 1 plan. The aim was to exclude ≥30% grade ≥3 (≥G3) acute (to 3 months (m)) non-genitourinary (GU) toxicity for AP in pts with no MIBC death by 3m (p0=0.7 p1=0.9 α=0.05 β=0.2). Secondary endpoints included 36Gy/6fr acute toxicity in pts who had ≥1 RT fr & proportion of AP fr using small/large plan. Adverse events (AEs) were assessed (CTCAE v4) weekly on RT, 4 weeks & 3m post RT. Blind independent review assessed relatedness of non-GU AEs to RT. Results: Between Apr 2014 & Aug 2016 65 pts were randomised (SP (n=32) AP (n=33)) from 12 UK sites. Median age was 85yrs; 68% male; 92% transitional cell MIBC; 99% grade 3; 25% clinical stage T3 & 6% T4. 58 pts are evaluable to date, ≥G3 acute non-GU adverse reactions (AR) were reported in 2/30 (7%; 90% CI: 1%–20%) AP (G3 hyperkalemia & hyponatremia; G3 diarrhea & dehydration) & 3/28 (11%; 90% CI: 3% –25%) SP pts (G3 fatigue; G3 hyperkalemia, weight loss & anorexia; G3 diarrhoea). 24/65 (37%; 90% CI: 27%-48%) pts who had ≥1 RT fr had ≥G3 acute AEs including G4 hyponatremia (2 AP pts), G5 pneumonia (1 SP, 1 AP), G5 sepsis (1 AP) & G5 renal failure (1 SP) (all G4/5 unrelated to RT). 7/65 pts received <6 fr RT due to toxicity. In the 33 AP pts 40/182 fr (22%) used a small plan & 29/182 (16%) large (adaption rate=38%; 95% CI: 31%-45%). Conclusions: Though overall ≥G3 AE rate was significant, 36Gy/6fr with AP is feasible, met predefined toxicity criteria (<30% ≥G3 acute non-GU ARs) & with >25% fr adapted has potential for benefit. Comparative randomised studies are needed to quantify benefits of AP over SP. Clinical trial information: 18815596.

The value of image-guided intensity-modulated radiotherapy in challenging clinical settings

OBJECTIVE

To illustrate the wider potential scope of image-guided intensity-modulated radiotherapy (IG-IMRT), outside of the "standard" indications for IMRT.

METHODS

Nine challenging clinical cases were selected. All were treated with radical intent, although it was accepted that in several of the cases the probability of cure was low. IMRT alone was not adequate owing to the close proximity of the target to organs at risk, the risk of geographical miss, or the need to tighten planning margins, making image-guided radiotherapy an essential integral part of the treatment. Discrepancies between the initial planning scan and the daily on-treatment megavoltage CT were recorded for each case. The three-dimensional displacement was compared with the margin used to create the planning target volume (PTV).

RESULTS

All but one patient achieved local control. Three patients developed metastatic disease but benefited from good local palliation; two have since died. A further patient died of an unrelated condition. Four patients are alive and well. Toxicity was low in all cases. Without daily image guidance, the PTV margin would have been insufficient to ensure complete coverage in 49% of fractions. It was inadequate by >3 mm in 19% of fractions, and by >5 mm in 9%.

CONCLUSION

IG-IMRT ensures accurate dose delivery to treat the target and avoid critical structures, acting as daily quality assurance for the delivery of complex IMRT plans. These patients could not have been adequately treated without image guidance.

ADVANCES IN KNOWLEDGE

IG-IMRT can offer improved outcomes in less common clinical situations, where conventional techniques would provide suboptimal treatment.

Consideration of the likely benefit from implementation of prostate image-guided radiotherapy using current margin sizes: a radiobiological analysis

OBJECTIVE

To estimate the benefit of introduction of image-guided radiotherapy (IGRT) to prostate radiotherapy practice with current clinical target volume-planning target volume (PTV) margins of 5-10 mm.

METHODS

Systematic error data collected from 50 patients were used together with a random error of σ=3.0 mm to model non-IGRT treatment. IGRT was modelled with residual errors of Σ=σ=1.5 mm. Population tumour control probability (TCP(pop)) was calculated for two three-dimensional conformal radiotherapy techniques: two-phase and concomitant boost. Treatment volumes and dose prescriptions were ostensibly the same. The relative field sizes of the treatment techniques, distribution of systematic errors and correlations between movement axes were examined.

RESULTS

The differences in TCP(pop) between the IGRT and non-IGRT regimes were 0.3% for the two-phase and 1.5% for the concomitant boost techniques. A 2-phase plan, in each phase of which the 95% isodose conformed to its respective PTV, required fields that were 3.5 mm larger than those required for the concomitant boost plan. Despite the larger field sizes, the TCP (without IGRT) in the two-phase plan was only 1.7% higher than the TCP in the concomitant boost plan. The deviation of craniocaudal systematic errors (p=0.02) from a normal distribution, and the correlation of translations in the craniocaudal and anteroposterior directions (p<0.0001) were statistically significant.

CONCLUSIONS

The expected population benefit of IGRT for the modelled situation was too small to be detected by a clinical trial of reasonable size, although there was a significant benefit to individual patients. For IGRT to have an observable population benefit, the trial would need to use smaller margins than those used in this study. Concomitant treatment techniques permit smaller fields and tighter conformality than two phases planned separately.

Accelerated BEP for metastatic germ cell tumors: Combined analysis of Australian and U.K. phase I/II trials

4531

Background: Standard chemotherapy for advanced germ cell tumors is 3-weekly BEP (bleomycin, etoposide, cisplatin). 5-year overall survival is > 90% in good risk disease, but only ~80% in intermediate and ~ 60% in poor risk disease. Accelerated versions of standard regimens have proven more effective in other malignancies. We aimed to determine tolerability and activity of accelerated (2-weekly) BEP by combining data from two single arm, multi-center, phase I/II trials. Methods: The UK trial (n=16) included patients with intermediate and poor risk metastatic germ cell tumours. The Australian trial (n=45) also included patients with radiologically measurable good risk disease. BEP chemotherapy was repeated every 2 weeks for 4 cycles (3 cycles for good risk). The Australian and UK regimens differed for cisplatin (20mg/m2 D1-5; 50mg/m2 D1-2), etoposide (100mg/m2 D1-5; 165mg/m2 D1-3), bleomycin (30kIU weekly x 12 or 9; 30kIU at 4-6 day intervals x 12), and pegylated G-CSF (6mg D6; 6mg D4) respectively. Primary endpoint for combined analysis was 2-year progression-free survival. Results: 61 patients were enrolled from 2004-09 (UK) and 2008-10 (Australia). 17 had poor risk, 28 intermediate risk, 16 good risk disease. Median follow-up is 27 months (range 6 to 81). Adverse events are presented in the table. 45 of 61 patients (74%) achieved a complete response to chemotherapy +/- surgery (9 of 17 poor risk (53%), 20 of 28 intermediate risk (71%), 16 of 16 good risk disease (100%)). 11 of 61 patients have relapsed. 2 patients have died of disease (both intermediate risk). 2 year overall survival is 98%. 2 year progression-free survival is 65% for poor risk, 86% for intermediate risk, and 92% for good risk disease. Conclusions: Efficacy data are promising, particularly for intermediate and poor risk disease. Adverse events appear comparable to standard BEP. These results provide the rationale for an international trial randomised trial comparing accelerated and standard versions of BEP. [Table: see text]

Practical issues in the implementation of image-guided radiotherapy for the treatment of prostate cancer within a UK department

AIMS

To study the feasibility of using implanted gold seeds in combination with a commercial software system for daily localisation of the prostate gland during conformal radiotherapy, and to assess the effect this may have on departmental workload.

MATERIALS AND METHODS

Six patients had three gold radio-opaque seeds implanted into the prostate gland before starting a course of radiotherapy. The seeds were identified on daily portal images and an automated online system provided immediate vector analysis of discrepancies between the planned and actual daily position of the intraprostatic seeds. In total, 138 interfractional displacements were analysed. The workload impact for the department was assessed using the basic treatment equivalence model, by comparing measurements of daily treatment session durations with a control group of patients receiving standard conformal radiotherapy, matched for treatment complexity.

RESULTS

No acute complications of seed insertion were observed. A number of developmental issues required solutions to be identified before clinical implementation was possible. The standard deviations of the set-up and organ motion systematic errors in the left-right, superior-inferior and anterior-posterior directions were 2.4, 3.0 and 2.5 mm, respectively. The standard deviations of the set-up and organ motion random errors calculated were 2.5, 2.9 and 3.7 mm. The mean treatment session duration with this daily prostate localisation system was increased by 3 min compared with matched controls using standard imaging practice. If all radical prostate patients in our department were to receive image-guided radiotherapy in this way, this would increase machine workload time by 2.2 h/day.

CONCLUSIONS

The implementation of this image-guided system is feasible. No additional linear accelerator modification is required and standard imaging devices can be used. It would be a useful addition to any department's image-guided radiotherapy developmental strategy.

Reaction of sorbic acid in wheat flour doughs: reaction with thiols

The general characteristics of the reaction between sorbic acid and thiols are reviewed. Cysteine adds to the conjugated diene in position 5 to form the substituted 3-hexenoic acid. This is labile in acid solution, yielding a quantitative amount of sorbic acid. When wheat flour doughs are treated with sorbic acid and heated, a significant amount of the sorbic acid is not recovered on extraction with methanol. The use of acidified methanol leads to a quantitative recovery of the preservation and evidence is presented to suggest that sorbic acid-thiol adducts are formed. This is the first report of 'reversibly bound' sorbic acid in a food.