Early Outcomes and Decision Regret Using PSMA/MRI-Guided Focal Boost for Prostate Cancer SBRT.

PURPOSE: Stereotactic body radiation therapy (SBRT) is a recognized treatment for low- and intermediate-risk prostate cancer, with 36.25 Gy in 5 fractions the most commonly used regimen. We explored the preliminary efficacy, patient recorded toxicity, and decision regret in intermediate- and high-risk prostate cancer receiving SBRT with prostate-specific membrane antigen (PSMA)/magnetic resonance imaging (MRI) guided focal gross tumor volume boost to 45 Gy. METHODS AND MATERIALS: Between July 2015 and June 2019, 120 patients received SBRT across 2 institutions with a uniform protocol. All patients had fiducial markers and hydrogel, MRI and PSMA positron emission tomography (PET) scan. All patients received a questionnaire asking the degree of urinary, bowel, and sexual bother experienced at set time points, including questions about treatment choice and decision regret. RESULTS: One hundred twelve of 120 patients consented. Their median age was 72 years and median follow-up was 2.3 years. As per National Comprehensive Cancer Network guidelines, 78% had intermediate risk and 20% high risk. Androgen deprivation was combined with radiation in 6 patients. Most patients (74%) reported that receiving SBRT significantly influenced their choice of treatment. Five men (4%) expressed "quite a lot" (n = 4) or "very much" regret (n = 1) regarding their choice of treatment, while 89% expressed "no regret." Similar to pretreatment levels, "quite a lot" or "very much" urinary or bowel bother was expressed in 8% and 6% of patients, respectively. Two patients experienced nadir +2 biochemical failure, both found to have bone metastases. A third patient underwent PSMA PET at nadir +1.7 and had disease at the penile bulb, which was out of field. Three year estimated freedom from biochemical failure was 99% for intermediate and 85% for high-risk groups. CONCLUSIONS: We have demonstrated promising efficacy and low toxicity with PSMA/MRI-guided SBRT focal boost. Less than 5% of patients expressed significant decision regret for their choice of treatment.

Interim Results of a Prospective Prostate-Specific Membrane Antigen-Directed Focal Stereotactic Reirradiation Trial for Locally Recurrent Prostate Cancer.

PURPOSE: To report the feasibility, toxicity, and preliminary outcomes (metabolic and biochemical) of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT)-directed focal prostate reirradiation using linear accelerator (LINAC)-based stereotactic body radiation treatment (SBRT). METHODS AND MATERIALS: From March 2016 to March 2019, 25 patients were enrolled in a prospective single institution trial (ACTRN12617000035325). Eligibility criteria included patients with biopsy proven isolated prostate recurrence after definitive irradiation, with concordant multiparametric MRI and 68Ga-PSMA PET/CT findings, and a prostate-specific antigen of less than 15 ng/mL at the time of recurrence. The study included a sequential dose escalation component with the first 18 patients receiving 36 Gy in 6 fractions on alternate days with subsequent patients receiving 38 Gy in 6 fractions assuming acceptable toxicity. RESULTS: Median age was 72 years (range, 62-83) with a median time between first radiation treatment and salvage SBRT of 8.3 years (range, 4.5- 13.6). Median prostate-specific antigen at reirradiation was 4.1 (range, 1.1-16.6). The median follow-up was 25 months (range, 13-46). Acute grade 1 and 2 genitourinary (GU) toxicity occurred in 6 (24%) and 1 (4%) men, respectively. Acute grade 1 gastrointestinal (GI) toxicity occurred in 8% with one acute grade 3 GI toxicity (4%) due to a rectal ulcer overlying the hydrogel. Late grade 1 and 2 GU toxicity occurred in 28% and 4%. Late grade 1 GI toxicity occurred in 8% with no grade 2 or greater toxicity. Twenty-four patients have undergone per-protocol 12-month 68Ga-PSMA PET/CT, of which 23 (92%) demonstrated a complete metabolic response. Biochemical freedom from failure was 80% at 2 years with 3 out of 4 of the biochemical failures exhibiting recurrent local disease. CONCLUSIONS: PSMA-directed salvage focal reirradiation to the prostate using linear accelerator-based SBRT is feasible and safe. Toxicity was low, with very favorable short term local and biochemical control in a carefully selected cohort of patients.

Delineating biochemical failure with 68Ga-PSMA-PET following definitive external beam radiation treatment for prostate cancer.

BACKGROUND AND PURPOSE: We investigated the role of 68Ga-PSMA-PET (PSMA) to determine the location of disease recurrence in those with a rising PSA following definitive external beam radiation treatment (EBRT). MATERIALS AND METHODS: 538men were treated with image guided EBRT to a dose of 78 or 82Gy between 2007 and 2014. Patients at least 24months post EBRT with biochemical failure (nadir+2) underwent PSMA scanning. Local recurrence (LR) was defined as increased uptake within the prostate or seminal vesicles. Distant disease included lymph node (LN), bone or visceral metastases. RESULTS: 419men formed the study cohort. Median follow-up was 50months, 70 patients (17%) had biochemical failure (BF), 13 of whom have died. Of the 57 survivors, 5 had metastases detected on conventional scans; 2 were lost to follow up. 48men (of 50 candidates) underwent PSMA; in all cases, the PSMA was unequivocally positive. Of the 48 positive scans, 25 patients (52%) failed beyond the prostate - 5 in bones, 16LN, 3 in both, and 1 in the lungs. Fifteen men (31%) failed within the gland and in either LN (11), bones (3), or both (1). Eight (17%) had an isolated LR, which represents 2% of patients managed with definitive EBRT and followed for at least 2years. CONCLUSIONS: PSMA was positive in all patients with BF. Site of failure following dose-escalated EBRT was generally distant. Isolated LR (on PSMA) occurred in only 8 of 419 patients post-EBRT.

78Gy with Fiducial Marker Image-Guided Radiotherapy in Prostate Cancer: Single Center Analysis of 301 Patients.

AIM: In prostate cancer, fiducial marker image-guided radiotherapy (FMIGRT) allows correction of setup errors and interfraction physiological motion resulting in improved accuracy of target and sparing of at risk organs. We aim to report outcomes and toxicities observed in patients treated with dose escalation to 78Gy with FMIGRT in our center. METHODS AND MATERIALS: Retrospective review of consecutive patients with histologically confirmed T1-4N0M0 localized prostate cancer treated with dose escalation to 78Gy with FMIGRT in our center. All patients had 3-D conformal radiotherapy. Duration of androgen deprivation therapy use was tailored to risk group. Toxicity was scored according to CTCAE.v04. Kaplan-Meier analysis was performed for freedom from biochemical failure (FFBF), prostate cancer-specific survival and overall survival. RESULTS: Median follow-up was 48.6 months. Median duration of androgen deprivation therapy was 6 and 23 months in the intermediate- and high-risk group, respectively. FFBF at 5 years was 88.8%. FFBFs when stratified to risk groups were 100% for low risk, 88.9% for low-intermediate risk, 89.9% for high-intermediate risk and 85.4% for high risk, respectively. Acute severe toxicity (grade≥3) rate for both genitourinary (GU) and gastrointestinal (GI) was 1%. Late moderate-to-severe toxicity (grade≥2) rates for GU and GI were 15% and 17%, respectively, with severe (grade≥3) toxicity rate for GU and GI at 2% and 3%, respectively. CONCLUSION: Dose escalation to 78Gy with FMIGRT in our series achieved good FFBF at 5 years with low acute and late toxicity rates. These results provide a good comparator cohort to our current use of image-guided intensity modulated radiotherapy.

Impact of cognitive function on communication in patients with primary or secondary brain tumours.

Communication support tools (CST) improve patient outcomes in oncology including: knowledge, satisfaction, self-management, and adherence to planned treatment. Little is known about communication support tools use in patients with primary or secondary brain tumours. We aimed to explore cognitive function and communication support tool use in this population. This prospective survey involved patients, caregivers and health professionals. Questionnaires were completed after initial brain radiotherapy consultation and 1-2 weeks later. Patients completed the Montreal Cognitive Assessment (MoCA). Descriptive statistics are reported. Fifty-three patients participated, median age 62 years, ECOG status 0-2 (90 %), with 75 % having secondary brain metastasis. 21/53 (40 %) patients reported needing help reading medical information. Only 28 % patients had normal cognition (MoCA score ≥ 26/30). Initially, 82 % of patients and 87 % of caregivers reported the consultation was 'extremely/quite clear, and 69 % of their health professionals thought consultation 'extremely/quite clear' to patient. At follow-up, fewer patients (75 %) reported health professionals' explanation as 'extremely/quite clear'. Although patients recalled discussed illness and treatment details, 82 % recalled treatment-related side effects and management thereof by 46 %. CST use was reported by 22 % patients, 19 % caregivers, and 27 %health professionals. When used, tools improved understanding according to 92 % patients, 100 % caregivers, and 91 % health professionals. The majority of patients have some level of cognitive impairment. Information discussed appears clear to most patients, but this is not sustained, and recall of treatment toxicity management is poor. Few CSTs are used in consultations, but when used, are reported as helpful by all.