Prospective Longitudinal Assessment of Quality of Life after Stereotactic Ablative Radiotherapy for Oligometastases: Analysis of the Population-Based SABR-5 Phase II Trial

PURPOSE/OBJECTIVE(S)

To evaluate longitudinal patient-reported quality of life (QoL) in patients treated with stereotactic ablative radiotherapy (SABR) for oligometastases.

MATERIALS/METHODS

The SABR-5 trial was a population-based single-arm phase II study of SABR to up to 5 sites of oligometastases, conducted in 6 regional cancer centers in British Columbia from 2016 to 2020. Prospective QoL was measured using treatment site-specific QoL questionnaires at pre-treatment baseline and 3, 6, 9, 12, 15, 18, 21, 24, 30, and 36 months after treatment. Patients with bone metastases were assessed with the Brief Pain Inventory (BPI). Patients with liver, adrenal, and abdominopelvic lymph node metastases were assessed with the Functional Assessment of Chronic Illness Therapy-Abdominal Discomfort (FACIT-AD). Patients with lung and intrathoracic lymph node metastases were assessed with the Prospective Outcomes and Support Initiative (POSI) lung questionnaire. The two one-sided test procedure was used to assess equivalence between the worst QoL score and baseline score of individual patients. Mean QoL at all time points was used to determine the trajectory of QoL response after SABR. The proportion of patients with "stable," "improved," or "worsened" QoL was determined for all time points based on standard minimal clinically important differences (MCID; BPI worst pain = 2, BPI Functional Interference Score [FIS] = 0.5, FACIT-AD Trial Outcome Index [TOI] = 8, POSI = 3).

RESULTS

All enrolled patients with baseline QoL assessment and at least 1 follow-up assessment were analyzed (n = 135). On equivalence testing, patients' worst QoL scores were clinically different from baseline scores and met MCID (BPI worst pain mean difference: 1.8, 90% CI [1.19 to 2.42]; BPI FIS mean difference: 1.68, 90% CI [1.15 to 2.21]; FACIT-AD TOI mean difference: -8.76, 90% CI [-11.29 to -6.24]; POSI mean difference: -4.61, 90% CI [-6.09 to -3.14]). However, the mean FIS transiently worsened at 9, 18 and 21 months but eventually returned to stable levels. The mean FACIT and POSI scores also worsened at 36 months, albeit with a limited number of responses (n = 4 and 8, respectively). The majority of patients reported stable QoL at all time points (range: BPI worst pain 71-82%, BPI FIS 45-78%, FACIT-AD TOI 50-100%, POSI 25-73%). Clinically significant stability, worsening, and improvement were seen in 70%/13%/18% of patients at 3 months, 53%/28%/19% at 18 months and 63%/25%/13% at 36 months.

CONCLUSION

SABR in the oligometastatic setting can lead to transient decreases in QoL. However, most patients experienced stable QoL relative to pre-treatment levels on long-term follow-up. Further studies are needed to characterize patients at greatest risk for decreased QoL.

Predictors of early polymetastatic relapse following stereotactic ablative radiotherapy for up to 5 oligometastases: a secondary analysis of the phase II SABR-5 trial

PURPOSE

A subset of patients with oligometastatic cancer experience early widespread cancer dissemination and do not benefit from metastasis-directed therapy such as stereotactic ablative radiotherapy (SABR). This study aimed to identify factors associated with early polymetastatic relapse (PMR).

METHODS AND MATERIALS

The XXX trial was a single arm phase II study conducted at all 6 regional cancer centres across XXX. SABR for oligometastases was only offered on trial. Patients with up to 5 oligometastatic lesions (total, progressing or induced) received SABR to all lesions. Patients were 18 years of age or older, ECOG 0-2 and life expectancy ≥ 6 months. This secondary analysis evaluated factors associated with early PMR, defined as disease recurrence within 6 months of SABR which is not amenable to further local treatment. Univariable and multivariable analyses were performed using binary logistic regression. The Kaplan Meier method and log-rank tests assessed PMR-free survival and differences between risk groups, respectively.

RESULTS

Between November 2016 and July 2020, 381 patients underwent treatment on XXX. A total of 16% of patients experienced PMR. Worse performance status (ECOG 1-2 vs 0; HR=2.01, p=0.018), non-prostate/breast histology (HR=3.64, p<0.001) and oligoprogression (HR=3.84, p<0.001) were independent predictors for early PMR. Risk groups were identified with median PMR-free survival ranging from 5 months to not yet reached at the time of analysis. Rates of 3-year OS were 0%, 53% (95% confidence interval [CI] 48 - 58), 77% (95% CI 73 - 81) and 93% (95% CI 90 - 96) in groups 1-4, respectively (p<0.001).

CONCLUSION

Four distinct risk groups for early PMR are identified, which differ significantly in PMR-free survival and overall survival. The group with all three risk factors had a median PMR-free survival of 5 months and may not benefit from local ablative therapy alone. This model should be externally validated with data from other prospective trials.

Progression-free survival and local control following stereotactic ablative radiotherapy for up to 5 oligometastases: an analysis from the population-based phase II SABR-5 trial

PURPOSE

Despite increasing utilization of stereotactic ablative therapy (SABR) for oligometastatic cancer, prospective outcomes are lacking. The purpose of this study was to determine progression-free survival (PFS), local control (LC) and prognostic factors from the population-based phase II XXX trial.

METHODS AND MATERIALS

The XXX trial was a single arm phase II study with the primary endpoint of toxicity, conducted at the 6 regional cancer centres across XXX, during which time SABR for oligometastases was only offered on trial. Patients with up to 5 oligometastases (total or not controlled by prior treatment, and including induced oligometastatic disease) underwent SABR to all lesions. Patients were 18 years of age or older, ECOG 0-2 and had life expectancy ≥ 6 months. The secondary outcomes of PFS and LC are presented here.

RESULTS

Between November 2016 and July 2020, 381 patients underwent SABR on trial. Median follow-up was 27 months (IQR 18-36). Median PFS was 15 months (95% CI 12-18). LC at 1 and 3 years were 93% (95% CI 91 - 95) and 87% (95% CI 84 - 90), respectively. On multivariable analysis, increasing tumor diameter (HR=1.09, p<0.001), declining performance status (HR=2.13, p<0.001), disease-free interval < 18 months (HR=1.52, p=0.003), four or more metastases at SABR (HR=1.48, p=0.048), initiation or change in systemic treatment (HR=0.50, p<0.001) and oligoprogression (HR=1.56, p=0.008) were significant independent predictors of PFS. Tumor diameter (SHR=1.28, p<0.001), colorectal histology (SHR=4.33, p=0.002) and "other" histology (SHR=3.90, p<0.001) were associated with worse local control.

CONCLUSIONS

In this population-based cohort including patients with genuine oligometastatic, oligoprogressive, and induced oligometastatic disease, the median PFS was 15 months and LC at 3 years was 87%. This supports ongoing efforts to randomize patients on phase III trials, even outside the original 1-5 metachronous oligometastatic paradigm.

Temporally selective contextual encoding in the dentate gyrus of the hippocampus

A recent model of the hippocampus predicts that the unique properties of the dentate gyrus allow for temporal separation of events. This temporal separation is accomplished in part through the continual generation of new neurons, which, due to a transient window of hyperexcitability, could allow for preferential encoding of information present during their development. Here we obtain in vivo electrophysiological recordings and identify a cell population exhibiting activity that is selective to single contexts when rats experience a long temporal separation between context exposures during training. This selectivity is attenuated as the temporal separation between context exposures is shortened and is further attenuated when neurogenesis is reduced. Our data reveal the existence of a temporal orthogonalizing neuronal code within the dentate gyrus, a hallmark feature of episodic memory.

The role of visual cortex acetylcholine in learning to discriminate temporally modulated visual stimuli

Cholinergic neurons in the basal forebrain innervate discrete regions of the cortical mantle, bestowing the cholinergic system with the potential to dynamically modulate sub-regions of the cortex according to behavioral demands. Cortical cholinergic activity has been shown to facilitate learning and modulate attention. Experiments addressing these issues have primarily focused on widespread cholinergic depletions, extending to areas involved in general cognitive processes and sleep cycle regulation, making a definitive interpretation of the behavioral role of cholinergic projections difficult. Furthermore, a review of the electrophysiological literature suggests that cholinergic modulation is particularly important in representing the fine temporal details of stimuli, an issue rarely addressed in behavioral experimentation. The goal of this work is to understand the role of cholinergic projections, specific to the sensory cortices, in learning to discriminate fine differences in the temporal structure of stimuli. A novel visual Go/No-Go task was developed to assess the ability of rats to learn to discriminate fine differences in the temporal structure of visual stimuli (lights flashing at various frequencies). The cholinergic contribution to this task was examined by selective reduction of acetylcholine projections to visual cortex (VCx) (using 192 IgG-saporin), either before or after discrimination training. We find that in the face of compromised cholinergic input to the VCx, the rats' ability to learn to perform fine discriminations is impaired, whereas their ability to perform previously learned discriminations remains unaffected. These results suggest that acetylcholine serves the role of facilitating plastic changes in the sensory cortices that are necessary for an animal to refine its sensitivity to the temporal characteristics of relevant stimuli.

Xanthoma disseminatum: a case report and literature review

This case report describes the neuro-opthalmologic and respiratory manifestations of xanthoma disseminatum, a rare histiocytosis syndrome characterized by disseminated lesions in a young male adult. Multimodality management of this disease, including the role of local radiotherapy, is discussed accompanied by a review of the literature.

Neoadjuvant hormone therapy and radical radiotherapy for localized prostate cancer: poorer biochemical outcome using flutamide alone

Since a recent meta-analysis of non-steroidal anti-androgen therapy in metastatic prostate cancer concluded that survival was worse compared with medical or surgical androgen withdrawal, we analyzed our experience with flutamide monotherapy and other forms of neoadjuvant hormone therapy (NHT) prior to radiation therapy in clinically localized prostate cancer. A total of 45 patients received flutamide and 328 patients received other NHT. Flutamide patients had higher PSA levels at diagnosis and shorter duration of treatment, which could bias the results against flutamide monotherapy. Kaplan Meier analysis of PSA -- disease free survival showed significantly poorer outcome with flutamide monotherapy. Multivariate analysis supported this conclusion. Until equivalence to other forms of NHT is shown, we do not recommend flutamide monotherapy prior to radical radiation. A prospective randomized trial would be necessary to confirm this conclusion.

Neoadjuvant hormone therapy and external beam radiation for localized prostate cancer: Vancouver Island Cancer Centre experience

OBJECTIVES

To evaluate the effects of neo-adjuvant hormone therapy (NAHT) given prior to radiation in patients with clinically localized adenocarcinoma of the prostate.

METHODS

Six hundred nine patients were treated between 1992 and 1997 with NAHT prior to radiation therapy. Clinical stage, presenting PSA and Gleason score were examined for influence on outcome. Time to post radiotherapy failure was defined from the first assessed PSA value over 4 microg/L at follow-up. Radiation therapy was confined to the prostate and seminal vesicles. Median follow-up was 2.6 years.

RESULTS

PSA disease free survival (PDFS) decreased with increasing cancer risk factors (p <.0.0001). The overall duration of NAHT was significant with patients receiving >8 months having a lower failure rate than those on therapy for <3 months (p <0.0001). The PSA prior to starting radiation correlated with outcome, a PSA <=0.1 microg\L having a better PDFS than those with a PSA >=4 microg\L (P <0.0001). NAHT for >8 months gave improved PDFS in intermediate grade Gleason score 5-7, (n = 256, p <0.0001), high grade Gleason score 8-10 (n = 80, p =0.005), but not in low grade, Gleason score <=4.

CONCLUSION

Neo-adjuvant hormone therapy for >8 months offers prolonged PSA disease free survival in patients with less well differentiated tumors, Gleason score >4. Clinical trials are required to confirm this.