Association of Apical Spacing with Bowel Quality-of-Life: A Secondary Analysis of the Hyaluronic Acid Randomized Trial

PURPOSE/OBJECTIVE(S)

Recently, a randomized trial (NCT04189913) reported that a hyaluronic acid (HA) rectal spacer reduced acute grade 2+ gastrointestinal (GI) toxicity for hypofractionated radiation therapy (RT). However, 26.5% of patients who received the spacer experienced a minimally clinically important difference (MCID; 5 points) in EPIC bowel quality-of-life (QOL). We evaluated whether characteristics of the spacer implant, particularly apical separation, were associated with change in bowel QOL at 3-months and acute grade 1+ GI toxicity.

MATERIALS/METHODS

We conducted a secondary analysis of 136 patients randomized to receive the HA spacer. The post-spacer implant structure sets and treatment plans were analyzed. The mid-plane (MP) was defined as the prostate center-of-mass. Four horizontal planes were defined at the superior (MP +1 cm), mid-gland, inferior (MP - 1 cm), and apex of the prostate. Separations between the prostate and anterior rectal wall at midline were computed at each plane in a custom Python programming environment. Implant symmetry was computed based on a previously published method (Fischer-Valuck, PRO, 2017). The volume of rectum receiving > = 30 Gy (rV30) was extracted from DVHs; rV30 has been associated with bowel frequency, fecal incontinence, and rectal pain for hypofractionated RT (Wilkins, IJROBP, 2020). First, we evaluated whether any of the 4 separation or symmetry variables were associated with rV30. Then, we evaluated whether significant spacing variables, rV30, and baseline bowel QOL were predictive of the change in bowel QOL at 3-months using multivariate linear regression. Finally, we evaluated whether significant spacing variables and rV30 were predictive of acute grade 1+ GI toxicity (21 events) within 3-months, utilizing multivariate logistic regression.

RESULTS

The mean (standard deviation) superior, mid-gland, inferior, and apex separations were 15.6 (SD 6.0), 12.7 (3.7), 11.2 (3.7), and 9.7 (4.0), respectively. 130 of 136 (95.6%) had a symmetry score of 1 (symmetric). Apical separation was the only variable significantly associated with rV30 (r = -0.32; p < 0.01). On multivariate analysis, apical separation (0.41/mm; p = 0.01) was significantly associated with the change in bowel QOL, after adjusting for baseline bowel score (p = 0.0002) and rectum V30 (p = 0.50). Mean (SD) changes in bowel QOL were 0.01 (5.9) and -3.7 (8.1) for apical separations > = 10 vs <10 mm, respectively. Respective percentages of patients with a bowel MCID were 14.8% and 36.6% (p = 0.006). However, apical separation was not associated with increased odds of experiencing grade 1+ GI toxicity (p = 0.98), when adjusted for rectum V30 (odds ratio 1.04; p = 0.04).

CONCLUSION

Increased apical separation may be associated with improved EPIC bowel QOL at 3-months for patients who received a HA rectal spacer prior to hypofractionated RT. This finding is clinically important, because HA can be deliberately injected into the perirectal space at the level of the prostate apex.

Association between Artificial Intelligence-Derived Tumor Volume and Oncologic Outcomes for Localized Prostate Cancer Treated with Radiation Therapy

PURPOSE/OBJECTIVE(S)

Although clinical features of multi-parametric magnetic resonance imaging (mpMRI) have been associated with biochemical recurrence in localized prostate cancer, such features are subject to inter-observer variability. We evaluated whether the volume of the dominant intraprostatic lesion (DIL), as provided by a deep learning segmentation algorithm, could provide prognostic information for patients treated with definitive radiation therapy (RT).

MATERIALS/METHODS

We conducted a retrospective study of 438 patients with localized prostate cancer who underwent an endorectal coil, high B-value, 3-Tesla mpMRI and were treated with definitive RT at our institution between 2010 and 2017. We utilized the publicly available nnUNet to train a segmentation model which was used to identify the DIL. We examined the association between the artificial intelligence (AI)-generated DIL volume and oncologic outcomes, including biochemical recurrence and metastasis risk, using cause-specific Cox regression and time-dependent receiver operating characteristic analysis.

RESULTS

The AI model identified DILs with an area under the receiver operating characteristic (AUROC) of 0.827 at the patient level. For the 233 patients with available PI-RADS scores, with a median follow-up of 5.6 years, there were 28 biochemical failures. AI-defined DIL volume was significantly associated with biochemical failure (adjusted hazard ratio 1.60, 95% confidence interval 1.14-2.24, p = 0.007) after adjustment for PI-RADS score. Among all 438 patients with a median follow-up of 6.9 years, there were 49 biochemical failures and 22 metastases. The AUROC for predicting 7-year biochemical failure for AI volume (0.790) was similar to that for National Comprehensive Cancer Network (NCCN) category (p = 0.17). The AUROC for predicting 7-year metastasis for AI volume trended towards being higher compared to NCCN category (0.854 vs 0.769, p = 0.06).

CONCLUSION

An AI algorithm using deep learning could identify the DIL with good performance. AI-defined DIL volume may be able to provide prognostic information independent of the NCCN risk group or other radiologic factors for patients with localized prostate cancer treated with RT.

Prostate Cancer Awareness in the Middle East

PURPOSE/OBJECTIVE(S)

A better understanding of cancer awareness is crucial to allow the appropriate implementation of interventions to improve screening and diagnosis. While the incidence of prostate cancer has been reported to increase over the last decade in the Middle East, data on prostate cancer awareness in this region remains limited. Therefore, an assessment of prostate cancer awareness is critically needed. The current study addresses this urgent need by investigating the level of awareness of prostate cancer among the general public in the Middle East.

MATERIALS/METHODS

A cross-sectional survey of men residing in 13 Middle Eastern countries was conducted in 2022. A validated prostate cancer awareness questionnaire was used to assess participants' knowledge on several domains of prostate cancer. Men younger than 40 years of age or history of prostate cancer were excluded from the study.

RESULTS

A total of 4,431 men completed the survey. The median age was 49 (range, 40-81) and the majority of participants (81%) had a formal education. Most participants (90%) were married and only 30% had a family history of cancer. Most participants (84%) reported hearing about prostate cancer in the past but only 31% of the participants recognized that prostate cancer is the most common malignancy in men and 22% thought that prostate cancer affects both men and women. Awareness of risk factors for prostate cancer was low: 29% of the participants recognized family history as a risk factor and 30% associated increasing age with prostate cancer. Most participants were not aware of screening, specifically only 19% of the participants knew that PSA test is used for PC screening. In terms of prognosis, participants thought that the majority of prostate cancer patients (mean, 75%) die due to their disease as opposed to old age or another cause of death.

CONCLUSION

Although the Middle Eastern men are familiar with the existence of prostate cancer, they are uninformed about the disease outcomes, risk factors, and screening. Overall, these results indicate critically low levels of awareness of prostate cancer in the Middle East. Thus, there is a vital need to target this population for practical interventions to increase awareness, in addition to screening and earlier diagnosis.

Clinical Presentation and Management of Prostate Cancer in the Middle East

PURPOSE/OBJECTIVE(S)

Prostate cancer is one of the most common malignancies worldwide and the incidence rate continues to increase in the Middle East. In the absence of large well-established cancer registries, there are no data to reflect the disease stage at initial presentation and patterns of care in this region. In order to mitigate the disease burden and help stakeholders to implement new policies to improve patient outcomes, it is important to study the disease stage at the initial presentation. The purpose of this study was to evaluate the clinical presentation and treatment of prostate cancer in the Middle East.

MATERIALS/METHODS

We performed a retrospective review of 7 institutional databases in 6 Middle Eastern countries to identify patients diagnosed with prostate cancer in 2021. Demographic, clinical, and treatment variables were abstracted. Patients who missed ≥2 scheduled radiation therapy (RT) appointments (excluding planned treatment breaks) were deemed "noncompliant."

RESULTS

A total of 1,132 patients were identified with a median age was 70 (range, 50-84). Most of the patients (78%) were diagnosed after developing symptoms and not on routine PSA screening. Diagnostic workup was completed in 87% of the patient. At time of diagnosis, 35% men presented with clinical T3 or T4 disease, 53% with metastatic disease and 42% with Gleason score ≥ 8. Mean PSA at time of presentation was 84 ng/ml. Among the nonmetastatic patients, 23% underwent a prostatectomy, 48% received definitive RT with or without androgen deprivation therapy (ADT), 9% received ADT alone and 20% received no treatment. No brachytherapy was used. Hypofractionated RT was used in 49% patients and only 8% were deemed "noncompliant". Among the metastatic patients, 74% received ADT with or without additional systemic therapy, 25% had palliative RT and 22% received no treatment.

CONCLUSION

In this large cohort of prostate cancer patients in the Middle East, most men presented with symptoms and were found to have advanced-stage disease. However, substantial proportion of patients did not receive any treatment. Further interventions to optimize prostate cancer diagnosis and treatment in in the Middle East are urgently needed.

Determining optimal eluter design by modeling physical dose enhancement in brachytherapy

PURPOSE

In situ drug release concurrent with radiation therapy has been proposed to enhance the therapeutic ratio of permanent prostate brachytherapy. Both brachytherapy sources and brachytherapy spacers have been proposed as potential eluters to release compounds, such as nanoparticles or chemotherapeutic agents. The relative effectiveness of the approaches has not been compared yet. This work models the physical dose enhancement of implantable eluters in conjunction with brachytherapy to determine which delivery mechanism provides greatest opportunity to enhance the therapeutic ratio.

MATERIALS AND METHODS

The combined effect of implanted eluters and radioactive sources were modeled in a manner that allowed the comparison of the relative effectiveness of different types of implantable eluters over a range of parameters. Prostate geometry, source, and spacer positions were extracted from treatment plans used for 125 I permanent prostate implants. Compound concentrations were calculated using steady-state solution to the diffusion equation including an elimination term characterized by the diffusion-elimination modulus (ϕb ). Does enhancement was assumed to be dependent on compound concentration up to a saturation concentration (csat ). Equivalent uniform dose (EUD) was used as an objective to determine the optimal configuration of eluters for a range of diffusion-elimination moduli, concentrations, and number of eluters. The compound delivery vehicle that produced the greatest enhanced dose was tallied for points in parameter space mentioned to determine the conditions under whether there are situations where one approach is preferable to the other.

RESULTS

The enhanced effect of implanted eluters was calculated for prostate volumes from 14 to 45 cm3 , ϕb from 0.01 to 4 mm-1 , csat from 0.05 to 7.5 times the steady-state compound concentration released from the surface of the eluter. The number of used eluters (ne ) was simulated from 10 to 60 eluters. For the region of (csat , Φ)-space that results in a large fraction of the gland being maximally sensitized, compound eluting spacers or sources produce equal increase in EUD. In the majority of the remaining (csat , Φ)-space, eluting spacers result in a greater EUD than sources even where sources often produce greater maximal physical dose enhancement. Placing eluting implants in planned locations throughout the prostate results in even greater enhancement than using only source or spacer locations.

CONCLUSIONS

Eluting brachytherapy spacers offer an opportunity to increase EUD during the routine brachytherapy process. Incorporating additional needle placements permits compound eluting spacer placement independent of source placement and thereby allowing a further increase in the therapeutic ratio. Additional work is needed to understand the in vivo spatial distribution of compound around eluters, and to incorporate time dependence of both compound release and radiation dose.

Utilization of biopsy-based genomic classifier to predict distant metastasis after definitive radiation and short-course ADT for intermediate and high-risk prostate cancer

BACKGROUND

We examined the ability of a biopsy-based 22-marker genomic classifier (GC) to predict for distant metastases after radiation and a median of 6 months of androgen deprivation therapy (ADT).

METHODS

We studied 100 patients with intermediate-risk (55%) and high-risk (45%) prostate cancer who received definitive radiation plus a median of 6 months of ADT (range 3-39 months) from 2001-2013 at a single center and had available biopsy tissue. Six to ten 4 micron sections of the needle biopsy core with the highest Gleason score and percentage of tumor involvement were macrodissected for RNA extraction. GC scores (range, 0.04-0.92) were determined. The primary end point of the study was time to distant metastasis. Median follow-up was 5.1 years. There were 18 metastases during the study period.

RESULTS

On univariable analysis (UVA), each 0.1 unit increase in GC score was significantly associated with time to distant metastasis (hazard ratio: 1.40 (1.10-1.84), P=0.006) and remained significant after adjusting for clinical variables on multivariable analysis (MVA) (adjusted hazard ratio: 1.36 (1.04-1.83), P=0.024). The c-index for 5-year distant metastasis was 0.45 (95% confidence interval: 0.27-0.64) for Cancer of the Prostate Risk Assessment score, 0.63 (0.40-0.78) for National Comprehensive Cancer Network (NCCN) risk groups, and 0.76 (0.57-0.89) for the GC score. Using pre-specified GC risk categories, the cumulative incidence of metastasis for GC>0.6 reached 20% at 5 years after radiation (P=0.02).

CONCLUSIONS

We believe this is the first demonstration of the ability of the biopsy-based GC score to predict for distant metastases after definitive radiation and ADT for intermediate- and high-risk prostate cancer. Patients with the highest GC risk (GC>0.6) had high rates of metastasis despite multi-modal therapy suggesting that they could potentially be candidates for treatment intensification and/or enrollment in clinical trials of novel therapy.

Incidence and determinants of 1-month mortality after cancer-directed surgery

BACKGROUND

Death within 1 month of surgery is considered treatment related and serves as an important health care quality metric. We sought to identify the incidence of and factors associated with 1-month mortality after cancer-directed surgery.

PATIENTS AND METHODS

We used the Surveillance, Epidemiology and End Results Program to study a cohort of 1 110 236 patients diagnosed from 2004 to 2011 with cancers that are among the 10 most common or most fatal who received cancer-directed surgery. Multivariable logistic regression analyses were used to identify factors associated with 1-month mortality after cancer-directed surgery.

RESULTS

A total of 53 498 patients (4.8%) died within 1 month of cancer-directed surgery. Patients who were married, insured, or who had a top 50th percentile income or educational status had lower odds of 1-month mortality from cancer-directed surgery {[adjusted odds ratio (AOR) 0.80; 95% confidence interval (CI) 0.79-0.82; P < 0.001], (AOR 0.88; 95% CI 0.82-0.94; P < 0.001), (AOR 0.95; 95% CI 0.93-0.97; P < 0.001), and (AOR 0.98; 95% CI 0.96-0.99; P = 0.043), respectively}. Patients who were non-white minority, male, or older (per year increase), or who had advanced tumor stage 4 disease all had a higher risk of 1-month mortality after cancer-directed surgery, with AORs of 1.13 (95% CI 1.11-1.15), P < 0.001; 1.11 (95% CI 1.08-1.13), P < 0.001; 1.02 (95% 1.02-1.03), P < 0.001; and 1.89 (95% CI 1.82-1.95), P < 0.001 respectively.

CONCLUSIONS

Unmarried, uninsured, non-white, male, older, less educated, and poorer patients were all at a significantly higher risk for death within 1 month of cancer-directed surgery. Efforts to reduce 1-month surgical mortality and eliminate sociodemographic disparities in this adverse outcome could significantly improve survival among patients with cancer.