Protecting Caribbean patients diagnosed with cancer from compounding disasters

Caribbean small island developing states are becoming increasingly vulnerable to compounding disasters, prominently featuring climate-related hazards and pandemic diseases, which exacerbate existing barriers to cancer control in the region. We describe the complexities of cancer prevention and control efforts throughout the Caribbean small island developing states, including the unique challenges of people diagnosed with cancer in the region. We highlight potential solutions and strategies that concurrently address disaster adaptation and cancer control. Because Caribbean small island developing states are affected first and worst by the hazards of compounding disasters, the innovative solutions developed in the region are relevant for climate mitigation, disaster adaptation, and cancer control efforts globally. In the age of complex and cascading disaster scenarios, developing strategies to mitigate their effect on the cancer control continuum, and protecting the health and safety of people diagnosed with cancer from extreme events become increasingly urgent. The equitable development of such strategies relies on collaborative efforts among professionals whose diverse expertise from complementary fields infuses the local community perspective while focusing on implementing solutions.

Beyond Average: α-Particle Distribution and Dose Heterogeneity in Bone Metastatic Prostate Cancer

α-particle emitters are emerging as a potent modality for disseminated cancer therapy because of their high linear energy transfer and localized absorbed dose profile. Despite great interest and pharmaceutical development, there is scant information on the distribution of these agents at the scale of the α-particle pathlength. We sought to determine the distribution of clinically approved [223Ra]RaCl2 in bone metastatic castration-resistant prostate cancer at this resolution, for the first time to our knowledge, to inform activity distribution and dose at the near-cell scale. Methods: Biopsy specimens and blood were collected from 7 patients 24 h after administration. 223Ra activity in each sample was recorded, and the microstructure of biopsy specimens was analyzed by micro-CT. Quantitative autoradiography and histopathology were segmented and registered with an automated procedure. Activity distributions by tissue compartment and dosimetry calculations based on the MIRD formalism were performed. Results: We revealed the activity distribution differences across and within patient samples at the macro- and microscopic scales. Microdistribution analysis confirmed localized high-activity regions in a background of low-activity tissue. We evaluated heterogeneous α-particle emission distribution concentrated at bone-tissue interfaces and calculated spatially nonuniform absorbed-dose profiles. Conclusion: Primary patient data of radiopharmaceutical therapy distribution at the small scale revealed that 223Ra uptake is nonuniform. Dose estimates present both opportunities and challenges to enhance patient outcomes and are a first step toward personalized treatment approaches and improved understanding of α-particle radiopharmaceutical therapies.

Does Chemo-Radiotherapy Improve Survival Outcomes vs. Radiotherapy Alone for High-Grade cT1 Urothelial Carcinoma of the Bladder?

BACKGROUND

Non-muscle invasive bladder cancer (non-MIBC) that is high-grade and confined to the lamina propria (HGT1) often has an aggressive clinical course. Currently, there is limited data on the comparative effectiveness of RT vs. CRT for HGT1 non-MIBC. We hypothesized that CRT would be associated with improved overall survival (OS) vs. RT in HGT1 bladder cancer.

METHODS

Patients diagnosed with HGT1 non-MIBC, and treated with transurethral resection of bladder tumor followed by either treatment with RT alone or CRT, were identified in the National Cancer Database. Inverse probability of treatment weighting (IPTW) was employed and weight-adjusted multivariable analysis (MVA) using Cox regression modeling was used to compare overall survival (OS) hazard ratios. OS was the primary endpoint, and was estimated using the Kaplan-Meier method and log-rank tests.

RESULTS

A total of 259 patients with HGT1 UC were treated with: (i) RT alone (n = 123) or (ii) CRT (n = 136). Propensity-weighted MVA showed that combined modality treatment with CRT was associated with improved OS relative to radiation alone (Hazard Ratio [HR]: 0.62, 95% Confidence Interval (95% CI): 0.44-0.88, P = .007). Four-year OS for the CRT vs. RT alone was 36% and 19%, respectively (log-rank P <.008).

CONCLUSION

For patients with HGT1 bladder cancer, concurrent CRT was associated with improved OS compared with radiation alone in a retrospective cohort. These results are hypothesis-generating. The NRG is currently developing a phase II randomized clinical trial comparing CRT to other novel, bladder preservation strategies.

Bridging the Gap of Radiotherapy Treatment Planning Quality between High-Income, and Low- and Middle-Income Countries Using Knowledge-Based Planning

PURPOSE/OBJECTIVE(S)

Radiotherapy departments in low- and middle-income countries (LMICs) like Guatemala have recently introduced intensity-modulated radiotherapy (IMRT). IMRT has become the standard of care in high-income countries (HIC) due to reduced toxicity and improved outcomes in some cancers. The purpose of this work is to show the feasibility of adapting knowledge-based (KB) models established in a HIC to a LMIC lacking experience in IMRT to improve plan quality and planning efficiency.

MATERIALS/METHODS

A Halcyon Linac was installed at our clinic in Guatemala in 2019 and has been used to treat approximately 90 patients daily with IMRT. A model developed on a cohort of head and neck cancer patients at a US academic radiotherapy center were applied at our center to create 20head and neck VMAT plans with different prescriptions, including simultaneous-integrated and sequential boosts.

RESULTS

The plans created using the KB models achieved similar coverage of the planning target volume for each plan KB plans showed better 1) Parotid sparing with a mean dose reduction between 5%-25% and spinal cord maximum dose reduction between 3%-15%. The time efficiency to create VMAT plans using KB model versus manual planning improved four-fold, on average one hour versus more than 4 hours, respectively.

CONCLUSION

Despite different prescriptions, guidelines and demographics of cancer patients between two institutions in a HIC and LMIC, this work demonstrates that KB planning can be used to generate better and more consistent VMAT plans versus manually created plans. In addition, KB planning has the potential to greatly increase planning efficiency higher efficiency and help address the shortage of medical physicists and dosimetrists in LMICs.

A Phase I/II Dose-Escalation Study Evaluating the Safety of 21 Gy, 23 Gy, and 25 Gy for High Dose Rate (HDR) Prostate Brachytherapy: An Interim Toxicity Report

PURPOSE/OBJECTIVE(S)

Single-fraction high dose rate (HDR) prostate brachytherapy has shown improved actuarial biochemical control rates from 66% to 82% with dose escalation from 19 to 20.5 Gy, respectively, but is still inferior to the reported low dose rate brachytherapy control rates of over 90%. We aimed to identify whether dose escalation to 21, 23, and 25 Gy can be safely accomplished.

MATERIALS/METHODS

Patients with previously untreated, pathologically confirmed, low-risk (cT1-T2a, Gleason ≤6, PSA <10 ng/mL) or favorable intermediate risk (Gleason 3+4, percentage of positive biopsy cores <50%, ≤1 NCCN intermediate risk factor) prostate adenocarcinoma were enrolled from a single institution. PSA and toxicity assessment were performed at baseline and at routine 6-month follow-ups.

RESULTS

From May 9, 2018 to May 12, 2022, 18 patients were enrolled. None had received prior androgen deprivation therapy, 44% had low risk disease, and 61% were ECOG 0 at baseline. Median age was 68 years (total range: 43-79), and 83% were Caucasian. Eight patients received 21 Gy, nine patients received 23 Gy, and one patient received 25 Gy, with the 25 Gy cohort still accruing. The mean prostate size and range, determined by pre-operative prostate volume study on trans-rectal ultrasound, were as follows: 21Gy cohort (mean: 41.2cc; range: 21.9-63.1cc), 23Gy Cohort (mean: 41.2cc, range 28.3-71.7cc), 25Gy cohort (65.3cc). A median of 17 catheters (range: 16-20) were implanted. At a median follow-up of 35.7 months (range: IQR 4.4 - 50.2), only one grade 3 toxicity was reported, which was an ulcerative colitis (UC) flare noted in a patient whose UC was poorly controlled, requiring multiple courses of prednisone in the 6 months prior to his brachytherapy. Regarding toxicities attributable to therapy, fourteen and four patients experienced a grade 1 and 2 genitourinary toxicity respectively; four and four patients experienced a grade 1 and 2 reproductive system toxicity respectively; one patient experienced a grade 1 GI toxicity. Two patients needed foley catheters upon discharge, with neither requiring the foley long term. There were two treatment failures in the 21Gy cohort at 1.39 and 1.67 years from date of HDR brachytherapy; date of failure was defined by the first PSA 2.0ng/mL over nadir. Of these patients, one underwent focal salvage HDR, whilst the other underwent radical prostatectomy with only 1% of the volume involved by prostate cancer. Of note, there was seminal vesicle involvement on restaging prostate biopsy for the patient that underwent radical prostatectomy, however, this was not appreciated on the final prostatectomy specimen. Both patients have no evidence of disease currently.

CONCLUSION

HDR brachytherapy appears well tolerated in patients with low to favorable intermediate risk prostate cancer at 21 and 23 Gy, with more accrual needed at 25Gy. Long-term follow-up needed to assess efficacy.

Standardizing LT Chest Wall Radiotherapy Treatment Planning in a Low- or Middle- Income Country Radiotherapy Clinic Using Knowledge Based Planning

PURPOSE/OBJECTIVE(S)

Radiotherapy departments in low- or middle-income countries (LMICs) tend to lag behind introducing emerging technologies like intensity-modulated radiotherapy (IMRT). IMRT has become the standard of care in high-income countries (HIC) due to reduced toxicity and improved outcomes in a wide variety of cancers. The purpose of this work is showing the results of left Chest-Wall knowledge-based planning (KBP) standardization and implementation in a LMIC setting.

MATERIALS/METHODS

A Halcyon Linac was installed at our clinic in Guatemala in 2019 and currently used to treat ∼90 IMRT patients daily. The standardization of IMRT procedures has been difficult for complex sites like chest-wall. The steps for standardization included: AAPM TG-263 nomenclature implementation, and planning workflows within the TPS, creation of optimization structures, and plan quality evaluation following RTOG1005 protocol hypofractionation arm. 25 plans were created manually achieving all RTOG1005 protocol constraints. The statistics were analyzed trough the model analytics tool provided by KPB manufacturer.

RESULTS

The results show that more plans are needed to improve the KBP model. This initial model was used to create a standardized clinical protocol in the TPS in order to continue adding plans to the KBP model database. This approach ensures that we obtain consistent plan quality and standardize our planning. The manual planning objectives achieved: CONCLUSION: The experience using the TPS to standardize our treatment planning process achieved good consistency in our planning objectives. This approach will help create KBP models according to our own clinic-specific requirements. Future work will be made to compare our LMIC KBP models with those made at a HIC academic radiotherapy center.

ARTIA-Bladder: Daily Online Adaptive Short-Course Radiation Therapy (RT) and Concurrent Chemotherapy for Muscle-Invasive Bladder Cancer (MIBC): A Prospective Trial of an Individualized Approach for Reducing Bowel and Bladder Toxicity

PURPOSE/OBJECTIVE(S)

Concurrent chemo-radiotherapy is commonly prescribed for muscle-invasive bladder cancer (MIBC). Post hoc analysis of two large, randomized trials found that hypofractionation improves loco-regional control (LRC) vs. standard fractionation in this population. A challenge in traditional image-guided radiotherapy of the bladder is that daily changes in bladder position and size requires large margins to ensure target coverage. This makes it difficult to spare uninvolved bladder from high-dose treatment, increases the risk of bowel toxicity, and results in historical rates of acute G3+ toxicity exceeding 20-30%. Daily online adaptive RT (ART) may enable reduced, personalized margins that maintain target coverage while reducing dose to OARs. This prospective clinical trial will test whether: 1) participants undergoing ART for MIBC have a lower rate of acute G3+ GI/GU toxicity compared with the 31% historical control rate (Stage III BC2001 trial), and 2) 2-year LRC with ART will be non-inferior to historical controls (75%).

MATERIALS/METHODS

This multi-national trial will enroll 165 adult subjects with stage cT2-T4aN0M0 urothelial MIBC. Subjects will have undergone an attempt at maximal transurethral resection of bladder tumor. Patients with clinically involved nodes or G2+ GI or G3+ GU symptoms/conditions at baseline are ineligible. Concurrent with chemotherapy, participants will receive (at the discretion of the investigator) either 55 Gy in 20 fx to whole-bladder or 46 Gy in 20 fx to whole-bladder plus simultaneous in-field boost of 55 Gy in 20 fx to tumor bed. A personalized ITV will be derived for each subject based on bladder expansion, as assessed on two CT simulations separated by 30 min. Daily ART will be attempted for all subjects. The primary endpoint is acute G3+ GI/GU toxicity. Secondary endpoints are LRC; quality of life (EORTC QLQ-BLM30, EPIC 26 bowel and urinary); global function (EQ-5D-5L ); 2-year disease-free, bladder intact event-free, and overall survival; 2-year bladder cancer-specific mortality; NTCP model of acute GI toxicity for hypofractionated bladder RT; workflow feasibility of ART; improved target coverage ± reduced dose to critical OARs vs. non-ART dosimetry; acute G3+ GI/GU toxicity rate in subjects with ≥75% of their treatments as ART; and acute G3+ GI/GU toxicity in the cohort treated with partial bladder boost. Exploratory translational and correlative endpoints will also be examined.

RESULTS

This trial opened to enrollment on Feb 2, 2023; the study duration is expected to be 4-5 years.

CONCLUSION

This prospective clinical trial will provide robust clinical data to inform healthcare providers' decisions on the use of daily online ART and hypofractionation as a bladder preservation strategy for this population.

Impact of AI-Based Auto-Segmentation on Radiotherapy Processes in Low and Middle-Income Countries

PURPOSE/OBJECTIVE(S)

Radiotherapy processes require significant human resources and expertise, creating a barrier for rapid deployment in low and middle-income countries (LMICs). Optimal radiotherapy (RT) relies on accurate segmentation of tumor targets and organs-at-risk (OARs) during the RT planning process. This study reports the impact of AI-based auto-segmentation on RT processes in an LMIC.

MATERIALS/METHODS

Ten patients including five head and neck (HN), and five prostate cancer patients were randomly selected. Their planning CT images were subjected to auto- segmentation using an FDA-approved AI software tool, and manual segmentation by an experienced radiation oncologist from a Sub-Saharan African RT clinic. The control data consisted of contours from an experienced radiation oncologist and dosimetrists at a large academic institution in the US. For prostate cases, the contours included the prostate, seminal vesicles, bladder, rectum, penile bulb, and both femoral heads. For HN cases, the contours included the brain, brainstem, bilateral eyes, lens, optic nerves, cochlea, parotids, optic chiasm, spinal cord, oral cavity, and mandible. The time to complete the segmentation was recorded for both auto-segmentation and manual contours from the LMIC. The DICE similarity coefficients were used for comparative evaluation.

RESULTS

The average time for contouring per patient was 2 minutes for AI compared to 57 minutes for manual contouring in the LMIC. When comparing the control data, AI pelvic contours provide a slightly better agreement than LMIC manual contours for all the OARs, with the following mean DICE coefficients for AI vs LMIC manual contours: bladder (0.971 vs 0.958), left femoral head (0.960 vs 0.949), right femoral head (0.959 vs 0.941), rectum (0.880 vs 0.867), prostate (0.836 vs 0.824), seminal vesicles (0.696 vs 0.580), and penile bulb (0.536 vs 0.528). For HN contours, AI provide a better agreement for 7 of 11 OARs than the LMIC manual contours, with the following mean DICE coefficients: brain (0.972 vs 0.982), mandible (0.877 vs 0.925), right parotid (0.847 vs 0.800), left parotid (0.798 vs 0.792), spinal cord (0.837 vs 0.821), left eye (0.875 vs 0.832), right eye (0.867 vs 0.836), brainstem (0.866 vs 852), oral cavity (0.796 vs 0.787), left lens (0.650 vs 0.729) and right lens (0.671 vs 0.682). Neither AI contours nor LMIC manual contours had good agreement with the control data (<0.600) for optic nerves, chiasm, and cochlea due to their small volumes.

CONCLUSION

AI-based auto-segmentation tools are capable of producing contours of comparable quality to those generated by manual segmentation for both pelvic and HN cancer patients in LMICs, while also resulting in substantial time savings. AI-based auto-segmentation holds tremendous potential for improving radiotherapy care in LMICs with limited sources.

Effect of Brachytherapy With External Beam Radiation Therapy Versus Brachytherapy Alone for Intermediate-Risk Prostate Cancer: NRG Oncology RTOG 0232 Randomized Clinical Trial

PURPOSE

To determine whether addition of external beam radiation therapy (EBRT) to brachytherapy (BT) (COMBO) compared with BT alone would improve 5-year freedom from progression (FFP) in intermediate-risk prostate cancer.

METHODS

Men with prostate cancer stage cT1c-T2bN0M0, Gleason Score (GS) 2-6 and prostate-specific antigen (PSA) 10-20 or GS 7, and PSA < 10 were eligible. The COMBO arm was EBRT (45 Gy in 25 fractions) to prostate and seminal vesicles followed by BT prostate boost (110 Gy if 125-Iodine, 100 Gy if 103-Pd). BT arm was delivered to prostate only (145 Gy if 125-Iodine, 125 Gy if 103-Pd). The primary end point was FFP: PSA failure (American Society for Therapeutic Radiology and Oncology [ASTRO] or Phoenix definitions), local failure, distant failure, or death.

RESULTS

Five hundred eighty-eight men were randomly assigned; 579 were eligible: 287 and 292 in COMBO and BT arms, respectively. The median age was 67 years; 89.1% had PSA < 10 ng/mL, 89.1% had GS 7, and 66.7% had T1 disease. There were no differences in FFP. The 5-year FFP-ASTRO was 85.6% (95% CI, 81.4 to 89.7) with COMBO compared with 82.7% (95% CI, 78.3 to 87.1) with BT (odds ratio [OR], 0.80; 95% CI, 0.51 to 1.26; Greenwood T P = .18). The 5-year FFP-Phoenix was 88.0% (95% CI, 84.2 to 91.9) with COMBO compared with 85.5% (95% CI, 81.3 to 89.6) with BT (OR, 0.80; 95% CI, 0.49 to 1.30; Greenwood T P = .19). There were no differences in the rates of genitourinary (GU) or GI acute toxicities. The 5-year cumulative incidence for late GU/GI grade 2+ toxicity is 42.8% (95% CI, 37.0 to 48.6) for COMBO compared with 25.8% (95% CI, 20.9 to 31.0) for BT (P < .0001). The 5-year cumulative incidence for late GU/GI grade 3+ toxicity is 8.2% (95% CI, 5.4 to 11.8) compared with 3.8% (95% CI, 2.0 to 6.5; P = .006).

CONCLUSION

Compared with BT, COMBO did not improve FFP for prostate cancer but caused greater toxicity. BT alone can be considered as a standard treatment for men with intermediate-risk prostate cancer.

Cellular states are coupled to genomic and viral heterogeneity in HPV-related oropharyngeal carcinoma

Head and neck squamous cell carcinoma (HNSCC) includes a subset of cancers driven by human papillomavirus (HPV). Here we use single-cell RNA-seq to profile both HPV-positive and HPV-negative oropharyngeal tumors, uncovering a high level of cellular diversity within and between tumors. First, we detect diverse chromosomal aberrations within individual tumors, suggesting genomic instability and enabling the identification of malignant cells even at pathologically negative margins. Second, we uncover diversity with respect to HNSCC subtypes and other cellular states such as the cell cycle, senescence and epithelial-mesenchymal transitions. Third, we find heterogeneity in viral gene expression within HPV-positive tumors. HPV expression is lost or repressed in a subset of cells, which are associated with a decrease in HPV-associated cell cycle phenotypes, decreased response to treatment, increased invasion and poor prognosis. These findings suggest that HPV expression diversity must be considered during diagnosis and treatment of HPV-positive tumors, with important prognostic ramifications.

Logistical, technical, and radiation safety aspects of establishing a radiopharmaceutical therapy program: A case in Lutetium-177 prostate-specific membrane antigen (PSMA) therapy

Prostate-specific membrane antigen (PSMA) is a cell surface protein highly expressed in nearly all prostate cancers, with restricted expression in some normal tissues. The differential expression of PSMA from tumor to non-tumor tissue has resulted in the investigation of numerous targeting strategies for therapy of patients with metastatic prostate cancer. In March of 2022, the FDA granted approval for the use of lutetium-177 PSMA-617 (Lu-177-PSMA-617) for patients with PSMA-positive metastatic castration-resistant prostate cancer (mCRPC) who have been treated with androgen receptor pathway inhibition and taxane-based chemotherapy. Therefore, the use of Lu-177-PSMA-617 is expected to increase and become more widespread. Herein, we describe logistical, technical, and radiation safety considerations for implementing a radiopharmaceutical therapy program, with particular focus on the development of operating procedures for therapeutic administrations. Major steps for a center in the U.S. to implement a new radiopharmaceutical therapy (RPT) program are listed below, and then demonstrated in greater detail via examples for Lu-177-PSMA-617 therapy.

A clinical and time savings evaluation of a deep learning automatic contouring algorithm

Automatic contouring algorithms may streamline clinical workflows by reducing normal organ-at-risk (OAR) contouring time. Here we report the first comprehensive quantitative and qualitative evaluation, along with time savings assessment for a prototype deep learning segmentation algorithm from Siemens Healthineers. The accuracy of contours generated by the prototype were evaluated quantitatively using the Sorensen-Dice coefficient (Dice), Jaccard index (JC), and Hausdorff distance (Haus). Normal pelvic and head and neck OAR contours were evaluated retrospectively comparing the automatic and manual clinical contours in 100 patient cases. Contouring performance outliers were investigated. To quantify the time savings, a certified medical dosimetrist manually contoured de novo and, separately, edited the generated OARs for 10 head and neck and 10 pelvic patients. The automatic, edited, and manually generated contours were visually evaluated and scored by a practicing radiation oncologist on a scale of 1-4, where a higher score indicated better performance. The quantitative comparison revealed high (> 0.8) Dice and JC performance for relatively large organs such as the lungs, brain, femurs, and kidneys. Smaller elongated structures that had relatively low Dice and JC values tended to have low Hausdorff distances. Poor performing outlier cases revealed common anatomical inconsistencies including overestimation of the bladder and incorrect superior-inferior truncation of the spinal cord and femur contours. In all cases, editing contours was faster than manual contouring with an average time saving of 43.4% or 11.8 minutes per patient. The physician scored 240 structures with > 95% of structures receiving a score of 3 or 4. Of the structures reviewed, only 11 structures needed major revision or to be redone entirely. Our results indicate the evaluated auto-contouring solution has the potential to reduce clinical contouring time. The algorithm's performance is promising, but human review and some editing is required prior to clinical use.

Survival Outcomes in Men with Unfavorable Intermediate-Risk and High-Risk Prostate Cancer Treated with Prostate-Only versus Whole Pelvic Radiation Therapy

PURPOSE

Men with unfavorable intermediate-risk (UIR-PCa) or high-risk prostate cancer (HR-PCa) are often treated with definitive external beam radiotherapy (EBRT) plus androgen deprivation therapy. Treatment is frequently intensified by electively treating the pelvic lymph nodes (LNs) with whole pelvis radiotherapy (WPRT), but practice patterns and the benefits of WPRT are not well defined. We hypothesized that men treated with WPRT would have improved overall survival (OS) relative to men treated with prostate-only radiotherapy.

MATERIALS AND METHODS

National Cancer Database records of men diagnosed between 2008-2015 with UIR-PCa or HR-PCa and treated with prostate EBRT±androgen deprivation therapy (72-86.4 Gy) with (15,175) or without (13,549) WPRT were reviewed. Risk of LN involvement was calculated using the Memorial Sloan Kettering Cancer Center nomogram. Measured confounders were balanced with inverse probability of treatment weighting and OS hazard ratios (HRs) were generated using multivariable Cox regression.

RESULTS

Of the men, 53% received WPRT. Every 1% increase in risk of LN involvement correlated with a 1% increase in risk of death (p <0.001). WPRT trended toward improved OS in all men with UIR-PCa and HR-PCa (HR: 0.95 [95% CI: 0.90-1.006], p=0.055). WPRT correlated with improved OS in men with Gleason 9 and 10 disease (HR: 0.87 [0.78-0.98], p=0.02) or risk of LN involvement ≥10% (HR: 0.93 [0.87-0.99], p=0.03).

CONCLUSIONS

Men with higher LN risk scores and Gleason grade benefited from WPRT. These results complement the recent POP-RT randomized trial in mostly positron emission tomography/computerized tomography-staged patients, demonstrating that a more heterogeneous population of men staged without functional imaging benefits from WPRT.

Propensity-Weighted Survival Analysis of SBRT vs. Conventional Radiotherapy in Unfavorable Intermediate-Risk Prostate Cancer

BACKGROUND

Prostate stereotactic body radiotherapy (SBRT), which delivers high-dose precision treatment in ≤5 fractions, is a shorter, more convenient, and less expensive alternative to conventionally fractionated radiotherapy (CRFT; ∼44 fractions) or moderately hypofractionated radiotherapy (MFRT; 20-28 fractions). SBRT has not been widely adopted but may have radiobiologic advantages over CFRT/MFRT. We hypothesized that SBRT would be associated with improved overall survival (OS) versus CFRT or MFRT ± androgen deprivation therapy (ADT) for unfavorable-intermediate-risk prostate cancer (UIR-PCa).

METHODS

Men with UIR-PCa treated with SBRT (35-40Gy in ≤5 fractions) or biologically equivalent doses of CFRT (72-86.4Gy in 1.8-2.0Gy/fraction) or MRFT (≥60Gy in 2.4-3.2Gy/fraction; biologically effective doses ≥120) were identified in the National Cancer Database (NCDB). Unweighted and propensity-weighted multivariable Cox analysis (MVA) was used to compare OS hazard ratios.

RESULTS

Of 28,028 men with UIR-PCa who received CFRT with (n = 12,872) or without ADT (n = 12,984); MFRT with (n = 251) or without ADT (n = 281); and SBRT with (n = 212) or without ADT (n = 1,428) were identified. Relative to CFRT without ADT, CFRT+ ADT (HR 0.92, 95% CI 0.87-0.97, P = .002) and SBRT without ADT (HR 0.74, 95% CI 0.61-0.89, P = .002) were both associated with improved OS on MVA. Relative to CFRT+ADT, SBRT without ADT correlated with improved OS on MVA (HR:0.81, 95% CI 0.67-0.99, P = .04). Propensity-weighted MVA demonstrated that SBRT (HR:0.80, 95% CI 0.65-0.98, P = .036) and ADT (HR:0.91, 95% CI 0.86-0.97, P = .002) correlated with improved OS. SBRT was not associated with improved OS versus MFRT.

CONCLUSION

SBRT, which offers a cheaper and shorter treatment course that mitigates COVID-19 exposure, was associated with improved OS versus CFRT for UIR-PCa. These results confirm guideline-based recommendations that SBRT is a viable option for UIR prostate cancer. The results from this large retrospective study require further validation in clinical trials.

Treatment Patterns and Overall Survival Outcomes Among Patients Aged 80 yr or Older with High-risk Prostate Cancer

BACKGROUND

Elderly patients diagnosed with high-risk prostate cancer (PCa) present a therapeutic dilemma of balancing treatment of a potentially lethal malignancy with overtreatment of a cancer that may not threaten life expectancy.

OBJECTIVE

To investigate treatment patterns and overall survival outcomes in this group of patients.

DESIGN SETTING AND PARTICIPANTS

A retrospective cohort study was conducted. We queried the National Cancer Database for high-risk PCa in patients aged 80 yr or older diagnosed during 2004-2016.

INTERVENTION

Eligible patients underwent no treatment following biopsy (ie, observation), androgen deprivation therapy (ADT) alone, radiation therapy (RT) alone, RT + ADT, or surgery.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Kaplan-Meier, log rank, and multivariate Cox proportional hazard regression was performed to compare overall survival (OS).

RESULTS AND LIMITATIONS

A total of 19 920 men were eligible for analysis, and the most common treatment approach was RT + ADT (7401 patients; 37.2%). Observation and ADT alone declined over time (59.3% in 2004 vs 47.5% in 2016). There was no observed difference in OS between observation and ADT alone (adjusted hazard ratio [HR] 1.04, 95% confidence interval [CI], 0.99-1.09; p = 0.105). Definitive local treatment was associated with improved OS compared with ADT alone (RT alone, HR 0.54, 95% CI, 0.50-0.59, p < 0.0001; ADT + RT, HR 0.48, 95% CI, 0.46-0.50, p < 0.0001; surgery, HR 0.50, 95% CI, 0.42-0.59, p < 0.0001).

CONCLUSIONS

This analysis demonstrates that the use of definitive local therapy, including surgery or RT ± ADT, is increasing and is associated with a 50% reduction in overall mortality compared with observation or ADT alone. While prospective validation is warranted, elderly men with high-risk disease eligible for definitive management should be counseled on the risks, including a possible compromise in OS, with deferring definitive management.

PATIENT SUMMARY

Elderly men are more often diagnosed with higher-risk prostate cancer but are less likely to receive curative treatment options than younger men. Our analysis demonstrates that for men ≥80 yr of age with high-risk prostate cancer, definitive local therapy, including surgery or radiation therapy and/or androgen deprivation therapy, is associated with a 50% reduction in overall mortality compared with observation or androgen deprivation therapy alone. We therefore recommend that life expectancy (ie, physiologic age) be taken into account, over chronologic age, and that elderly men with good life expectancy (eg, >5 yr; minimal comorbidity) should be offered definitive, life-prolonging therapy.

Outcomes of Patients With Unfavorable Intermediate-Risk Prostate Cancer Treated With External-Beam Radiotherapy Versus Brachytherapy Alone

BACKGROUND

The NCCN Guidelines for Prostate Cancer currently recommend several definitive radiotherapy (RT) options for men with unfavorable intermediate-risk (UIR) prostate cancer: external-beam RT (EBRT) plus androgen deprivation therapy (ADT) or EBRT plus brachytherapy boost with or without ADT. However, brachytherapy alone with or without ADT is not well defined and is currently not recommended for UIR prostate cancer. We hypothesized that men treated with brachytherapy with or without ADT have comparable survival rates to men treated with EBRT with or without ADT.

METHODS

A total of 31,783 men diagnosed between 2004 and 2015 with UIR prostate cancer were retrospectively reviewed from the National Cancer Database. Men were stratified into 4 groups: EBRT (n=12,985), EBRT plus ADT (n=12,960), brachytherapy (n=4,535), or brachytherapy plus ADT (n=1,303). Inverse probability of treatment weighting (IPTW) was used to adjust for covariable imbalances, and weight-adjusted multivariable analysis (MVA) using Cox regression modeling was used to compare overall survival (OS) hazard ratios (HRs).

RESULTS

Relative to EBRT alone, the following treatments were associated with improved OS: EBRT plus ADT (HR, 0.92; 95% CI, 0.87-0.97; P=.002), brachytherapy alone (HR, 0.90; 95% CI, 0.83-0.98; P=.01), and brachytherapy plus ADT (HR, 0.78; 95% CI, 0.69-0.88; P=.00006). Brachytherapy correlated with improved OS relative to EBRT in men who were not treated with ADT (HR, 0.92; 95% CI, 0.84-0.99; P=.03) and in those receiving ADT (HR, 0.84; 95% CI, 0.75-0.95; P=.004). At 10-year follow-up, 56% and 63% of men receiving EBRT and brachytherapy, respectively, were alive (P<.0001). IPTW was used to determine the average treatment effect of definitive brachytherapy. Relative to EBRT, definitive brachytherapy correlated with improved OS (HR, 0.90; 95% CI, 0.84-0.97; P=.009) on weight-adjusted MVA.

CONCLUSIONS

Definitive brachytherapy was associated with improved OS compared with EBRT. The addition of ADT to both EBRT and definitive brachytherapy was associated with improved OS. These results suggest that definitive brachytherapy should be considered as an option for men with UIR prostate cancer.

Quality of Life Implications of Dose-Escalated External Beam Radiation for Localized Prostate Cancer: Results of a Prospective Randomized Phase 3 Clinical Trial, NRG/RTOG 0126

PURPOSE

External beam radiation therapy (EBRT) dose escalation has been tested in multiple prospective trials. However, the impact on patient reported outcomes (PROs) associated with higher doses of EBRT remain poorly understood. We sought to assess the differences in PROs between men treated with a dose of 70.2 Gy versus 79.2 Gy of EBRT for prostate cancer.

METHODS AND MATERIALS

The phase 3 clinical trial RTOG 0126 randomized 1532 patients with prostate cancer between March 2002 and August 2008 to 79.2 Gy over 44 fractions versus 70.2 Gy over 39 fractions. Eligible patients participated in the PRO data collection. PROs completed included the International Index of Erectile Function Questionnaire (IIEF), Functional Alterations due to Changes in Elimination (FACE), and the Spitzer Quality of Life Index (SQLI). The timepoints for the IIEF were collected pre-entry and at 6, 12, and 24 months. The FACE and SQLI were collected pre-entry and at 3, 6, 12, 18, and 24 months. The impact of EBRT dose to normal structures (penile bulb, rectum, and bladder) on PROs was also examined. Mixed effects models were used to analyze trends across time.

RESULTS

In total, 1144 patients completed baseline IIEF forms and of these, 56%, 64%, and 61% completed the IIEF at 6, 12, and 24 months, respectively; 1123 patients completed the FACE score at baseline and 50%, 61%, 73%, 61%, and 65% completed all 15 items for the FACE metric at timepoints of 3, 6, 12, 18, and 24 months, respectively. Erectile dysfunction at 12 months based on the single question was not significantly different between arms (38.1% for the standard dose radiation therapy arm vs 49.7% for the dose escalated radiation therapy arm; P = .051). Treatment arm (70.2 vs 79.2) had no significant impact on any PRO metrics measured across all collected domains. Comprehensive dosimetric analyses are presented and reveal multiple significant differences to regional organs at risk.

CONCLUSIONS

Compliance with PRO data collection was lower than anticipated in this phase 3 trial. Examining the available data, dose escalated EBRT did not appear to be associated with any detriment to PROs across numerous prospectively collected domains. These data, notwithstanding limitations, add to our understanding of the implications of EBRT dose escalation in prostate cancer. Furthermore, these results illustrate challenges associated with PRO data collection.

Development and Implementation of an Open Source Template Interpretation Class Library for Automated Treatment Planning

PURPOSE

Widespread implementation of automated treatment planning in radiation therapy remains elusive due to variability in clinic and physician preferences making it difficult to ensure consistent plan parameters. We have developed an open-source class library with the aim to improve efficiency and consistency for automated treatment planning in radiation therapy.

METHODS AND MATERIALS

An open source class library has been developed that interprets clinical templates within a commercial treatment planning system into a treatment plan for automated planning. This code was leveraged for the automated planning of 39 patients and retrospectively compared to the 78 clinically approved manual plans.

RESULTS

From the initial 39 patients, 74 of 78 plans were successfully generated without manual intervention. Target dose was more homogenous for automated plans, with an average homogeneity index of 3.30 vs 3.11 for manual and automated plans, respectively (p = 0.107). Generalized equivalent uniform dose decreased in the femurs and rectum for automated plans, with mean gEUD of 3746 cGy vs 3338 cGy (p ≤ 0.001) and 5761 cGy vs 5634 cGy (p ≤ 0.001) for femurs and rectum, respectively. Dose metrics for bladder and rectum (V6500 cGy and V4000 cGy) show recognizable but insignificant improvements. All automated plans delivered for quality assurance passed a gamma analysis (>95%) with an average composite pass rate of 99.3% and 98.8% for pelvis and prostate plans, respectively. Deliverability parameters such as total monitor units and aperture complexity indicate deliverable plans.

CONCLUSIONS

Prostate cancer and pelvic node radiotherapy can be automated using VMAT planning and clinical templates based on a standardized clinical workflow. The class library developed in this study conveniently interfaces between the plan template and the treatment planning system to automatically generate high quality plans on customizable templates.

Feasibility of Same-Day Prostate Fiducial Markers, Perirectal Hydrogel Spacer Placement, and Computed Tomography and Magnetic Resonance Imaging Simulation for External Beam Radiation Therapy for Low-Risk and Intermediate-Risk Prostate Cancer

PURPOSE

The use of prostate fiducial markers and perirectal hydrogel spacers can reduce the acute and late toxic effects associated with prostate radiation therapy. These procedures are usually performed days to weeks before simulation during a separate clinic visit to ensure resolution of procedure-related inflammation. The purpose of this study was to assess whether same-day intraprostatic fiducial marker placement, perirectal hydrogel injection, and computed tomography (CT) and magnetic resonance imaging (MRI) simulation were feasible without adversely affecting hydrogel volume, perirectal spacing, or rectal dose. If feasible, performing these procedures on the same day as simulation would expedite the start of radiation therapy, improve patient convenience, and reduce costs.

METHODS AND MATERIALS

Twenty-one patients with clinically localized prostate cancer who were enrolled on a prospective clinical trial (NCT01617161) underwent same-day marker placement, hydrogel injection, and CT and MRI simulation, then underwent T2 MRI verification scans 3 to 4 weeks later. The MRI scans were fused to the CT planning scans by clinical target volumes (CTVs) to generate comparison treatment plans (70 Gy in 28 fractions). Hydrogel volume and symmetry, perirectal spacing, CTV dose, and organ-at-risk dose were evaluated.

RESULTS

Verification scans occurred a mean of 24.9 ± 4.6 days after simulation and 9.3 ± 4.9 days after treatment start. Prostate volume did not change between scans (median, 67.3 ± 22.1 cm³ vs 64.1 ± 21.8 cm³; P = .64). The median hydrogel change between simulation and verification was ^-1.8% ± 4.5% (P = .27). No significant differences in perirectal spacing (midgland: 1.33 ± 0.45 cm vs 1.3 ± 0.7 cm; 1 cm superior: 1.25 ± 0.95 cm vs 1.43 ± 0.91 cm; 1 cm inferior: 1.16 ± 0.28 cm vs 1.41 ± 0.49 cm) were identified. No significant differences in rectal V66 (median 2.3 ± 2.18% vs 2.3 ± 2.28%; P = .99), V35 (median 14.79 ± 7.61 vs 14.67 ± 8.4; P = .73), or D1cc (65.7 ± 9.2 Gy vs 68.2 ± 9.0 Gy; P = .80) were found. All plans met CTV and organ-at-risk constraints.

CONCLUSION

Same-day placement of intraprostatic fiducial markers, perirectal hydrogel, and simulation scans was feasible and did not significantly affect hydrogel volume, position, CTV coverage, or rectal dose.

A Rational Approach to Unilateral Neck RT for Head and Neck Cancers in the Era of Immunotherapy

Radiotherapy plays an important role in the definitive and adjuvant treatment of head and neck squamous cell carcinoma (HNSCC). However, standard courses of radiation therapy may contribute to the depletion of circulating lymphocytes and potentially attenuate optimal tumor antigen presentation that may be detrimental to the efficacy of novel immunotherapeutic agents. This review explores the advantages of restricting radiation to the primary tumor/tumor bed and ipsilateral elective neck as it pertains to the evolving field of immunotherapy.

Impact of human papillomavirus on the tumor microenvironment in oropharyngeal squamous cell carcinoma

Increasing evidence has elucidated the clinicopathological significance of tumor microenvironment (TME) cells. However, TME differences associated with human papillomavirus (HPV) infection in oropharyngeal squamous cell carcinoma (OPSCC) have not been well characterized. In our study, we comprehensively determined the TME infiltration patterns in 315 OPSCC patients, and systematically correlated the TME phenotypes with genomic characteristics and clinical features of OPSCCs. In this way, we observed the enrichment of high endothelial cells and adaptive immune cells in HPV-positive (HPV+) OPSCCs, in contrast to the enrichment of fibroblasts and capillary endothelial cells in HPV- negative (HPV-) OPSCCs. By focusing on immune checkpoint genes, we constructed a coexpression network using genes that were differentially expressed between HPV+ and HPV- OPSCCs. Functional analysis of the network indicated that HPV+ OPSCCs had elevated immune activities by promoting adaptive immune response and suppressing activities related to extracellular matrix organization. Subsequently, clinical analysis showed that identified TME-relevant genes were closely associated with the prognosis and therapy response in OPSCC. Importantly, results from the TME analysis were further validated using an independent OPSCC cohort.

Association Between Surgical Margins Larger Than 1 cm and Overall Survival in Patients With Merkel Cell Carcinoma

Importance

Current recommendations regarding the size of local excision (LE) margins for Merkel cell carcinoma (MCC) have not been well established.

Objective

To assess whether larger clinical LE margins and receipt of adjuvant radiotherapy are associated with improvements in overall survival (OS) among patients with localized MCC.

Design, Setting, and Participants

This large multicenter retrospective cohort study used records from the National Cancer Database to identify adult patients with localized stage I or stage II MCC who underwent LE between January 1, 2004, and December 31, 2015. Data were analyzed from August 1, 2020, to January 25, 2021.

Exposures

Local excision margin size and adjuvant radiotherapy.

Main Outcomes and Measures

Overall and net survival were assessed using Cox multivariable regression analysis.

Results

A total of 6156 patients with localized MCC (median age at diagnosis, 77 years [range, 27-90 years]; 2500 women [40.6%]). In the multivariable regression analysis, LE clinical margins larger than 1.0 cm were associated with improvements in OS (HR, 0.88; 95% CI, 0.81-0.95; P < .001) compared with margins of 1.0 cm or smaller, regardless of tumor subsite. At 5 years after surgery, LE margins of 1.0 cm or smaller were associated with a net survival of 76.7%, while LE margins larger than 1.0 cm were associated with a net survival of 89.8% (P < .001). Stratification of LE margins into 3 subgroups indicated that LE margins of 1.1 to 2.0 cm (HR, 0.87; 95% CI, 0.76-0.99; P = .047) and larger than 2.0 cm (HR, 0.84; 95% CI, 0.72-0.98; P = .03) were associated with improvements in OS compared with margins of 1.0 cm or smaller. In patients with less aggressive disease (ie, those who were immunocompetent and had tumors ≤1.0 cm, no lymphovascular invasion, and negative pathologic margins), LE margins larger than 1.0 cm were also associated with improvements in OS (HR, 0.87; 95% CI, 0.78-0.97; P = .01). Among patients who received adjuvant radiotherapy, larger LE margins were associated with improvements in OS (HR, 0.87; 95% CI, 0.76-0.98; P = .03). Receipt of adjuvant radiotherapy was also associated with improvements in OS within the 3 LE margin subgroups. Patients who received adjuvant radiotherapy and had LE margins of 1.0 cm or smaller (HR, 0.81; 95% CI, 0.74-0.89; P < .001) experienced OS that was comparable to that in patients who did not receive adjuvant radiotherapy and had LE margins larger than 1.0 cm (HR, 0.80; 95% CI, 0.71-0.89; P = .87).

Conclusions and Relevance

In this study, LE clinical margins larger than 1.0 cm were associated with improvements in OS, and these improvements were independent of tumor subsite, receipt of adjuvant radiotherapy, positive pathologic margins, or adverse pathologic features for stage I to stage II MCC. Patients with LE margins of 1.0 cm or smaller who received adjuvant radiotherapy experienced OS that was similar to that of patients with larger LE margins who did not receive radiotherapy. The combination of LE clinical margins larger than 1.0 cm and adjuvant radiotherapy was associated with the highest OS.

Does the sequence of high-dose rate brachytherapy boost and IMRT for prostate cancer impact early toxicity outcomes? Results from a single institution analysis

•

The optimal sequence of HDR-BT boost and EBRT for prostate cancer is unclear.

•

We compared early toxicity based on the timing of HDR-BT boost.

•

The timing of HDR-BT was not based on any specific patient or clinical factors.

•

We found no difference in early GI/GU toxicity between the two groups.

•

Longer follow-up is needed to evaluate late toxicity and long-term disease control.

Background

We present the first report comparing early toxicity outcomes with high-dose rate brachytherapy (HDR-BT) boost upfront versus intensity modulated RT (IMRT) upfront combined with androgen deprivation therapy (ADT) as definitive management for intermediate risk or higher prostate cancer.

Methods and Materials

We reviewed all non-metastatic prostate cancer patients who received HDR-BT boost from 2014 to 2019. HDR-BT boost was offered to patients with intermediate-risk disease or higher. ADT use and IMRT target volume was based on NCCN risk group. IMRT dose was typically 45 Gy in 25 fractions to the prostate and seminal vesicles ± pelvic lymph nodes. HDR-BT dose was 15 Gy in 1 fraction, delivered approximately 3 weeks before or after IMRT. The sequence was based on physician preference. Biochemical recurrence was defined per ASTRO definition. Gastrointestinal (GI) and Genitourinary (GU) toxicity was graded per CTCAE v5.0. Pearson Chi-squared test and Wilcoxon tests were used to compare toxicity rates. P-value < 0.05 was significant.

Results

Fifty-eight received HDR-BT upfront (majority 2014–2016) and 57 IMRT upfront (majority 2017–2018). Median follow-up was 26.0 months. The two cohorts were well-balanced for baseline patient/disease characteristics and treatment factors. There were differences in treatment sequence based on the year in which patients received treatment. Overall, rates of grade 3 or higher GI or GU toxicity were <1%. There was no significant difference in acute or late GI or GU toxicity between the two groups.

Conclusion

We found no significant difference in GI/GU toxicity in intermediate-risk or higher prostate cancer patients receiving HDR-BT boost upfront versus IMRT upfront combined with ADT. These findings suggest that either approach may be reasonable. Longer follow-up is needed to evaluate late toxicity and long-term disease control.

A MicroRNA Expression Signature as Prognostic Marker for Oropharyngeal Squamous Cell Carcinoma

BACKGROUND

Improved prognostication of oropharyngeal squamous cell carcinoma (OPSCC) may facilitate individualized patient management. The goal of this study was to develop and validate a prognostic signature based on microRNA sequencing (miRNA-seq) analysis.

METHODS

We collected tumor specimens for miRNA-seq analysis from OPSCC patients treated at Washington University in St Louis (n = 324) and Vanderbilt University (n = 130). OPSCC patients (n = 79) from The Cancer Genome Atlas Program were also included for independent validation. Univariate and multivariable Cox regression analyses were performed to identify miRNAs associated with disease outcomes. All statistical tests were 2-sided.

RESULTS

By miRNA-seq profiling analysis, we identified a 26-miRNA signature. Based on computed risk scores of the signature, we classified the patients into low- and high-risk groups. In the training cohort, the high-risk group had much shorter overall survival compared with the low-risk group (hazard ratio [HR] = 3.80, 95% confidence interval [CI] = 2.37 to 6.10, P < .001). Subgroup analysis further revealed that the signature was prognostic for HPV-positive OPSCCs (HR = 3.07, 95% CI = 1.65 to 5.71, P < .001). Multivariable analysis indicated that the signature was independent of common clinicopathologic factors for OPSCCs. Importantly, the miRNA signature was a statistically significant predictor of overall survival in independent validation cohorts (The Cancer Genome Atlas Program cohort: HR = 6.05, 95% CI = 2.10 to 17.37, P < .001; Vanderbilt cohort: HR = 7.98, 95% CI = 3.99 to 15.97, P < .001; Vanderbilt HPV-positive cohort: HR = 8.71, 95% CI = 2.70 to 28.14, P < .001).

CONCLUSIONS

The miRNA signature is a robust and independent prognostic tool for risk stratification of OPSCCs including HPV-positive OPSCCs.

Quantitative Analysis of Practice Size Consolidation in Radiation Oncology: A Trend Toward Bigger and Fewer Practices

PURPOSE

There is evidence of practice consolidation in US health care in recent years. To our knowledge, a detailed quantitative study of recent changes in radiation oncology practice size has not been performed. We aim to evaluate radiation oncology practice size changes between 2012 and 2020 in the United States.

MATERIALS AND METHODS

Using the Medicare Physician Compare Database, we identified practices employing radiation oncologists using their taxpayer identification number and individual radiation oncologists using their national provider identifier. We grouped individual radiation oncologists into categories by practice size (which includes the number of physicians of all specialties) and compared the number of radiation oncologists in each category between 2012 and 2020. Further analyses by US geographic census region, single-specialty practice, academic practice, and high- and low-population density areas were performed.

RESULTS

Between 2012 and 2020, the total number of practicing radiation oncologists increased by 9%, and the number of practices employing radiation oncologists decreased by 11.5%. The number of radiation oncologists in practices of size 1 to 2, 3 to 9, 10 to 24, and 25 to 49 decreased by 3.7%, 4.7%, 4.9%, and 2%, respectively, and the number of radiation oncologists in practices of size 50 to 99, 100 to 499, and 500+ increased by 1.4%, 2.1%, and 11.8%, respectively (all 500+ practices are multispecialty groups). The increase in practice size was significant in all regions, for single-specialty and multispecialty practices, academic and nonacademic practices, and for practices in high-, middle-, and low-population density areas (P < .05 for all comparisons). The proportion of single-specialty practices has decreased significantly (P < .001), and the proportion of academic practices increased significantly (P = .004). Additionally, the proportion of practices and physicians in high- and low-population density regions remained stable during this period (P > .05).

CONCLUSIONS

Our analysis suggests that practice size consolidation has occurred within the US radiation oncology workforce from 2012 to 2020. The impact of this consolidation on quality, cost, and patient access deserves further attention.

Modified full-face snorkel mask as COVID-19 personal protective equipment: Quantitative results

The COVID-19 crisis has resulted in a shortage of personal protective equipment (PPE). Adapting commercially available full-faced snorkel masks has been proposed as an alternative to narrow the gap in PPE. An advantage of the full-faced snorkel mask design is that it serves two critical purposes: eye and face protection, and high quality air filtration to protect against SARS-CoV-2. We performed quantitative testing on various full-faced snorkel masks with 3D printed adapters that accept commercially available particulate filters, and report on a design that passed Occupational Safety and Health Administration (OSHA) full-facepiece respirator standards.

A prognostic gene expression signature for oropharyngeal squamous cell carcinoma

BACKGROUND

Robust prognostic stratification of patients with oropharyngeal squamous cell carcinoma (OPSCC) is important for developing individualized treatment plans. This study was conducted to develop and validate a clinically feasible prognostic classifier based on transcriptome-wide gene expression profiles.

METHODS

Tumor tissues were collected from 208 OPSCC patients treated at Washington University in St. Louis and 130 OPSCC patients treated at Vanderbilt University, used for model training and validation, respectively. OPSCC patients (n = 70) from the TCGA cohort were also included for independent validation. Based on RNA-seq profiling data, Cox proportional hazards regression analysis was performed to identify genes associated with disease outcomes. Then, Lasso-penalized multivariate survival models were constructed to identify biomarker genes for developing a prognostic gene signature.

FINDINGS

A 60-gene signature was identified by RNA-seq profiling analysis. Computed risk score of the gene signature was significantly predictive of 5-year overall survival of the training cohort (Hazard ratio (HR) 28·32, P = 4·3E-41). Subgroup analysis stratified by HPV status revealed that the signature was prognostic in HPV-positive OPSCC patients (HR 30·55, P = 7·0E-37) and was independent of clinical features. Importantly, the gene signature was validated in two independent patient cohorts, including the TCGA cohort (HR 3·94, P = 0·0018) and the Vanderbilt cohort (HR 8·50, P = 5·7E-09) for overall survival.

INTERPRETATION

The prognostic gene signature is a robust tool for risk stratification of OPSCC patients. The signature remains prognostic among HPV-positive OPSCC patients.

FUNDING

National Institutes of Health.

Review: Brain Metastases in Bladder Cancer

Nearly 50% of bladder cancer patients either present with metastatic disease or relapse distantly following initial local therapy. Prior to platinum-based chemotherapy, the incidence of bladder cancer central nervous system metastases was approximately 1%; however, their incidence has increased to 3–16% following definitive treatment as platinum-based regimens have changed the natural history of the disease. Bladder cancer brain metastases are generally managed similarly to those from more common malignancies such as non-small cell lung cancer, with surgery +/–adjuvant radiotherapy, or radiotherapy alone using stereotactic radiosurgery or whole brain radiotherapy. Limited data suggest that patients with inoperable urothelial carcinoma brain metastases who are not candidates for stereotactic radiosurgery may benefit from shorter whole brain radiation therapy courses compared to other histologies, but data is hypothesis-generating. Given improvements in the efficacy of systemic therapy and supportive care strategies for metastatic urothelial carcinoma translating in improved survival, the incidence of intracranial failures may increase. Immune checkpoint blockade therapy may benefit cisplatin-ineligible metastatic urothelial carcinoma patients as first-line therapy; however, the effectiveness of immune checkpoint blockade to treat central nervous system disease has not been established. In this review, we discuss the incidence and management of bladder cancer brain metastases and considerations regarding variations in management relative to more commonly encountered non-urothelial histologies.

Neoadjuvant and Adjuvant Pembrolizumab in Resectable Locally Advanced, Human Papillomavirus-Unrelated Head and Neck Cancer: A Multicenter, Phase II Trial

PURPOSE

Pembrolizumab improved survival in patients with recurrent or metastatic head and neck squamous-cell carcinoma (HNSCC). The aims of this study were to determine if pembrolizumab would be safe, result in pathologic tumor response (pTR), and lower the relapse rate in patients with resectable human papillomavirus (HPV)-unrelated HNSCC.

PATIENTS AND METHODS

Neoadjuvant pembrolizumab (200 mg) was administered and followed 2 to 3 weeks later by surgical tumor ablation. Postoperative (chemo)radiation was planned. Patients with high-risk pathology (positive margins and/or extranodal extension) received adjuvant pembrolizumab. pTR was quantified as the proportion of the resection bed with tumor necrosis, keratinous debris, and giant cells/histiocytes: pTR-0 (<10%), pTR-1 (10%-49%), and pTR-2 (≥50%). Coprimary endpoints were pTR-2 among all patients and 1-year relapse rate in patients with high-risk pathology (historical: 35%). Correlations of baseline PD-L1 and T-cell infiltration with pTR were assessed. Tumor clonal dynamics were evaluated (ClinicalTrials.gov NCT02296684).

RESULTS

Thirty-six patients enrolled. After neoadjuvant pembrolizumab, serious (grades 3-4) adverse events and unexpected surgical delays/complications did not occur. pTR-2 occurred in eight patients (22%), and pTR-1 in eight other patients (22%). One-year relapse rate among 18 patients with high-risk pathology was 16.7% (95% confidence interval, 3.6%-41.4%). pTR ≥10% correlated with baseline tumor PD-L1, immune infiltrate, and IFNγ activity. Matched samples showed upregulation of inhibitory checkpoints in patients with pTR-0 and confirmed clonal loss in some patients.

CONCLUSIONS

Among patients with locally advanced, HPV-unrelated HNSCC, pembrolizumab was safe, and any pathologic response was observed in 44% of patients with 0% pathologic complete responses. The 1-year relapse rate in patients with high-risk pathology was lower than historical.

Management of Muscle-Invasive Bladder Cancer During a Pandemic: Impact of Treatment Delay on Survival Outcomes for Patients Treated With Definitive Concurrent Chemoradiotherapy

Introduction

During the coronavirus disease 2019 (COVID-19) pandemic, providers and patients must engage in shared decision making to ensure that the benefit of early intervention for muscle-invasive bladder cancer exceeds the risk of contracting COVID-19 in the clinical setting. It is unknown whether treatment delays for patients eligible for curative chemoradiation (CRT) compromise long-term outcomes.

Patients and Methods

We used the National Cancer Data Base to investigate whether there is an association between a ≥ 90-day delay from transurethral resection of bladder tumor (TURBT) in initiating CRT and overall survival. We included patients with cT2-4N0M0 muscle-invasive bladder cancer from 2004 to 2015 who underwent TURBT and curative-intent concurrent CRT. Patients were grouped on the basis of timing of CRT: ≤ 89 days after TURBT (earlier) vs. ≥ 90 and < 180 days after TURBT (delayed).

Results

A total of 1387 (87.5%) received earlier CRT (median, 45 days after TURBT; interquartile range, 34-59 days), and 197 (12.5%) received delayed CRT (median, 111 days after TURBT; interquartile range, 98-130 days). Median overall survival was 29.0 months (95% CI, 26.0-32.0) versus 27.0 months (95% CI, 19.75-34.24) for earlier and delayed CRT (P = .94). On multivariable analysis, delayed CRT was not associated with an overall survival difference (hazard ratio, 1.05; 95% CI, 0.87-1.27; P = .60).

Conclusion

Although these results are limited and require validation, short, strategic treatment delays during a pandemic can be considered on the basis of clinician judgment.

Management of primary skin cancer during a pandemic: Multidisciplinary recommendations

During the coronavirus disease 2019 (COVID‐19) pandemic, providers and patients must engage in shared decision making regarding the pros and cons of early versus delayed interventions for localized skin cancer. Patients at highest risk of COVID‐19 complications are older; are immunosuppressed; and have diabetes, cancer, or cardiopulmonary disease, with multiple comorbidities associated with worse outcomes. Physicians must weigh the patient's risk of COVID‐19 complications in the event of exposure against the risk of worse oncologic outcomes from delaying cancer therapy. Herein, the authors have summarized current data regarding the risk of COVID‐19 complications and mortality based on age and comorbidities and have reviewed the literature assessing how treatment delays affect oncologic outcomes. They also have provided multidisciplinary recommendations regarding the timing of local therapy for early‐stage skin cancers during this pandemic with input from experts at 11 different institutions. For patients with Merkel cell carcinoma, the authors recommend prioritizing treatment, but a short delay can be considered for patients with favorable T1 disease who are at higher risk of COVID‐19 complications. For patients with melanoma, the authors recommend delaying the treatment of patients with T0 to T1 disease for 3 months if there is no macroscopic residual disease at the time of biopsy. Treatment of tumors ≥T2 can be delayed for 3 months if the biopsy margins are negative. For patients with cutaneous squamous cell carcinoma, those with Brigham and Women's Hospital T1 to T2a disease can have their treatment delayed for 2 to 3 months unless there is rapid growth, symptomatic lesions, or the patient is immunocompromised. The treatment of tumors ≥T2b should be prioritized, but a 1‐month to 2‐month delay is unlikely to worsen disease‐specific mortality. For patients with squamous cell carcinoma in situ and basal cell carcinoma, treatment can be deferred for 3 months unless the individual is highly symptomatic.

During the coronavirus disease 2019 (COVID‐19) pandemic, providers must help patients to make informed decisions regarding skin cancer management and assess the risk of potential COVID‐19–associated morbidity and/or mortality versus primary skin cancer morbidity and/or mortality. In this article, the authors summarize current data regarding the risk of COVID‐19 complications and mortality based on age and comorbidities, and review the literature assessing how treatment delays affect oncologic outcomes. They provide multidisciplinary recommendations regarding the timing of local therapy for patients with early‐stage skin cancers.

Childhood tonsillectomy alters the primary distribution of HPV-related oropharyngeal squamous cell carcinoma

OBJECTIVES

We investigated how tonsillectomy during childhood may influence the distribution of human papillomavirus (HPV) positive cancer of the tonsils in adult life using p16 as a surrogate marker for HPV infection.

STUDY DESIGN

Retrospective observational study.

METHODS

A total of 280 patients diagnosed with oropharyngeal squamous cell carcinoma (OPSCC) and known p16 status were eligible for this study. Each participant was called to obtain the childhood tonsillectomy history. Respondents were subgrouped by p16 status and the primary tumor location. Patient demographic and clinical information was analyzed for association with Fisher's exact and Wilcoxon rank sum tests. Location of tumor was modeled using univariate (UVA) and multivariate (MVA) logistic regression with associated odds ratios (OR) and 95% confidence intervals.

RESULTS

Of the 280 patients, 115 (41%) were respondents: 104 (90.4%) were p16 positive and 11 (9.6%) were p16 negative. For p16 positive patients, we observed a majority (93%) of intact tonsils in those with tonsil cancer, compared to 45% of intact tonsils in patients with p16 positive cancer elsewhere in the oropharynx (P < .001). MVA logistic regression showed that female gender (OR = 4.16, P = .0675), prior smoking history (OR = 2.6, P = .0367), and intact tonsils (OR = 15.2, P < .0001) were associated with tonsillar OPSCC.

CONCLUSION

We found that patients with p16 positive OPSCC at a non-tonsil site were much more likely to have had prior tonsillectomy vs those with p16 positive OPSCC arising within the tonsil. Nevertheless, we do not advocate tonsillectomies as a public health policy to reduce HPV-related OPSCC.

LEVEL OF EVIDENCE

6.

A Brief Review of Low-Dose Rate (LDR) and High-Dose Rate (HDR) Brachytherapy Boost for High-Risk Prostate

For patients with unfavorable or high-risk prostate cancer, dose escalated radiation therapy leads to improved progression free survival but attempts to deliver increased dose by external beam radiation therapy (EBRT) alone can be limited by late toxicities to nearby genitourinary and gastrointestinal organs at risk. Brachytherapy is a method to deliver dose escalation in conjunction with EBRT with a potentially improved late toxicity profile and improved prostate cancer related outcomes. At least three randomized controlled trials have demonstrated improved biochemical control with the addition of either low-dose rate (LDR) or high-dose rate (HDR) brachytherapy to EBRT, although only ASCENDE-RT compared brachytherapy to dose-escalated EBRT but did report an over 50% improvement in biochemical failure with a LDR boost. Multiple single institution and comparative research series also support the use of a brachytherapy boost in the DE-EBRT era and demonstrate excellent prostate cancer specific outcomes. Despite improved oncologic outcomes with a brachytherapy boost in the high-risk setting, the utilization of both LDR, and HDR brachytherapy use is declining. The acute genitourinary toxicities when brachytherapy boost is combined with EBRT, particularly a LDR boost, are of concern in comparison to EBRT alone. HDR brachytherapy boost has many physical properties inherent to its rapid delivery of a large dose which may reduce acute toxicities and also appeal to the radiobiology of prostate cancer. We herein review the evidence for use of either LDR or HDR brachytherapy boost for high-risk prostate cancer and summarize comparisons between the two treatment modalities.

Treatment patterns of high-dose-rate and low-dose-rate brachytherapy as monotherapy for prostate cancer

PURPOSE

Monotherapy with high-dose-rate (HDR) or low-dose-rate (LDR) brachytherapy are both recommended modalities for prostate cancer. The choice between HDR and LDR is dependent on patient, physician, and hospital preferences. We sought to identify treatment patterns and factors associated with receipt of HDR or LDR monotherapy.

MATERIAL AND METHODS

We queried the National Cancer Database (NCDB) for patients with localized low- or intermediate-risk prostate cancer treated with HDR or LDR monotherapy. Descriptive statistics were used to analyze patterns of HDR vs. LDR. Patient characteristics were correlated with HDR vs. LDR using multivariable logistic regression.

RESULTS

We identified 50,326 patients from 2004-2014: LDR 37,863 (75.2%) vs. HDR 12,463 (24.8%). Median follow-up was 70.3 months. The overall use of monotherapy declined over time. HDR application declined relative to LDR. In 2004, 27.0% of cases were HDR compared to 19.2% in 2014. Factors associated with increased likelihood of HDR on multivariable analysis included: increasing age (OR: 1.01, 95% CI: 1.01-1.01), cT2c disease (OR: 1.25, 95% CI: 1.11-1.41), treatment at an academic center (OR: 2.45, 95% CI: 2.24-2.65), non-white race (OR: 1.34, 95% CI: 1.27-1.42), and income > $63,000 (OR: 1.73, 95% CI: 1.59-1.88). LDR was more common in 2010-2014 (OR: 0.59, 95% CI: 0.54-0.65), Charlson-Deyo comorbidity index > 0 (OR: 0.89, 95% CI: 0.84-0.95), and for patients receiving hormone therapy (OR: 0.88, 95% CI: 0.83-0.93). No difference in prostate-specific antigen (PSA) or Gleason score and receipt of HDR vs. LDR was observed. Mean overall survival was 127.0 months for HDR and 125.4 for LDR, and was not statistically different.

CONCLUSIONS

We observed an overall decrease in brachytherapy (BT) monotherapy use since 2004 for localized prostate cancer. Despite similar survival outcomes, the use of HDR monotherapy declined relative to LDR.

Effectiveness of postoperative radiotherapy after radical cystectomy for locally advanced bladder cancer

BACKGROUND

Local-regional failure (LF) for locally advanced bladder cancer (LABC) after radical cystectomy (RC) is common even with chemotherapy and is associated with high morbidity/mortality. Postoperative radiotherapy (PORT) can reduce LF and may enhance overall survival (OS) but has no defined role. We hypothesized that the addition of PORT would improve OS in LABC in a large nationwide oncology database.

METHODS

We identified ≥ pT3pN0-3M0 LABC patients in the National Cancer Database diagnosed 2004-2014 who underwent RC ± PORT. OS was calculated using Kaplan-Meier and Cox proportional hazards regression modeling was used to identify predictors of OS. Propensity matching was performed to match RC patients who received PORT vs those who did not.

RESULTS

15,124 RC patients were identified with 512 (3.3%) receiving PORT. Median OS was 20.0 months (95% CI, 18.2-21.8) for PORT vs 20.8 months (95% CI, 20.3-21.3) for no PORT (P = 0.178). In multivariable analysis, PORT was independently associated with improved OS: hazard ratio 0.87 (95% CI, 0.78-0.97); P = 0.008. A one-to-three propensity match yielded 1,858 patients (24.9% receiving PORT and 75.1% without). In the propensity-matched cohort, median OS was 19.8 months (95% CI, 18.0-21.6) for PORT vs 16.9 months (95% CI, 15.6-18.1) for no PORT (P = 0.030). In the propensity-matched cohort of urothelial carcinoma patients (N = 1,460), PORT was associated with improved OS for pT4, pN+, and positive margins (P < 0.01 all).

CONCLUSION

In this observational cohort, PORT was associated with improved OS in LABC. While the data should be interpreted cautiously, these results lend support to the use of PORT in selected patients with LABC, regardless of histology. Prospective trials of PORT are warranted.

Lessons Learned From Hurricane Maria in Puerto Rico: Practical Measures to Mitigate the Impact of a Catastrophic Natural Disaster on Radiation Oncology Patients

PURPOSE

Although the wind, rain, and flooding of Hurricane Maria in Puerto Rico abated shortly after its landfall on September 20, 2017, the disruption of the electrical, communications, transportation, and medical infrastructure of the island was unprecedented in scope and caused lasting harm for many months afterward. A compilation of recommendations from radiation oncologists who were in Puerto Rico during the disaster, and from a panel of American Society for Radiation Oncology (ASTRO) cancer experts was created.

METHODS AND MATERIALS

Radiation oncologists throughout Puerto Rico collaborated and improvised to continue treating patients in the immediate aftermath of the storm and as routine clinical operations were restored gradually. Empirical lessons from the experience of radiation therapy administration in this profoundly altered context of limited resources, impaired communication, and inadequate transportation were organized into a recommended template, applicable to any radiation oncology practice. ASTRO disease-site experts provided evidence-guidelines for mitigating the impact of a 2- to 3-week interruption in radiation therapy.

RESULTS

Practical measures to mitigate the medical impact of a disaster are summarized within the framework of "Prepare, Communicate, Operate, Compensate." Specific measures include the development of an emergency operations plan tailored to specific circumstances, prospective coordination with other radiation oncology clinics before a disaster, ongoing communications with emergency management organizations, and routine practice of alternate methods to disseminate information among providers and patients.

CONCLUSIONS

These recommendations serve as a starting point to assist any radiation oncology practice in becoming more resiliently prepared for a local or regional disruption from any cause. Disease-site experts provide evidence-based guidelines on how to mitigate the impact of a 2- to 3-week interruption in radiation therapy for lung, head and neck, uterine cervix, breast, and prostate cancers through altered fractionation or dose escalation.

Radiation therapy dose de-escalation compared to standard dose radiation therapy in definitive treatment of HPV-positive oropharyngeal squamous cell carcinoma

BACKGROUND

Despite existing evidence that human papillomavirus (HPV)-positive oropharyngeal squamous cell carcinoma (OPSCC) has a favorable prognosis compared to HPV-negative OPSCC, randomized studies have yet to report the effect of de-escalating radiation therapy (RT) dose for definitive treatment. The aim of this study was to assess the effectiveness of dose de-escalated RT (DDRT) vs. standard dose RT (SDRT) in patients with HPV-positive OPSCC.

METHODS

This was an observational study using the National Cancer Database (Year 2010-2014) to identify patients who had HPV-positive OPSCC and were treated with definitive RT or chemo-RT. Patients undergoing surgery were excluded. Patients receiving ≥50 Gy, but <66 Gy were categorized as receiving DDRT. Patients receiving ≥66 Gy were categorized as receiving SDRT. Inverse probability of treatment weighting (IPTW) using propensity scores was used to balance the two groups. Kaplan-Meier analysis was used to estimate overall survival (OS). Subset analyses in patients receiving RT alone and concurrent chemo-RT were also performed. Multivariable Cox proportional hazards modeling was used to evaluate factors associated with OS.

RESULTS

759 patients with HPV-positive OPSCC were identified: 104 received DDRT and 655 received SDRT. The median follow-up was 30.5 (2.4-81.4) months. After IPTW-adjusted analysis, there was no difference in the 3-yr OS between the two groups (82.2% vs. 79.3%; P = 0.85). In the subset of patients receiving concurrent chemoradiotherapy, IPTW-adjusted analysis also did not show a difference in the 3-yr OS between the two groups (83.1% vs. 79.6%; P = 0.83). On multivariable analysis, DDRT was not associated with an inferior OS (HR 0.88; 95% CI, 0.53-1.47; P = 0.63).

CONCLUSIONS

In this study, DDRT was not associated with an inferior OS compared to SDRT in patients with HPV-positive OPSCC. Randomized clinical trials to address DDRT in this patient population are currently ongoing.

A propensity analysis comparing definitive chemo-radiotherapy for muscle-invasive squamous cell carcinoma of the bladder vs. urothelial carcinoma of the bladder using the National Cancer Database

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Limited information is known about treatment outcomes for squamous cell carcinoma of the bladder (SqCC).

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Treatment for SqCC is extrapolated from urothelial carcinoma.

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Outcomes of chemoRT for SqCC are very limited.

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Following chemoRT, patients with SqCC do worse than counterparts with urothelial carcinoma.

Introduction

Squamous cell carcinoma (SqCC) is the second most common histology of primary bladder cancer, but still very limited information is known about its treatment outcomes. Most bladder cancer trials have excluded SqCC, and the current treatment paradigm for localized SqCC is extrapolated from results in urothelial carcinoma (UC). In particular, there is limited data on the efficacy of definitive chemo-radiotherapy (CRT). In this study, we compare overall survival outcomes between SqCC and UC patients treated with definitive CRT.

Materials/methods

We queried the National Cancer Database (NCDB) for muscle-invasive (cT2-T4 N0 M0) bladder cancer patients diagnosed from 2004 to 2013 who underwent concurrent CRT. Propensity matching was performed to match patients with SqCC to those with UC. OS was analyzed using the Kaplan-Meier survival method, and the log-rank test and Cox regression were used for analyses.

Results

3332 patients met inclusion criteria of which 79 (2.3%) had SqCC. 73.4% of SqCC patients had clinical T2 disease compared to 82.5% of UC patients. Unadjusted median OS for SqCC patients was 15.6 months (95% CI, 11.7–19.6) versus 29.1 months (95% CI, 27.5–30.7) for those with UC (P < 0.0001). On multivariable analysis, factors associated with worse OS included: SqCC histology [HR: 1.53 (95% CI, 1.19–1.97); P = 0.001], increasing age [HR: 1.02 (95% CI, 1.02–1.03); P < 0.0001], increasing clinical T-stage [HR: 1.21 (95% CI, 1.13–1.29); P < 0.0001], and Charlson-Deyo comorbidity index [HR: 1.26 (95% CI, 1.18–1.33); P < 0.0001]. Seventy-seven SqCC patients were included in the propensity-matched analysis (154 total patients) with a median OS for SqCC patients of 15.1 months (95% CI, 11.1–18.9) vs. 30.4 months (95% CI, 19.4–41.4) for patients with UC (P = 0.013).

Conclusions

This is the largest study to-date assessing survival outcomes for SqCC of the bladder treated with CRT. In this study, SqCC had worse overall survival compared to UC patients. Histology had a greater impact on survival than increasing T-stage, suggesting that histology should be an important factor when determining a patient’s treatment strategy and that treatment intensification in this subgroup may be warranted.

Predictors of acute throat or esophageal patient reported pain during radiation therapy for head and neck cancer

Background and purpose

Acute pain during weekly radiotherapy (RT) to the head and neck is not well characterized. We studied dose-volume metrics and clinical variables that are plausibly associated with throat or esophageal pain as measured with a weekly questionnaire during RT.

Materials and methods

We prospectively collected weekly patient-reported outcomes from 122 head and neck cancer patients during RT. The pain score for each question consisted of a four-level scale: none (0), mild (1), moderate (2), and severe (3). Univariate and multivariate ordinal logistic regression analyses were performed to investigate associations between both esophageal and throat pain and clinical as well as dosimetric variables.

Results

In multivariate analysis, age was significantly associated with both types of pain, leading to odds ratio (OR) = 0.95 (p = 0.008) and OR = 0.95 (p = 0.007) for esophageal and throat pain, respectively. For throat pain, sex (OR = 4.12; p = 0.010), with females at higher risk, and fractional organ at risk (OAR) mean dose (OR = 3.30; p = 0.014) were significantly associated with throat pain.

Conclusions

A fractional OAR mean dose of 1.1 Gy seems a reasonable cutoff for separating no or mild pain from moderate to severe esophageal and throat pain. Younger patients who received RT experienced more esophageal and throat pain. Females experienced more throat pain, but not esophageal pain.