Intratumoral androgen biosynthesis associated with 3ß-hydroxysteroid dehydrogenase 1 promotes resistance to radiotherapy in prostate cancer.

Half of all men with advanced prostate cancer (PCa) inherit at least 1 copy of an adrenal-permissive HSD3B1 (1245C) allele, which increases levels of 3ß-hydroxysteroid dehydrogenase 1 (3ßHSD1) and promotes intracellular androgen biosynthesis. Germline inheritance of the adrenally permissive allele confers worse outcomes in men with advanced PCa. We investigated whether HSD3B1 (1245C) drives resistance to combined androgen deprivation and radiotherapy. Adrenally permissive 3ßHSD1 enhanced resistance to radiotherapy in PCa cell lines and xenograft models engineered to mimic the human adrenal/gonadal axis during androgen deprivation. The allele-specific effects on radiosensitivity were dependent on availability of DHEA, the substrate for 3ßHSD1. In lines expressing the HSD3B1 (1245C) allele, enhanced expression of DNA damage response (DDR) genes and more rapid DNA double-strand break (DSB) resolution were observed. A correlation between androgen receptor (AR) expression and increased DDR gene expression was confirmed in 680 radical prostatectomy specimens. Treatment with the nonsteroidal antiandrogen enzalutamide reversed the resistant phenotype of HSD3B1 (1245C) PCa in vitro and in vivo. In conclusion, 3ßHSD1 promotes prostate cancer resistance to combined androgen deprivation and radiotherapy by upregulating DNA DSB repair. This work supports prospective validation of early combined androgen blockade for high-risk men harboring the HSD3B1 (1245C) allele.

Neutrophil to lymphocyte ratio (NTLR) predicts local control and overall survival after stereotactic body radiotherapy (SBRT) in metastatic sarcoma.

The neutrophil to lymphocyte ratio (NTLR) and absolute lymphocyte count (ALC) recovery are prognostic across many cancers. We investigated whether NLTR predicts SBRT success or survival in a metastatic sarcoma cohort treated with SBRT from 2014 and 2020 (N = 42). Wilcox Signed Rank Test and Friedman Test compare NTLR changes with local failure vs. local control (N = 138 lesions). Cox analyses identified factors associated with overall survival. If local control was successful, NLTR change was not significant (p = 0.30). However, NLTR significantly changed in patients with local failure (p = 0.027). The multivariable Cox model demonstrated higher NLTR before SBRT was associated with worse overall survival (p = 0.002). The optimal NTLR cut point was 5 (Youden index: 0.418). One-year overall survival in SBRT metastatic sarcoma cohort was 47.6% (CI 34.3%-66.1%). Patients with an NTLR above 5 had a one-year overall survival of 37.7% (21.4%-66.3%); patients with an NTLR below 5 had a significantly improved overall survival of 63% (43.3%-91.6%, p = 0.014). Since NTLR at the time of SBRT was significantly associated with local control success and overall survival in metastatic sarcoma treated with SBRT, future efforts to reduce tumor inhibitory microenvironment factors and improve lymphocyte recovery should be investigated.

Validation of the 2022 National Comprehensive Cancer Network Risk Stratification for Cutaneous Squamous Cell Carcinoma.

Importance: The 2022 National Comprehensive Cancer Network (NCCN) reclassified cutaneous squamous cell carcinoma (CSCC) into low-, high-, and very high-risk groups to better risk stratify tumors. Mohs micrographic surgery (Mohs) or peripheral and deep en face margin assessment (PDEMA) became preferred surgical modalities for high- and very high-risk tumors. This new risk stratification and the recommendation for Mohs or PDEMA in high- and very high-risk groups have not been validated. Objective: To compare outcomes in very high-, high-, and low-risk NCCN groups of CSCCs and in CSCCs treated with Mohs or PDEMA compared with wide local excision (WLE). Design, Setting, and Participants: This retrospective cohort study of CSCCs was performed in 2 tertiary care academic medical centers. Patients 18 years or older and diagnosed between January 1, 1996, and December 31, 2019, at Brigham and Women's Hospital and Cleveland Clinic Foundation were included. Data were analyzed from October 20, 2021, to March 29, 2023. Exposures: NCCN risk group, Mohs or PDEMA, and WLE. Main Outcomes and Measures: Local recurrence (LR), nodal metastasis (NM), distant metastasis (DM), and disease-specific death (DSD). Results: A total of 10 196 tumors from 8727 patients were stratified by NCCN guidelines into low-, high-, and very high-risk groups (6003 [59.0%] men; mean [SD] age, 72.4 [11.8] years). Compared with the low-risk group, the high- and very high-risk groups demonstrated a greater risk of LR (high-risk subhazard ratio [SHR], 1.99 [95% CI, 1.21-3.27; P = .007]; very high-risk SHR, 12.66 [95% CI, 7.86-20.39; P < .001]), NM (high-risk SHR, 4.26 [95% CI, 1.28-14.23; P = .02]; very high-risk SHR, 62.98 [95% CI, 19.24-206.17; P < .001]), DM (high-risk SHR, 2.2 × 107 [95% CI, 4.7 × 103-1.1 × 1011; P < .001]; very high-risk SHR, 6.3 × 108 [95% CI, 1.4 × 105-2.9 × 1012; P < .001]), and DSD (high-risk SHR, 4.02 [95% CI, 1.18-13.71; P = .03]; very high-risk SHR, 93.87 [95% CI, 29.19-301.85; P < .001]). Adjusted 5-year cumulative incidence was significantly higher in very high- vs high- and low-risk groups for LR (9.4% [95% CI, 9.2%-14.0%] vs 1.5% [95% CI, 1.4%-2.1%] and 0.8% [95% CI, 0.5%-1.2%], respectively), NM (7.3% [95% CI, 6.8%-10.9%] vs 0.5% [95% CI, 0.4%-0.8%] and 0.1% [95% CI, 0.03%-0.3%], respectively), DM (3.9% [95% CI, 2.6%-5.6%] vs 0.1% [95% CI, 0.04%-0.2%] and 0.01% [95% CI, not applicable], respectively), and DSD (10.5% [95% CI, 10.3%-15.4%] vs 0.5% [95% CI, 0.4%-0.8%] and 0.1% [95% CI, 0.04%-0.3%], respectively). Compared with CSCCs treated with WLE, those treated with Mohs or PDEMA had lower risk of LR (SHR, 0.65 [95% CI, 0.46-0.90]; P = .009), DM (SHR, 0.38 [95% CI, 0.18-0.83]; P = .02), and DSD (SHR, 0.55 [95% CI, 0.36-0.84]; P = .006). Conclusions and Relevance: The findings of this cohort study suggest that the NCCN high- and very high-risk groups identify CSCCs at greatest risk for developing poor outcomes. Further, Mohs or PDEMA resulted in lower LR, DM, and DSD compared with WLE.

Neutrophil to Lymphocyte Ratio (NTLR) Predicts Local Control Failure and Overall Survival after Stereotactic Body Radiotherapy (SBRT) In Metastatic Sarcoma.

The neutrophil to lymphocyte ratio (NTLR) and absolute lymphocyte count (ALC) recovery are prognostic across many cancers. We investigated whether NLTR predicts SBRT success or survival in a metastatic sarcoma cohort treated with SBRT from 2014 and 2020 (N = 42). Wilcox Signed Rank Test and Friedman Test compare NTLR changes with local failure vs. local control (N = 138 lesions). Cox analyses identified factors associated with overall survival. If local control was successful, NLTR change was not significant (p = 0.30). However, NLTR significantly changed in patients local failure (p = 0.027). The multivariable Cox model demonstrated higher NLTR before SBRT was associated with worse overall survival (p = 0.002). The optimal NTLR cut point was 5 (Youden index: 0.418). One-year overall survival in SBRT metastatic sarcoma cohort was 47.6% (CI 34.3%-66.1%). Patients with an NTLR above 5 had a one-year overall survival of 37.7% (21.4%-66.3%); patients with an NTLR below 5 had a significantly improved overall survival of 63% (43.3%-91.6%, p = 0.014). Since NTLR at the time of SBRT was significantly associated with local control success and overall survival in metastatic sarcoma treated with SBRT, future efforts to reduce tumor inhibitory microenvironment factors and improved lymphocyte recovery should be investigated.

18F-fluciclovine PET/CT to distinguish radiation necrosis from tumor progression for brain metastases treated with radiosurgery: results of a prospective pilot study.

PURPOSE: Distinguishing radiation necrosis from tumor progression among patients with brain metastases previously treated with stereotactic radiosurgery represents a common diagnostic challenge. We performed a prospective pilot study to determine whether PET/CT with 18F-fluciclovine, a widely available amino acid PET radiotracer, repurposed intracranially, can accurately diagnose equivocal lesions. METHODS: Adults with brain metastases previously treated with radiosurgery presenting with a follow-up tumor-protocol MRI brain equivocal for radiation necrosis versus tumor progression underwent an 18F-fluciclovine PET/CT of the brain within 30 days. The reference standard for final diagnosis consisted of clinical follow-up until multidisciplinary consensus or tissue confirmation. RESULTS: Of 16 patients imaged from 7/2019 to 11/2020, 15 subjects were evaluable with 20 lesions (radiation necrosis, n = 16; tumor progression, n = 4). Higher SUVmax statistically significantly predicted tumor progression (AUC = 0.875; p = 0.011). Lesion SUVmean (AUC = 0.875; p = 0.018), SUVpeak (AUC = 0.813; p = 0.007), and SUVpeak-to-normal-brain (AUC = 0.859; p = 0.002) also predicted tumor progression, whereas SUVmax-to-normal-brain (p = 0.1) and SUVmean-to-normal-brain (p = 0.5) did not. Qualitative visual scores were significant predictors for readers 1 (AUC = 0.750; p < 0.001) and 3 (AUC = 0.781; p = 0.045), but not for reader 2 (p = 0.3). Visual interpretations were significant predictors for reader 1 (AUC = 0.898; p = 0.012) but not for reader 2 (p = 0.3) or 3 (p = 0.2). CONCLUSIONS: In this prospective pilot study of patients with brain metastases previously treated with radiosurgery presenting with a contemporary MRI brain with a lesion equivocal for radiation necrosis versus tumor progression, 18F-fluciclovine PET/CT repurposed intracranially demonstrated encouraging diagnostic accuracy, supporting the pursuit of larger clinical trials which will be necessary to establish diagnostic criteria and performance.

Radiation necrosis or tumor progression? A review of the radiographic modalities used in the diagnosis of cerebral radiation necrosis.

PURPOSE: Cerebral radiation necrosis is a complication of radiation therapy that can be seen months to years following radiation treatment. Differentiating radiation necrosis from tumor progression on standard magnetic resonance imaging (MRI) is often difficult and advanced imaging techniques may be needed to make an accurate diagnosis. The purpose of this article is to review the imaging modalities used in differentiating radiation necrosis from tumor progression following radiation therapy for brain metastases. METHODS: We performed a review of the literature addressing the radiographic modalities used in the diagnosis of radiation necrosis. RESULTS: Differentiating radiation necrosis from tumor progression remains a diagnostic challenge and advanced imaging modalities are often required to make a definitive diagnosis. If diagnostic uncertainty remains following conventional imaging, a multi-modality diagnostic approach with perfusion MRI, magnetic resonance spectroscopy (MRS), positron emission tomography (PET), single photon emission spectroscopy (SPECT), and radiomics may be used to improve diagnosis. CONCLUSION: Several imaging modalities exist to aid in the diagnosis of radiation necrosis. Future studies developing advanced imaging techniques are needed.

Immune status does not independently influence cutaneous squamous cell carcinoma metastasis and death when stratified by tumor stage: A dual-center retrospective cohort analysis of primary N0 disease.

BACKGROUND: Although immunocompromised patients have a higher risk of developing cutaneous squamous cell carcinomas, it is unknown whether immune status is an independent risk factor for poor outcomes. OBJECTIVE: To compare cutaneous squamous cell carcinoma outcomes in immunocompromised and immunocompetent patients when controlling for T-stage. METHODS: We performed a retrospective cohort study at 2 tertiary care centers, examining 989 primary tumors from 814 immunocompromised patients (solid organ transplant: 259 [31.7%], chronic lymphocytic leukemia: 113 [13.9%]) and 6608 tumors from 4198 immunocompetent patients. Our primary outcome was the composite of disease-specific death or tumor metastasis ("poor outcomes"). RESULTS: Immunocompromised patients had 50% more high T-stage tumors (ie, Brigham and Women's Hospital stage T2b and T3), than immunocompetent patients (3.3% vs 4.9%, respectively; P < .001). Significant predictors of poor outcomes included tumor stage (sub hazards ratio [SHR], 14.8 for high T-stage tumors; 95% confidence interval [CI], 8.0-27.6; P < .001) and male sex (SHR, 2.3; 95% CI, 1.4-3.8; P = .002). Immune status was not a significant predictor (SHR, 1.04; 95% CI, 0.69-1.6; P = .85). LIMITATIONS: This study is retrospective. CONCLUSION: Although immunocompromised patients had 50% more high T-stage tumors than immunocompetent patients, immunocompromised patients had a similar chance of metastasis and disease-specific death when adjusting for T-stage in our cohort of primary tumors.

A Reappraisal of Definitive Chemoradiotherapy for Older Adults With Advanced Head and Neck Cancer.

BACKGROUND/AIM: Definitive treatment for locally advanced head and neck squamous cell carcinoma (LAHNSCC) is often compromised in older adults due to concerns about potential treatment toxicity intolerance. We reviewed our institutional experience with definitive management of older adults with LAHNSCC. PATIENTS AND METHODS: From our Institutional Review Board-approved registry, we identified patients aged >60 years with stage III-IV, M0 LAHNSCC (seventh/earlier editions of the American Joint Committee on Cancer classification) treated with definitive radiotherapy from 1993-2019. Indications for concurrent chemotherapy included T3-4 or N2-3 disease. Multivariable analysis using Fine and Gray regression was performed to identify risk factors associated with recurrence. The cumulative incidence method was used to calculate recurrence rates. RESULTS: Overall, 350 patients were identified: 223 aged 60-69, 82 aged 70-74, and 45 aged ≥75 years. Median follow-up was 36.3 months. Two-year recurrence rates were 13.7%, 20.2% and 34.8%, respectively; human papillomavirus-positive disease was present in 190 (85%), 44 (54%), and 25 (56%), respectively; and systemic therapy was given to 194 (87%), 64 (88%), and 23 (56%) patients, respectively. Factors significantly associated with increased risk of recurrence included age ≥75 years, Karnofsky performance status 70-80, clinical N2c-N3, and Charlson score 2-3. CONCLUSION: Patients aged ≥75 years received less aggressive therapy and experienced increased recurrence compared to younger patients. Outcomes for those aged 70-74 years were similar to younger patients treated with aggressive therapy, despite their inferior performance status/comorbidity, and such patients should not routinely be excluded from standard-of-care therapy. Further study is needed to optimize therapy for a redefined older adult (age ≥75 years) population.

Coronary intravascular brachytherapy for in-stent restenosis: A review of the contemporary literature.

Intracoronary stent restenosis (ISR) is a clinically relevant challenge in the modern era. Heterogeneity in patient- and lesion-specific factors can further compound this clinical challenge. Coronary intravascular brachytherapy (IVBT) was the standard therapeutic approach for ISR prior to the advent of drug-eluting stents (DES). Despite prospective data describing the superiority of DES over IVBT for treating de novo ISR, IVBT remains a treatment option for patients with complex disease. The purpose of this review is to evaluate the historical and contemporary literature surrounding IVBT in order to elucidate its role in modern cardiac care and to describe opportunities for future investigations to improve patient selection. Herein, we provide a review of the contemporary literature describing IVBT as a safe and effective treatment option for patients with recurrent, refractory ISR after multilayer DES and no good surgical or mechanical option. Combination therapy with emerging technologies such as DCBs may further increase efficacy.

Adjuvant radiation following clear margin resection of high T-stage cutaneous squamous cell carcinoma halves the risk of local and locoregional recurrence: A dual-center retrospective study.

BACKGROUND: Although adjuvant radiation (ART) following clear margin surgery is recommended for select high-risk cutaneous squamous cell carcinomas, efficacy data are limited. OBJECTIVE: To evaluate the impact of ART on outcomes following clear margin surgery for high T-stage cutaneous squamous cell carcinomas. METHODS: A 20-year retrospective cohort study at 2 academic centers of high T-stage cutaneous squamous cell carcinomas (Brigham and Women's Hospital T2b or T3) with negative histologic margins post resection. Local recurrence (LR) and locoregional recurrence (LRR) were compared by whether tumors received ART or observation. RESULTS: A total of 508 tumors were included, of which 96 underwent ART (ART+). ART+ had a lower 5-year cumulative incidence of LR (ART+, 3.6% [95% CI, 1.6%-7.7%] vs ART-, 8.7% [95% CI, 6.3%-12.0%]) and LRR (ART+, 7.5% [95% CI, 4.4%-11.9%] vs ART-, 15.3% [95% CI, 11.9%-22.1%]). Recurrent tumors ≥6 cm or Brigham and Women's Hospital T3 tumors were classified as high-risk due to a higher 5-year cumulative incidence of LRR (High-risk, 26.3% [95% CI, 19.0%-35.7%]). High-risk tumors treated with ART had a lower 5-year cumulative incidence of LRR (ART+, 17.2% [95% CI, 11.9%-26.4%] vs ART-, 31.0% [95% CI, 26.1%-40.8%]). LIMITATIONS: Retrospective design, heterogeneous population, variations in radiation protocols. CONCLUSION: ART following clear margin surgery for high T-stage cutaneous squamous cell carcinomas resulted in half the risk of LR and LRR.

Limited Toxicity of Hypofractionated Intensity Modulated Radiation Therapy for Head and Neck Cancer.

BACKGROUND/AIM: Hypofractionated radiation therapy is not commonly used in head and neck cancers (HNC) due to increased toxicity observed in historical cohorts. This study reviews our institutional experience using hypofractionated intensity modulated radiation therapy (H-IMRT) for HNC. PATIENTS AND METHODS: A retrospective cohort study of 56 patients with HNC treated with H-IMRT with ≥50 Gy in 20 fractions was conducted. The primary outcomes were acute and late toxicity. RESULTS: Two-year locoregional control was 87% and median overall survival was 46 months. There were no acute or late grade 4 or 5 toxicities. Acute grade 2 and 3 toxicity was seen in 79% (N=44) and 25% (N=14), respectively. Late grade 2 toxicity was seen in 9% (N=5). No patients required the placement of a feeding tube or tracheostomy. CONCLUSION: H-IMRT for the definitive or post-operative treatment of HNC using ≥50 Gy in 20 fractions appears safe and well tolerated with modest toxicity.

Implications of Satellitosis or In-transit Metastasis in Cutaneous Squamous Cell Carcinoma: A Prognostic Omission in Cancer Staging Systems.

IMPORTANCE: Unlike Merkel cell carcinoma and melanoma, satellitosis or in-transit metastasis (S-ITM) is not incorporated into the current cutaneous squamous cell carcinoma (CSCC) staging systems. It is important to determine if the clinical outcomes of S-ITM are relevant to prognosis for patients with CSCC. OBJECTIVES: To evaluate the association of S-ITM with clinical outcomes in patients with CSCC and to determine its prognostic implications. DESIGN, SETTINGS, AND PARTICIPANTS: A dual-institution (Cleveland Clinic and Brigham and Women's Hospital) database was queried for patients who were treated for CSCC in 2010 to 2020. Patients who were node-negative and had S-ITM-the presence of dermal lesions between the primary tumor and first-echelon lymphatic nodal basins at any point in the disease course-were identified. Subcohorts of patients with T3N0 tumors, T4N0 tumors (bone invasive), N1 to 3, and M1 disease were identified for comparison. The American Joint Committee on Cancer staging system was used to define cancer stages. Data were analyzed from January 15 to March 31, 2021. MAIN OUTCOMES AND MEASURES: Pairwise comparison of CSCC recurrence and disease-specific survival in patients with and without S-ITM was performed using Cox proportional hazard modeling. Kaplan-Meier and Fine-Gray competing risk methods were used to estimate disease-specific survival and CSCC recurrence, respectively. RESULTS: In a total of 518 patients with CSCC, S-ITM was present in 72 (13.9 %) patients (median age [range], 73.9 [31.6-95.8] years; 59 [82%] men; 69 [96%] White non-Hispanic individuals; 25 [35%] patients with immunosuppression) who were node-negative. The subcohorts were composed of 341 patients with T3N0 cancer, 36 with T4N0, 70 with N1 to 3, and 19 with M1 disease. Pairwise comparisons between disease levels using Cox proportional hazard model demonstrated lower cumulative incidence of CSCC recurrence rates in the T3N0 (HR, 0.21; 95% CI, 0.14-0.30; P < .001) and T4N0 (HR, 0.36; 95% CI, 0.19-0.68; P = .001) cohorts compared with the S-ITM cohort. No significant difference was observed between patients who were node-positive and those with S-ITM (HR, 0.74; 95% CI, 0.48-1.14; P = .16). The 5-year disease-specific survival rates were 76% for T3N0, 64% for T4N0, 41% for S-ITM, and 39% for N1 to 3. Compared with the S-ITM cohort, DSS was significantly higher in the T3N0 (HR, 0.23; 95% CI, 0.15-0.35; P < .0001) and T4N0 (HR, 0.37; 95% CI, 0.19-0.76; P = .01) cohorts, and not significantly different in the node-positive (HR, 0.77; 95% CI, 0.84-3.93; P = .30) and metastatic cohorts (HR, 1.81; 95% CI, 0.84-3.93; P = .13). CONCLUSIONS AND RELEVANCE: This multi-institutional cohort study found that patients with CSCC and S-ITM appear to have clinical outcomes comparable to those of patients who are node-positive, and an increased risk of recurrence and worse survival compared with patients who have T3 and T4 disease. These outcomes are similar to those observed for Merkel cell carcinoma and melanoma. Given that S-ITM may be a powerful prognostic factor, it should be incorporated into clinical staging systems.

Higher metastasis and death rates in cutaneous squamous cell carcinomas with lymphovascular invasion.

BACKGROUND: Lymphovascular invasion (LVI) is an aggressive histologic finding but is excluded from current staging systems due to its lack of demonstrated independent prognostic significance. OBJECTIVE: To evaluate the impact of LVI on cutaneous squamous cell carcinoma tumor outcomes. METHODS: In total, 10,707 cutaneous squamous cell carcinoma tumors from a 20-year, retrospective, multicenter cohort were stratified by the presence (LVI+) or absence (LVI-) of LVI. Outcomes (local recurrence, in-transit metastasis, nodal metastasis, disease-specific death) were compared based on low (Brigham and Women's Hospital [BWH] stage T1/T2a) and high (BWH T2b/T3) tumor stages. RESULTS: Of the 10,707 tumors, 78 had LVI. The analysis of low-stage BWH tumors showed the LVI+ group had a significantly higher 5-year cumulative incidence of local recurrence (LVI+: 12.3%; LVI-: 1.1%; P < .01), metastasis (LVI+: 4.2%; LVI-: 0.4%; P < .01), and disease-specific death (LVI+: 16.2%; LVI-: 0.4%; P < .01). The analysis of BWH high-stage tumors showed the LVI+ group maintained a higher 5-year cumulative incidence of metastasis (LVI+: 28.5%; LVI-: 16.8%; P = .06) and disease-specific death (LVI+: 25.3%; LVI-: 13.9%; P = .03), however, there was no difference in local recurrence (LVI+: 16.3%; LVI-: 15.8%; P = .11). LIMITATIONS: Retrospective study design. CONCLUSION: LVI+ cutaneous squamous cell carcinomas have higher rates of metastasis and death at 5 years. Future staging systems should consider incorporating LVI.

Identifying Brigham and Women's Hospital stage T2a cutaneous squamous cell carcinomas at risk of poor outcomes.

BACKGROUND: Although most of the poor outcomes with cutaneous squamous cell carcinoma (CSCC) occur in high-stage tumors, 26% of nodal metastases and 8% of disease-specific deaths develop in Brigham and Women's Hospital (BWH) T2a tumors. OBJECTIVE: To determine risk factors associated with poor outcomes (nodal metastasis, distant metastases, and disease-specific deaths) in BWH T2a CSCC. METHODS: A 17-year retrospective multi-institutional cohort study of primary CSCC BWH T2a tumors. A predictive model based on tumor characteristics was developed to identify those at higher risk of poor outcomes. RESULTS: Presence of 1 major criterion (primary tumor diameter ≥40 mm, invasion depth beyond subcutaneous fat, poor differentiation, or large-caliber perineural invasion) and ≥ 1 minor criterion (invasion depth in subcutaneous fat, moderate differentiation, small-caliber perineural invasion, or lymphovascular invasion) was most predictive of developing poor outcomes (area under the curve, 0.53; C-statistic, 0.60). This model has a sensitivity of 7.7%, specificity of 97.4%, and a positive and negative predictive value of 33.3% and 86.1%, respectively. The 5-year cumulative incidence of poor outcomes in these tumors is 8.0% (95% CI, 5.1-13.7) compared to 2.8% (95% CI, 1.9-4.1) in other T2a tumors (sub-hazard ratio, 3.0; 95% CI, 1.5-5.8). LIMITATIONS: Multi-institutional cohort study was not externally validated. CONCLUSIONS: BWH T2a-high CSCCs have an 8% chance of developing poor outcomes.

125I Interstitial brachytherapy with or without androgen deprivation therapy among unfavorable-intermediate and high-risk prostate cancer.

PURPOSE/OBJECTIVE(S): To determine if patients with unfavorable intermediate-risk (UIR), high-risk (HR), or very high-risk (VHR) prostate cancer (PCa) treated with 125I interstitial brachytherapy benefit from androgen deprivation therapy (ADT). MATERIALS/METHODS: We reviewed our institutional database of patients with UIR, HR, or VHR PCa, per 2018 NCCN risk classification, treated with definitive 125I interstitial brachytherapy with or without ADT from 1998-2017. Outcomes including biochemical failure (bF), distant metastases (DM), and overall survival (OS) were analyzed with the Kaplan-Meier method and Cox proportional hazards regression. PCa-specific mortality (PCSM) was analyzed with Fine-Gray competing-risk regression. RESULTS: Of 1033 patients, 262 (25%) received ADT and 771 (75%) did not. Median ADT duration was 6 months. By risk group, 764 (74%) patients were UIR, 219 (21%) HR, and 50 (5%) VHR. ADT was more frequently given to HR (50%) and VHR (56%) patients compared to UIR (16%; p<0.001), to older patients (p<0.001), corresponding with increasing PSA (p<0.001) and Grade Group (p<0.001). Median follow-up was 4.9 years (0.3-17.6 years). On multivariable analysis accounting for risk group, age, and year of treatment, ADT was not associated with bF, DM, PCSM, or OS (p≥0.05 each). CONCLUSION: Among patients with UIR, HR, and VHR PCa, the addition of ADT to 125I interstitial brachytherapy was not associated with improved outcomes, and no subgroup demonstrated benefit. Our findings do not support the use of ADT in combination with 125I interstitial brachytherapy. Prospective studies are required to elucidate the role of ADT for patients with UIR, HR, and VHR PCa treated with prostate brachytherapy.

Updated Outcomes of Split Course Radiotherapy in Elderly or Infirm Patients With Advanced Cancers of the Head and Neck.

BACKGROUND/AIM: Head and neck cancers are often treated with extended courses of radiotherapy (RT), which may prove excessively toxic for frail patients. Split course RT (SCRT) delivers two courses of RT separated by 4-6 weeks, personalizing treatment intensity based on response. In this study, we present our updated experience using this technique. PATIENTS AND METHODS: From a single institution database, we identified patients considered for SCRT. For patients undergoing a second course of RT, cumulative incidence of locoregional recurrence (LRR) and overall survival (OS) are reported. RESULTS: A total of 98 patients were included, of whom seventy-five percent underwent a second course of RT. The most common fractionation was 30 Gy in 10 fractions for each course, with a median cumulative dose of 60 Gy. In those undergoing a second course of RT, median OS was 9.7 months and cumulative incidence of LRR at 6, 12, and 24 months was 17.0%, 23.1%, and 29.4%, respectively. CONCLUSION: SCRT offers an attractive treatment paradigm to personalize radiation intensity based on patient tolerance, while maintaining reasonable safety and efficacy in those unfit for standard full course RT.

Approach to Oligometastatic Cancer in the Elderly Patient.

PURPOSE OF REVIEW: Patients with advanced cancer who have "oligometastatic" disease (OMD) have a limited burden of metastatic sites such that they may benefit from definitive therapies with limited toxicities. The incidence of cancers diagnosed in the elderly is increasing and treatment choices for them are often made because of their vulnerability to side effects. The present review discusses treatment of the elderly with OMD considering cancer outcomes and treatment toxicity. RECENT FINDINGS: Stereotactic body radiation therapy (SBRT) is emerging as a standard in the management of OMD because of its excellent local control and minimal toxicity. Phase II trials suggest that SBRT added to palliative therapy may improve overall survival and may delay the initiation of systemic therapy in OMD patients. Elderly patients are well represented in OMD studies SBRT will contribute significantly to the management of OMD in the elderly patient population by optimizing cancer control and limiting side effects.

Stereotactic body radiotherapy for the treatment of oligometastatic gynecological malignancy in the abdomen and pelvis: A single-institution experience.

PURPOSE/OBJECTIVES: Metastasis-directed therapy with stereotactic body radiotherapy (SBRT) in the setting of oligometastatic disease is a rapidly evolving paradigm given ongoing improvements in systemic therapies and diagnostic modalities. However, SBRT to targets in the abdomen and pelvis is historically associated with concerns about toxicity. The purpose of this study was to evaluate the safety and efficacy of SBRT to the abdomen and pelvis for women with oligometastases from primary gynecological tumors. MATERIALS/METHODS: From our IRB-approved registry, all patients who were treated with SBRT between 2014 and 2020 were identified. Oligometastatic disease was defined as 1 to 5 discrete foci of clinical metastasis radiographically diagnosed by positron emission tomography (PET) and/or computerized tomography (CT) imaging. The primary endpoint was local control at 12 months. Local and distant control rates were estimated using the Kaplan-Meier method. Time intervals for development of local progression and distant progression were calculated based on follow up visits with re-staging imaging. Acute and late toxicity outcomes were determined based on Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. RESULTS: We identified 34 women with 43 treated lesions. Median age was 68 years (range 32-82), and median follow up time was 12 months (range 0.2-54.0). Most common primary tumor sites were ovarian (n=12), uterine (n=11), and cervical (n=7). Median number of previous lines of systemic therapy agents at time of SBRT was 2 (range 0-10). Overall, SBRT was delivered to 1 focus of oligometastasis in 29 cases, 2 foci in 2 cases, 3 foci in 2 cases, and 4 foci in 1 case. All patients were treated comprehensively with SBRT to all sites of oligometastasis. Median prescription dose was 24 Gy (range 18-54 Gy) in 3 fractions (range 3-6) to a median prescription isodose line of 83.5% (range 52-95). Local control by lesion at 12 and 24 months was 92.5% for both time points. Local failure was observed in three treated sites among two patients, two of which were at 11 months in one patient, and the other at 30 months. Systemic control rate was 60.2% at 12 months. Overall survival at 12 and 24 months was 85% and 70.2%, respectively. Acute grade 2 toxicities included nausea (n=3), and there were no grade > 3 acute toxicities. Late grade 1 toxicities included diarrhea (n=1) and fatigue (n=1), and there were no grade > 2 toxicities. CONCLUSION: SBRT to oligometastatic gynecologic malignancies in the abdomen and pelvis is feasible with encouraging preliminary safety and local control outcomes. This approach is associated with excellent local control and low rates of toxicity during our follow-up interval. Further investigations into technique, dose-escalation and utilization are warranted.