Reirradiation of metastases of the central nervous system: part 2-metastatic epidural spinal cord compression.

An increasing number of patients irradiated for metastatic epidural spinal cord compression (MESCC) experience an in-field recurrence and require a second course of radiotherapy. Reirradiation can be performed with conventional radiotherapy or highly-conformal techniques such as intensity-modulated radiation therapy (IMRT), volumetric modulated arc therapy (VMAT), and stereotactic body radiation therapy (SBRT). When using conventional radiotherapy, a cumulative biologically effective dose (BED) ≤120 calculated with an α/ß value of 2 Gy (Gy2) was not associated with radiation myelopathy in a retrospective study of 124 patients and is considered safe. In that study, conventional reirradiation led to improvements of motor deficits in 36% of patients and stopped further symptomatic progression in another 50% (overall response 86%). In four other studies, overall response rates were 82-89%. In addition to the cumulative BED or equivalent dose in 2 Gy fractions (EQD2), the interval between both radiotherapy courses <6 months and a BED per course ≥102 Gy2 (corresponding to an EQD2 ≥51 Gy2) were identified as risk factors for radiation myelopathy. Without these risk factors, a BED >120 Gy2 may be possible. Scoring tools have been developed that can assist physicians in estimating the risk of radiation myelopathy and selecting the appropriate dose-fractionation regimen of re-treatment. Reirradiation of MESCC may also be performed with highly-conformal radiotherapy. With IMRT or VMAT, rates of pain relief and improvement of neurologic symptoms of 60-93.5% and 42-73%, respectively, were achieved. One-year local control rates ranged between 55% and 88%. Rates of myelopathy or radiculopathy and vertebral compression fractures were 0% and 0-9.3%, respectively. With SBRT, rates of pain relief were 65-86%. Two studies reported improvements in neurologic symptoms of 0% and 82%, respectively. One-year local control rates were 74-83%. Rates of myelopathy or radiculopathy and vertebral compression fractures were 0-4.5% and 4.5-13.8%, respectively. For SBRT, a cumulative maximum EQD2 to thecal sac ≤70 Gy2, a maximum EQD2 of SBRT ≤25 Gy2, a ratio ≤0.5 of thecal sac maximum EQD2 of SBRT to maximum cumulative EQD2, and an interval between both courses ≥5 months were associated with a lower risk of myelopathy. Additional prospective trials are required to better define the options of reirradiation of MESCC.

Novel Postoperative Hypofractionated Accelerated Radiation Dose-Painting Approach for Soft Tissue Sarcoma.

Purpose: Hypofractionated radiation therapy (RT) offers benefits in the treatment of soft tissue sarcomas (STS), including exploitation of the lower α/ß, patient convenience, and cost. This study evaluates the acute toxicity of a hypofractionated accelerated RT dose-painting (HARD) approach for postoperative treatment of STS. Methods and Materials: This is a retrospective review of 53 consecutive patients with STS who underwent resection followed by postoperative RT. Standard postoperative RT dosing for R0/R1/gross disease with sequential boost (50 Gy + 14/16/20 Gy in 32-35 fractions) were replaced with dose-painting, which adapts dose based on risk of disease burden, to 50.4 and 63, 64.4, 70 Gy in 28 fractions, respectively. The first 10 patients were replanned with a sequential boost RT approach and dosimetric indices were compared. Time-to-event outcomes, including local control, regional control, distant control, and overall survival, were estimated with Kaplan-Meier analysis. Results: Median follow-up was 25.2 months. Most patients had high-grade (59%) STS of the extremity (63%) who underwent resection with either R1 (40%) or close (36%) margins. Four patients experienced grade 3 acute dermatitis which resolved by the 3-month follow-up visit. The 2-year local control, regional control, distant control, and overall survival were 100%, 92%, 68%, and 86%, respectively. Compared with the sequential boost plan, HARD had a significantly lower field size (total V50 Gy; P = .002), bone V50 (P = .031), and maximum skin dose (P = .008). Overall treatment time was decreased by 4 to 7 fractions, which translated to a decrease in estimated average treatment cost of $3056 (range, $2651-$4335; P < .001). Conclusions: In addition to benefits in cost, convenience, and improved biologic effect in STS, HARD regimen offers a safe treatment approach with dosimetric advantages compared with conventional sequential boost, which may translate to improved long-term toxicity.

Reirradiation of metastases of the central nervous system: part 1-brain metastasis.

Because of improved survival of cancer patients, more patients irradiated for brain metastases develop intracerebral recurrences requiring subsequent courses of radiotherapy. Five studies focused on reirradiation with whole-brain radiation therapy (WBRT) after initial WBRT for brain metastases. Following the second WBRT course, improvement of clinical symptoms was found in 31-68% of patients. Rates of neurotoxicity, such as encephalopathy or cognitive decline, were reported in two studies (1.4% and 32%). In another study, severe or unexpected adverse events were not observed. Survival following the second WBRT course was generally poor, with median survival times of 2.9-4.1 months. The survival prognosis of patients receiving two courses of WBRT can be estimated by a scoring tool considering five prognostic factors. Three studies investigated reirradiation with single-fraction stereotactic radiosurgery (SF-SRS) following primary WBRT. One-year local control rates were 74-91%, and median survival times ranged between 7.8 and 14 months. Rates of radiation necrosis (RN) after reirradiation were 0-6%. Seven studies were considered that investigated re-treatment with SF-SRS or fractionated stereotactic radiation therapy (FSRT) following initial SF-SRS or FSRT. One-year local control rates were 60-88%, and the median survival times ranged between 8.3 and 25 months. During follow-up after reirradiation, rates of overall (asymptomatic or symptomatic) RN ranged between 12.5% and 30.4%. Symptomatic RN occurred in 4.3% to 23.9% of cases (patients or lesions). The risk of RN associated with symptoms and/or requiring surgery or corticosteroids appears lower after reirradiation with FSRT when compared to SF-SRS. Other potential risk factors of RN include the volume of overlap of normal tissue receiving 12 Gy at the first course and 18 Gy at the second course of SF-SRS, maximum doses ≥40 Gy of the first or the second SF-SRS courses, V12 Gy >9 cm3 of the second course, initial treatment with SF-SRS, volume of normal brain receiving 5 Gy during reirradiation with FSRT, and systemic treatment. Cumulative EQD2 ≤100-120 Gy2 to brain, <100 Gy2 to brainstem, and <75 Gy2 to chiasm and optic nerves may be considered safe. Since most studies were retrospective in nature, prospective trials are required to better define safety and efficacy of reirradiation for recurrent or progressive brain metastases.

International case series of metastasis to penis.

Objectives: To evaluate clinical characteristics associated with survival in patients with metastases to the penis. Methods: After approval by the IRB, records of collaborating centres in Leuven, London, Rostock, Amsterdam and Tampa were screened for men presenting with metastatic disease to penis. Multivariate logistic regression analyses were used to identify covariables associated with survival. We analysed clinical data on 34 patients. Results: Primary sites were most frequently prostate (n = 14, 41%) and bladder (n = 9, 26%). Twenty-eight of 34 (82%) presented with metachronous penile metastases, and 11 (32%) patients had penile metastases as the sole metastatic site. Penile metastatic locations were most frequently in the corpora (n = 18; 53%). Seven (21%) patients with penile metastases had priapism on presentation. Systemic therapy was frequent and variable (chemotherapy n = 12; immunotherapy n = 5; hormones n = 3). Local management included either surgery (n = 10) or RT (n = 8). Twelve- and 24-month overall survival rate were 67% and 35%, respectively. No clinical parameter including primary histology, synchronous or metachronous metastases or priapism showed statistical survival benefit or detriment. Conclusion: Metastasis to penis arises most frequently from pelvic primaries. Priapism does not appear to correlate with survival in this large, well-defined series.

Multiplex Immunofluorescence Captures Progressive Immune Exhaustion with Advancing Penile Squamous Cell Cancer Stage.

Penile squamous cell carcinoma (PSCC) is a rare and deadly malignancy. Therapeutic advances have been stifled by a poor understanding of disease biology. Specifically, the immune microenvironment is an underexplored component in PSCC and the activity of immune checkpoint inhibitors observed in a subset of patients suggests immune escape may play an important role in tumorigenesis. Herein, we explored for the first time the immune microenvironment of 57 men with PSCC and how it varies with the presence of human papillomavirus (HPV) infection and across tumor stages using multiplex immunofluorescence of key immune cell markers. We observed an increase in the density of immune effector cells in node-negative tumors and a progressive rise in inhibitory immune players such as type 2 macrophages and upregulation of the PD-L1 checkpoint in men with N1 and N2-3 disease. There were no differences in immune cell densities with HPV status.

Thirty-day mortality as a metric for palliative radiotherapy in pediatric patients.

PURPOSE OF REVIEW: Thirty-day mortality (30DM) is an emerging consideration for determining whether terminally ill adult patients may benefit from palliative radiotherapy (RT). However, the efficacy and ethics of delivering palliative RT at the end of life (EOL) in children are seldom discussed and not well-established. RECENT FINDINGS: Palliative RT is perhaps underutilized among patients ≤21 years old with rates as low as 11%. While effective when delivered early, clinical benefit decreases when administered within the last 30 days of life. Pediatric 30DM rates vary widely between institutions (0.7-30%), highlighting the need for standardized practices. Accurate prognosis estimation remains challenging and prognostic models specific to palliative pediatric patients are limited. Discordance between provider and patient/parent perceptions of prognosis further complicates decision-making. SUMMARY: RT offers effective symptom control in pediatric patients when administered early. However, delivering RT within the last 30 days of life may provide limited clinical benefit and hinder optimal EOL planning and care. Early referral for palliative RT, preferably with fewer fractions (five or fewer), along with multidisciplinary supportive care, optimizes the likelihood of maintaining patients' quality of life. Prognosis estimation remains difficult, and improving patient and family understanding is crucial. Further research is needed to refine prognostic models and enhance patient-centered care.

Management of Lymph Node-positive Penile Cancer: A Systematic Review.

CONTEXT: Lymph node (LN) involvement in penile cancer is associated with poor survival. Early diagnosis and management significantly impact survival, with multimodal treatment approaches often considered in advanced disease. OBJECTIVE: To assess the clinical effectiveness of treatment options available for the management of inguinal and pelvic lymphadenopathy in men with penile cancer. EVIDENCE ACQUISITION: EMBASE, MEDLINE, the Cochrane Database of Systematic Reviews, and other databases were searched from 1990 to July 2022. Randomised controlled trials (RCTs), nonrandomised comparative studies (NRCSs), and case series (CSs) were included. EVIDENCE SYNTHESIS: We identified 107 studies, involving 9582 patients from two RCTs, 28 NRCSs, and 77 CSs. The quality of evidence is considered poor. Surgery is the mainstay of LN disease management, with early inguinal LN dissection (ILND) associated with better outcomes. Videoendoscopic ILND may offer comparable survival outcomes to open ILND with lower wound-related morbidity. Ipsilateral pelvic LN dissection (PLND) in N2-3 cases improves overall survival in comparison to no pelvic surgery. Neoadjuvant chemotherapy in N2-3 disease showed a pathological complete response rate of 13% and an objective response rate of 51%. Adjuvant radiotherapy may benefit pN2-3 but not pN1 disease. Adjuvant chemoradiotherapy may provide a small survival benefit in N3 disease. Adjuvant radiotherapy and chemotherapy improve outcomes after PLND for pelvic LN metastases. CONCLUSIONS: Early LND improves survival in nodal disease in penile cancer. Multimodal treatments may provide additional benefit in pN2-3 cases; however, data are limited. Therefore, individualised management of patients with nodal disease should be discussed in a multidisciplinary team setting. PATIENT SUMMARY: Spread of penile cancer to the lymph nodes is best managed with surgery, which improves survival and has curative potential. Supplementary treatment, including the use of chemotherapy and/or radiotherapy, may further improve survival in advanced disease. Patients with penile cancer with lymph node involvement should be treated by a multidisciplinary team.

Systematic Review and Meta-analysis of Minimally Invasive Procedures for Surgical Inguinal Nodal Staging in Penile Carcinoma.

CONTEXT: There are several procedures for surgical nodal staging in clinically node-negative (cN0) penile carcinoma. OBJECTIVE: To evaluate the diagnostic accuracy, perioperative outcomes, and complications of minimally invasive surgical procedures for nodal staging in penile carcinoma. EVIDENCE ACQUISITION: A systematic review of the Medline, Embase, and Cochrane controlled trials databases and ClinicalTrials.gov was conducted. Published and ongoing studies reporting on the management of cN0 penile cancer were included without any design restriction. Outcomes included the false negative (FN) rate, the number of nodes removed, surgical time, and postoperative complications. EVIDENCE SYNTHESIS: Forty-one studies were eligible for inclusion. Four studies comparing robot-assisted (RA-VEIL) and video-endoscopic inguinal lymphadenectomy (VEIL) to open inguinal lymph node dissection (ILND) were suitable for meta-analysis. A descriptive synthesis was performed for single-arm studies on modified open ILND, dynamic sentinel node biopsy (DSNB) with and without preoperative inguinal ultrasound (US), and fine-needle aspiration cytology (FNAC). DSNB with US + FNAC had lower FN rates (3.5-22% vs 0-42.9%) and complication rates (Clavien Dindo grade I-II: 1.1-20% vs 2.9-11.9%; grade III-V: 0-6.8% vs 0-9.4%) in comparison to DSNB alone. Favourable results were observed for VEIL/RA-VEIL over open ILND in terms of major complications (2-10.6% vs 6.9-40.6%; odds ratio [OR] 0.18; p < 0.01). Overall, VEIL/RA-VEIL had lower wound-related complication rates (OR 0.14; p < 0.01), including wound infections (OR 0.229; p < 0.01) and skin necrosis (OR 0.16; p < 0.01). The incidence of lymphatic complications varied between 20.6% and 49%. CONCLUSIONS: Of all the surgical staging options, DSNB with inguinal US + FNAC had the lowest complication rates and high diagnostic accuracy, especially when performed in high-volume centres. If DSNB is not available, favourable results were also found for VEIL/RA-VEIL over open ILND. Lymphatic-related complications were comparable across open and video-endoscopic ILND. PATIENT SUMMARY: We reviewed studies on different surgical approaches for assessing lymph node involvement in cases with penile cancer. The results show that a technique called dynamic sentinel node biopsy with ultrasound guidance and fine-needle sampling has high diagnostic accuracy and low complication rates. For lymph node dissection in penile cancer cases, a minimally invasive approach may offer favourable postoperative outcomes.

Trimodal Therapy Using an MR-guided Radiation Therapy Partial Bladder Tumor Boost in Muscle Invasive Bladder Cancer.

Purpose: Bladder preservation with trimodal therapy (TMT; maximal tumor resection followed by chemoradiation) is an effective paradigm for select patients with muscle invasive bladder cancer. We report our institutional experience of a TMT protocol using nonadaptive magnetic resonance imaging-guided radiation therapy (MRgRT) for partial bladder boost (PBB). Methods and Materials: A retrospective analysis was performed on consecutive patients with nonmetastatic muscle invasive bladder cancer who were treated with TMT using MRgRT between 2019 and 2022. Patients underwent intensity modulated RT-based nonadaptive MRgRT PBB contoured on True fast imaging with steady state precession (FISP) images (full bladder) followed sequentially by computed tomography-based RT to the whole empty bladder and pelvic lymph nodes with concurrent chemotherapy. MRgRT treatment time, table shifts, and dosimetric parameters of target coverage and normal tissue exposure were described. Prospectively assessed acute and late genitourinary and gastrointestinal (GI) toxicity were reported. Two-year local control was assessed with Kaplan-Meier methods. Results: Seventeen patients were identified for analysis. PBB planning target volume margins were ≤8 mm in 94% (n = 16) of cases. Dosimetric target coverage parameters were favorable and all normal tissue dose constraints were met. For MRgRT PBB fractions, median table shifts were 0.4 cm (range, 0-3.15), 0.45 cm (0-2.65), and 0.75 cm (0-4.8) in the X, Y, and Z planes, respectively. Median treatment time for MRgRT PBB fractions was 9 minutes (range, 6.9-17.4). We identified 32 out of 100 total MRgRT fractions that may have benefitted from online adaptation based on changes in organ position relative to planning target volume, predominantly because of small bowel (13/32, 41%) or rectum (8/32, 25%). Two patients discontinued RT prematurely. The incidence of highest-grade acute genitourinary toxicity was 1 to 2 (69%) and 3 (6%), whereas the incidence of acute GI toxicity was 1 to 2 (81%) and 3 (6%). There were no late grade 3 events; 17.6% had late grade 2 cystitis and none had late GI toxicity. With median follow-up of 18.2 months (95% CI, 12.4-22.5), the local control rate was 92%, and no patient has required salvage cystectomy. Conclusions: Nonadaptive MRgRT PBB is feasible with favorable dosimetry and low resource utilization. Larger studies are needed to evaluate for potential benefits in toxicity and local control associated with this approach in comparison to standard treatment techniques.

Corporal Skip Metastases in Penile Squamous Cell Carcinoma: An Unknown and Distinct Pattern of Spread with Poor Prognosis.

BACKGROUND: Penile squamous cell carcinoma (PSCC) is characterised by stepwise lymphatic dissemination. Skip metastases (SkMs) are rare metastases in the corpus cavernosum or spongiosum without continuity to the primary tumour or its resection site. OBJECTIVE: To assess the distinct pattern of spread in SkM+ patients and the effect of SkM on prognosis. DESIGN, SETTING, AND PARTICIPANTS: We conducted a retrospective analysis of patients with SkM+ PSCC at ten high-volume international referral centres between January 2006 and May 2022. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We evaluated histopathological data, primary lymph node (LN) staging, and metastatic spread. We included a cohort of patients matched for pT stage, LN status, and grade who did not have SkM (SkM-) to compare the SkM prognosis and predictive value for cancer-specific mortality (CSM). RESULTS AND LIMITATIONS: Among the 63 SkM+ patients who met our inclusion criteria, the SkM diagnosis was synchronous in 54.0% and metastases were mostly located in the corpus cavernosum. SkM was symptomatic in 14% of cases, was detected on imaging in 32%, and was found incidentally on pathological examination in 27%. Fifty-one patients (81%) presented with positive LNs and 28 (44%) developed distant metastases. Seven patients (11%) presented with or developed distant metastasis without displaying any LN involvement. The 2-yr cancer-specific survival estimates were 36% (95% confidence interval [CI] 25-52%) for SkM+ and 66% (95% CI 55-80%) for matched SkM- patients (p < 0.001). On multivariable Cox regression analysis, SkM presence was an independent predictor for higher CSM (hazard ratio 2.05, 95% CI 1.06-4,12; p = 0.03). CONCLUSIONS: PSCC-related SkM is associated with aggressive disease behaviour and poor survival outcomes. Palpation of the entire penile shaft is essential, and distant staging is recommended in patients suspected of having SkM owing to the tendency for distant metastatic spread. PATIENT SUMMARY: We investigated outcomes for patients with cancer of the penis who had metastases in the tissues responsible for erection. We found that metastases in this location were associated with poor prognosis, even in the absence of more typical spread of cancer via the lymph nodes.

Stereotactic body radiation therapy versus conventional external beam radiotherapy for spinal metastases: A systematic review and meta-analysis of randomized controlled trials.

INTRODUCTION: This study aimed to compare SBRT and cEBRT for treating spinal metastases through a systematic review and meta-analysis of randomized controlled trials (RCTs). METHODS: PubMed, EMBASE and Cochrane Library were searched up to 6 May 2023 for RCTs comparing SBRT and cEBRT for spinal metastases. Overall and complete pain response, local progression, overall survival, quality of life and adverse events were extracted. Data were pooled using random-effects models. Results were reported as risk ratios (RRs) for dichotomous outcomes, and hazard ratios (HRs) for time-to-event outcomes, along with their 95% confidence intervals (CIs). Heterogeneity was evaluated using the I2 statistic. RESULTS: Three RCTs were identified involving 642 patients. No differences were seen in overall pain response comparing SBRT and cEBRT (RR at 3 months: 1.12, 95% CI, 0.74-1.70, p = 0.59; RR at 6 months: 1.29, 95% CI, 0.97-1.72, p = 0.08). Only two of three studies presented complete pain response data. SBRT demonstrated a statistically significant improvement in complete pain response compared to cEBRT (RR at 3 months: 2.52; 95% CI, 1.58-4.01; P < 0.0001; RR at 6 months: 2.48; 95% CI, 1.23-4.99; P = 0.01). There were no significant differences in local progression and overall survival. Adverse events were similar, except for any grade radiation dermatitis, which was significantly lower in SBRT arm (RR 0.17, 95% CI 0.03-0.96, P = 0.04). CONCLUSION: SBRT is a safe treatment option for spine metastases. It may provide better complete pain response compared to cEBRT. Additional trials are needed to determine the potential benefits of SBRT in specific patient subsets.

Palliative whole brain radiation therapy: an international state of practice.

BACKGROUND: Improvements in radiation delivery and systemic therapies have resulted in few remaining indications for palliative whole brain radiation therapy (WBRT). Most centers preferentially use stereotactic radiotherapy (SRT) and reserve WBRT for those with >15 lesions, leptomeningeal presentation, rapidly progressive disease, or limited estimated survival. Despite regional differences among preferred dose, fractionation, and treatment technique, we predict survival post-WBRT will remain poor-indicating appropriate application of WBRT in this era of SRT and improved systemic therapies. METHODS: A multi-center, international retrospective analysis of patients receiving WBRT in 2022 was performed. Primary end point was survival after WBRT. De-identified data were analyzed centrally. Patients receiving WBRT as part of a curative regimen, prophylactically, or as bridging therapy were excluded. The collected data consisted of patient parameters including prescription dose and fractionation, use of neurocognitive sparing techniques and survival after WBRT. Survival was calculated via the Kaplan-Meier method. RESULTS: Of 29,943 international RT prescriptions written at ten participating centers in 2022, 462 (1.5%) were for palliative WBRT. Participating centers were in the United States (n=138), the United Kingdom (n=111), Hong Kong (n=72), Italy (n=49), Belgium (n=45), Germany (n=27), Ghana (n=15), and Cyprus (n=5). Twenty-six different dose regimens were used. The most common prescriptions were for 3,000 cGy over 10 fractions (45.0%) and 2,000 cGy over 5 fractions (43.5%) with significant regional preferences (P<0.001). Prior SRT was delivered in 32 patients (6.7%), hippocampal avoidance (HA) was used in 44 patients (9.5%), and memantine was prescribed in 93 patients (20.1%). Survival ranged from 0 days to still surviving at 402 days post-treatment. The global median overall survival (OS) was 84 days after WBRT [95% confidence interval (CI): 68.0-104.0]. Actuarial survival at 7 days, 1 month, 3 months, and 6 months were 95%, 78%, 48%, and 32%, respectively. Twenty-seven patients (5.8%) were unable to complete their prescribed WBRT. CONCLUSIONS: This moment-in-time analysis confirms that patients with poor expected survival are being appropriately selected for WBRT-illustrating the dwindling indications for WBRT-and demonstrates the variance in global practice. Since poor survival precludes patients from deriving benefit, memantine and HA are best suited in carefully selected cases.

An Assessment of the Penile Squamous Cell Carcinoma Surfaceome for Biomarker and Therapeutic Target Discovery.

Penile squamous cell carcinoma (PSCC) is a rare malignancy in most parts of the world and the underlying mechanisms of this disease have not been fully investigated. About 30-50% of cases are associated with high-risk human papillomavirus (HPV) infection, which may have prognostic value. When PSCC becomes resistant to upfront therapies there are limited options, thus further research is needed in this venue. The extracellular domain-facing protein profile on the cell surface (i.e., the surfaceome) is a key area for biomarker and drug target discovery. This research employs computational methods combined with cell line translatomic (n = 5) and RNA-seq transcriptomic data from patient-derived tumors (n = 18) to characterize the PSCC surfaceome, evaluate the composition dependency on HPV infection, and explore the prognostic impact of identified surfaceome candidates. Immunohistochemistry (IHC) was used to validate the localization of select surfaceome markers. This analysis characterized a diverse surfaceome within patient tumors with 25% and 18% of the surfaceome represented by the functional classes of receptors and transporters, respectively. Significant differences in protein classes were noted by HPV status, with the most change being seen in transporter proteins (25%). IHC confirmed the robust surface expression of select surfaceome targets in the top 85% of expression and a superfamily immunoglobulin protein called BSG/CD147 was prognostic of survival. This study provides the first description of the PSCC surfaceome and its relation to HPV infection and sets a foundation for novel biomarker and drug target discovery in this rare cancer.

The Prognostic Role of Human Papillomavirus and p16 Status in Penile Squamous Cell Carcinoma-A Systematic Review.

PSCC is a rare cancer, with approximately half of all cases related to HPV. While HPV and p16 IHC testing have proven their prognostic value for oropharyngeal cancer, this is not yet established for PSCC. The current level of evidence exploring the relation between PSCC and HPV is moderate, so we conducted a systematic review following PRISMA guidelines to evaluate the prognostic role of HPV and p16 IHC in PSCC clinical outcomes. We searched the PubMed, Embase, and Cochrane databases and identified 34 relevant studies that met our inclusion criteria. Of these, 33 were retrospective cohort studies, and one was a cross-sectional study. Nine studies reported that HPV-positive and p16-positive PSCC had better overall survival (OS) and disease-free survival (DFS). This study highlights the need for a meta-analysis to determine the role of routine HPV status or p16 staining testing as part of the initial diagnosis and staging of PSCC patients worldwide.

Feasibility and Toxicity of Full-Body Volumetric Modulated Arc Therapy Technique for High-Dose Total Body Irradiation.

Introduction: High-dose total body irradiation (TBI) is often part of myeloablative conditioning in acute leukemia. Modern volumetric modulated arc therapy (VMAT)-based plans employ arcs to the inferior-most portion of the body that can be simulated in a head-first position and use 2D planning for the inferior body which can result in heterogeneous doses. Here, we describe our institution's unique protocol for delivering high-dose TBI entirely with VMAT and retrospectively compare dosimetric outcomes with helical tomotherapy (HT) plans. Additionally, we describe our method of oropharyngeal mucosal sparing that was implemented after fatal mucositis occurred in two patients. Methods: Thirty-one patients were simulated and treated in head-first (HFS) and feet-first (FFS) orientations. Patients were treated with VMAT (n = 26) or HT (n = 5). In VMAT plans, to synchronize doses between the orientations, images were deformably registered and the HFS dose was transferred to the FFS plan and used as a background dose when optimizing plans. Six to eight isocenters with two arcs per isocenter were generated. HT was delivered with an established technique. Patients were treated to 13.2 Gy over eight twice daily fractions. Dosimetric outcomes and toxicities were retrospectively compared. Results: Prescription dose and organ at risk (OAR) constraints were met for all patients. Lower lung doses were achieved with VMAT relative to HT plans (7.4 vs 7.7 Gy, P = .009). Statistically significant improvement in mucositis was not achieved after adopting a mucosal-sparing technique, however lower doses to the oropharyngeal mucosal were achieved (6.9 vs 14.1 Gy, P = .009), and no further mucositis-related deaths occurred. Conclusions: This full-body VMAT method of TBI achieves dose goals, eliminates risk of heterogenous doses within the femur, and demonstrates that selective OAR sparing with the purpose of reducing TBI-related morbidity and mortality is possible at any institution with a VMAT-capable linear accelerator.