Reducing radiotherapy target volume expansion for patients with HPV-associated oropharyngeal cancer

A systematic review and proportional meta-analysis of image-based pattern of loco-regional failure analyses outcomes in head and neck squamous cell carcinoma

BACKGROUND AND PURPOSE

The prognosis following loco-regional failure after primary radiotherapy (RT) for head and neck squamous cell carcinoma (HNSCC) is poor. The hypothesis that most failures occur as a consequence of tumor radioresistance, can be evaluated by proxy as the proportion of failures that occur in the high-dose region. Several studies have investigated possible reasons for treatment failure by an image-based pattern of failure analyses (POF), comparing the initial planning CT scan with a scan conducted upon failure. The aim of the present systematic review and meta-analysis was to evaluate the proportion of failures that occurred in the high-dose region of all analyzed failures.

MATERIALS AND METHODS

A systematic database search from 2000 to 2023, was performed for studies including results from image-based loco-regional POF, regardless of the method, after primary RT for HNSCC. Proportions of volumetrically in-field (opposed to marginal or outfield) failures, point of origin-based inside high-dose targets, or covered by curative doses for both the number of patients and the number of failure sites were analyzed in proportional meta-analyses. The review was registered at Prospero (CRD42023412545).

RESULTS

Out of 56 included studies, accumulated image-based POF results were available from 1,161 patients and 658 individual failure sites. The majority of patients had in-field failures in volumetric-based studies (84 % (95 % CI: 77;90)), inside failures in point of origin-based studies (82 % (95% CI:61;85)) or failures covered by 95 % of dose prescribed to CTV1 (84 % (95% CI:69;95)). A trend toward increasing proportions of non-high-dose failures in more recently treated patients was observed.

CONCLUSION

Most loco-regional failures for patients treated with primary RT for HNSCC are related to the high-dose volume. Therefore, a focus on biomarkers predicting individual tumor radiosensitivity is warranted to enable individualized treatment intensification to increase loco-regional control.

High-dose loco-regional pattern of failure after primary radiotherapy in p16 positive and negative head and neck squamous cell carcinoma - A DAHANCA 19 study

Introduction

Patients with failure after primary radiotherapy (RT) for head and neck squamous cell carcinoma (HNSCC) have a poor prognosis. This study investigates pattern of failure after primary curatively intended IMRT in a randomized controlled trial in relation to HPV/p16 status.

Material and methods

Patients with HNSCC of the oral cavity, oropharynx (OPSCC), hypopharynx or larynx were treated with primary curative IMRT (+/-cisplatin) and concomitant nimorazole between 2007 and 12. Of 608 patients, 151 had loco-regional failure within five years, from whom 130 pairs of scans (planning-CT and diagnostic failure scan) were collected and deformably co-registered. Point of origin-based pattern of failure analysis was conducted, including distance to CTV1 and GTV, and estimated dose coverage of the point of origin.

Results

Of 130 patients with pairs of scans, 104 (80 %) had at least one local or regional failure site covered by 95 % of prescribed dose and 87 (67 %) of the failures had point of origin within the high-dose CTV (CTV1). Of failures from primary p16 + OPSCC, the majority of both mucosal (84 %) and nodal (61 %) failures were covered by curative doses. For p16- tumors (oral cavity, OPSCC p16neg, hypopharynx and larynx), 75 % of mucosal and 66 % of nodal failures were high-dose failures.

Conclusion

Radioresistance is the primary cause of failure after RT for HNSCC irrespective of HPV/p16 status. Thus, focus on predictors for the response to RT is warranted to identify patients with higher risk of high-dose failure that might benefit from intensified treatment regimens.

Outcomes of transoral robotic surgery for early-stage oropharyngeal squamous cell carcinoma with low rates of adjuvant therapy: A consecutive single-institution study from 2013 to 2020

INTRODUCTION

The incidence of oropharyngeal squamous cell carcinoma (OPSCC) has increased in recent decades, driven by infection with human papillomavirus (HPV). Transoral robotic surgery (TORS) and neck dissection (ND) has been employed as an alternative to radiotherapy/chemoradiotherapy. The current literature is lacking studies providing an exhaustive overview of recurrence characteristics and long-term outcomes in TORS-treated OPSCC-patients.

METHODS

All patients treated for OPSCC with primary TORS + ND in Eastern Denmark between 2013 and 2020 were included in the study. The aim was to explore overall survival (OS), recurrence-free survival (RFS), recurrence patterns, and ultimate failure rate (UFR). OS and RFS were examined using the Kaplan-Meier method. Cox proportional regression analyses were employed to examine effect of different variables on risk of death and recurrence.

RESULTS

The study included 153 patients of which 88.9 % (n = 136) were treated with TORS alone while 11.1 % (n = 17) received adjuvant therapy. The 1-, 3-, and 5-year OS were 97.4 %, 94.1 %, and 87.6 % while 1-, 3-, and 5-year RFS were 96.6 %, 87.8 %, and 84.9 %. The UFR was 6.5 % in the cohort. Patients with HPV+/p16 + OPSCC had a significantly better 5-year OS of 92.3 % than patients with discordant or double-negative HPV/p16 status (OS = 73.3 %). No differences in outcomes between patients treated with or without adjuvant therapy were found in regression analysis.

CONCLUSION

Excellent survival and disease control was obtained with TORS + ND in this cohort, despite lesser application of adjuvant therapy than other TORS-centers, implying that TORS without adjuvant therapy can be successfully applied in treatment of early-stage OPSCC.

Post-treatment PET/CT for p16-positive oropharynx cancer treated with definitive proton therapy

Objectives

Given emerging data suggesting that uncertainty in the relative biologic effectiveness at the distal end of the Bragg peak results in increased mucosal injury in patients with oropharynx cancer receiving adjuvant proton therapy, we evaluated the results of post-treatment positron emission tomography-computed tomography (PET/CT) in patients with p16-positive oropharynx cancer (p16+OPC) treated with definitive intensity-modulated proton therapy (IMPT).

Material and Methods

A retrospective cohort study of patients with p16+OPC treated with definitive IMPT between 2016 and 2022 was performed at a single institution. Patients with PET/CT scans within 6 months following completion of IMPT were included in the study. Positive post-treatment scans were defined by a maximum standard uptake values (SUVmax) >4.0 or a <65% reduction in SUVmax in either the primary tumor or lymph node. The Fisher's exact test was used to evaluate factors associated with positive post-treatment PET/ CT values.

Results

Sixty-two patients were included for analysis. Median follow-up was 21 months (range: 3-71 months) with a median time to post-treatment PET/CT of 3 months (range: 2-6 months). Median post-treatment SUVmax of the primary disease and nodal disease was 0 (mean: 0.8, range: 0-7.7) and 0 (mean: 0.7, range: 0-9.5), respectively. Median post-treatment percent reduction in SUVmax for the primary site and lymph node was 100% (mean: 94%, range: 31.3-100%) and 100% (mean: 89%, range: 23-100%), respectively. Eleven patients had a positive post-treatment PET/CT with one biopsy-proven recurrence. Negative and positive predictive values (NPV and PPV) were 98% and 9.1%, respectively. There were no factors associated with positive post-treatment PET/CT.

Conclusion

Similar to patients treated with photon-based radiation therapy, post-treatment PET/CT has a high NPV for patients with p16+OPC treated with definitive proton therapy and should be used to guide patient management. Additional patients and more events are needed to confirm the PPV of a post-treatment PET/CT in this favorable patient cohort.

The Metabolic Footprint of Systemic Effects in the Blood Caused by Radiotherapy and Inflammatory Conditions: A Systematic Review

Response to radiotherapy (RT) includes tissue toxicity, which may involve inflammatory reactions. We aimed to compare changes in metabolic patterns induced at the systemic level by radiation and inflammation itself. Patients treated with RT due to head and neck cancer and patients with inflammation-related diseases located in the corresponding anatomical regions were selected. PubMed and Web of Science databases were searched from 1 January 2000 to 10 August 2023. Twenty-five relevant studies where serum/plasma metabolic profiles were analyzed using different metabolomics approaches were identified. The studies showed different metabolic patterns of acute and chronic inflammatory diseases, yet changes in metabolites linked to the urea cycle and metabolism of arginine and proline were common features of both conditions. Although the reviewed reports showed only a few specific metabolites common for early RT response and inflammatory diseases, partly due to differences in metabolomics approaches, several common metabolic pathways linked to metabolites affected by radiation and inflammation were revealed. They included pathways involved in energy metabolism (e.g., metabolism of ketone bodies, mitochondrial electron transport chain, Warburg effect, citric acid cycle, urea cycle) and metabolism of certain amino acids (Arg, Pro, Gly, Ser, Met, Ala, Glu) and lipids (glycerolipids, branched-chain fatty acids). However, metabolites common for RT and inflammation-related diseases could show opposite patterns of changes. This could be exemplified by the lysophosphatidylcholine to phosphatidylcholine ratio (LPC/PC) that increased during chronic inflammation and decreased during the early phase of response to RT. One should be aware of dynamic metabolic changes during different phases of response to radiation, which involve increased levels of LPC in later phases. Hence, metabolomics studies that would address molecular features of both types of biological responses using comparable analytical and clinical approaches are needed to unravel the complexities of these phenomena, ultimately contributing to a deeper understanding of their impact on biological systems.

A comparison of loco-regional relapse pattern in HPV positive vs negative oropharyngeal cancers following radiotherapy; relation to pretreatment FDG-PET and radiotherapy target volumes

BACKGROUND

Previous studies have shown that a large proportion of relapses in head-and neck squamous cell carcinoma (HNSCC) following radiotherapy (RT) occur in the pretreatment FDG-PET avid volume (GTV-PET). The aim of the current work was to see if this was valid also in an oropharynx squamous cell carcinoma (OPSCC) only population, and to compare the loco-regional relapse pattern between HPV positive and HPV negative patients.

MATERIAL AND METHODS

Among 633 OPSCC patients treated between 2009 and 2017, 46 patients with known HPV (p16) status and isolated loco-regional relapse were included. Oncologists contoured relapse volumes (RV) on relapse scans (PET/CT, CT or MR), which were thereafter deformed to match the anatomy of the planning CTs. The point of origin (center of volume) of the deformed RVs were determined and analyzed in relation to the RT target volumes (GTV-PET, GTV and CTVs). The relapse pattern was compared between HPV positive and HPV negative patients using Fischer's exact test.

RESULTS

Sixty RVs were contoured in the 46 patients. 55% (95% CI 44-67%) of relapses originated in GTV-PET, while the other RT volumes harbored 12% (5-20%) (GTV), 18% (9-28%) (high risk CTV) and 5% (0-11%) (low risk CTV) of relapses. Six relapses were found outside the RT target volumes. No significant difference in relapse pattern between HPV positive and HPV negative patients was found (p = .95).

CONCLUSION

There were no signs of difference in loco-regional relapse pattern between HPV positive and HPV negative patients. In agreement with previous findings, GTV-PET was the most frequent RT target volume of relapse.

DOSE AND VOLUME DE-ESCALATION OF RADIOTHERAPY IN HEAD AND NECK CANCER

Radiotherapy plays a key role in the treatment of head and neck cancer. However, irradiation of the head and neck region is associated with high rates of acute and chronic toxicity. Technological advances have led to better visualisation of target volumes and critical structures and improved dose conformality in the treatment volume. Despite this, acute toxicity has not been substantially reduced and late toxicity has a significant impact on patients' quality of life. The greater radiosensitivity of tumours associated with the HPV and the development of new imaging techniques have encouraged research into new deintensified strategies to reduce the side effects of radiotherapy. The aim of this paper is to review the literature on the strategies of de-escalated treatment in dose and/or volume in head and neck cancer.

Gross tumor volume margin and local control in p16-positive oropharynx cancer patients treated with intensity modulated proton therapy

BACKGROUND

To determine if the extent of high-dose gross tumor volume (GTV) to clinical target volume (CTV) expansion is associated with local control in patients with p16-positive oropharynx cancer (p16+ OPC) treated with definitive intensity modulated proton therapy (IMPT).

METHODS

We performed a retrospective analysis of patients with p16+ OPC treated with IMPT at a single institution between 2016 and 2021. Patients with a pre-treatment PET-CT and restaging PET-CT within 4 months following completion of IMPT were analyzed.

RESULTS

Sixty patients were included for analysis with a median follow-up of 17 months. The median GTV to CTV expansion was 5 mm (IQR: 2 mm). Thirty-three percent of patients (20 of 60) did not have a GTV to CTV expansion. There was one local failure within the expansion group (3%).

CONCLUSION

Excellent local control was achieved using IMPT for p16+ OPC independent of GTV expansion. IMPT with minimal target expansions represent a potential harm-minimization technique for p16-positive oropharynx cancer.

Patterns of failure for hypopharynx cancer patients treated with limited high-dose radiotherapy treatment volumes

PURPOSE

Optimal radiotherapy treatment volumes for patients with locally advanced hypopharynx squamous cell carcinoma should ensure maximal tumor coverage with minimal inclusion of normal surrounding structures. Here we evaluated the effectiveness of a direct 3-mm high-dose gross tumor volume to planning target volume expansion on clinical outcomes for hypopharynx cancers.

MATERIALS AND METHODS

We performed a retrospective analysis of patients with hypopharynx carcinoma treated between 2004 and 2018 with primary radiotherapy using a direct high-dose gross tumor volume to planning target volume expansion and with or without concurrent systemic therapy. Diagnostic imaging of recurrences was co-registered with the planning CT. Spatial and volumetric analyses of contoured recurrences were compared with planned isodose lines. Failures were initially defined as in field, marginal, elective nodal, and out of field. Each failure was further classified as central high-dose, peripheral high-dose, central intermediate/low-dose, peripheral intermediate/low-dose, and extraneous. Clinical outcomes were analyzed by Kaplan-Meier estimation.

RESULTS

Thirty-six patients were identified. At a median follow-up at 52.4 months, estimated 5-year overall survival was 59.3% (95% confidence interval [CI], 36.3%-74.1%), 5-year local and nodal control was 71.7% (95% CI, 47.1%-86.3%) and 69.9% (95% CI, 57.0%-82.6%), respectively. The most common failure was in the high-dose primary target volume. The gastrostomy tube retention rate at 1 year among patients without recurrence was 13.0% (95% CI, 3.2%-29.7%).

CONCLUSION

Minimal high-dose target volume expansions for hypopharynx cancers were associated with favorable locoregional control. This approach may enable therapy intensification to improve clinical outcomes.

Prospective Study of PET/MRI Tumor Response During Chemoradiotherapy for Patients With Low-risk and Intermediate-risk p16-positive Oropharynx Cancer

OBJECTIVE

The objective of this study was to examine tumor response with positron emission tomography (PET)/magnetic resonance imaging (MRI) during chemoradiotherapy as a predictor of outcome in patients with p16-positive oropharynx cancer.

MATERIALS AND METHODS

Patients with p16-positive oropharynx cancer were treated with chemoradiotherapy. Low-risk (LR) disease was defined as T1-T3 and N0-2b and ≤10 pack-years and intermediate-risk (IR) disease as T4 or N2c-3 or >10 pack-years. Patients underwent a PET/MRI scan pretreatment and at fraction 10. Change in value of imaging means were analyzed by analysis of variance. K-means clustering with Euclidean distance functions were used for patient clustering. Silhouette width was used to determine the optimal number of clusters. Linear regression was performed on all radiographic metrics using patient and disease characteristics.

RESULTS

Twenty-four patients were enrolled with 7 LR and 11 IR patients available for analysis. Pretreatment imaging characteristics between LR and IR patients were similar. Patients with LR disease exhibited a larger reduction in maximum standardized uptake value (SUV) compared with IR patients (P<0.05). Cluster analysis defined 2 cohorts that exhibited a similar intratreatment response. Cluster 1 contained 7 of 7 LR patients and 8 of 11 IR patients. Cluster 2 contained 3 of 11 IR patients. Cluster 2 exhibited significant differences compared with cluster 1 in the change in primary tumor peak SUV and largest lymph node median SUV.

CONCLUSIONS

We identified that IR p16-positive oropharynx cancers exhibit heterogeneity in their PET/MRI response to chemoradiotherapy. These data support further study of intratreatment imaging response as a potential mechanism to identify patients with IR oropharynx cancer suitable for treatment deintensification.

Treatment de-escalation for HPV+ oropharyngeal cancer: A systematic review and meta-analysis

Human Papillomavirus (HPV) related oropharyngeal carcinoma (OPC) carries a better prognosis compared with HPV-counterparts, thereby pushing the adoption of de-intensification treatment approaches as new strategies to preserve superior oncologic outcomes while minimizing toxicity. We evaluated the effect of treatment de-intensification in terms of overall survival (OS), progression-free survival (PFS), locoregional and distant control (LRC and DM) by selecting prospective or retrospective studies, providing outcome data with reduced intensification versus standard curative treatment in HPV+ OPC patients, with a systematic analysis till September 2020. The primary outcome of interest was OS. Secondary endpoints were PFS, LRC, and DM expressed as HR. A total of 55 studies (from 1393 screened references) were employed for quantitative synthesis for 38 929 patients. Among n = 48 studies with data available, de-intensified treatments reduced OS in HPV+ OPCs (HR = 1.33, 95% CI 1.17-1.52; p < 0.01). In de-escalated treatments, PFS was also decreased (HR = 2.11, 95% CI 1.65-2.69; p < 0.01). Compared with standard treatments, reduced intensity approaches were associated with reduced locoregional and distant disease control (HR = 2.51, 95% CI 1.75-3.59; p < 0.01; and HR = 1.9, 95% CI 1.25-2.9; p < 0.01). Chemoradiation improved survival in a definitive curative setting compared with radiotherapy alone (HR = 1.42, 95% CI 1.16-1.75; p < 0.01). When adjuvant treatments were compared, standard and de-escalation strategies provided similar OS. In conclusion, in patients with HPV+ OPC, de-escalation treatments should not be widely and agnostically adopted in clinical practice, as therein lies a concrete risk of offering a sub-optimal treatment to patients.

Reducing target volume in definitive radiotherapy for human papillomavirus-associated tonsil cancer

BACKGROUND

To evaluate the efficacy and safety of reducing target volume in definitive radiotherapy for HPV-associated tonsil cancer.

METHODS

A single-institution cohort of 90 patients with human papillomavirus (HPV)-associated tonsil cancer who received definitive radiotherapy with a 5-mm expansion from the gross tumor volume to clinical target volume between 2008 and 2019 were included. The overlapping volume of initial planning target volume and the recurrent tumor was calculated and categorized as one of three failure types: in-field: ≥95%; marginal-field: 50%-94%; and out-field: <50%.

RESULTS

With a median follow-up of 59.4 months, the 3-year and 5-year local control rates were 94.4% and 92.8%, respectively. A total of seven local failures were identified, of which 4 (4.4%) were in-field, 2 (2.2%) were marginal-field, and 1 (1.1%) was out-field. Grade 3 acute and late toxicities developed in 30 (33.3%) and 5 (5.6%) patients, respectively.

CONCLUSIONS

Reducing target volume could be an alternative option for selected patients with HPV-associated tonsil cancer.

Defining high-risk elective contralateral neck radiation volumes for oropharynx cancer

BACKGROUND

To define the location of the initial contralateral lymph node (LN) metastasis in patients with oropharynx cancer.

METHODS

The location of the LN centroids from patients with oropharynx cancer and a single radiographically positive contralateral LN was defined. A clinical target volume (CTV) inclusive of all LN centroids was created, and its impact on dose to organs at risk was assessed.

RESULTS

We identified 55 patients of which 49/55 had a single contralateral LN in level IIA, 4/55 in level III, 1/55 in level IIB, and 1/55 in the retropharynx. Mean radiation dose to the contralateral parotid gland was 15.1 and 21.0 Gy, (p <0.001) using the modeled high-risk elective CTV and a consensus CTV, respectively.

CONCLUSIONS

We present a systematic approach for identifying the contralateral nodal regions at highest risk of harboring subclinical disease in patients with oropharynx cancer that warrants prospective clinical study.

Imaging of Complications of Chemoradiation

Chemoradiation for head and neck cancer is associated with a variety of early and late complications. Toxicities may affect the aero-digestive tract (mucositis, salivary gland injury), regional osseous and cartilaginous structures (osteoradionecrosis (ORN) and chondronecrosis), vasculature (progressive radiation vasculopathy and carotid blow out syndromes), and neural structures (optic neuritis, myelitis, and brain injury). These may be difficult to distinguish from tumor recurrence on imaging, and may necessitate the use of advanced MRI and molecular imaging techniques to reach the correct diagnosis. Secondary radiation-induced malignancies include thyroid cancer and a variety of sarcomas that may manifest several years after treatment. Checkpoint inhibitors can cause a variety of adverse immune events, including autoimmune hypophysitis and encephalitis.

Improving the therapeutic ratio of radiotherapy against radioresistant cancers: Leveraging on novel artificial intelligence-based approaches for drug combination discovery

Despite numerous advances in cancer radiotherapy, tumor radioresistance remain one of the major challenges limiting treatment efficacy of radiotherapy. Conventional strategies to overcome radioresistance involve understanding the underpinning molecular mechanisms, and subsequently using combinatorial treatment strategies involving radiation and targeted drug combinations against these radioresistant tumors. These strategies exploit and target the molecular fingerprint and vulnerability of the radioresistant clones to achieve improved efficacy in tumor eradication. However, conventional drug-screening approaches for the discovery of new drug combinations have been proven to be inefficient, limited and laborious. With the increasing availability of computational resources in recent years, novel approaches such as Quadratic Phenotypic Optimization Platform (QPOP), CURATE.AI and Drug Combination and Prediction and Testing (DCPT) platform have emerged to aid in drug combination discovery and the longitudinally optimized modulation of combination therapy dosing. These platforms could overcome the limitations of conventional screening approaches, thereby facilitating the discovery of more optimal drug combinations to improve the therapeutic ratio of combinatorial treatment. The use of better and more accurate models and methods with rapid turnover can thus facilitate a rapid translation in the clinic, hence, resulting in a better patient outcome. Here, we reviewed the clinical observations, molecular mechanisms and proposed treatment strategies for tumor radioresistance and discussed how novel approaches may be applied to enhance drug combination discovery, with the aim to further improve the therapeutic ratio and treatment efficacy of radiotherapy against radioresistant cancers.

Decreasing treatment burden in HPV-related OPSCC: A systematic review of clinical trials

INTRODUCTION

Favorable outcomes are observed after treatment with standard chemoradiotherapy (CRT) for Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) patients. The consistent growing interest on treatment-related toxicity burden, potentially jeopardizing survivors' quality of life, led clinicians to investigate possible de-escalation strategies.

MATERIALS AND METHODS

A comprehensive systematic literature search of clinical trials was performed through the EMBASE database to provide an overview of the de-escalation strategies spectrum. Additionally, hand searching and clinicaltrials.gov were also used.

RESULTS

Herein, we report and discuss different approaches to de-escalation of therapy, with respect to both local and systemic strategies.

CONCLUSIONS

Several promising de-escalation experiences have been published. However, while further evidence is awaited, no changes in the management nor deviation from the standard of care should be made outside of clinical trials.

De-Escalation After DE-ESCALATE and RTOG 1016: A Head and Neck Cancer InterGroup Framework for Future De-Escalation Studies

Human papillomavirus (HPV)-positive oropharyngeal cancer (OPC) is increasing rapidly. The younger age, significantly improved prognosis, and relative morbidity of the standard-of-care cisplatin and radiotherapy in this population have led to the popularization of the concept of treatment de-escalation. The recent results of the first 3 randomized de-escalation trials, however, have shown a clear detriment in survival when cisplatin is omitted or substituted. In view of these results, the Head and Neck Cancer International Group identified the need to issue guidance regarding future de-escalation studies for patients with HPV-positive head and neck cancer to avoid the possibility of patients being harmed. We review the current state of the literature regarding HPV de-escalation trials and present a framework and guidance on future and existing clinical trials for treatment de-escalation of HPV-positive OPC. De-escalation paradigms of HPV-positive OPC should be evaluated in phase II studies, and results should be awaited before proceeding to phase III studies. Implementation into clinical practice before high-level evidence is available should not be undertaken in this context. Finally, harm-minimization techniques should also be evaluated as an alternative to de-escalation of treatment in these patient groups.

Volume de-escalation in radiation therapy: state of the art and new perspectives

PURPOSE

New RT techniques and data emerging from follow-up for several tumor sites suggest that treatment volume de-escalation may permit to minimize therapy-related side effects and/or obtain better clinical outcomes. Here, we summarize the main evidence about volume de-escalation in RT.

METHOD

The relevant literature from PubMed was reviewed in this article. The ClinicalTrials.gov database was searched for clinical trials related to the specific topic.

RESULTS

In Lymphoma, large-volume techniques (extended- and involved-field RT) are being successfully replaced by involved-site RT and involved-node RT. In head and neck carcinoma, spare a part of elective neck is controversial. In early breast cancer, partial breast irradiation has been established as a treatment option in low-risk patients. In pancreatic cancer stereotactic body radiotherapy may be used to dose escalation. Stereotactic radiosurgery should be the treatment choice for patients with oligometastatic brain disease and a life expectancy of more than 3 months, and it should be considered an alternative to WBRT for patients with multiple brain metastases.

CONCLUSION

Further clinical trials are necessary to improve the identification of suitable patient cohorts and the extent of possible volume de-escalation that does not compromise tumor control.

Clinical outcomes for larynx patients with cancer treated with refinement of high-dose radiation treatment volumes

BACKGROUND

To evaluate disease control, toxicities, and dose to dysphagia/aspiration risk structures (DARS) using a direct gross tumor volume (GTV_70Gy ) to planning target volume expansion (dPTV_70Gy ) for patients with squamous cell carcinoma of the larynx (LSCC).

METHODS

A retrospective review was performed on patients with LSCC treated between 2003 and 2018. Clinical outcomes, toxicities, and dosimetric data were analyzed.

RESULTS

Seventy-three patients were identified. Overall survival at 5-years was 57.8%. Five-year local and regional control was 79.8% and 88.2%, respectively. Distant metastatic-only failure was 2.7%. Eighty percent of failures were 95% contained within the dPTV_70Gy . Mean dose and the volume of DARS receiving 70 Gy was significantly lower for dPTV_70Gy compared to a consensus-defined PTV_70Gy .

DISCUSSION

Judicious reduction in high-dose target volumes can preserve high tumor control rates while reducing dose to normal surrounding structures underscoring the potential benefit of this approach in enabling local therapy intensification to improve locoregional control.