Work Outcomes after Intensity-Modulated Proton Therapy (IMPT) versus Intensity-Modulated Photon Therapy (IMRT) for Oropharyngeal Cancer

De-escalation of Adjuvant Therapy in Operatively Managed HPV Associated Oropharyngeal Carcinoma: Current Status and Future Directions

Human papillomavirus (HPV) associated oropharyngeal carcinoma is currently the most frequently diagnosed head and neck cancer in the United States. Due to the generally high cure rates with standard therapies, de-intensification strategies are being explored to reduce acute and long-term side effects. For patients treated with definitive chemoradiation, unselected de-escalation has shown worse progression-free survival compared to standard therapy. Concurrently, surgical management is becoming more prevalent, and adjuvant de-escalation appears promising. Further research is required to identify optimal candidacy for adjuvant de-escalation and to understand the relationship between dose and volume de-escalation. Biomarkers such as ctDNA may assist in candidate selection, but validation and alignment with pathological criteria are necessary.

Dosimetric benefits of customised mouth-bite for head neck cancer patients undergoing modern proton therapy - An audit

BACKGROUND AND AIMS

Proton therapy (PRT) for Head Neck Cancer (HNC), in view of the Bragg peak, spares critical structures like oral mucosa better than IMRT. In PRT, mouth-bites, besides immobilising and separating mucosal surfaces, may also negate the end-of-range effect. We retrospectively analysed the details and dosimetric impact of mouth-bites in PRT for HNC.

MATERIALS AND METHODS

The data of consecutive HNC patients treated with IMPT from May 2020 to August 2022 were studied retrospectively. Details of the mouth-bite used, compliance and resultant mucosal separation were noted. Further analysis, restricted to previously unirradiated patients, comprised volumetric dosimetric data pertaining to the mouth-bite and distal mucosal surfaces. High LET zones, corresponding to 6-12 keV/micron, for mouth-bite doses above 30 Gy, were recalculated from existing plans.

RESULTS

A mouth-bite was used in 69 of 80 consecutively treated patients, ranging from 8 to 42 mm in thickness, and 12 to 52 mm in the resultant mucosal sparing. In 42 patients in whom the mouth-bite V 32 Gy was > 0, median Dmean, absolute V32, V39, V50 and V60 GyE (Gray Equivalent) of the mouth bite was 35.65 GyE (Range: 2.65 - 60 GyE), 10 cc (Range: 0.1 - 32 cc), 7.6 cc (Range: 0.1 - 30.8 cc), 5.7 cc (Range: 0.2 - 29.2 cc) and 1.45 cc (Range: 0.2 - 18.1 cc) respectively, all significantly more than the spared adjacent mucosal surface. In absence of a mouth-bite, the spared mucosa would have at least partially received the high dose received by the mouth-bite. High LET zones were noted in 12 of 48 mouth-bites.

CONCLUSION

In PRT for HNC, mouth-bites play a vital role in improving the sparing of mucosa outside the target.

ACR-ARS Practice Parameter for the Performance of Proton Beam Therapy

Purpose

This practice parameter for the performance of proton beam radiation therapy was revised collaboratively by the American College of Radiology (ACR) and the American Radium Society (ARS). This practice parameter was developed to serve as a tool in the appropriate application of proton therapy in the care of cancer patients or other patients with conditions in which radiation therapy is indicated. It addresses clinical implementation of proton radiation therapy, including personnel qualifications, quality assurance (QA) standards, indications, and suggested documentation.

Materials and Methods

This practice parameter for the performance of proton beam radiation therapy was developed according to the process described under the heading The Process for Developing ACR Practice Parameters and Technical Standards on the ACR website (https://www.acr.org/Clinical-Resources/Practice-Parameters-and-Technical-Standards) by the Committee on Practice Parameters - Radiation Oncology of the ACR Commission on Radiation Oncology in collaboration with the ARS.

Results

The qualifications and responsibilities of personnel, such as the proton center Chief Medical Officer or Medical Director, Radiation Oncologist, Radiation Physicist, Dosimetrist and Therapist, are outlined, including the necessity for continuing medical education. Proton therapy standard clinical indications and methodologies of treatment management are outlined by disease site and treatment group (e.g. pediatrics) including documentation and the process of proton therapy workflow and equipment specifications. Additionally, this proton therapy practice parameter updates policies and procedures related to a quality assurance and performance improvement program (QAPI), patient education, infection control, and safety.

Conclusion

As proton therapy becomes more accessible to cancer patients, policies and procedures as outlined in this practice parameter will help ensure quality and safety programs are effectively implemented to optimize clinical care.

Proton Therapy: Current Status and Controversies

Expert commentary on the evolving role of proton therapy, discussing the current status and controversies of proton therapy in the modern era.

Current Status and Future Directions of Proton Therapy for Head and Neck Carcinoma

The growing interest in proton therapy (PT) in recent decades is justified by the evidence that protons dose distribution allows maximal dose release at the tumor depth followed by sharp distal dose fall-off. But, in the holistic management of head and neck cancer (HNC), limiting the potential of PT to a mere dosimetric advantage appears reductive. Indeed, the precise targeting of PT may help evaluate the effectiveness of de-escalation strategies, especially for patients with human papillomavirus associated-oropharyngeal cancer (OPC) and nasopharyngeal cancer (NPC). Furthermore, PT could have potentially greater immunogenic effects than conventional photon therapy, possibly enhancing both the radiotherapy (RT) capability to activate anti-tumor immune response and the effectiveness of immunotherapy drugs. Based on these premises, the aim of the present paper is to conduct a narrative review reporting the safety and efficacy of PT compared to photon RT focusing on NPC and OPC. We also provide a snapshot of ongoing clinical trials comparing PT with photon RT for these two clinical scenarios. Finally, we discuss new insights that may further develop clinical research on PT for HNC.

Comparing the Oncologic Outcomes of Proton Therapy and Intensity-Modulated Radiation Therapy for Head and Neck Squamous Cell Carcinoma

PURPOSE

To compare the oncologic outcomes between proton therapy and intensity-modulated radiation therapy (IMRT) for head and neck squamous cell carcinoma (HNSCC) patients undergoing curative radiotherapy (RT).

EXPERIMENTAL DESIGN

We studied HNSCC patients who underwent curative-intent RT from 2015 to 2019, comparing the oncologic outcomes of proton therapy and IMRT. Our national retrospective HNSCC cohort study involved three institutes with proton therapy and 17 institutes (medical center levels) with IMRT in Taiwan. We utilized the Taiwan Cancer Registry Database to collect medical data for this study. We classified patients into two groups based on treatment method: Group 1 received IMRT, while Group 2 received proton therapy. 3:1 propensity score matching was performed to minimize the impact of potential confounders. Cox proportional hazards models were used to evaluate oncologic outcomes.

RESULTS

This study of 60,485 patients with HNSCC found that proton therapy was associated with better overall and cancer-specific survival and lower locoregional recurrence rates than IMRT. After matching, 982 patients were analyzed, with well-balanced factors. Proton therapy was a significant predictor of all-cause mortality, cancer-specific death, and locoregional recurrence (LRR). Patients who received proton therapy had significantly lower risks of all-cause mortality (adjusted hazard ratio, aHR=0.43), cancer-specific death (aHR=0.44), and LRR (aHR=0.61) than those who received IMRT.

CONCLUSION

Proton therapy is associated with superior outcomes in terms of overall survival, cancer-specific survival, and locoregional recurrence rates compared to IMRT in patients with HNSCC. These results provide valuable evidence for clinicians and patients in decision-making regarding the choice of radiation therapy for HNSCC.

Advances and Challenges in Conducting Clinical Trials With Proton Beam Therapy

Advances in proton therapy have garnered much attention and speculation in recent years as the indications for proton therapy have grown beyond pediatric, prostate, spine, and ocular tumors. To achieve and maintain consistent access to this cancer treatment and to ensure the future viability and availability of proton centers in the United States, a call for evidence has been heard and answered by proton radiation oncologists. Answers provided in this review include the evolution of proton therapy research, rationale for proton clinical trial design, challenges in and barriers to the conduct of proton therapy research, and other unique considerations for the study of proton therapy.

Proton Beam Radiation Therapy for Oropharyngeal Squamous Cell Carcinoma

Purpose

To discuss the role of proton beam therapy (PBT) in the treatment of patients with oropharyngeal squamous cell carcinoma (OPSCC).

Materials and Methods

A review of the pertinent literature.

Results

Proton beam therapy likely results in reduced acute and late toxicity as compared with intensity-modulated radiation therapy (IMRT). The extent of the reduced toxicity, which may be modest, depends on the endpoint and technical factors such as pencil beam versus passive scattered PBT and adaptive replanning. The disease control rates after PBT are likely similar to those after IMRT.

Conclusion

Proton beam therapy is an attractive option to treat patients with OPSCC. Whether it becomes widely available depends on access.

Why subclinical involvement is prescribed the same high dose as gross tumor volume: A study on high-dose clinical target volume in intensity-modulated radiotherapy plan of nasopharyngeal carcinoma

BACKGROUND

Most nasopharyngeal carcinoma (NPC) protocols define primary gross tumor volume (GTVnx) plus a range from 2 to 5 mm as the high-dose clinical target volume (hd-CTV). However, in China, hd-CTV is defined as GTVnx plus 0 mm.

METHODS

A total of 40 patients with newly diagnosed nonmetastatic NPC (T1-T4 ten cases each) treated with IMRT were consecutively enrolled. Real and virtual treatment plans were designed according to the definitions of hd-CTV recommended by China and Radiation Therapy Oncology Group (RTOG), respectively.

RESULTS

The hd-CTV in China was significantly smaller than that of RTOG. Exposure doses to 5 mm subclinical involvement and OARs as well as NTCP in the China treatment plan were significantly lower than those of RTOG.

CONCLUSION

It could be recommended to divide the hd-CTV into GTV and subclinical target volume and to prescribe different doses for the GTV and subclinical involvement in the IMRT plan of NPC.

Toxicity Profiles and Survival Outcomes Among Patients With Nonmetastatic Oropharyngeal Carcinoma Treated With Intensity-Modulated Proton Therapy vs Intensity-Modulated Radiation Therapy

IMPORTANCE

Patients with oropharyngeal carcinoma (OPC) treated with radiotherapy often experience substantial toxic effects, even with modern techniques such as intensity-modulated radiation therapy (IMRT). Intensity-modulated proton therapy (IMPT) has a potential advantage over IMRT due to reduced dose to the surrounding organs at risk; however, data are scarce given the limited availability and use of IMPT.

OBJECTIVE

To compare toxic effects and oncologic outcomes among patients with newly diagnosed nonmetastatic OPC treated with IMPT vs IMRT with or without chemotherapy.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included patients aged 18 years or older with newly diagnosed nonmetastatic OPC who received curative-intent radiotherapy with IMPT or IMRT at a single-institution tertiary academic cancer center from January 1, 2018, to December 31, 2021, with follow-up through December 31, 2021.

EXPOSURES

IMPT or IMRT with or without chemotherapy.

MAIN OUTCOMES AND MEASURES

The main outcomes were the incidence of acute and chronic (present after ≥6 months) treatment-related adverse events (AEs) and oncologic outcomes, including locoregional recurrence (LRR), progression-free survival (PFS), and overall survival (OS). Fisher exact tests and χ2 tests were used to evaluate associations between toxic effects and treatment modality (IMPT vs IMRT), and the Kaplan-Meier method was used to compare LRR, PFS, and OS between the 2 groups.

RESULTS

The study included 292 patients with OPC (272 [93%] with human papillomavirus [HPV]-p16-positive tumors); 254 (87%) were men, 38 (13%) were women, and the median age was 64 years (IQR, 58-71 years). Fifty-eight patients (20%) were treated with IMPT, and 234 (80%) were treated with IMRT. Median follow-up was 26 months (IQR, 17-36 months). Most patients (283 [97%]) received a dose to the primary tumor of 70 Gy. Fifty-seven of the patients treated with IMPT (98%) and 215 of those treated with IMRT (92%) had HPV-p16-positive disease. There were no significant differences in 3-year OS (97% IMPT vs 91% IMRT; P = .18), PFS (82% IMPT vs 85% IMRT; P = .62), or LRR (5% IMPT vs 4% IMRT; P = .59). The incidence of acute toxic effects was significantly higher for IMRT compared with IMPT for oral pain of grade 2 or greater (42 [72%] IMPT vs 217 [93%] IMRT; P < .001), xerostomia of grade 2 or greater (12 [21%] IMPT vs 68 [29%] IMRT; P < .001), dysgeusia of grade 2 or greater (16 [28%] IMPT vs 134 [57%] IMRT; P < .001), grade 3 dysphagia (4 [7%] IMPT vs 29 [12%] IMRT; P < .001), mucositis of grade 3 or greater (10 [53%] IMPT vs 13 [70%] IMRT; P = .003), nausea of grade 2 or greater (0 [0%] IMPT vs 18 [8%] IMRT; P = .04), and weight loss of grade 2 or greater (22 [37%] IMPT vs 138 [59%] IMRT; P < .001). There were no significant differences in chronic toxic effects of grade 3 or greater, although there was a significant difference for chronic xerostomia of grade 2 or greater (6 IMPT [11%] vs 22 IMRT [10%]; P < .001). Four patients receiving IMRT (2%) vs 0 receiving IMPT had a percutaneous endoscopic gastrostomy tube for longer than 6 months.

CONCLUSIONS AND RELEVANCE

In this study, curative-intent radiotherapy with IMPT for nonmetastatic OPC was associated with a significantly reduced acute toxicity burden compared with IMRT, with few chronic toxic effects and favorable oncologic outcomes, including locoregional recurrence of only 5% at 2 years. Prospective randomized clinical trials comparing these 2 technologies and of patient-reported outcomes are warranted.

Patient-Reported Financial Toxicity in a Population-Based Cohort of Oropharynx Cancer Survivors

PURPOSE

Patients with oropharyngeal squamous cell carcinoma (OPSCC) are at high risk for financial toxicity (FT), but the nature, extent, and predictors of FT experienced after primary radiation therapy (RT) or surgery are poorly understood.

METHODS AND MATERIALS

We used a population-based sample of patients from the Texas Cancer Registry with stage I to III OPSCC diagnosed from 2006 to 2016 and treated with primary RT or surgery. Of 1668 eligible patients, 1600 were sampled, 400 responded, and 396 confirmed OPSCC. Measures included the MD Anderson Symptom Inventory Head and Neck, Neck Dissection Impairment Index, and a financial toxicity instrument adapted from the Individualized Cancer Care (iCanCare) study. Multivariable logistic regression evaluated associations of exposures with outcomes.

RESULTS

Of 396 analyzable respondents, 269 (68%) received primary RT and 127 (32%) surgery. The median time from diagnosis to survey was 7 years. Due to OPSCC, 54% of patients experienced material sacrifice (including 28% who reduced food spending and 6% who lost their housing), 45% worried about financial problems, and 29% experienced long-term FT. Independent factors associated with more long-term FT included female sex (odds ratio [OR], 1.72; 95% confidence interval [CI], 1.23-2.40), Black non-Hispanic race (OR, 2.98; 95% CI, 1.26-7.09), unmarried status (OR, 1.50; 95% CI, 1.11-2.03), feeding tube use (OR, 3.98; 95% CI, 2.29-6.90), and worst versus best quartile on the MD Anderson Symptom Inventory Head and Neck (OR, 1.89; 95% CI, 1.23-2.90) and Neck Dissection Impairment Index (OR, 5.62; 95% CI, 3.79-8.34). Factors associated with less long-term FT included age >57 years (OR, 0.54; 95% CI, 0.41-0.71; P < .001) and household income ≥$80,000 (OR, 0.60; 95% CI, 0.44-0.82; P = .001). Primary RT versus surgery was not associated with long-term FT (OR, 0.92; 95% CI, 0.68-1.24).

CONCLUSIONS

Oropharynx cancer survivors experience high rates of material sacrifice and long-term FT, and we identified important risk factors. Chronic symptom burden was associated with significantly worse long-term financial status, supporting the hypothesis that toxicity mitigation strategies may reduce long-term FT.

Navigating financial toxicity in patients with cancer: A multidisciplinary management approach

Approximately one-half of individuals with cancer face personal economic burdens associated with the disease and its treatment, a problem known as financial toxicity (FT). FT more frequently affects socioeconomically vulnerable individuals and leads to subsequent adverse economic and health outcomes. Whereas multilevel systemic factors at the policy, payer, and provider levels drive FT, there are also accompanying intervenable patient-level factors that exacerbate FT in the setting of clinical care delivery. The primary strategy to intervene on FT at the patient level is financial navigation. Financial navigation uses comprehensive assessment of patients' risk factors for FT, guidance toward support resources, and referrals to assist patient financial needs during cancer care. Social workers or nurse navigators most frequently lead financial navigation. Oncologists and clinical provider teams are multidisciplinary partners who can support optimal FT management in the context of their clinical roles. Oncologists and clinical provider teams can proactively assess patient concerns about the financial hardship and employment effects of disease and treatment. They can respond by streamlining clinical treatment and care delivery planning and incorporating FT concerns into comprehensive goals of care discussions and coordinated symptom and psychosocial care. By understanding how age and life stage, socioeconomic, and cultural factors modify FT trajectory, oncologists and multidisciplinary health care teams can be engaged and informative in patient-centered, tailored FT management. The case presentations in this report provide a practical context to summarize authors' recommendations for patient-level FT management, supported by a review of key supporting evidence and a discussion of challenges to mitigating FT in oncology care. CA Cancer J Clin. 2022;72:437-453.

HPV as a Carcinomic Driver in Head and Neck Cancer: a De-escalated Future?

OPINION STATEMENT

Patients with HPV-associated oropharyngeal squamous cell carcinoma have improved prognosis relatively to those with tumors not driven by HPV. Both definitive radiotherapy (typically with concurrent chemotherapy) and transoral robotic surgery (with adjuvant therapies based on pathologic risk factors) are both acceptable treatment options for patients. The decision on which treatment is optimal depends on individual patient factors and should be made in a multi-disciplinary setting with input from a radiation oncologist, head and neck surgeon, and medical oncologist. Where appropriate, patients in this setting should be considered for enrollment on clinical studies evaluating de-escalation of treatment intensity given the very favorable outcomes and high toxicity profile associated with conventional therapies. However, caution is needed given negative data for de-escalation in the definitive chemotherapy and radiation setting. It remains unclear what the prognostic significance of HPV status is in patients with squamous cell carcinomas of the head and neck outside of the oropharynx.