Magnitude of benefit for adjuvant radiotherapy following minimally invasive surgery in intermediate to high risk HPV-positive oropharyngeal squamous cell carcinoma

Radiation Therapy for HPV-Positive Oropharyngeal Squamous Cell Carcinoma: An ASTRO Clinical Practice Guideline

PURPOSE

Human Papilloma Virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC) is a distinct disease from other head and neck tumors. This guideline provides evidence-based recommendations on the critical decisions in its curative treatment, including both definitive and postoperative radiation therapy (RT) management.

METHODS

ASTRO convened a task force to address 5 key questions on the use of RT for management of HPV-associated OPSCC. These questions included indications for definitive and postoperative RT and chemoradiation; dose-fractionation regimens and treatment volumes; preferred RT techniques and normal tissue considerations; and posttreatment management decisions. The task force did not address indications for primary surgery versus RT. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

Concurrent cisplatin is recommended for patients receiving definitive RT with T3-4 disease and/or 1 node >3 cm, or multiple nodes. For similar patients who are ineligible for cisplatin, concurrent cetuximab, carboplatin/5-fluorouracil, or taxane-based systemic therapy are conditionally recommended. In the postoperative setting, RT with concurrent cisplatin (either schedule) is recommended for positive surgical margins or extranodal extension. Postoperative RT alone is recommended for pT3-4 disease, >2 nodes, or a single node >3 cm. Observation is conditionally recommended for pT1-2 disease and a single node ≤3 cm without other risk factors. For patients treated with definitive RT with concurrent systemic therapy, 7000 cGy in 33 to 35 fractions is recommended, and for patients receiving postoperative RT without positive surgical margins and extranodal extension, 5600 to 6000 cGy is recommended. For all patients receiving RT, intensity modulated RT over 3-dimensional techniques with reduction in dose to critical organs at risk (including salivary and swallowing structures) is recommended. Reassessment with positron emission tomography-computed tomography is recommended approximately 3 months after definitive RT/chemoradiation, and neck dissection is recommended for convincing evidence of residual disease; for equivocal positron emission tomography-computed tomography findings, either neck dissection or repeat imaging is recommended.

CONCLUSIONS

The role and practice of RT continues to evolve for HPV-associated OPSCC, and these guidelines inform best clinical practice based on the available evidence.

World Workshop on Oral Medicine VIII: Development of a Core Outcome Set for Dry Mouth: A Systematic Review of Outcome Domains for Xerostomia

OBJECTIVE

The purpose of this study was to identify all outcome domains used in clinical studies of xerostomia, that is, subjective sensation of dry mouth. This study is part of the extended project "World Workshop on Oral Medicine Outcomes Initiative for the Direction of Research" to develop a core outcome set for dry mouth.

STUDY DESIGN

A systematic review was performed on MEDLINE, EMBASE, CINAHL, and Cochrane Central Register of Controlled Trials databases. All clinical and observational studies that assessed xerostomia in human participants from 2001 to 2021 were included. Information on outcome domains was extracted and mapped to the Core Outcome Measures in Effectiveness Trials taxonomy. Corresponding outcome measures were summarized.

RESULTS

From a total of 34,922 records retrieved, 688 articles involving 122,151 persons with xerostomia were included. There were 16 unique outcome domains and 166 outcome measures extracted. None of these domains or measures were consistently used across all the studies. The severity of xerostomia and physical functioning were the 2 most frequently assessed domains.

CONCLUSION

There is considerable heterogeneity in outcome domains and measures reported in clinical studies of xerostomia. This highlights the need for harmonization of dry mouth assessment to enhance comparability across studies and facilitate the synthesis of robust evidence for managing patients with xerostomia.

A Prospective Study of Mucosal Sparing Radiation Therapy in Resected Oropharyngeal Cancer Patients

PURPOSE

Our objective was to report the prospective results of mucosal sparing radiation therapy in human papillomavirus-related oropharyngeal squamous cell carcinoma.

METHODS AND MATERIALS

From March 2016 through May 2019, patients were enrolled in this institutional review board-approved prospective cohort study at a multisite institution. Inclusion criteria included p16+ American Joint Committee on Cancer seventh edition pathologic T1 or T2, N1 to N3, and M0 oropharyngeal cancers. Proton therapy (PT) was delivered to at-risk nodal regions, excluding the primary mucosal site. Secondary to insurance denial for PT, intensity modulated radiation therapy (IMRT) was allowed. European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Head and Neck Module and Patient-Reported Outcomes Measurement Information System surveys (quality of life [QOL]) and modified barium swallowing impairment profiles (MBSImP) were obtained at baseline before radiation therapy, then 3 and 12 months after radiation therapy. Kaplan-Meier estimates were calculated for time-to-event clinical outcomes, and repeated measures mixed models were used to explore changes in QOL over time. A comparison of QOL and swallowing outcomes with standard-of-care treatment was analyzed.

RESULTS

There were 61 evaluable patients with a median follow-up of 38 months (range, 10-64); 44 (72%) were treated with PT and 17 (28%) were treated with IMRT. The 2-year local control, locoregional control, distant metastasis-free survival, and overall survival were 98%, 97%, 98%, and 100%, respectively. There were 6 grade ≥3 events related to treatment. Two IMRT patients required percutaneous endoscopic gastrostomy tube placement during treatment secondary to significant nausea due to dysgeusia. Patients noted significant QOL improvement over time in the pain, swallowing, speech, social eating, social contact, mouth opening, and use of pain medication domains (all P < .02). The MBSImP overall severity score as well as oral and pharyngeal impairment scores showed stability with no significant change over time. For the 44 patients treated with PT, the mean D95 to the primary target was 10.7 Gy (standard deviation = 12.5 Gy).

CONCLUSIONS

Mucosal sparing radiation is well tolerated in select resected human papillomavirus-related oropharyngeal squamous cell carcinoma with a low risk of recurrence at the mucosal primary site, a low rate of percutaneous endoscopic gastrostomy tube placement, and few radiation-related grade ≥3 adverse events.

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.

The omission of intentional primary site radiation following transoral robotic surgery in 59 patients: No local-regional failures

BACKGROUND

We assessed locoregional control with omission of intentional primary site radiation after transoral robotic surgery (TORS) and quantified nontargeted primary site dose.

METHODS

Following Institutional Review Board (IRB) approval, patients treated with primary TORS resection for squamous cell carcinomas of the oropharynx were reviewed. Patients with cT1-2 tumors, >2 mm margins, in whom the surgeon resected the primary without revising specimen-driven margins, qualified for omission of primary site radiation.

RESULTS

From 2014 to 2019, 112 patients met criteria. Fifty-nine (52%) patients did not receive radiation targeting the primary site; of whom, 22 received no radiation. In this group, there were no local failures; mean age was 58 years and median follow-up was 25 months. Thirty-seven patients received adjuvant radiation targeting the neck, mean bystander dose to the primary site was 28.8 Gy (range, 13.3-50.6 Gy).

CONCLUSION

In a 59 patient population, omission of radiation to the primary site after TORS resulted in no locoregional failures.

Dosimetric Results for Adjuvant Proton Radiation Therapy of HPV-Associated Oropharynx Cancer

Purpose

One significant advantage of proton therapy is its ability to improve normal tissue sparing and toxicity mitigation, which is relevant in the treatment of oropharyngeal squamous cell carcinoma (OPSCC). Here, we report our institutional experience and dosimetric results with adjuvant proton radiation therapy (PRT) versus intensity-modulated radiotherapy (IMRT) for Human Papilloma Virus (HPV)-associated OPSCC.

Materials and Methods

This was a retrospective, single institutional study of all patients treated with adjuvant PRT for HPV-associated OPSCC from 2015 to 2019. Each patient had a treatment-approved equivalent IMRT plan to serve as a reference. Endpoints included dosimetric outcomes to the organs at risk (OARs), local regional control (LRC), progression-free survival (PFS), and overall survival (OS). Descriptive statistics, a 2-tailed paired t test for dosimetric comparisons, and the Kaplan-Meier method for disease outcomes were used.

Results

Fifty-three patients were identified. Doses delivered to OARs compared favorably for PRT versus IMRT, particularly for the pharyngeal constrictors, esophagus, larynx, oral cavity, and submandibular and parotid glands. The achieved normal tissue sparing did not negatively impact disease outcomes, with 2-year LRC, PFS, and OS of 97.0%, 90.3%, and 97.5%, respectively.

Conclusion

Our study suggests that meaningful normal tissue sparing in the postoperative setting is achievable with PRT, without impacting disease outcomes.

Treatment De-intensification for HPV-associated Oropharyngeal Cancer: A Definitive Surgery Paradigm

Human papillomavirus-associated oropharyngeal squamous cell carcinoma (HPV+OPSCC) constitutes the majority of head and neck diagnoses within the United States. Patients with HPV+OPSCC have biologically and demographically distinct disease, leading to high cure rates after standard treatments. This long survivorship period coupled with the toxicity of standard treatments makes de-intensification strategies an urgent research question. Surgery has generally been avoided for HPV+OPSCC as historical surgical techniques were invasive and morbid. With the advent of minimally invasive transoral techniques, definitive surgical options are becoming more popular. Minimally invasive surgery offers unique opportunities in a de-intensification paradigm, including more detailed patient selection, radiation volume reduction, and radiation dose de-intensification. Nevertheless, careful patient selection must be exercised as surgical defects may lead to quality of life decrements beyond what is gained through de-intensification. Ongoing phase III efforts will help clarify the patient cohorts best suited for surgically oriented de-intensification.

Extracapsular extension, pathologic node status, and adjuvant treatment in primary surgery patients with human papillomavirus-mediated oropharyngeal cancer: A national hospital-based retrospective cohort analysis

BACKGROUND

The significance of extracapsular extension (ECE) and adjuvant treatment paradigm in patients with surgically managed human papillomavirus-positive (HPV+) oropharyngeal cancer (OPC) is debated.

METHODS

National, hospital-based, retrospective cohort study of 2663 patients pN+ HPV+ OPC who underwent primary surgery.

RESULTS

Patients with ECE had a 1.74-times risk of death (95% confidence interval [CI]: 1.26-2.40, p = 0.001) compared to patients without ECE. Among patients with pN1, ECE-positive disease, risk of overall mortality was similar across treatment paradigms (surgery alone: ref; adjuvant radiation therapy [RT]: aHR: 0.81; 95% CI: 0.36-1.85; p = 0.62; adjuvant CRT: aHR: 0.66; 95% CI: 0.34-1.32; p = 0.24). Patients with pN2 ECE-positive disease treated with adjuvant RT alone exhibited similar risk of all-cause mortality (hazard ratio: 1.04, 95% CI: 0.24-4.47, p = 0.96) compared to adjuvant chemoradiation (CRT). In patients with advanced, ECE-positive disease (e.g., pT3-T4pN2), adjuvant CRT did not reduce the risk of overall mortality relative to adjuvant RT.

CONCLUSION

Although pathologic ECE negatively predicts for survival in patients with HPV+ OPC, our analyses support expansion of postoperative de-intensification clinical trial eligibility criteria in patients with ECE-positive disease.

A Phase 2 Trial of Alternative Volumes of Oropharyngeal Irradiation for De-intensification (AVOID): Omission of the Resected Primary Tumor Bed After Transoral Robotic Surgery for Human Papilloma Virus-Related Squamous Cell Carcinoma of the Oropharynx

PURPOSE

This trial tested the safety and efficacy of a novel, deintensified radiation therapy (RT) approach after initial surgical resection for patients with human papilloma virus (HPV)-associated oropharyngeal squamous cell carcinoma (OPSCC).

METHODS AND MATERIALS

This single-arm phase 2 prospective clinical trial enrolled 60 patients with stage pT1-pT2 N1-3 HPV-associated OPSCC treated with transoral robotic surgery (TORS) and selective neck dissection at a single institution between May 2014 and September 2017. Patients had favorable features at the primary site (negative surgical margins ≥2 mm, no perineural invasion, and no lymphovascular invasion) but required adjuvant therapy based on lymph node involvement. Surgeries were all performed at a high-volume head and neck cancer center with expertise in TORS. Patients received postoperative RT to at-risk areas in the involved neck (60-66 Gy) and uninvolved neck (54 Gy). The resected primary site was treated as an active avoidance structure in the treatment planning of postoperative RT. Concurrent chemotherapy was administered for patients with extranodal extension.

RESULTS

Median follow-up of the 60 patients enrolled was 2.4 years (range, 8.5-53.8 months). A single patient recurred at the primary site, for 2-year local control of 98.3%. One patient (1.7%) developed a regional neck recurrence, and 2 patients (3.3%) developed distant metastases. Measured 2-year local recurrence-free survival was 97.9% (95% confidence interval, 86.1%-99.7%). Overall survival was 100% at the time of analysis. The mean radiation dose to the primary site was 36.9 Gy (standard deviation, 10.3 Gy). Two patients (3.3%) experienced late soft tissue necrosis in the primary site surgical bed that resolved within 2 months. Feeding tube dependence rates were 0% during RT, 3.3% temporarily during follow-up, and 0% at last follow-up.

CONCLUSIONS

Deintensified postoperative RT that avoids the resected primary tumor site and targets only the at-risk neck after TORS for selected patients with HPV-associated OPSCC may be safe and is worthy of further study.

Phase II Evaluation of Aggressive Dose De-Escalation for Adjuvant Chemoradiotherapy in Human Papillomavirus-Associated Oropharynx Squamous Cell Carcinoma

PURPOSE

The purpose of this study was to determine if dose de-escalation from 60 to 66 Gy to 30 to 36 Gy of adjuvant radiotherapy (RT) for selected patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma could maintain historical rates for disease control while reducing toxicity and preserving swallow function and quality of life (QOL).

PATIENTS AND METHODS

MC1273 was a single-arm phase II trial testing an aggressive course of RT de-escalation after surgery. Eligibility criteria included patients with p16-positive oropharyngeal squamous cell carcinoma, smoking history of 10 pack-years or less, and negative margins. Cohort A (intermediate risk) received 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks along with 15 mg/m2 docetaxel once per week. Cohort B included patients with extranodal extension who received the same treatment plus a simultaneous integrated boost to nodal levels with extranodal extension to 36 Gy in 1.8-Gy fractions twice per day. The primary end point was locoregional tumor control at 2 years. Secondary end points included 2-year progression-free survival, overall survival, toxicity, swallow function, and patient-reported QOL.

RESULTS

Accrual was from September 2013 to June 2016 (N = 80; cohort A, n = 37; cohort B, n = 43). Median follow-up was 36 months, with a minimum follow-up of 25 months. The 2-year locoregional tumor control rate was 96.2%, with progression-free survival of 91.1% and overall survival of 98.7%. Rates of grade 3 or worse toxicity at pre-RT and 1 and 2 years post-RT were 2.5%, 0%, and 0%. Swallowing function improved slightly between pre-RT and 12 months post-RT, with one patient requiring temporary feeding tube placement.

CONCLUSION

Aggressive RT de-escalation resulted in locoregional tumor control rates comparable to historical controls, low toxicity, and little decrement in swallowing function or QOL.

De-intensified adjuvant (chemo)radiotherapy versus standard adjuvant chemoradiotherapy post transoral minimally invasive surgery for resectable HPV-positive oropharyngeal carcinoma

BACKGROUND

More than 400,000 cases of oropharyngeal squamous cell cancer (OPSCC) are diagnosed every year worldwide and this is rising. Much of the increase has been attributed to human papillomavirus (HPV). HPV-positive OPSCC patients are often younger and have significantly improved survival relative to HPV-negative patients. Traditional management of OPSCC has been with radiotherapy with or without chemotherapy, as this was shown to have similar survival to open surgery but with significantly lower morbidity. Techniques have evolved, however, with the development of computerised planning and intensity-modulated radiotherapy, and of minimally invasive surgical techniques. Acute and late toxicities associated with chemoradiotherapy are a significant burden for OPSCC patients and with an ever-younger cohort, any strategies that could decrease treatment-associated morbidity should be investigated.

OBJECTIVES

To assess the effects of de-intensified adjuvant (chemo)radiotherapy in comparison to standard adjuvant (chemo)radiotherapy in patients treated with minimally invasive transoral surgery (transoral robotic surgery or transoral laser microsurgery) for resectable HPV-positive oropharyngeal squamous cell carcinoma.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the Cochrane ENT Trials Register; Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 26 April 2018.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in patients with carcinoma of the oropharynx (as defined by the World Health Organization classification C09, C10). Cancers included were primary HPV-positive squamous cell tumours originating from the oropharyngeal mucosa. Tumours were classified as T1-4a with or without nodal spread and with no evidence of distant metastatic spread. The intervention was minimally invasive transoral surgery followed by de-intensified adjuvant therapy (either omission of chemotherapy or reduced-dose radiotherapy). The comparator was minimally invasive transoral surgery followed by standard concurrent chemoradiotherapy or standard-dose radiotherapy. The treatments received were of curative intent and patients had not undergone any prior intervention, other than diagnostic biopsy.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane. Our primary outcomes were overall survival (disease-related survival was to be studied where possible) and disease-free survival, measured at one, two, three and five years. Our secondary outcomes included assessment of swallowing ability and voice, measured at one, six, 12 and 24 months. We planned to use GRADE to assess the quality of evidence for each outcome.

MAIN RESULTS

We did not identify any completed RCTs that met our inclusion criteria. However, three eligible studies are in progress:ADEPT is a phase III trial comparing postoperative radiotherapy with or without cisplatin in HPV-positive T1-4a OPSCC patients. Included patients must have received minimally invasive surgery and demonstrated extra-capsular spread from disease in the neck.ECOG-E3311 is a phase II trial of treatment for HPV-positive locally advanced OPSCC (stages III-IVa + IVb without distant metastasis). Patients are stratified after minimally invasive surgery. Medium-risk patients are randomised to either standard or reduced-dose radiotherapy.PATHOS is a phase III trial of treatment for HPV-positive OPSCC (T1-3, N0-2b). Patients are stratified after minimally invasive surgery. Medium-risk patients are randomised to either standard or reduced-dose radiotherapy. High-risk patients are randomised to radiotherapy with or without concurrent cisplatin.

AUTHORS' CONCLUSIONS

This review highlights the current lack of high-quality randomised controlled trials studying treatment de-escalation after minimally invasive surgery in patients with HPV-positive OPSCC. However, trials that will meet the inclusion criteria for this review are in progress with results expected between 2021 and 2023.