Safety and Effectiveness of De-escalated Radiation Dose in T1-3 Nasopharyngeal Carcinoma: A Propensity Matched Analysis

Using the genomic adjusted radiation dose (GARD) to personalize the radiation dose in nasopharyngeal cancer

BACKGROUND

Locally advanced nasopharyngeal cancer (NPC) patients undergoing radiotherapy are at risk of treatment failure, particularly locoregional recurrence. To optimize the individual radiation dose, we hypothesize that the genomic adjusted radiation dose (GARD) can be used to correlate with locoregional control.

METHODS

A total of 92 patients with American Joint Committee on Cancer / International Union Against Cancer stage III to stage IVB recruited in a randomized phase III trial were assessed (NPC-0501) (NCT00379262). Patients were treated with concurrent chemo-radiotherapy plus (neo) adjuvant chemotherapy. The primary endpoint is locoregional failure free rate (LRFFR).

RESULTS

Despite the homogenous physical radiation dose prescribed (Median: 70 Gy, range 66-76 Gy), there was a wide range of GARD values (median: 50.7, range 31.1-67.8) in this cohort. In multivariable analysis, a GARD threshold (GARDT) of 45 was independently associated with LRFFR (p = 0.008). By evaluating the physical dose required to achieve the GARDT (RxRSI), three distinct clinical subgroups were identified: (1) radiosensitive tumors that RxRSI at dose < 66 Gy (N = 59, 64.1 %) (b) moderately radiosensitive tumors that RxRSI dose within the current standard of care range (66-74 Gy) (N = 20, 21.7 %), (c) radioresistant tumors that need a significant dose escalation above the current standard of care (>74 Gy) (N = 13, 14.1 %).

CONCLUSION

GARD is independently associated with locoregional control in radiotherapy-treated NPC patients from a Phase 3 clinical trial. GARD may be a potential framework to personalize radiotherapy dose for NPC patients.

Impact of adaptive radiotherapy on survival in locally advanced nasopharyngeal carcinoma treated with concurrent chemoradiotherapy

PURPOSE

To investigate the clinical significance of adaptive radiotherapy (ART) in locally advanced nasopharyngeal carcinoma treated with intensity-modulated radiotherapy (IMRT).

MATERIALS AND METHODS

Eligible patients were treated with concurrent chemoradiotherapy using IMRT. Planning computed tomography in ART was performed during radiotherapy, and replanning was performed. Since ART was started in May 2011 (ART group), patients who were treated without ART up to April 2011 (non-ART group) were used as the historical control. The Kaplan-Meier method was used to calculate overall survival (OS), locoregional recurrence-free survival (LRFS), progression-free survival (PFS), and distant metastasis-free survival (DMFS). LRFS for the primary tumor (LRFS_P) and regional lymph node (LRFS_LN) were also studied for more detailed analysis. Statistical significance was evaluated using the log-rank test for survival.

RESULTS

The ART group tended to have higher radiation doses. The median follow-up period was 127 months (range, 10 to 211 months) in the non-ART group and 61.5 months (range, 5 to 129 months) in the ART group. Compared to the non-ART group, the ART group showed significantly higher 5-year PFS (53.8% vs. 81.3%, p = 0.015) and LRFS (61.2% vs. 85.3%, p = 0.024), but not OS (80.7% vs. 80.8%, p = 0.941) and DMFS (84.6% vs. 92.7%, p = 0.255). Five-year LRFS_P was higher in the ART group (61.3% vs. 90.6%, p = 0.005), but LRFS_LN did not show a significant difference (91.9% vs. 96.2%, p = 0.541).

CONCLUSION

Although there were differences in the patient backgrounds between the two groups, this study suggests the potential effectiveness of ART in improving locoregional control, especially in the primary tumor.

Reduced-dose radiotherapy for Epstein-Barr virus DNA selected staged III nasopharyngeal carcinoma: A single-arm, phase 2 trial

BACKGROUND

Radiotherapy-related toxicities of nasopharyngeal carcinoma (NPC) caused by a standard dose of 70 Gy remain a critical issue. Therefore, we assessed whether a radiotherapy dose of 60 Gy was non-inferior to the standard dose in patients with low-risk stage III NPC with a favourable response to induction chemotherapy (IC).

PATIENTS AND METHODS

We did a single-arm, single-centre, phase II clinical trial in China. Patients with low-risk (Epstein-Barr virus [EBV] DNA level <4000 copies/ml) stage III NPC were treated with two cycles IC. Patients with complete/partial response and undetectable EBV DNA level were assigned 60 Gy intensity-modulated radiotherapy concurrently with three cycles of cisplatin. The primary end-point was 2-year progression-free survival (PFS). This trial is registered with ClinicalTrials.gov, number NCT03668730.

RESULTS

One patient quit because of withdrawal of informed consent after IC. In total, 215 patients completed two cycles of IC, after which 116 (54.0%) and 99 (46.0%) patients were assigned 60 and 70 Gy radiotherapy, respectively. For 215 patients, the 2-year PFS was 90.7% (95% CI, 86.8%-94.6%) with a median follow-up of 43.9 months (interquartile range [IQR], 39.8-46.2). For patients treated with 60 Gy radiotherapy, the 2-year PFS rate was 94.8% (95%CI 90.7%-98.9%) with a median follow-up of 43.9 months (IQR 40.2-46.2). The most common late toxicity was grade 1-2 dry mouth (incidence rate: 54.3%). No grade 3+ long-term adverse event was observed, and most quality-of-life items, domains, and symptom scores returned to baseline by 6 months.

CONCLUSION

Reduced-dose radiation (60 Gy) is associated with favourable survival outcomes and limited treatment-related toxicities in patients with low-risk stage III NPC sensitive to IC.

Elderly nasopharyngeal carcinoma patients (aged ≥70 years): Survival and treatment strategies

BACKGROUND

With the coming of the aging society, the incidence of elderly nasopharyngeal carcinoma (NPC) has been increasing which may result in considerable disease burden; however, the optimal treatment strategy for elderly patients is still debatable.

METHODS AND RESULTS

Clinical data on 294 elderly NPC patients aged ≥70 treated between 2009 and 2019 was analyzed. Kaplan-Meier method was used to estimate overall survival (OS) and cancer-specific survival (CSS) rates. With a median follow-up of 53.25 months, the 5-year estimated OS and CSS for the entire group were 59.5% and 69.8%, respectively. 146 patients died within the follow-up period, of which recurrence + metastasis (48%) and internal medical disease unrelated to NPC (32%) are the primary causes of death. On univariable analysis, (IMRT vs. 3D-CRT) (p = 0.001; p = 0.000), T stage (p = 0.001; p = 0.000), N stage (p = 0.013; p = 0.000) and clinical stage (p = 0.000; p = 0.000) were associated with OS and CSS; Charlson Comorbidity Index (CCI) (p = 0.016) was associated with OS. The addition of chemotherapy (CT) correlated with better CSS (p = 0.039), but did not improve OS (p = 0.056) for stage III-IV subgroup. On multivariate analysis, advanced clinical stage independently predicted poorer OS (p = 0.002) and CSS (p = 0.000). In addition, the application of IMRT was an independent protective factor on both OS (p = 0.028) and CSS (p = 0.030).

CONCLUSION

IMRT is a reasonable treatment strategy to improve survival for elderly NPC patients aged over 70 years; consideration of adding chemotherapy for elderly population should be weighed carefully.

Current Radiotherapy Considerations for Nasopharyngeal Carcinoma

Radiotherapy is the primary treatment modality for nasopharyngeal carcinoma (NPC). Successful curative treatment requires optimal radiotherapy planning and precise beam delivery that maximizes locoregional control while minimizing treatment-related side effects. In this article, we highlight considerations in target delineation, radiation dose, and the adoption of technological advances with the aim of optimizing the benefits of radiotherapy in NPC patients.

Long-term results of the phase II dose and volume de-escalation trial for locoregionally advanced nasopharyngeal carcinoma

OBJECTIVE

Patients with locoregionally advanced nasopharyngeal carcinoma (LANPC) were assigned to dose and volume de-escalated intensity-modulated radiation therapy (IMRT) based on response to induction chemotherapy (IC) to limit treatment related toxicity while preserving efficacy.

METHODS AND MATERIALS

A single-arm de-escalated phase II trial was performed in this study. Patients with LANPC received two cycles of IC with docetaxel 60 mg/m² d1, cisplatin 25 mg/m²/day d1-3 and 5-fluorouracil 500 mg/m²/day d1-5 q21d, followed by IMRT. The gross tumor volume of the primary intracavity nasopharyngeal tumor and involved lymph nodes were delineated based on the post-IC tumor extension. Part of the prescribed doses were reduced from 70.4 Gy to 66 Gy for T3-4 diseases. The primary end point was 5-year progression-free survival (PFS) in stage III and IVA-B NPC compared with historical controls of 50% and 35%.

RESULTS

Between January 2010 and November 2013, 48 and 83 eligible patients with stage III and IVA-B NPC were accrued to this trial. With a median follow-up of 92 months, the 5-year and 8-year estimated PFS were 89.6% and 76.0%, 63.9% and 58.0% for patients with stage III and IVA-B disease, which were all improved in comparison with historical controls. Grade 3 acute mucositis were developed in 27.5% patients. Cranial neuropathy and asymptomatic temporal lobe necrosis were found in 2.3% and 1.5% patients.

CONCLUSION

Dose and volume de-escalated IMRT was associated with high PFS and mild late neurological toxicities for IC responders. Further exploration of de-escalation strategies in appropriate patients is needed.

CLINICAL TRIAL REGISTRATION

Clinical trials.gov identifier: NCT03389295.

Treatment Deescalation Strategies for Nasopharyngeal Cancer: A Review

IMPORTANCE

Since the advent of modern radiotherapy techniques and incorporation of systemic chemotherapy for nasopharyngeal cancer, locoregional control has been excellent. However, the rate of treatment-related complications, many of which are irreversible, remains high. New approaches are being explored to determine whether the toxic effects of treatment can be relieved while maintaining disease control. This review presents the current state of deescalation strategies for nasopharyngeal cancer.

OBSERVATIONS

A review of the literature shows that deescalation approaches can be generally categorized into deescalating systemic therapy vs deescalating radiotherapy. This review discusses studies that have explored sparing chemotherapy in selected patients with stage II cancer as well as altering the chemotherapy scheduling, dosing, and agent from the current standard of care, cisplatin. Deescalating radiotherapy has involved decreasing the dose and the treatment volume. In many cases, these approaches are being guided by measuring Epstein-Barr virus DNA levels, which is a robust biomarker for screening, treatment monitoring, and surveillance. Ongoing work with various imaging modalities, such as fluorodeoxyglucose positron emission tomography and dynamic contrast-enhanced or diffusion-weighted magnetic resonance imaging sequences, have shown promise as another biomarker to safely guide practitioners toward deescalation.

CONCLUSIONS AND RELEVANCE

Various strategies to deescalate treatment in nasopharyngeal cancer have been explored, and outcomes have remained excellent in most approaches. Patient selection remains key, and long-term outcomes and late complications are still to be determined. Continued investigation with prospective, multi-institutional studies are needed to better elucidate how treatment for nasopharyngeal carcinoma can best be individualized and deescalated.

Quality of Life, Toxicity and Unmet Needs in Nasopharyngeal Cancer Survivors

Concerted research efforts over the last three decades have resulted in improved survival and outcomes for patients diagnosed with nasopharyngeal carcinoma (NPC). The evolution of radiotherapy techniques has facilitated improved dose delivery to target volumes while reducing dose to the surrounding normal tissue, improving both disease control and quality of life (QoL). In parallel, clinical trials focusing on determining the optimal systemic therapy to use in conjunction with radiotherapy have been largely successful, resulting in improved locoregional, and distant control. As a consequence, neoadjuvant chemotherapy (NACT) prior to definitive chemoradiotherapy has recently emerged as the preferred standard for patients with locally advanced NPC. Two of the major challenges in interpreting toxicity and QoL data from the published literature have been the reliance on: (1) clinician rather than patient reported outcomes; and (2) reporting statistical rather than clinical meaningful differences in measures. Despite the lower rates of toxicity that have been achieved with highly conformal radiotherapy techniques, survivors remain at moderate risk of persistent and long-lasting treatment effects, and the development of late radiation toxicities such as hearing loss, cranial neuropathies and cognitive impairment many years after successful treatment can herald a significant decline in QoL. Future approaches to reduce long-term toxicity will rely on: (1) identifying individual patients most likely to benefit from NACT; (2) development of response-adapted radiation strategies following NACT; and (3) anticipated further dose reductions to organs at risk with proton and particle therapy. With increasing numbers of survivors, many in the prime of their adult life, research to identify, and strategies to address the unmet needs of NPC survivors are required. This contemporary review will summarize our current knowledge of long-term toxicity, QoL and unmet needs of this survivorship group.