Carboplatin Versus Cetuximab Chemoradiation in Cisplatin Ineligible Patients with Locally Advanced p16 Negative Head and Neck Squamous Cell Carcinoma

A Multicenter Evaluation of Different Chemotherapy Regimens in Older Adults With Head and Neck Squamous Cell Carcinoma Undergoing Definitive Chemoradiation

PURPOSE

The number of older adults with head and neck squamous cell carcinoma (HNSCC) is increasing, and treatment of these patients is challenging. Although cisplatin-based chemotherapy concomitantly with radiation therapy is considered the standard regimen for patients with locoregionally advanced HNSCC, there is substantial real-world heterogeneity regarding concomitant chemotherapy in older patients with HNSCC.

METHODS AND MATERIALS

The SENIOR study is an international multicenter cohort study including older patients (≥65 years) with HNSCC treated with definitive radiation therapy at 13 academic centers in the United States and Europe. Patients with concomitant chemoradiation were analyzed regarding overall survival (OS) and progression-free survival (PFS) via Kaplan-Meier analyses. Fine-Gray competing risk regressions were performed regarding the incidence of locoregional failures and distant metastases.

RESULTS

Six hundred ninety-seven patients with a median age of 71 years were included in this analysis. Single-agent cisplatin was the most common chemotherapy regimen (n = 310; 44%), followed by cisplatin plus 5-fluorouracil (n = 137; 20%), carboplatin (n = 73; 10%), and mitomycin C plus 5-fluorouracil (n = 64; 9%). Carboplatin-based regimens were associated with diminished PFS (hazard ratio [HR], 1.39 [1.03-1.89]; P < .05) and a higher incidence of locoregional failures (subdistribution HR, 1.54 [1.00-2.38]; P = .05) compared with single-agent cisplatin, whereas OS (HR, 1.15 [0.80-1.65]; P = .46) was comparable. There were no oncological differences between single-agent and multiagent cisplatin regimens (all P > .05). The median cumulative dose of cisplatin was 180 mg/m2 (IQR, 120-200 mg/m2). Cumulative cisplatin doses ≥200 mg/m2 were associated with increased OS (HR, 0.71 [0.53-0.95]; P = .02), increased PFS (HR, 0.66 [0.51-0.87]; P = .003), and lower incidence of locoregional failures (subdistribution HR, 0.50 [0.31-0.80]; P = .004). Higher cumulative cisplatin doses remained an independent prognostic variable in the multivariate regression analysis for OS (HR, 0.996 [0.993-0.999]; P = .009).

CONCLUSIONS

Single-agent cisplatin can be considered in the standard chemotherapy regimen for older patients with HNSCC who can tolerate cisplatin. Cumulative cisplatin doses are prognostically relevant in older patients with HNSCC.

Cetuximab-Based vs Carboplatin-Based Chemoradiotherapy for Patients With Head and Neck Cancer

Importance

Cetuximab-based and carboplatin-based chemoradiotherapy (CRT) are often used for patients with locally advanced head and neck cancer who are ineligible for cisplatin. There are no prospective head-to-head data comparing cetuximab-based and carboplatin-based regimens for radiosensitization.

Objective

To compare survival with cetuximab-based and carboplatin-based CRT in locally advanced head and neck squamous cell carcinoma (HNSCC).

Design, Setting, and Participants

This cohort study included US veterans who received a diagnosis of HNSCC between January 2006 and December 2020 and were treated with systemic therapy and radiation. Data cutoff was March 1, 2022 and data analysis was conducted from April-May 2022.

Exposures

Cisplatin, cetuximab, or carboplatin-based systemic therapy as captured in VA medication data and cancer registry.

Main Outcomes and Measures

Overall survival by systemic therapy was estimated using Kaplan-Meier methods. We used propensity score and inverse probability weighting to achieve covariate balance between cetuximab-treated and carboplatin-treated patients and used Cox regression to estimate cause-specific hazard ratios of death associated with carboplatin vs cetuximab. We also performed subgroup analyses of patients with oropharynx vs nonoropharynx primary sites.

Results

A total of 8290 patients (median [IQR] age, 63 [58-68] years; 8201 men [98.9%]; 1225 [15.8%] Black or African American and 6424 [82.6%] White individuals) with nonmetastatic HNSCC were treated with CRT with cisplatin (5566 [67%]), carboplatin (1231 [15%]), or cetuximab (1493 [18%]). Compared with cisplatin-treated patients, patients treated with carboplatin and cetuximab were older with worse performance status scores and higher comorbidity burden. Median (IQR) overall survival was 74.4 (22.3-162.2) months in patients treated with cisplatin radiotherapy (RT), 43.4 (15.3-123.8) months in patients treated with carboplatin RT, and 31.1 (12.4-87.8) months in patients treated with cetuximab RT. After propensity score and inverse probability weighting, carboplatin was associated with improved overall survival compared with cetuximab (cause-specific hazard ratio, 0.85; 95% CI, 0.78-0.93; P = .001). This difference was prominent in the oropharynx subgroup.

Conclusions and Relevance

In this cohort study of a US veteran population with HNSCC undergoing treatment with CRT, almost a third of patients were ineligible to receive treatment with cisplatin and received cetuximab-based or carboplatin-based radiosensitization. After propensity score matching, carboplatin-based systemic therapy was associated with 15% improvement in overall survival compared with cetuximab, suggesting that carboplatin may be the preferred radiosensitizer, particularly in oropharynx cancers.

Current landscape of immunotherapy trials in locally advanced and high-risk head and neck cancer

The current standard of therapy for locally advanced (LA) head and neck squamous cell carcinoma (HNSCC) is limited by toxicity and suboptimal control. The role of immunotherapy (IO) is being evaluated in the LA setting. This review aims to summarize the recent advances and the direction of clinical trials in IO in LA or high-risk HNSCC. Despite negative results in some studies, several early phase trials suggest the feasibility and efficacy of IO-based strategies in LA or high-risk HNSCC. Further refining of patient selection and biomarker development is warranted for successful incorporation of IO in this patient population.