INTRODUCTION
Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous group of epithelial malignancies that arise from the sinus, oral cavity, oropharynx, hypopharynx, and larynx. HNSCC is the sixth most common malignancy worldwide, with 532,000 new cases every year [
1]. In Korea, HNSCC is the tenth most common malignancy, with around 4,700 new cases each year and around one third of new cases occur in older patients with aged ≥ 70 years [
2,
3]. HNSCC is common in the older population, and thus, its incidence is expected to increase soon in countries with an aged population, such as Korea [
4,
5]. Therefore, interests focusing on the treatment and care for older HNSCC patients. In particular, multi-modal treatment approaches have significant potential to result in better outcomes in locally advanced (LA)-HNSCC patients. Considering tumor and patient characteristics, LA-HNSCC patients are recommended to undergo surgery, radiotherapy, and chemotherapy, either sequentially or simultaneously.
However, compared with younger patients, older patients are more likely to be frail, and thus, aggressive treatment modalities can be dangerous [
6]. Older patients also tend to have impaired functional status and more comorbidities, which can also affect treatment compliance. Furthermore, regarding the occurrence of treatment-related adverse events, older patients have a higher risk of treatment interruption or early discontinuation than younger patients, thus affecting survival and quality of life among the older population [
7,
8]. Therefore, proper treatment planning for older patients is warranted. Despite this, however, there are limited reports regarding tumor characteristics and treatment patterns in older LA-HNSCC patients. Thus, in this study, we focused on older patients (aged ≥ 70 years) who were included in a large nationwide cohort of patients with stage III–IVB LA-HNSCC. This study aimed to investigate and compare differences in clinical characteristics, real-world treatment patterns, outcomes, and prognostic factors between older and younger patients.
DISCUSSION
In this retrospective nationwide investigation of a Korean cohort of patients with stage III–IV LA-HNSCC, older patients accounted for 18.7% (83/445) of all patients. Compared with younger patients, older patients have poor clinical characteristics and poor survival probabilities. The proportion of advanced T stage or poor PS was higher among older patients than among younger patients, while the proportion of older patients with oropharyngeal cancer or HPV positive cancer was lower than that of younger patients. In particular, older patients with oral cavity cancer had the worst OS. In previous epidemiological studies on geriatric patients, a greater proportion of oral cavity or larynx tumors were reported, but the proportion of oropharyngeal cancer was low [
4,
5,
11]. Moreover, patients with oral cavity cancer, especially the older population, had a significantly poor survival [
12]. In addition, although HPV is known to be a good prognostic factor in younger patients with oropharyngeal cancer, it is infrequently reported in older patients, which is also consistent with the results of this study [
13–
15]. Altogether, the evidence indicates that older patients have poor prognostic tumor factors (
Fig. 2A).
Treatment patterns were similar between the two age groups (≥ 70 years vs. < 70 years) (
Fig. 1). There was no survival difference according to treatment modalities such as CCRT or surgery (
Fig. 2D) or administration of IC (
Fig. 2C). The proportion of older patients who completed their planned treatments was lower than that of younger patients (
Fig. 1). The survival of older patients who did not finish their planned treatments tended to be poor (
Table 3).
Still, the role of age as a prognostic factor is not clearly defined in LA-HNSCC. Previous retrospective or epidemiologic-based analysis of various tumor status or treatment conditions revealed that chronologic age was not a significant prognostic factor [
16–
18]. Furthermore, there is limited data on the survival of older LA-HNSCC patients undergoing multi-modal treatments. In a large-sized study using a cancer registry, older patients aged ≥ 70 years had a two-fold poorer survival than younger aged patients. In a subgroup analysis of patients with stage III or IV laryngeal cancer, patients who received single modality treatment had extremely poor survival than all other patients [
19]. In fact, in the real-world practice, LA-HNSCC patients aged ≥ 70 years tend to receive less-aggressive strategies [
20]. In our analysis, older patients received weaker IC and CCRT intensity regimens. Eight of 12 patients who received IC did not receive definitive treatment. The failure to complete planned treatments among older patients was associated with a poor survival tendency, although owing to the small number of patients, this difference was not statistically significant. Consequently, in our study, treatment-related factors and poor tumor-related factors among older patients might contribute to poor survival outcomes compared with those among younger patients.
In the clinical practice, treatment strategies for LA-HNSCC are decided through multidisciplinary consultation and considering multifaceted clinical factors. In our analysis, surgery and definitive CCRT as primary treatment was performed in 41.0% and 44.6% of older patients, respectively. As expected, there was no significant difference in survival with each treatment strategy. Approximately 27.7% (23/83) of older patients received IC as initial treatment. Among them, upfront administration of IC did not show statistical difference in survival. There were no significant differences in survival among treatment modalities; however, there were differences especially in application of chemotherapeutic agents in ICT and CCRT for older patients comparing with younger patients.
In the older group, only one patient received docetaxel, cisplatin, and 5-fluorouracil (TPF) as IC treatment, which is regarded as a standard regimen of IC, whereas 30.4% of younger patients who received IC were treated with TPF. Most (91.3%) older patients received doublet regimens such as DP or FP for IC. Though the intensity of doublet regimen might be weaker than triple regimen of TPF, the facts that substantial portion of older patients receiving IC did not continue further definitive treatment suggest the physician need to focus on safety rather than the effectiveness of specific treatments.
The reason of the majority of patients who received IC were treated with doublet regimen is suspected from oncologist’s concern for frailty of older patients. To obtain the best efficacy through IC, three cycles of treatment with TPF is the strong recommended regimen because IC using TPF regimen provided survival benefit compared to FP in phase III clinical trials and meta-analysis [
21–
24]. However, TPF issued because of its toxicities. TPF showed more incidence of grade 3–4 neutropenia, febrile neutropenia and neutropenic infection compared to FP [
22,
23]. In addition, IC with TPF is discussed because it could compromise the following treatment because of toxicity. In a CONDOR study, only 22% of the patients received CCRT with cumulative dose of cisplatin > 200 mg/m
2 after three cycles of IC with TPF [
25]. Also, in a phase III trial that compared TPF-IC or FP-IC followed by CCRT versus definitive CCRT alone, a lower proportion of patients in the TPF-IC arm could receive CCRT than that of patients in the FP-IC arm [
26]. Such results indicate that IC using triplet regimen can decrease the chances of receiving CCRT and also decrease the dose of therapeutic cisplatin combined with CCRT. Serious adverse events occurring during IC can affect further treatment or decrease treatment intensity, which consequently can affect patients’ chances of being cured. However, it is important to note that in our analysis, despite the low intensity of IC, survival did not differ between the IC and non-IC groups. Therefore, IC with doublet regimen rather than triple regimen is recommendable for older patients. Given the lack of studies regarding the best IC regimen for older patients, a well-organized study aiming to identify the most suitable IC regimen for older patients is needed to avoid unnecessary chemotherapy-related toxicities and achieve better treatment outcomes.
In a group of definitive CCRT, 24.3% (9/37) of older patients received CCRT after IC and 75.7% (28/37) received definitive CCRT as the primary treatment. There was no significant difference in selecting a concomitant chemotherapy regimen between older and younger patients in Korea. However, meaningful differences in the efficacy between a weekly or 3-weekly cisplatin during CCRT are not yet clearly defined. In a previous retrospective study conducted in Korea, weekly cisplatin showed comparable therapeutic outcomes compared with 3-weekly cisplatin [
27]. Because weekly cisplatin regimen is more compliant and has less toxicities related to myelosuppression, nephrotoxicity, and emesis, weekly cisplatin might be more considerable in older patients [
28]. In addition, survival of patients who received CCRT was not different from that of patients who underwent surgery.
This study had some limitations. First, this study was retrospectively designed; therefore, exact information regarding comorbidities, treatment toxicities, and quality of life could not be obtained. Thus, we could not evaluate the correlation between these factors and treatment results in detail. However, because LA-HNSCC patient data for this study were retrieved from 13 nationwide referral hospitals, the data reflect of real treatment patterns for older patients in Korea. Second, patients with various primary sites of head and neck cancer were included, but interpretation of specific cancer status, especially regarding HPV positivity, needs to be performed with caution because we could only obtain information on HPV status in 30.1% of patients. In conclusion, we defined poor tumor characteristics and real-world treatment patterns of older LA-HNSCC patients in Korea. Older LA-HNSCC patients had aggressive tumor characteristics and received less intensive treatment, which resulted in poor survival, especially in cases of oral cavity cancer. There were no survival differences among treatment modalities. Future research focusing on older patients is necessary to determine an optimal treatment strategy that can improve survival.