The present study was conducted in a university hospital, department of otolaryngology with the permission of local ethics committee (2014 – 23/11). A total of 269 patients who underwent neck dissection from January 1, 2007 to December 31, 2014 with the diagnosis of laryngeal carcinoma were retrospectively reviewed.

Patients who underwent simultaneous laryngectomy (partial or total) and neck dissection due to laryngeal SCC as the primary treatment were included in the analysis. Patients who were having surgery as salvage treatment (34 patients) or who did not have simultaneous laryngectomy and neck dissection (25 patients) were excluded, as were cases with synchronous tumors (3 patients) or who were lost to follow-up (13 patients). A follow-up period of at least one year was sought except for patients who had deceased prior to the completion of one postoperative year.

Neck dissection materials, which were separated into zones peroperatively, were saturated in formalin for 24h. Nodular lesions were separated (macroscopic pathological dissection) and embedded in paraffin blocks individually. These blocks were sectioned in their entirety at 4μm thickness and sections were stained with H&E.

Any tumoral mass in the soft tissues of the neck dissection materials, with or without regular contours that did not have lymph node architecture were diagnosed as STD (Fig. 1).

Figure 1.

Histologic section of the soft tissue deposit. Irregular nodular mass composed of malign tumor cells infiltrating the lipomatous tissue is observed (H&E, ×40).

(0.5MB).

The primary evaluation was the impact of STDs on oncologic outcome, which was represented by recurrence rate, overall and disease-specific survival rates.

Demographical (age, sex, smoking, alcohol consumption), clinical (comorbid diseases, preoperative tracheotomy) and pathological variables (histopathology and differentiation of tumor, LVI, PNI, surgical margins, ENE, conglomerated lymph nodes, STD) were analyzed according to free tumor implants and investigated as prognostic factors. TNM stage was calculated according to American Joint Committee on Cancer (AJCC) 2007 staging system.9

The follow-up and status of patients were established from hospital records. The adherence to adjuvant treatment, complications, local/regional recurrences, distant metastasis, second primaries and cause of death was identified accordingly. The patients were grouped according to their final status as No Evidence of Disease (NED), Alive With Disease (AWD), Dead from Another Cause (DAC) and Dead Of Disease (DOD). Deaths due to postoperative complications were accepted as DAC.

Analyses were performed with SPSS v.22.0 (IBM, NY, USA). Chi Square test was employed for categorical variables, Mann–Whitney-U test employed for numerical variables that did not show normal distribution. Kaplan–Meier survival curves were used to calculate 2 and 5year disease-specific and overall survival estimates. The Kaplan–Meier estimates were compared using log-rank test to signify the effect of factors on survival individually. Cox proportional hazards regression model was used to calculate survival hazard ratios and 95% CIs. The level of statistical significance was defined as p<0.05.

Of the 194 patients with laryngeal carcinoma included in the study, 189 were men (97.4%) and 5 were women (2.6%). The mean age of patients was 60.8±8.6 with a range of 41–84years.

Demographical, clinical and pathological variables were analyzed according to presence or absence of free tumor implants (Table 1). N stage was more advanced and ENE, conglomerated lymph nodes, PNI and LVI were more frequent in patients who had STD compared to those who did not.

Type of surgery and utilization of adjuvant treatment were similar in respect of STD whereas, STD was found more frequently in the comprehensive neck specimens (Table 2).

The mean follow-up duration was 36.6±23.4months. Ten patients (5.2%) developed local and 16 (8.2%) developed regional recurrences. Two patients had both local and regional recurrences thus; the overall loco-regional recurrence rate was established as 12.4%. Distant metastases were diagnosed in 15 patients (7.7%). Second primary tumors appeared in 24 patients (12.4%) during follow-up. Regional recurrences were found to be more common in patients with STD (Table 3).

Final status of 131 patients (67.5%) was NED, 9 (4.6%) AWD, 25 (12.9%) DOD, 22 (11.3%) DAC, and 7 (3.6%) were lost due to perioperative complications that were also accepted as DAC.

Disease specific survival was 79.8±2.3 and overall survival was 68.1±2.8months for the whole study group according to Kaplan–Meier estimates.

Disease specific survival was 45.1±6.9months for patients with STD and 81.1±2.2months for those without STD. Two and 5years disease specific survival rates were 90.3% and 84.8% in patients without STD and 74% and 49.4% respectively in patients with STD (Table 4, Fig. 2). STD was found to have a significant influence on disease specific survival (p=0.041).

Figure 2.

Kaplan–Meier plots demonstrating (A) overall and (B) disease-specific survival rates by soft tissue deposits.

(0.14MB).

Overall survival was 35.3±6.2months in patients with STD and 70.3±2.8months in patients free of STD. Two and 5year overall survival rates were 84.3% and 71.2% when there was no evidence of STD in the specimen. On the other hand, it was to be 49.1% and 16.4% respectively in cases where STD was present. Overall survival rates were significantly lower in the presence of STD compared to its absence (p=0.002).

T stage, preoperative tracheotomy, tumor type and differentiation, LVI and comorbid diseases did not affect the survival rates.

History of smoking, PNI, surgical margins for the laryngeal specimen, N stage, ENE, conglomerated lymph nodes and STD for the neck specimen, type of neck dissection, and recurrences or distant metastasis were found to have detrimental effects on survival (Table 4).

Significant factors from univariate analysis were tested with multivariate Cox regression analysis (Table 5). ENE was found to increase the risk of death from the laryngeal cancer 3.47 times. Positive surgical margin was also a significant factor for disease specific survival. Overall survival was significantly reduced by smoking and PNI. ENE was found to be related to overall survival, however, to a lesser extent.