# The Role of Surveillance Imaging in Patients with Advanced Laryngeal Cancer
## 4 Discussion  
In this study, we wished to examine whether follow-up imaging after treatment for laryngeal SCC may be associated with the detection of clinically occult recurrence at an early stage and improved prognosis. This retrospective cohort of 123 patients with advanced-stage laryngeal SCC demonstrated that serial imaging follow-up is associated with earlier diagnosis of recurrent disease. However, patients with recurrent disease identified earlier by imaging were not able to demonstrate improved OS or DSS compared with patients diagnosed by their symptoms or physical examination findings. As most recurrences of head and neck SCC occur during the first two years after treatment, the NCCN guidelines dictate close clinical follow-up recommendations: every 1-3 months in the first year, 2-6 months in the second year, 4-8 months during years 3-5, and every 12 months afterwards [7]. Nevertheless, even with close clinical follow-up and physical examination, tumor recurrence can at times be obscured by edema, granulation tissue, or fibrosis. While the NCCN guidelines provide clear recommendations regarding patient clinical follow-up after completion of treatment for head and neck SCC, they do not specify whether serial imaging follow-up is advised in head and neck SCC in general or in laryngeal SCC specifically. However, the routine use of PET-CT imaging performed 3 months after treatment completion has been shown to be beneficial in detecting cases of disease persistence  
Figure 4: Overall survival from diagnosis of distant recurrence by diagnostic modality. and to distinguish them from post-operative inflammatory changes [10,11]. Furthermore, the United States Preventive Services Task Force does recommend serial low-dose chest CT follow-up in patients aged 50 to 80 years with a 20-pack-year smoking history who currently smoke or have quit within the last 15 years [12], as randomized controlled trials have demonstrated that screening by low-dose CT can improve survival among these high-risk patients [13,14]. Several studies have attempted to describe the yield of imaging surveillance after treatment for head and neck SCC. [PERSON] et al. [15] evaluated the diagnostic value of PET-CT in 91 patients with head and neck SCC, out of whom 27 (29.7%) had laryngeal SCC. They performed PET-CT 12 months after the initial treatment when no clinical evidence of disease was demonstrated and showed a 100% sensitivity, 85% specificity, and a negative predictive value of 100% for diagnosis of recurrent disease. This study did not attempt to evaluate the prognostic effect of PET-CT surveillance. A different study by [PERSON] et al. [8] evaluated the role of PET-CT performed at 12 and 24 months after treatment for detection of recurrences in head and neck SCC. Imaging performed after one year was able to diagnose clinically occult disease in 9% of cases (15 of 175), and imaging performed after 2 years diagnosed clinically occult recurrent disease in 4% of cases (3 out of 77). No difference regarding disease-free or overall survival was demonstrated between clinically and radiologically diagnosed recurrences in this cohort. This study included 284 patients with head and neck SCC whose initial imaging (either PET-CT or MRI) performed 3 months after treatment was negative. However, within the 284 cases, only 10 cases of laryngeal SCC were included (3.5%), making it difficult to extrapolate these results to laryngeal cancer cases specifically. Our results are in agreement with the findings by [PERSON] et al. regarding the lack of improvement in prognosis for patients with head and neck cancer and diagnosed with recurrent disease by imaging. Our results, however, focus on laryngeal SCC cases only, unlike the study by [PERSON] et al., which included very few laryngeal cancer cases. Furthermore, as recurrences after treatment for early-stage laryngeal SCC can be diagnosed in the clinic in most cases, we excluded these patients from our cohort and decided to focus on the yield of imaging follow-up for advanced-stage disease alone.