What is the recommended imaging surveillance protocol for a patient with pT2, N1 squamous cell carcinoma (SCC) of the tonsil after radiation therapy (RT)?

From the Guidelines

For a patient with pT2, N1 squamous cell carcinoma of the tonsil after radiation therapy, the recommended imaging surveillance protocol includes a baseline PET/CECT at 8 to 12 weeks after completion of definitive therapy, followed by CECT or PET/CECT 6 months later if the initial scan is negative. This approach is based on the guidelines outlined by the ACR NI-RADS committee, which emphasize the importance of institutional surveillance imaging policies to direct the timing and frequency of posttreatment scans 1.

The rationale behind this protocol is that combined FDG-PET/CECT provides both metabolic information and high-resolution anatomic detail, making it more accurate than either PET or CECT alone for surveillance in head and neck squamous cell carcinoma (HN SCCA) patients 1. The timing of the PET/CECT at 8 to 12 weeks posttreatment is considered optimal, as it allows for the detection of residual disease or early recurrence. If the initial PET/CECT is negative, a follow-up CECT or PET/CECT 6 months later is recommended, with further imaging intervals determined based on the results of these scans.

Key points to consider in this surveillance protocol include:

• The use of PET/CECT as the primary imaging modality for surveillance due to its high negative predictive value in HN SCCA 1.
• The majority of asymptomatic recurrences are detected within the first 24 months after treatment, which guides the intensity of the surveillance schedule 1.
• MRI may be reserved for specific cases, such as tumors near or involving the skull base, where evaluation for perineural, intracranial, or intraorbital tumor extension is necessary 1.
• The potential to stop surveillance imaging if two consecutive PET/CECT studies are scored as NI-RADS 1, indicating a low risk of recurrence 1.

This approach prioritizes the detection of early recurrence and residual disease while also considering the potential for false positives and the need for tailored surveillance based on individual patient risk factors and response to treatment. Regular clinical examinations should accompany this imaging protocol to ensure comprehensive follow-up care.

From the Research

Imaging Surveillance Protocol

The recommended imaging surveillance protocol for a patient with pT2, N1 squamous cell carcinoma (SCC) of the tonsil after radiation therapy (RT) is not explicitly stated in the provided studies. However, we can infer some information from the available evidence:

• A study published in 2005 2 suggests that close surveillance of the neck is recommended for patients who have achieved a complete response after radiation therapy with or without chemotherapy for tonsillar squamous cell carcinoma with advanced cervical metastases.
• Another study published in 2020 3 recommends obtaining a PET/CT scan 3 months after adjuvant therapy to predict disease recurrence and survival in patients with locally advanced oral squamous cell carcinoma.

Key Points to Consider

• The patterns of treatment failure in patients treated with surgery alone or surgery combined with postoperative radiation therapy for squamous cell carcinoma of the tonsil are mainly above the clavicles 4.
• Unilateral radiotherapy for patients with TX-T2, N0-N2b primary tonsil carcinoma results in high rates of disease control, with low rates of contralateral nodal failure and a low incidence of acute toxicity requiring gastrostomy 5.
• Lymphovascular invasion is an independent predictor of outcome in patients with tonsillar SCC 6.

Surveillance Strategies

• Close surveillance of the neck is recommended for patients who have achieved a complete response after radiation therapy with or without chemotherapy for tonsillar squamous cell carcinoma with advanced cervical metastases 2.
• PET/CT scan 3 months after adjuvant therapy can be used to predict disease recurrence and survival in patients with locally advanced oral squamous cell carcinoma 3.

Limitations

• The provided studies do not specifically address the recommended imaging surveillance protocol for a patient with pT2, N1 SCC of the tonsil after radiation therapy.
• More research is needed to determine the optimal imaging surveillance protocol for this specific patient population.