Improving imaging diagnosis of persistent nodal metastases after definitive therapy for oropharyngeal carcinoma: specific signs for CT and best performance of combined criteria

Pre- and Post-Radiotherapy Radiologic Nodal Features and Oropharyngeal Cancer Outcomes

OBJECTIVES

To assess the prognostic value of pre-/post-radiotherapy (pre-/post-RT) radiologic lymph node (LN) features in human papillomavirus (HPV)-positive and HPV-negative oropharyngeal carcinoma (OPC) patients treated with definitive (chemo-)RT.

METHODS

Clinical node-positive OPCs treated from 2011 to 2015 were reviewed. Nodal features were reviewed by a radiologist on pre-/post-RT computed tomography (CTs). Univariable analysis calculated hazard ratio (HR) for regional failure (RF), distant metastasis (DM), and deaths. Multivariable analysis estimated adjusted HR (aHR) of significant nodal features identified in univariable analysis adjusting for confounders.

RESULTS

Pre-RT CT was undertaken in 344 HPV-positive and 94 HPV-negative OPC patients, of whom 242 (70%) HPV-positive and 67 (71%) HPV-negative also had a post-RT CT. Median follow-up was 4.9 years. Pre-RT LN calcification (pre-RT_LN-cal) increased the risk of RF in HPV-negative (aHR: 5.3, P = .007) but not HPV-positive patients (P = .110). Pre-RT radiologic extranodal extension (pre-RT_rENE+) increased the risk of DM and death in both HPV-negative (DM: aHR 6.6, P < .001; death: aHR 2.1, both P = .019) and HPV-positive patients (DM: aHR 4.9; death: aHR 3.0, both P < .001). Increased risk of RF occured with < 20% post-RT LN size reduction in both HPV-negative (HR 6.0, P = .002) and HPV-positive cases (HR 3.0, P = .049). Post-RT_LN-cal did not affect RF, DM, or death regardless of tumor HPV status (all P > .05).

CONCLUSION

Pre-RT_LN-cal is associated with higher RF risk in HPV-negative but not in HPV-positive patients. Pre-RT_rENE increases risk of DM and death regardless of tumor HPV status. Minimal post-RT LN size reduction (< 20%) increases risk of RF in both diseases. Post-RT_LN-cal + has no apparent influence on outcomes in either disease.

LEVEL OF EVIDENCE

4 (a single institution case-control series) Laryngoscope, 131:E1162-E1171, 2021.

The prognostic value of location and size change of pathological lymph nodes evaluated on CT-scan following radiotherapy in head and neck cancer

BACKGROUND

Overall survival after chemo-radiotherapy (CRT) for head and neck cancer ranges between 50 and 60% after 5 year of follow-up. Local and/or regional recurrence is the most frequent form of therapy failure. The aim of this study is to investigate whether the initial location and size change of pathological lymph nodes as evaluated on Computed Tomography (CT) studies can help predict outcome.

METHODS

One hundred eighty-three patients with lymph node-positive head and neck cancer were treated with radiotherapy (RT) or CRT. CT studies pre- and post-treatment were reviewed for lymph node size and location. Data were correlated with local control, regional control, metastasis free survival, disease free survival and overall survival.

RESULTS

Regarding the risk for distant metastasis, a significant influence was seen for the location of the pathological lymph nodes. The metastatic risk increases when levels IV-V are affected rather than levels I-III. A similar observation is seen for levels VI-VII. Regional control improves with decreasing lymph node diameter and volume as evaluated on CT.

CONCLUSIONS

Both location and size change of pathological lymph nodes are of prognostic value after CRT for head and neck cancer.

Post-treatment 18F-FDG-PET/CT versus contrast-enhanced CT in patients with oropharyngeal squamous cell carcinoma: comparative effectiveness study

OBJECTIVE

To compare the accuracy of same-day therapy-assessment PET/computed tomography (PET/CT) and conventional contrast-enhanced computed tomography (CECT) in patients with oropharyngeal squamous cell carcinoma (OPSCC).

METHODS

A total of 110 (95 men and 15 women; mean age 59 years) patients with biopsy-proven OPSCC were evaluated with same-day PET/CT and CECT pair scans as part of follow-up therapy assessment. Scans were performed within 6 months after the completion of primary treatment (median time: 3.1 months; range: 0.5-6 months). PET/CT and CECT scans were reviewed retrospectively for residual primary site disease, and right and left cervical lymph node involvement. Histopathology or 6 month clinical/imaging follow-up were used as the gold standard. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for the primary site and cervical nodal disease.

RESULTS

Of 110 OPSCC patients, 90.9% were human papilloma virus positive, 80.8% were stage 4, and 76.4% received chemoradiation as the primary treatment. The sensitivity, specificity, PPV, NPV, and accuracy of PET/CT and CECT were similar in the evaluation of the primary cancer site (PET/CT: 75.0, 91.5, 25.0, 99.0, and 90.9, respectively, versus CECT: 75.0, 90.6, 23.1, 99.0, and 90.0, respectively). In evaluating cervical lymph node involvement, PET/CT appeared to have higher accuracy (96.8 vs. 81.7%), specificity (97.7 vs. 81.7%), and PPV (45.8 vs. 16.5%), comparable NPV (99.4% for both), and lower sensitivity (65 vs. 75%) compared with same-day CECT.

CONCLUSION

Same-day PET/CT and CECT scans had comparable accuracy in the evaluation of primary tumor sites after completion of therapy in patients with OPSCC. PET/CT showed higher accuracy in the evaluation of cervical lymph node involvement.

CT-based follow-up following radiotherapy or radiochemotherapy for locally advanced head and neck cancer; outcome and development of a prognostic model for regional control

OBJECTIVE

The purpose of this study was to make a prognostic model for regional relapse in head and neck cancer using clinical and CT parameters.

METHODS

183 patients with lymph node-positive head and neck cancer were treated between 2002 and 2012 with radiotherapy or concurrent chemoradiotherapy. CT studies pre- and post-treatment were reviewed for lymph node size and the presence of necrosis, extracapsular spread (ECS) and calcifications. For every patient, correlations with 3-year regional control (RC), metastasis-free survival (MFS), disease-free survival (DFS) and overall survival (OS) were made.

RESULTS

3-year outcome rates were as follows: local control of 84%, RC of 80%, MFS of 74%, DFS of 61% and OS of 63%. Pre-treatment nodal size and the presence of necrosis were associated with a poorer outcome. This was also the case for post-treatment lymph node size, the presence of necrosis and ECS. We developed a CT-based prognostic model for RC with an area under the curve of 0.78 (95% confidence interval 0.63; 0.85).

CONCLUSION

We reached a good outcome in our patient cohort using a CT-based follow-up approach. A CT-based model was developed, which can aid in predicting RC. Advances in knowledge: A prognostic model is proposed, which can aid in predicting RC and the necessity for post-radiotherapy neck dissection using clinical parameters and parameters derived from the post-treatment CT study. This is the first article to propose a prognostic model for regional relapse in head and neck cancer based on these parameters.

Characteristics and kinetics of cervical lymph node regression after radiation therapy for human papillomavirus-associated oropharyngeal carcinoma: quantitative image analysis of post-radiotherapy response

BACKGROUND AND PURPOSE

We sought to characterize the pattern of lymph node regression and morphology following definitive radiation therapy (RT) for human papilloma virus (HPV)-associated oropharyngeal carcinoma in patients with disease control.

MATERIALS AND METHODS

Radiographically positive cervical lymph nodes from patients treated with definitive RT for HPV-associated oropharyngeal carcinoma were segmented on initial pre- and subsequent post-RT contrast enhanced CT images. Pre-specified quantitative nodal parameters were calculated. Initial nodal parameter correlates of final nodal size, final nodal volume, and time to <1 cm short-axis diameter were determined.

RESULTS

Sixty-six radiographically positive lymph node were analyzed in 36 patients. Lymph nodes exhibited initial volume decreases with size stabilization at ∼4 months. Fifteen nodes (23%) underwent complete radiographic response (median 6.4 months following RT; range 2.9-25.6 months). On multivariate time-to-event analysis, initial hypodense/fat component, nodal volume, and short-axis diameter exhibited inverse association, while higher HU standard deviation exhibited a positive association, with reaching <1 cm short-axis diameter (all p<0.05).

CONCLUSIONS

Our results showed a substantial decrease in nodal volume within the first 1-2 months following RT. These findings support our current nodal imaging paradigm, propose a quantitative methodology, and describe a reference dataset for further validation and comparison studies.