Association of follow-up imaging frequency with temporal incidence and patterns of distant failure following (chemo) radiotherapy for HPV related oropharyngeal cancer

OBJECTIVES

Emerging data supports radical intent therapy for oligometastatic (OM) relapsed human papilloma virus (HPV+) related oropharyngeal cancer (OPC). We assess the association of follow-up imaging frequency amongst HPV + OPC, with temporal and spatial patterns of distant relapse, to inform rationalisation of routine post-treatment imaging.

MATERIALS AND METHODS

A retrospective single centre cohort study was carried out of consecutive HPV + OPC patients treated with radical intent (chemo)radiotherapy ((CT)RT) between 2011 and 2019. OM state was defined as ≤ 5 metastasis, none larger than 3 cm (OMs) or, if interval from last negative surveillance imaging > 6-months, then ≤ 10 metastasis, none larger than 5 cm, (OMp). Patients not meeting OMs / OMp criteria were deemed to have incurable diffuse metastatic disease (DMdiffuse).

RESULTS

793 HPV-OPC patients were identified with median follow-up 3.15years (range 0.2-8.9). 52 (6.6 %) patients had radiologically identified DM at first failure and were considered for analysis. The median time to recurrence was 15.1 months (range: 2.6-63 months). 87 % of distant metastasis (DM) occurred in the first two years after treatment. Twenty-seven (52 %) patients had OM (OMs or OMp) at time of failure, with 31 % having OMs. The median time from completion of treatment to diagnosis of DMdiffuse vs OM was 22.2 months (range: 2.6-63.1 months) vs 11.6 months (range: 3.5-32.5 months). The probability of being diagnosed with OM vs DMdiffuse increased with reducing interval from last negative surveillance scan to imaging identifying DM (≤6 months 88.9 %, 7-12 months 71.4 %, 13-24 months 35 %, > 24 months 22.2 %).

CONCLUSION

We demonstrate that a reduced interval between last negative imaging and subsequent radiological diagnosis of DM is associated with increased likelihood of identification of OM disease. Consideration of increased frequency of surveillance imaging during the first two years of follow up is supported, particularly for patients at high risk of distant failure.

Temporal Incidence and Patterns of Distant Failure for Human Papillomavirus (HPV) Related Oropharyngeal Cancer

PURPOSE/OBJECTIVE(S)

HPV related oropharyngeal cancer (HPV-OPC) enjoys improved treatment outcomes relative to non-HPV related disease but suffers from similar rates of distant metastases (DM) following treatment. Emerging data supports radical intent therapy for oligometastatic relapsed HPV-OPC, suggesting early diagnosis of DM may be beneficial to outcome. We assess temporal patterns in distance relapse to investigate rationalization of post treatment imaging.

MATERIALS/METHODS

A retrospective single center cohort study was carried out of consecutive HPV-OPC treated with radical intent (chemo)radiotherapy ((CT)RT) between 2011 and 2020. Electronic records were reviewed to identify location and timing of development of DM. Oligometastatic (OM) state was defined as

RESULTS

A total of 793 HPV-OPC patients were identified with median follow-up 3.15 years (range 0.2-8.9). The median time to recurrence was 15.1 months (range: 2.6-63 months). 87% of DM occurred in the first two years after treatment. Pattern of failure by stage are shown in table 1. Indications for scans performed identifying DM alone were symptoms (66%), follow-up imaging based on previous radiological findings (15%), disease response assessment imaging (15%), and incidental findings (4%). Sites of distant metastasis were lung (64%), thoracic nodes (36.5%), bone (27%), visceral (23%), brain (4%) and skin (2%). The sites of visceral metastasis involvement included liver (92%), Adrenal (18%), kidney (18%), and spleen (9%). Treatment offered to patients with OM alone was best supportive care (46%), palliative chemotherapy (15.4%), palliative RT (23%), immunotherapy (8%), and one patient lost to follow up (8%). SBRT was not available during time period. Median survival following diagnosis was 17.5 months (range 4.4-85.4 months).

CONCLUSION

Despite no routine imaging beyond initial treatment response assessment, we identify a small minority of HPV OPC patients with OM recurrence that is associated with better outcome and occasional long-term cure from aggressive therapy. The majority (69%) of DM occur in the thorax/upper abdomen of patients in the first two years post treatment. This finding supports the potential utility of regular imaging of thorax/upper abdomen during early follow.

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Affiliation(s)

J Gaffney The Christie NHS Foundation Trust, Manchester, United Kingdom
A Ramzan Department of Radiology, The Christie NHS Foundation Trust, Manchester, United Kingdom
T Dinizulu Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom
D O Onamusi The University of Manchester, Manchester, United Kingdom
G Motamedi-Ghahfarokhi The University of Manchester, Manchester, United Kingdom
H Mistry The University of Manchester, Manchester, United Kingdom
G Price The Christie NHS Foundation Trust, Manchester, United Kingdom; The University of Manchester, Manchester, United Kingdom
K Garcez Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom
C Hughes Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom
D D Thomson The Christie NHS Foundation Trust, Manchester, United Kingdom
L W Lee Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom
Y Jain Department of Radiology, The Christie NHS Foundation Trust, Manchester, United Kingdom
J M Price Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester, United Kingdom
A McPartlin Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada

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