New Challenges in Evaluating Outcomes after Immunotherapy in Recurrent and/or Metastatic Head and Neck Squamous Cell Carcinoma

Abstract

In many recurrent and/or metastatic cancers, the advent of immunotherapy opens up new scenarios of treatment response, with new phenomena, such as pseudoprogression and hyperprogression. Because of this, different immune-related response criteria have been developed, and new therapeutic strategies adopted, such as treatment beyond progression. Moreover, the role of progression-free survival as a surrogate has been questioned, and new surrogate endpoint hypotheses have arisen. A proper understanding of radiological imaging, an assessment of the biological events triggered by therapy, and the clinical evolution of the lesions and of the patient performance status are all factors that should be considered to guide the oncologist’s treatment choice. The primary aim of this article is to discuss how all these concepts apply to recurrent/metastatic head and neck squamous cell carcinoma patients when treated with immunotherapy.

Role of Surgical Pathologist for Detection of Immunooncologic Predictive Factors in Head and Neck Cancer

“…79 The occurrence of pseudoprogression is rare in HNSCC patients treated by immunotherapy, but its distinction from true progression is of fundamental importance to avoid inappropriate immunotherapy interruption or to start a new line of treatment in case of true progression. 80 A biopsy of the tumor bed can help in the distinction, as in case of pseudoprogression a dense infiltrate of CD3 + lymphocytes is detected rather than neoplastic cells. 79…”

“…A paradoxical effect of immunotherapy is represented by the phenomenon of pseudoprogression, which consists of an increase in the size of the tumor due to the recruitment and infiltration of the tumor tissue by immune cells and not by tumor cell proliferation itself, as it is in true progression 79. The occurrence of pseudoprogression is rare in HNSCC patients treated by immunotherapy, but its distinction from true progression is of fundamental importance to avoid inappropriate immunotherapy interruption or to start a new line of treatment in case of true progression 80. A biopsy of the tumor bed can help in the distinction, as in case of pseudoprogression a dense infiltrate of CD3 + lymphocytes is detected rather than neoplastic cells 79…”