Cell kinetics and tumor regression during radiotherapy in head and neck squamous-cell carcinomas

Abstract

Head and neck squamous-cell carcinoma (HN-SCC) patient management is mainly based on TNM classification and needs be improved by considering other potentially useful prognostic factors. We examined the pre-radiotherapy tumor potential doubling time (Tpot) evaluated after in vivo infusion of bromodeoxyuridine and flow-cytometric analysis and the early clinical tumor regression after 40 Gy (40 Gy-TR). Tpot values and clinical 40 Gy-TR classes (minor and major) were available for 82 HN-SCC patients. Radiation therapy completion was done either with 1 dose per day (conventional regimen) or 2 doses per day (accelerated regimen). Local control was also available for follow-up times above 4 years. We found that major 40 Gy-TR was strongly correlated with fast tumor growth, characterized by Tpot values below 5 days, and that patients with major 40 Gy-TR showed better local control than those with minor 40 Gy-TR, independently from the radiotherapy regimen type. We also found that treatment completion with accelerated radiotherapy gave better local control for patients with major 40 Gy-TR and fast tumor growth than conventional radiotherapy. Multivariate analysis, performed on all patients, assigned an independent prognostic value to Tpot, tumor classification and 40 Gy-TR.

Prognostic significance of ploidy and S-phase fraction in primary intraoral squamous cell carcinoma and their corresponding metastatic lymph nodes

“…In most of the researches flow cytometric data of intraoral squamous cell carcinoma (OSCC) have been lumped with tumors of the head and neck [7][8][9][10] due to its lower incidence rate. However, these results do not necessarily reflect the clinical importance of DNA ploidy in site specific tumors [11].…”

Role of Computed Tomography Imaging in Predicting Response of Nasopharyngeal Carcinoma to Definitive Radiation Therapy

“…Prognostic value of radiosensitivity associated with better local control has been suggested for some head and neck cancers excluding NPC 3–6 . Regression of tumor during or shortly after curative radiation therapy has been suggested to provide an in vivo indication of tumor radiosensitivity 6,7 .…”

“…Prognostic value of radiosensitivity associated with better local control has been suggested for some head and neck cancers excluding NPC 3–6 . Regression of tumor during or shortly after curative radiation therapy has been suggested to provide an in vivo indication of tumor radiosensitivity 6,7 . However, the volume by which a tumor changes after irradiation depends on multiple factors such as the percentage of cancer cells killed, the mode of cell death, the architecture of the tumor, the amount of radiation induced surrounding tissue changes, including inflammation and/or necrosis, and the efficiency of clearance of dead cells from the diseased area.…”

“…Local control is prognostically important in nasopharyngeal cancer 2 ; however, despite aggressive local treatment with radiotherapy, more than 30% of patients with NPC still died of local failure 3,4 . Although the most reliable factor for predicting outcome from definitive radiotherapy is the pretreatment cancer stage, 5 some data have suggested that regression of tumor during or shortly after the course of radiation is an in vivo indication of tumor radiosensitivity of certain head and neck cancers and may also have prognostic significance 6,7 …”

“…3,4 Although the most reliable factor for predicting outcome from definitive radiotherapy is the pretreatment cancer stage, 5 some data have suggested that regression of tumor during or shortly after the course of radiation is an in vivo indication of tumor radiosensitivity of certain head and neck cancers and may also have prognostic significance. 6,7 It is certain that clinical complete response is not universal at the completion of radiation or after shortterm follow up. However, the significance of residual disease discovered in imaging studies, particularly postradiation computed tomography (CT) scans, at the primary site of NPC after curative radiotherapy has not been investigated, and the timing of tumor regression of NPC in relation to disease prognosis has not been explored.…”