[Tumor and individual radiosensitivity. An introduction]

Radiotherapy Combined With Concurrent Nedaplatin-Based Chemotherapy for Stage II–III Esophageal Squamous Cell Carcinoma

Objective

This study was conducted to explore the appropriate radical radiation dose in concurrent chemoradiotherapy (CCRT) for patients with inoperable stage II–III esophageal squamous cell carcinoma (ESCC).

Methods

This retrospective study included patients with esophageal cancer (EC) from the database of patients treated at the Affiliated Zhangjiagang Hospital of Soochow University (1/2015–12/2019). Overall survival (OS), progression-free survival (PFS), objective remission rate (ORR), first failure pattern, and toxicities were collected.

Results

112 patients treated with intensity-modulated radiation therapy (IMRT) combined with concurrent chemotherapy of nedaplatin-based regimens were included. Fifty-eight (51.8%) and 54 (48.2%) patients received 60 (HD) and 50.4 (LD) Gy of radiotherapy, respectively. The HD group showed superior OS and a trend for longer PFS compared with the LD group (median OS: 25.5 vs 17.5 months, P = .021; median PFS: 14.0 vs 10.5 months, P = .076). There were more patients with a complete remission (CR) in the HD group than in the LD group (P=.016). The treatment-related toxicities were generally acceptable, but HD radiotherapy would increase the incidence of grade ≥3 late radiotoxicity (22.4% vs 5.6%, P = .011).

Conclusion

In nedaplatin-based CCRT for stage II–III ESCC, the radiotherapy dose of 60 Gy achieved a better prognosis.

Strengths and limitations of this study

A comparative study of 50.4 Gy and 60 Gy was conducted to evaluate whether 50.4 Gy can be used as a radical radiotherapy dose for inoperable stage II–III esophageal squamous cell carcinoma from a real-world perspective. The highly consistent selection criteria in our study make analysis results highly reliable and scientific. The existing research results support that nedaplatin can be used in concurrent chemoradiotherapy for esophageal squamous cell carcinoma, and this study focuses on the discovery of a better nedaplatin-based combination regimen. The findings of this study are limited to a single-center study with a non-large sample size. Inevitably, recall bias may exist in this retrospective study. Surgery was not involved in the follow-up treatment after concurrent chemoradiotherapy, which may worsen the prognosis of some patients.

Genetic and epigenetic features in radiation sensitivity

Recent progress especially in the field of gene identification and expression has attracted greater attention to genetic and epigenetic susceptibility to cancer, possibly enhanced by ionising radiation. It has been proposed that the occurrence and severity of the adverse reactions to radiation therapy are also influenced by such genetic susceptibility. This issue is especially important for radiation therapists since hypersensitive patients may suffer from adverse effects in normal tissues following standard radiation therapy, while normally sensitive patients could receive higher doses of radiation offering a better likelihood of cure for malignant tumours. This paper, the first of two parts, reviews the main mechanisms involved in cell response to ionising radiation. DNA repair machinery and cell signalling pathways are considered and their role in radiosensitivity is analysed. The implication of non-targeted and delayed effects in radiosensitivity is also discussed.

[Reversibility of radiation-induced fibroatrophy]

PURPOSE

The radiation-induced fibro-atrophic process described in numerous tissues and organs is a localized and irreversible late effect of high-dose radiation therapy. Our purpose is to show that this process is today reversible.

CURRENT KNOWLEDGE AND KEY POINTS

This review describes a synthesis of various clinical, paraclinical and histopathological aspects of radiation-induced fibro-atrophic process, and of cellular and molecular process regulation. Schematically, there exists a prefibrotic aspecific inflammatory phase, then a constituted and cellular phase, then a matricial densification and remodeling phase, associated in some cases with a tissular terminal necrosis. The respective parts and their evolution during time of the main protagonists as myofibroblast, extracellular matrix and growth factor TGF beta 1 are clarified. From the pathophysiological mechanisms described, curative therapeutic attitudes are proposed for the different progressive phases. Especially, superoxide dismutase (not available) and the pentoxifylline-tocopherol combination seem to allow reduction and reversibility of the fibro-atrophic radiation-induced established process, in clinics as in animal experiments.

FUTURE PROSPECTS AND PROJECTS

Some phase II trials try to assess the therapeutic interest of combined pentoxifylline-tocopherol in various radiation-induced sequelae, as in osteo-radionecrosis. A clinical randomized trial phase III has just been achieved and could support the results of these experimental and retrospective clinical trials.

[Radiation-induced superficial fibrosis and TGF-alpha 1]

Radiation-induced fibrosis is a late sequela of both therapeutic and accidental irradiations, which has been described in various tissues, including the lung, liver, kidney and skin. This review presents different aspects of superficial radiation-induced fibrosis, such as clinical observations, histological changes, cellular and molecular regulations, and medical management. Recent evidence on the critical role played by TGF-beta 1 in the initiation, development and persistence of fibrosis are discussed, as well as the possibility that this cytokine may constitute a specific target for antifibrotic agents.