CLINICAL STUDY IN ACCELERATED HYPERFRACTIONATED IRRADIATION IN THE TREATMENT OF LOCAL ADVANCED NON-SMALL CELL LUNG CANCER

Objective To evaluate the effect of accelerated hyperfractionated irradiation (AHFJ) and conventional fractionated irradiation (CFI) for local advanced non- small cell lung cancer (NSCLC). Methods The patients of AI-IFJ group were irradiated to large-field target volume by a daily fraction of 2Gy, and small-field target volume by a daily fraction of 1Gy with more than 6h interval. The total dose of large-field target volume was SOGy/25Fx/SW and of small-field target volume was 7SGy/SOFx/5W. The patients in CFI group were irradiated by a daily fraction of 2Gy to the total dose of 66Gy/33Fx/6. 6W. After 3 months of radiotherapy, the tumor response rates of complete recovery (CR), partial recovery (PR), and no change (NC) and 1- and 2- year survival rate in the two groups were observed. Results The tumor response rates of CR,PR,NC in AHFI group and CFI group were 22.9%(8/35), 60.0%(21/35), 17.1%(6/35) and 11.4% (4/35), 51.4% (18/35), 37.2% (13/35) respectively (P>0. 05). All patients were followed up 2 years or more. The 1- and 2- year survival rates in AHFI group and CFI group were 62.9% (22/35), 31 .4% (11/35) and 42.9% (15/35) , 17.1% (6/35) respectively (P< 0.05). The incidences of esophagitis and pneumonitis in AHFI group and CFI group were 34.3% (12/35), 22. 9% (8/35) and 40.0% (14/35), 17.1% (6/35)(P>0. 05). Conclusion In comparison with CFI, AHFI may increase 1- and 2- year sur-vival rate after treatment of local advanced non-small cell lung cancer, while the radio-reactions, either early or late, did not increase significantly.

Making radiation therapy more effective in the era of precision medicine

Cancer has become a leading cause of death and constitutes an enormous burdenworldwide.Radiation is a principle treatment modality used alone or in combination with other forms of therapy,with 50%–70%of cancer patients receiving radiotherapy at some point during their illness.It has been suggested that traditional radiotherapy(daily fractions of approximately 1.8–2 Gy over several weeks)might select for radioresistant tumor cell sub-populations,which,if not sterilized,give rise to local treatment failure and distant metastases.Thus,the challenge is to develop treatment strategies and schedules to eradicate the resistant subpopulation of tumorigenic cells rather than the predominant sensitive tumor cell population.With continued technological advances including enhanced conformal treatment technology,radiation oncologists can increasinglymaximize the dose to tumors while sparing adjacent normal tissues,to limit toxicity and damage to the latter.Increased dose conformality also facilitates changes in treatment schedules,such as changes in dose per treatment fraction and number of treatment fractions,to enhance the therapeutic ratio.For example,the recently developed large dose per fraction treatment schedules(hypofractionation)have shown clinical advantage over conventional treatment schedules in some tumor types.Experimental studies suggest that following large acute doses of radiation,recurrent tumors,presumably sustained by the most resistant tumor cell populations,may in fact be equally or more radiation sensitive than the primary tumor.In this review,we summarize the related advances in radiotherapy,including the increasing understanding of the molecular mechanisms of radioresistance,and the targeting of thesemechanisms with potent small molecule inhibitors,whichmay selectively sensitize tumor cells to radiation.