Optimal positive lymph node ratio showing the benefit of postoperative radiotherapy in pathologic N2 non-small cell lung cancer: an exploratory study using the Surveillance, Epidemiology, and End Results data.

PURPOSE: This study aimed to identify the clinical parameters having the beneficial effect of postoperative radiotherapy (PORT) in pathologic N2 (pN2) non-small cell lung cancer (NSCLC) using the Surveillance, Epidemiology, and End Results (SEER) data. MATERIALS AND METHODS: Among non-metastatic NSCLC patients in the SEER data, we included patients who diagnosed after 2002, who confirmed as pN2 after lobectomy or pneumonectomy, and who coded as underwent PORT or observation. Patients who survived less than 4 months of diagnosis were excluded in consideration of the perioperative mortality. After performing propensity score matching (PSM) on the selected patients, we compared PORT group with surgery alone group. We also performed exploratory subgroup analysis to find patients who could benefit from PORT. RESULTS: Among the selected 4,456 patients, 1,729 patients received PORT, and 2,727 patients did not. There was no survival benefit of PORT in all patients with pN2 disease (hazard ratio [HR] = 1.03, p = 0.5). In subgroup analyses, the patients with a positive lymph node (LN) ratio of 60%-80% showed the significant benefit of PORT (HR = 0.71, p = 0.002). CONCLUSION: PORT did not show the significant survival benefit in patients with pN2 disease after correcting the confoundedness in the SEER data. However, a specific range of LN ratios can be a potential indicator maximizing the survival benefit of PORT.

COVID-19 pandemic: a new cause of unplanned interruption of radiotherapy in breast cancer patients.

The purpose of this study was to investigate the impact of the coronavirus disease 2019 (COVID-19) pandemic on patients undergoing radiotherapy by comparing the patterns of unplanned radiotherapy interruption before and after the COVID-19 pandemic. We enrolled patients who received their first dose of radiotherapy for breast cancer between January 28 and July 31, 2019 and between January 28, 2020, and July 31, 2020. We compared the radiotherapy interruption patterns in 2019 with those in 2020 to analyze the impact of the COVID-19 pandemic on treatment interruption. Between January 28 and July 31, 2019, 287 patients with breast cancer received radiotherapy. Among them, 19 patients (6.6%) experienced treatment interruption; the reasons for treatment interruption were radiotherapy-related side effects (10 patients, 52.6%), other medical reasons (three patients, 15.8%), and personal reasons (six patients, 31.6%). Between January 28 and July 31, 2020, 279 patients with breast cancer received radiotherapy. Among them, 23 patients (8.2%) experienced treatment interruption; the reasons for treatment interruption were radiotherapy-related side effects (eight patients, 35%) and COVID-19 screening clinic-related reasons (six patients, 26.1%). Among the six patients with screening clinic-related causes of radiotherapy interruption, five had asymptomatic fever and one had mild cold-like symptoms. The duration of treatment interruption was longer in patients with screening clinic-related interruptions than in those with interruptions because of other causes (p = 0.019). Multivariate analysis showed that cancer stage and radiotherapy volume did not significantly affect treatment interruption. The radiotherapy of certain patients was suspended despite the lack of a confirmed COVID-19 diagnosis. Precise and systematic criteria for the management of patients with suspected COVID-19 are needed, and the opinion of radiation oncologist in charge of the patient must also be considered.

Association Between Radiation Tolerance of Lymphocytes and Clinical Outcomes in Cervical Cancer.

BACKGROUND/AIM: This study evaluated whether the lymphocyte tolerance factor (LTF) was an indicator of radiation tolerance of lymphocytes (RTL) using the relative lymphocyte count (RLC), and considering clinical outcomes. PATIENTS AND METHODS: A total of 92 cervical cancer patients treated with concurrent chemoradiotherapy (CCRT) were analysed. RLC0 was pre-treatment RLC, and RLC1, and RLC2 were at the first and second week of CCRT, respectively. LTF1 was RLC1:RLC2. LTF2 was the dimension of the convex or concave shape comprising the three RLC vertexes. Patients were divided into three groups: good RTL group, low LTF1; moderate RTL group, high LTF1 and low LTF2; and poor RTL group, high LTF1 and high LTF2. RESULTS: Patients with good tumour response to radiotherapy were mostly included in the good RTL group than in the other groups. The poor RTL group had lower 3-year progression-free survival (57.1% vs. 83.8% and 82%, p=0.01) and 5-year disease-specific survival (71.8% vs. 90.4% and 94.9%, p=0.062) rates than the moderate and good RTL groups. Multivariate analyses showed that poor RTL was a significant survival predictor. CONCLUSION: The poor RTL group according to LTF is a potential predictor of clinical outcome.