Survival after subsequent non-Hodgkin's lymphoma and non-small cell lung cancer in patients with malignant thymoma

Conditional survival analysis of four treatment strategies for patients with stage I non-small cell lung cancer

Conditional survival (CS) is used to describe dynamic survival possibility, taking account of the change in the survival risk that occurs with longevity. The present study aimed to explore the CS of four treatment strategies for stage I non-small cell lung cancer (NSCLC), staged according to the eighth edition of the American Joint Committee on Cancer/Union for International Cancer Control NSCLC staging system. Using the Surveillance, Epidemiology and End Results Program cohort obtained between 2004-2014, the current study first extracted data for 27,116 patients with stage I NSCLC. The actuarial cancer-specific survival rates (ACSs) and conditional cancer-specific survival rates of four treatment strategies were then compared. ACS was assessed using the Kaplan-Meier method and a log-rank test. The 3-year conditional cancer-specific survival (CCS3) of patients who had already survived for n years was calculated as CCS3=ACS(n+3)/ACS(n). Cox regression and propensity-score matching (PSM) was applied to adjust confounding factors. The 5-year ACS of patients who underwent lobectomy, sublobar resection, radiation and observation was 80.3, 72.0, 40.8 and 19.6%, respectively. The 5-year CCS3 of patients who underwent lobectomy, sublobar resection, radiation and observation was 91.7, 86.4, 77.0 and 58.2%, respectively. CCS3 increased with an increase in survival time and patients who underwent lobectomy had the highest CCS3 estimates and flattest growth, with the smallest survival gap between CCS3 and ACS. The results were similar in the PSM analysis. In conclusion, CS estimates may provide a more accurate survival prediction for patients with stage I NSCLC, and may assist with treatment decisions and surveillance strategies. In addition, the current study provided evidence that suggests lobectomy may be the optimal treatment strategy for stage I NSCLC compared with sublobar resection.

Rationale and early outcomes for the management of thymoma with proton therapy

Background

Radiotherapy for thymic malignancies is technically challenging due to their close proximity to the heart, lungs, esophagus, and breasts, raising concerns about significant acute and late toxicities from conventional photon radiotherapy. Proton therapy (PT) may reduce the radiation dose to these vital organs, leading to less toxicity. We reviewed the dosimetry and outcomes among patients treated with PT for thymic malignancies at our institution.

Methods

From January 2008 to March 2017, six patients with de novo Masaoka stages II-III thymic malignancies were treated with PT on an IRB-approved outcomes tracking protocol. Patients were evaluated weekly during treatment, then every 3 months for 2 years, then every 6 months for 3 more years, and then annually for CTCAE vs. four toxicities and disease recurrence. Comparison intensity-modulated radiotherapy (IMRT) plans were developed for each patient. Mean doses to the heart, esophagus, bilateral breasts, lungs, and V20 of bilateral lungs were evaluated for the two treatment plans.

Results

At last follow-up (median follow-up, 2.6 years), there were two patients with recurrences, including metastatic disease in the patient treated definitively with chemotherapy and PT without surgery and a local-regional recurrence in the lung outside the proton field in one of the post-operative cases. No patients with de novo disease experienced grade ≥3 toxicities after PT. The mean dose to the heart, lung, and esophagus was reduced on average by 36.5%, 33.5%, and 60%, respectively, using PT compared with IMRT (P<0.05 for each dose parameter).

Conclusions

PT achieved superior dose sparing to the heart, lung, and esophagus compared to IMRT for thymic malignancies. Patients treated with PT had few radiation-induced toxicities and similar survival compared to historic proton data.