The Role of Radiotherapy in Epidermal Growth Factor Receptor Mutation-positive Patients with Oligoprogression: A Matched-cohort Analysis.

AIMS: Almost all patients with epidermal growth factor receptor (EGFR) mutations will develop resistance to first-line EGFR tyrosine kinase inhibitors (TKIs). The management of oligoprogression on EGFR TKI is controversial. Irradiating progressing tumours may potentially eradicate the resistant clone and allow continuation of EGFR TKI, but the clinical data remain sparse. We aimed to assess the effect of radiotherapy on survival outcomes in patients with oligoprogression in a matched-cohort study. MATERIALS AND METHODS: This was a retrospective matched-cohort study comparing patients with EGFR mutation-positive stage IV non-small cell lung cancer receiving radiotherapy versus chemotherapy for progression. Patients in the radiotherapy group received radiotherapy (mainly stereotactic ablative radiotherapy) for oligoprogression, whereas the chemotherapy group received only systemic chemotherapy upon progression. Key prognostic factors including gender, age, performance status, time to first progression and mutation subtypes were matched. RESULTS: Twenty-five patients with oligoprogression (radiotherapy group) were identified, and a matched chemotherapy group with the same number of patients was generated. The median duration of follow-up was 24.3 and 34 months for the radiotherapy and chemotherapy groups, respectively. The median overall survival of the radiotherapy group was significantly longer than the chemotherapy group, 28.2 versus 14.7 months (P = 0.026). The median progression-free survival (PFS) was 7.0 and 4.1 months after radiotherapy and chemotherapy, respectively (P = 0.0017). The use of radiotherapy was an independent predictive factor of overall survival and PFS in multivariate analysis. Only one patient had ≥grade 3 toxicity after radiotherapy. The frequency of secondary T790M mutation and subsequent Osimertinib exposure were similar in both groups. CONCLUSION: Radiotherapy may effectively extend EGFR TKI therapy for patients with oligoprogression on TKI. Improved PFS and overall survival were observed, although potential biases should not be overlooked. Further randomised studies are warranted.

Wide local excision and radiotherapy for the treatment of ductal carcinoma in situ of the breast: the Hong Kong experience.

AIMS: Breast conservation treatment for ductal carcinoma in situ (DCIS) was unpopular in the Chinese population and the outcome was seldom reported. We conducted a single-centre retrospective study to examine the clinical outcome of women in Hong Kong. MATERIALS AND METHODS: Seventy-five Chinese women were treated with wide local excision and radiotherapy for DCIS of the breast between 1994 and 2003. Only 26 (34.7%) women had non-palpable DCIS detected by screening mammograms. All women were treated with whole breast irradiation of 50 Gy in 2 Gy daily fractions, with 50 (66.7%) women receiving an additional electron boost of 10-16 Gy. RESULTS: The median follow-up was 5.1 years (range 2.0-10.7). At the last assessment, four women developed local recurrences, but all remained disease-free after salvage mastectomy. The 5-year actuarial local failure-free rate and cause-specific survival rate were 92.9% (95% confidence interval 89.4-96.4) and 100.0%, respectively. Cosmetic results were rated as good to excellent in all women. On univariate analysis of prognostic factors for local failure, only a close (< or = 2 mm) final resection margin approached statistical significance (hazard ratio 9.108; 95% confidence interval 0.946-87.655; P = 0.056). The 5-year actuarial local failure-free rates for women with a close (< or = 2 mm) final resection margin and women with wider margins were 77.0 and 98.2%, respectively. CONCLUSIONS: Despite geographical and demographic differences, the clinical outcome after wide local excision and radiotherapy for DCIS of the breast in Chinese women is comparable with that in Western series. Efforts are needed to achieve cosmetically acceptable tumour-free margins greater than 2 mm.