Background: Concomitant boost irradiation (CB) in adjuvant whole breast radiotherapy (WBI) is increasingly prevalent. Multiple studies have reported the effect of CB; however, long-term outcomes after CB remain unknown. Methods: Totally 266 patients administered breast-conserving surgery from March 2007 to November 2012 were included in this retrospective analysis. They were administered WBI at 45 Gy (range, 43.2-46) in 23 fractions (range, 18-25). CB irradiation was delivered shortly after WBI completion with 9 or 12 Mevβ electrons at a dose of 13.8 Gy (range, 7.2-15) in 23 fractions (range, 18-25). Sequential boost irradiation (SB) was conducted sequentially after the entire WBI treatment at a dose of 14 Gy (range, 10-15) in 7 fractions (range, 4-8). Then, 10-year survival, local control, and toxicity in these two groups were analyzed. Results: Median follow-up time was 124 months, ranging from 121.6 to 126.4. The 10-year disease-free (DFS) and overall (OS) survival rates were similar in both groups, both before and after PSM. Both distant metastasis and recurrence rates in the CB group were similar to those of the SB group after PSM. Moreover, both groups had similar cosmetic outcomes and radiation-associated late toxicity. Conclusions: Survival, local tumor control, cosmetic outcome, and late toxicity were comparable in the CB and SB groups. WBI with CB can be considered an effective therapeutic tool in early-stage breast cancer.

5542 Background: Cisplatin-based concurrent chemoradiation regimens have been suggested to be beneficial in recurrent or metastatic cervical cancer. Immunotherapy has also shown good therapeutic efficacy in recurrent or metastatic cervical cancer. Among them, Pembrolizumab in combination with chemotherapy has been used for first-line treatment of advanced PD-L1-positive cervical cancer. Meanwhile, Camrelizumab has shown good anti-tumor activity and manageable toxicity in patients with locally advanced cervical cancer. The primary objective of this study is to evaluate the efficacy and safety of Camrelizumab in combination with concurrent chemoradiation in patients with recurrent or metastatic cervical cancer. Methods: Patients diagnosed with recurrent or metastatic cervical cancer received Camrelizumab combined with concurrent chemoradiotherapy, radiotherapy:External beam radiotherapy (EBRT) 1.8-2.15 Gy/f, a total of 28 fractions; Brachytherapy: high-risk CTV using image guidance 28 Gy in 4 fractions (18 Gy in 3 fractions for posthysterectomy recurrent patients); chemotherapy regimen used TP regimen (paclitaxel: 175 mg/m2, cisplatin: 75 mg/m2, Q3W 6 cycles); Camrelizumab 200 mg Q3W 6 cycles. The primary endpoint of this trial was objective response rate (ORR), and secondary endpoints were progression-free survival (PFS), overall survival (OS), disease control rate (DCR), and incidence of adverse reactions. Results: From September 16, 2020 to September 30, 2022, a total of 29 patients were recruited. 27 of these patients completed 6 cycles of planned treatment. 27 patients had a median age of 53 years (33-73 years), ECOG PS 0 (n = 8), ECOG PS 1 (n = 14), ECOG PS 2 (n = 1). The ORR rate was 96.30% (26/27), including 17 patients with CR, 9 patients with PR, and 1 patient with SD Treatment-related AEs were mainly lymphocyte count decreased, anemia, and white blood cell count decreased, with overall safety manageable and no treatment-related deaths. Conclusions: Camrelizumab combined with concurrent chemoradiation in patients with recurrent or metastatic cervical cancer has good efficacy, low side effects and acceptable toxicity. Clinical trial information: NCT04884906 .