Hypofractionated whole breast irradiation in association with hypofractionated or normofractionated boost to the tumor bed in early breast cancer: tolerance and efficacy analysis

Background The boost to the tumor bed improves local control in breast cancer and it is an important part of the breast conserving therapy. However, information about the use of a hypofractionated boost is sparse, thus further studies are needed. We conducted a retrospective study with the aim of comparing hypofractionated boost (HB) and normofractionated boost (NB) on skin toxicity and local control. Materials and methods A total of 96 women with early breast cancer undergoing breast-conserving surgery and hypofractionated whole breast irradiation (WBI) were retrospectively analyzed divided into hypofractionated boost group and conventional fractionation boost group. Forty-nine patients were treated with NB with 16 Gy in 8 fractions and 47 patients were treated with HB with 13.35 Gy in 5 fractions. We examined acute and chronic toxicity with CTCAE version 5. Results The median follow-up was 49.5 months (26–67). Median age was 57 years (36–82). Sixty-six patients (68.7%) were younger than 60 years at the time of boost and 30 (31.2%) were older than 60 years who received the boost due to poor prognostic factors. No differences were found between the two groups in terms of patient, tumor or treatment characteristics. Grade 2 acute skin toxicity was 6.3% in the NB group and 4.2% in the HB group. Chronic skin induration was 4.2% in the NB group and 1% in the HB group. They did not show grade 3 skin toxicity. There were also no differences in acute or late skin toxicity between the two groups. No local recurrences were evidenced. Conclusions Hypofractionated WBI associated with HB treatment is a viable option in the management of conservative breast therapy given the good tolerance and similar local control (AU)

Hypofractionated whole breast irradiation in association with hypofractionated or normofractionated boost to the tumor bed in early breast cancer: tolerance and efficacy analysis.

BACKGROUND: The boost to the tumor bed improves local control in breast cancer and it is an important part of the breast conserving therapy. However, information about the use of a hypofractionated boost is sparse, thus further studies are needed. We conducted a retrospective study with the aim of comparing hypofractionated boost (HB) and normofractionated boost (NB) on skin toxicity and local control. MATERIALS AND METHODS: A total of 96 women with early breast cancer undergoing breast-conserving surgery and hypofractionated whole breast irradiation (WBI) were retrospectively analyzed divided into hypofractionated boost group and conventional fractionation boost group. Forty-nine patients were treated with NB with 16 Gy in 8 fractions and 47 patients were treated with HB with 13.35 Gy in 5 fractions. We examined acute and chronic toxicity with CTCAE version 5. RESULTS: The median follow-up was 49.5 months (26-67). Median age was 57 years (36-82). Sixty-six patients (68.7%) were younger than 60 years at the time of boost and 30 (31.2%) were older than 60 years who received the boost due to poor prognostic factors. No differences were found between the two groups in terms of patient, tumor or treatment characteristics. Grade 2 acute skin toxicity was 6.3% in the NB group and 4.2% in the HB group. Chronic skin induration was 4.2% in the NB group and 1% in the HB group. They did not show grade 3 skin toxicity. There were also no differences in acute or late skin toxicity between the two groups. No local recurrences were evidenced. CONCLUSIONS: Hypofractionated WBI associated with HB treatment is a viable option in the management of conservative breast therapy given the good tolerance and similar local control.

Dose escalation in advanced floor of the mouth cancer: a pilot study using a combination of IMRT and stereotactic boost.

PURPOSE: We evaluated the efficiency and toxicity of stereotactic hypofractionated boost in combination with conventionally fractionated radiotherapy in the treatment of advanced floor of the mouth cancer. METHODS: Thirty-seven patients with advanced stage of the floor of the mouth cancer, histologically confirmed squamous cell carcinoma (p16 negative) ineligible for surgical treatment, were indicated for radiochemotherapy or hyperfractionated accelerated radiotherapy (HART). The radiotherapy protocol combined external beam radiotherapy (EBRT) and a stereotactic hypofractionated boost to the primary tumor. The dose delivered from EBRT was 70-72.5 Gy in 35/50 fractions. The hypofractionated boost followed with 10 Gy in two fractions. For the variables-tumor volume, stage and grade a multivariate analysis was performed to find the relationship between overall survival, local progression and metastasis. Toxicity was evaluated according to CTCAE scale version 4. RESULTS: After a median follow-up of 16 months, 23 patients (62%) achieved complete remission. The median time to local progression and metastasis was 7 months. Local control (LC) at 2 and 5-years was 70% and 62%, respectively. Progression-free survival (PFS) and overall survival (OS) were 57% and 49% at 2 years and 41% and 27% at 5 years, respectively. Statistical analysis revealed that larger tumors had worse overall survival and a greater chance of metastasis. Log-Rank GTV > 44 ccm (HR = 1.96; [95% CI (0.87; 4.38)]; p = 0.11). No boost-related severe acute toxicity was observed. Late osteonecrosis was observed in 3 patients (8%). CONCLUSION: The combination of EBRT and stereotactic hypofractionated boost is safe and seems to be an effective option for dose escalation in patients with advanced floor of the mouth tumors who are ineligible for surgical treatment and require a non-invasive approach.