Which technique of positioning and immobilization is better for breast cancer patients in postmastectomy IMRT, single-pole or double-pole immobilization?

PURPOSE: Our purpose was to explore which immobilization is more suitable for clinical practice in postmastectomy intensity modulation radiotherapy, the single-pole position or the double-pole position? METHODS: Patients treated with postmastectomy intensity modulation radiotherapy were eligible. They were selected randomly for single-pole position or double-pole position. Dose-volume histogram (DVH) was used to evaluate plans. After their first radiotherapy, the physicians asked a question about the comfort level of their position. The dosimetric parameters, comfort levels, and reproducibility of the two immobilization techniques were collected and analyzed after all patients had finished the whole radiotherapy. RESULTS: Totally, 94 patients were enrolled. Of these, 54 patients were treated with the single-pole position, 28 (51.9%)had left-sided lesions. While 40 patients were treated with the double-pole position, 20 (50%) had left-sided lesions. Patients' characteristics in two groups were comparable. The single-pole and double-pole immobilizations had similar conformity (0.60 ± 0.05 vs 0.60 ± 0.06, P = 0.887) and homogeneity index (0.14 ± 0.03 vs 0.13 ± 0.03, P = 0.407). Compared to single-pole position, double-pole position typically increased the mean dose, V20 , and V30 of heart (P < 0.05). Moreover, patients in the single-pole group felt more comfortable than another group (P < 0.05). There was no difference in reproducibility between the two groups (P > 0.05). CONCLUSIONS: Single-pole position seems to be more comfortable and can reduce dose coverage to heart. Both devices allow for reproducible setup and acceptable dosimetry.

Postmastectomy intensity modulation radiated therapy of chest wall and regional nodes: Retrospective analysis of the performance and complications up for 5 years.

To retrospectively evaluate the performance and complications of postmastectomy intensity modulation radiated therapy (IMRT) technique.From January 2010 to December 2014, IMRT technique was applied to 200 patients after modified radical mastectomy. The acute and late radiation toxicities have been followed up for 5 years. The treatment performance, toxicity incidence, and risk factors were investigated.All patients included had at least 1-year of follow-up; mean follow-up was 28.5 months. Three patients had grade 3 acute radiation dermatitis; 1 patient received grade 2 acute radiation induced lung injury, while 3 patients received acute radiation esophagitis. Seven patients had edema at the end of radiotherapy. Multivariate analyses revealed that neoadjuvant chemotherapy and hypertension were the most significant risk factors for acute skin dermatitis and acute radiation induced lung injury, respectively. Trastuzumab treatment was the independent risk factor for late radiation lung injury. Internal mammary nodes irradiation might relate to acute and late radiation induced lung injury. In the follow-ups there were 125 patients that were followed up with for >2 years. The 2-year local-regional recurrence (LRR), distant metastasis (DM), and disease free survival (DFS) were 1.6%, 6.4%, and 92.80%, respectively.Postmastectomy treatment with the IMRT technique can reduce the incidence rate of radiation toxicity by decreasing organs at risk (OARs) irradiation. Patients with risk factors for radiation toxicity should be strictly surveyed throughout radiotherapy.

Autophagy influences the low-dose hyper-radiosensitivity of human lung adenocarcinoma cells by regulating MLH1.

PURPOSE: To investigate the impact of autophagy on the low-dose hyper-radiosensitivity (HRS) of human lung adenocarcinoma cells via MLH1 regulation. MATERIALS AND METHODS: Immunofluorescent staining, Western blotting, and electron microscopy were utilized to detect autophagy in A549 and H460 cells. shRNA was used to silence MLH1 expression. The levels of MLH1, mTOR, p-mTOR, BNIP3, and Beclin-1 were measured by real-time polymerase chain reaction (PCR) and Western blotting. RESULTS: A549 cells, which have low levels of MLH1 expression, displayed HRS/induced radioresistance (IRR). Conversely, the radiosensitivity of H460 cells, which express high levels of MLH1, conformed to the linear-quadratic (LQ) model. After down-regulating MLH1 expression, A549 cells showed increased HRS and inhibition of autophagy, whereas H460 cells exhibited HRS/IRR. The levels of mTOR, p-mTOR, and BNIP3 were reduced in cells harboring MLH1 shRNA, and the changes in the mTOR/p-mTOR ratio mirrored those in MLH1 expression. CONCLUSIONS: Low MLH1-expressing A549 cells may exhibit HRS. Both the mTOR/p-mTOR and BNIP3/Beclin-1 signaling pathways were found to be related to HRS, but only mTOR/p-mTOR is involved in the regulation of HRS via MLH1 and autophagy.