Strontium-89 chloride delivery for painful bone metastases in patients with a history of prior irradiation.

BACKGROUND: Re-irradiation of a previously irradiated site must be done with careful consideration to minimize dose to organs at risk. AIMS: To evaluate pain response and safety of Sr-89 administration for painful bone metastases after prior irradiation. METHODS: We retrospectively reviewed patients with Sr-89 injection for painful bone metastasis in a previously irradiated site. All patients were seen in follow-up at 1, 2, 3, and 4 months after injection and every 6 months thereafter. Pain control, toxicity, and pain progression-free survival were analyzed. Correlation of pain relapse with the following characteristics was analyzed: gender, age, primary tumor, tumor pathology, baseline performance status, and baseline verbal rating scale. RESULTS: Among 25 patients analyzed (10 male, 15 female), median age was 68 (range, 50-81) years. Primary tumor sites included lung (n = 11), breast (n = 3), uterine cervix (n = 3), prostate (n = 3), and others (n = 5). Median follow-up was 25 (range, 1-76) months. Pain relief was observed in 24 patients (96.0%). One- and 2-year pain progression-free survival rates in these patients were 54.5% and 48.4%, respectively. Median time to pain progression was 5 (range, 2-16) months. Statistically significantly lower pain progression-free survival was observed in patients with osteolytic bone metastases (p < 0.01). No grade 3 or worse adverse events were observed. CONCLUSION: Sr-89 injection showed pain relief in most of our patients with painful bone metastases in a previously irradiated site and caused no grade 3 or worse adverse events. Sr-89 is an option for patients with a painful bone metastasis in a previously irradiated site.

Effective clinical applications of Monte Carlo-based independent secondary dose verification software for helical tomotherapy.

PURPOSE: To investigate the scope of the effective clinical application of Monte Carlo (MC)-based independent dose verification software for helical tomotherapy. METHODS: DoseCHECK was selected as the MC-based dose calculation software. First, the dose calculation accuracy of DoseCHECK was evaluated with film and chamber measurements in a water-equivalent phantom. Second, the dose calculation accuracy was examined in several heterogeneous materials. Finally, dosimetric comparisons between DoseCHECK and the treatment planning system (TPS) were performed for clinical patient plans. Prostate IMRT, head and neck IMRT (HN), total body irradiation (TBI), and brain stereotactic radiotherapy (SRT) were evaluated. RESULT: The DoseCHECK calculations agreed with the chamber and film measurements in the homogenous phantom. For heterogeneous phantom cases, the dose differences between DoseCHECK and TPS were within 3 %, except in air, in which large dose differences of 20 % were observed. In clinical patient plans, the median dose differences between the lung Dmean in TBI cases and the normal brain Dmean in brain SRT cases were significantly >3 %. For HN and brain SRT cases, the median target dose differences were >3 %. CONCLUSION: Our results show that independent dose verification with the MC algorithm can detect systematic errors caused by the lack of heterogeneity correction in the TPS. In particular, MC-based independent dose verification is required for HN, TBI, and brain SRT cases in helical tomotherapy.

Radiosensitization using hydrogen peroxide in patients with cervical cancer.

The purpose of the present study was to analyze the feasibility and safety of radiosensitization using hydrogen peroxide for cervical cancer. In superficial tumors, breast cancer and hepatocellular carcinoma, the safety and effectiveness of radiosensitization has been reported; to the best of our knowledge, however, there are no reports on cervical cancer. A total of 20 patients with cervical cancer were recruited. Inclusion criteria were as follows: Patients who required radical external beam radiotherapy (RT); ineligible for or refused brachytherapy; age, ≥20 years; no hematogenous metastasis; Eastern Cooperative Oncology Group Performance Status up to 2; and had not undergone prior treatment. Hydrogen peroxide was used twice a week in combination with RT. A 3% hydrogen peroxide solution-soaked gauze was inserted into the vagina during RT. A total of 45 Gy was delivered in 25 fractions to the whole pelvis with a boost of 10 Gy in 5 fractions if pelvic or para-aortic metastatic lymph nodes were observed. Ultimately, 18 patients were evaluated. Among the 17 patients (excluding one patient with tumor in situ), the one- and two-year overall survival rates were both 90% in patients with stage I/II and 86% in stage III/IV cervical cancer. The adverse events were well tolerated with no severe acute or late adverse events. Although limited by small sample size, short observation time and low radiation dose, the present study demonstrated that radiosensitization treatment may be an option for patients who cannot undergo brachytherapy. The study was retrospectively registered at the university hospital medical information network center (no. UMIN000039045) on January 6, 2020.