Impact of delivery time factor on treatment time and plan quality in tomotherapy.

Delivery time factor (DTF) is a new parameter introduced by the RayStation treatment planning system for tomotherapy treatment planning. This study investigated the effects of this factor on various tomotherapy plans. Twenty-five patients with cancer (head and neck, 6; lung, 9; prostate, 10) were enrolled in this study. Helical tomotherapy plans with a field width of 2.5 cm, pitch of 0.287, and DTF of 2.0 were created. All the initial plans were recalculated by changing the DTF parameter from 1.0 to 3.0 in increments of 0.1. Then, DTF's impact on delivery efficiency and plan quality was evaluated. Treatment time and modulation factor increased monotonically with increasing DTF. Increasing the DTF by 0.1 increased the treatment time and modulation factor by almost 10%. This relationship was similar for all treatment sites. Conformity index (CI), homogeneity index, and organ at risk doses were improved compared to plans with a DTF of 1.0, except for the CI in the lung cancer case. However, the improvement in most indices ceased at a certain DTF; nevertheless, treatment time continued to increase following an increase in DTF. DTF is a critical parameter for improving the quality of tomotherapy plans.

Dosimetric investigation of whole-brain radiotherapy with helical intensity modulated radiation therapy and volumetric modulated arc therapy for scalp sparing.

Objective: Intensity-modulated radiotherapy (IMRT) is a well-established radiotherapy technique for delivering radiation to cancer with high conformity while sparing the surrounding normal tissue. Two main purposes of this study are: (1) to investigate dose calculation accuracy of helical IMRT (HIMRT) and volumetric-modulated arc therapy (VMAT) on surface region and (2) to evaluate the dosimetric efficacy of HIMRT and VMAT for scalp-sparing in whole brain radiotherapy (WBRT). Methods: First, using a radiochromic film and water-equivalent phantom with three types of boluses (1, 3, 5 mm), calculation/measurement dose agreement at the surface region in the VMAT and HIMRT plans were examined. Then, HIMRT, 6MV-VMAT and 10MV-VMAT with scalp-sparing, and two conventional three-dimensional conformal radiotherapy plans (6MV-3DCRT and 10MV-3DCRT; as reference data) were created for 30 patients with brain metastasis (30 Gy/10 fractions). The mean dose to the scalp and the scalp volume receiving 24 and 30 Gy were compared. Results: The percentage dose differences between the calculation and measurement were within 7%, except for the HIMRT plan at a depth of 1 mm. The averaged mean scalp doses [Gy], V24Gy [%], and V30Gy [%] (1SD) for 6MV-3DCRT, 10MV-3DCRT, HIMRT, 6MV-VMAT, and 10MV-VMAT were [26.6 (1.1), 86.4 (7.3), 13.2 (4.2)], [25.4 (1.0), 77.8 (7.5), 13.2 (4.2)], [23.2 (1.5), 42.8 (19.2), 0.2 (0.5)], [23.6 (1.6), 47.5 (17.9), 1.2 (1.8)], and [22.7 (1.7), 36.4 (17.6), 0.7 (1.1)], respectively. Conclusion: Regarding the dose parameters, HIMRT achieved a lower scalp dose compared with 6MV-VMAT. However, the highest ability to reduce the mean scalp dose was showed in 10MV-VMAT. Advances in knowledge: Scalp-sparing WBRT using HIMRT or VMAT may prevent radiation-induced alopecia in patients with BM.

Hepatocellular carcinoma effective stereotactic body radiotherapy using Gold Anchor and the Synchrony system: Two case reports and review of literature.

BACKGROUND: Radiotherapy for hepatocellular carcinoma (HCC) is considered to have limited efficacy because of treatment intensity considering that the irradiated area includes the liver, which is highly radiosensitive. In this report, we present two cases in which tumor control by surgical resection, radiofrequency ablation, transcatheter arterial chemoembolization (TACE), and lenvatinib administration was difficult, but stereotactic body radiotherapy (SBRT) using the Synchrony system by Radixact™ and Gold Anchor® (GA) was effective. CASE SUMMARY: A 60-year-old man had a single 10-cm HCC in the right lobe. Viable lesions remained after TACE, and levels of alpha-fetoprotein and protein induced by vitamin K antagonists II (PIVKA-II) decreased and quickly re-elevated. We performed SBRT with GA. Three weeks after implantation, localized radiotherapy (SBRT; 40 Gy/5 fractions) was performed using the Synchrony system by Radixact™. Four weeks later, the viable lesion had disappeared, and the PIVKA-II levels decreased. A 77-year-old man had a single 12-cm HCC in the right lobe. The patient experienced recurrence after hepatectomy. Further recurrence occurred after TACE, and we performed SBRT with GA. Because of the proximity of the HCC to the gastrointestinal tract, localized radiotherapy (SBRT; 39 Gy/13 fractions) to the HCC was performed 3 wk after implantation using the Synchrony system by Radixact™. Four weeks later, the viable lesion had disappeared on computed tomography, and the PIVKA-Ⅱ levels decreased. CONCLUSION: SBRT using the Synchrony system and GA can deliver a large dose accurately and safely, and could have a high therapeutic effect.

Treatment Outcome of the Combination Therapy of High-dose rate Intracavitary Brachytherapy and Intensity-modulated Radiation Therapy With Central-shielding for Cervical Cancer.

BACKGROUND/AIM: This study aimed to evaluate the clinical outcome of intensity-modulated radiation therapy (IMRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT) in uterine cervical cancer (UCC). IMRT consisted of whole-pelvic radiation therapy (WPRT) and sequential WPRT with central-shielding (WPRT-CS). PATIENTS AND METHODS: Thirty UCC patients treated with IMRT using TomoTherapy, were retrospectively analyzed. RESULTS: The median dose of WPRT and WPRT-CS was 36 and 14.4 Gy and the median total dose of these was 50 Gy in 25 fractions (Fr). Median HDR-ICBT dose/Fr to Point A was 25 Gy/5 Fr. Median 2 Gy per fraction-equivalent dose (EQD2) of combined WPRT and HDR-ICBT to Point A (α/ß=10) was 71.0 Gy. The 3-year local control, disease-free survival, and overall survival rates were 89.9%, 83.3%, and 86.3%. CONCLUSION: IMRT of WPRT and WPRT-CS given in combination with HDR-ICBT was a feasible therapy resulting in good disease control and tolerance in patients with UCC.

Intensity-modulated Radiation Therapy for Lymph Node Oligo-recurrence.

BACKGROUND/AIM: This study aimed to evaluate the effect of intensity-modulated radiation therapy (IMRT) on the clinical outcomes of patients with lymph node (LN) oligo-recurrence and a controlled primary tumor. PATIENTS AND METHODS: We retrospectively reviewed the medical records of 21 patients diagnosed with LN oligo-recurrence who received IMRT with curative intent. Patients with tumor of various primary sites and histopathological types were included in this study. RESULTS: The 3-year overall survival (OS) and in-field progression-free survival (PFS) rates were 75% and 52%, respectively. Statistical analysis showed that lower dose to the gross tumor volume (GTV) and larger GTV were significantly associated with poorer OS; adenocarcinoma and lower dose to GTV were significantly associated with poorer in-field PFS. No patients experienced severe adverse events. CONCLUSION: IMRT may provide a safe and effective treatment for patients with LN oligo-recurrence. Tumor dose-escalation sparing normal tissue using IMRT technology may improve the OS and in-field PFS.

Definitive radiation therapy for extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is frequently inoperable because of old age and/or coexisting disease. We therefore reviewed the efficacy and toxicity of radiation therapy for EMPD. PATIENTS AND METHODS: Fourteen patients with EMPD underwent definitive radiation therapy. Three patients had regional lymph node metastases before radiation therapy, but none had distant metastasis. Total doses of 52-80.2 Gy (median=60.6 Gy) were delivered to tumor sites in 26-43 fractions (median=33 fractions). RESULTS: Four patients had developed recurrence at a median follow-up period of 47 months. The 5-year local control and disease-free rates were 71% and 63%, respectively. Two patients died of old age and renal failure at 6 and 51 months, respectively, after irradiation. The 5-year disease-free, cause-specific and overall survival rates were 46%, 100% and 79%, respectively. No therapy-related toxicities of grade 3 or greater were observed. CONCLUSION: Radiation therapy is effective and safe, and appears to offer a curative treatment option for patients with EMPD.

Assessment of tumor hypoxia by 62Cu-ATSM PET/CT as a predictor of response in head and neck cancer: a pilot study.

OBJECTIVE: In radiotherapy and chemotherapy tumor hypoxia is recognized as a major obstacle to effective treatment. We undertook a pilot study in patients with locally advanced head and neck cancer to determine whether there is a relationship between tumor uptake of (62)Cu-ATSM and response to chemoradiotherapy. METHODS: Seventeen patients were studied using PET/CT with (62)Cu-ATSM and (18)F-FDG prior to the initiation of radiotherapy and chemotherapy. All patients had locally advanced head and neck cancer (stage III or IV). Tumor uptake in all patients was measured by region of interest analysis using the maximal standardized uptake value (SUVmax). A total dose of 50.4-70.2 Gy (median 70.2 Gy) was delivered in 29-39 fractions (median 39 fractions) to tumor. In patients with (non CR) and without (CR) residual/recurrent tumors at 2-year post irradiation, the statistical significance of the differences in tumor (62)Cu-ATSM SUVmax, T/M ratio, (18)F-FDG SUVmax and tumor volume were analyzed using Student's t test and Welch test. The relationship between clinical outcome and (62)Cu-ATSM/(18)F-FDG uptake patterns was analyzed using Kruskal-Wallis test. The correlation between SUVmax of (62)Cu-ATSM and (18)F-FDG was compared by Spearman's rank correlation test. RESULTS: Two of the 17 patients that were enrolled in our study were excluded from the final analysis. Of the 15 remaining patients, 9 patients were free of disease and 6 patients had residual/recurrent tumors. The SUVmax differed significantly (p < 0.05) between patients with or without residual/recurrent tumor on (62)Cu-ATSM PET/CT. Six of the 10 patients with tumors SUVmax >5.00 had residual/recurrent tumor, whereas all of the 5 patients with tumors SUVmax <5.00 were free of disease. There was no significant difference in FDG uptake between patients with and without residual/recurrent tumor. CONCLUSIONS: The results of this pilot study suggested that (62)Cu-ATSM uptake may be a predictive indicator of tumor response to chemoradiotherapy in patients with locally advanced head and neck cancer.

Role of radiotherapy as curative treatment of extramammary Paget's disease.

PURPOSE: Extramammary Paget's disease (EMPD) is a relatively rare malignancy that usually arises in the genital areas. Wide surgical excision remains the standard and most reliable curative treatment of EMPD. However, surgery is sometimes not possible, because many patients are elderly, and complete excision can be difficult owing to the tumor location. We, therefore, performed a review to determine the role of radiotherapy (RT) for EMPD. METHODS AND MATERIALS: A total of 22 patients with EMPD in their external genitalia (4 men and 18 women, age 52-94 years at RT) underwent RT with curative intent. Nine patients had regional lymph node metastases. A total dose of 45-70.2 Gy (median, 60) was delivered to the pelvis, including the tumors, in 25-39 fractions (median, 33). RESULTS: In all but 3 patients, the irradiated tumors were controlled during a follow-up period of 8-133 months (median, 42). Of the 22 patients, 13 developed recurrences, including local progression within the radiation field in 3 and lymph node and/or distant metastases outside the radiation field in 10, at 3-43 months after treatment. The 2- and 5-year local progression-free rates were 91% and 84%, respectively. Of the 22 patients, 7 patients had died at 33-73 months after RT. The cause of death was tumor progression in 4, infectious pneumonia in 2, and renal failure in 1 patient. The overall and cause-specific survival rates were 100% for both at 2 years and 53% and 73% at 5 years, respectively. No therapy-related Grade 3 or greater toxicity was observed. CONCLUSIONS: RT is safe and effective for patients with EMPD. It appears to contribute to prolonged survival as a result of good tumor control.

Treatment effects and sequelae of radiation therapy for orbital mucosa-associated lymphoid tissue lymphoma.

PURPOSE: Among extranodal lymphomas, orbital mucosa-associated lymphoid tissue (MALT) lymphoma is a relatively rare presentation. We performed a review to ascertain treatment efficacy and toxicity of radiation therapy for orbital MALT lymphoma. We also evaluated changes in visual acuity after irradiation. METHODS AND MATERIALS: Thirty patients with orbital MALT lymphoma underwent radiation therapy with curative intent. Clinical stages at diagnosis were stage IEA in 29 patients and stage IIEA in 1 patient. Total doses of 28.8 to 45.8 Gy (median, 30 Gy) in 15 to 26 fractions (median, 16 fractions) were delivered to the tumors. RESULTS: All irradiated tumors were controlled during the follow-up period of 2 to 157 months (median, 35 months) after treatment. Two patients had relapses that arose in the cervical lymph node and the ipsilateral palpebral conjunctiva outside the radiation field at 15 and 67 months after treatment, respectively. The 5-year local progression-free and relapse-free rates were 100% and 96%, respectively. All 30 patients are presently alive; the overall and relapse-free survival rates at 5 years were 100% and 96%, respectively. Although 5 patients developed cataracts of grade 2 at 8 to 45 months after irradiation, they underwent intraocular lens implantation, and their eyesight recovered. Additionally, there was no marked deterioration in the visual acuity of patients due to irradiation, with the exception of cataracts. No therapy-related toxicity of grade 3 or greater was observed. CONCLUSIONS: Radiation therapy was effective and safe for patients with orbital MALT lymphoma. Although some patients developed cataracts after irradiation, visual acuity was well preserved.