Radiation Oncology Journal最新文献

Purpose: The safety of online contouring and planning for adaptive radiotherapy is unknown. This study aimed to evaluate the dosimetric difference of the organ-at-risk (OAR) according to the extent of contouring in stereotactic magnetic resonance image-guided adaptive RT (SMART) for pancreatic cancer.

Materials and methods: We reviewed the treatment plan data used for SMART in patients with pancreatic cancer. For the online contouring and planning, OARs within 2 cm from the planning target volume (PTV) in the craniocaudal direction were re-controlled daily at the attending physician's discretion. The entire OARs were re-contoured retrospectively for data analysis. We termed the two contouring methods the Rough OAR and the Full OAR, respectively. The proportion of dose constraint violation and other dosimetric parameters was analyzed.

Results: Nineteen patients with 94 fractions of SMART were included in the analysis. The dose constraint was violated in 10.6% and 43.6% of the fractions in Rough OAR and Full OAR methods, respectively (p = 0.075). Patients with a large tumor, a short distance from gross tumor volume (GTV) to OAR, and a tumor in the body or tail were associated with more occult dose constraint violations-large tumor (p = 0.027), short distance from GTV to OAR (p = 0.061), tumor in body or tail (p = 0.054). No dose constraint violation occurred outside 2 cm from the PTV.

Conclusion: More occult dose constraint violations can be found by the Full OAR method in patients with pancreatic cancer with some clinical factors in the online re-planning for SMART. Re-contouring all the OARs would be helpful to detect occult dose constraint violations in SMART planning. Since the dosimetric profile of SMART cannot be represented by a single fraction, patient selection for the Full OAR method should be weighted between the clinical usefulness and the time and workforce required.

Pigmented villonodular synovitis (PVNS) is a proliferative, recurrent and locally invasive disease of the synovium. The symptoms of the disorder are not typical and thus it is very often misdiagnosed. Most of the times, magnetic resonance imaging presents the nodular model of development and sets the basis for the diagnosis. The final diagnosis will be set by the pathological evaluation of the lesion's biopsy. PVNS may be localized (nodule with a clear boundary with/without presence of single pedicle) or diffuse (extensive involvement of the adjacent nerves and vessels). Depending on the extension of the PVNS, a different management approach is performed, lesion excision vs. resection, followed by radiotherapy respectively. We report a case of diffuse PVNS in the knee joint, treated with surgical excision and adjuvant radiotherapy as well as follow-up imaging after a time period of 3 years.

Purpose: Optimal radiotherapy treatment volumes for patients with locally advanced hypopharynx squamous cell carcinoma should ensure maximal tumor coverage with minimal inclusion of normal surrounding structures. Here we evaluated the effectiveness of a direct 3-mm high-dose gross tumor volume to planning target volume expansion on clinical outcomes for hypopharynx cancers.

Materials and methods: We performed a retrospective analysis of patients with hypopharynx carcinoma treated between 2004 and 2018 with primary radiotherapy using a direct high-dose gross tumor volume to planning target volume expansion and with or without concurrent systemic therapy. Diagnostic imaging of recurrences was co-registered with the planning CT. Spatial and volumetric analyses of contoured recurrences were compared with planned isodose lines. Failures were initially defined as in field, marginal, elective nodal, and out of field. Each failure was further classified as central high-dose, peripheral high-dose, central intermediate/low-dose, peripheral intermediate/low-dose, and extraneous. Clinical outcomes were analyzed by Kaplan-Meier estimation.

Results: Thirty-six patients were identified. At a median follow-up at 52.4 months, estimated 5-year overall survival was 59.3% (95% confidence interval [CI], 36.3%-74.1%), 5-year local and nodal control was 71.7% (95% CI, 47.1%-86.3%) and 69.9% (95% CI, 57.0%-82.6%), respectively. The most common failure was in the high-dose primary target volume. The gastrostomy tube retention rate at 1 year among patients without recurrence was 13.0% (95% CI, 3.2%-29.7%).

Conclusion: Minimal high-dose target volume expansions for hypopharynx cancers were associated with favorable locoregional control. This approach may enable therapy intensification to improve clinical outcomes.

Historical conventional fractionated radiation therapy (RT) for breast cancer consisted of 1.8-2.0 Gy per fraction with a total dose of 45-60 Gy over 5-7 weeks. Based on radiobiological characteristics, a low α/β is suspected of breast cancer resulting in sensitivity to higher dose per fraction (2.5-3.0 Gy). Over the past 10 years, multiple clinical trials support the application of shorter treatment regimen with hypofractionated RT (HypoRT). Recently, ultra-HypoRT with 5 fractions showed favorable outcomes. Although the safety and efficacy of HypoRT has been supported by high-quality randomized trials, there are still some worries and doubts around HypoRT from radiation oncologists. However, the radiation oncology community have now reached an important timepoint for adopting HypoRT during the COVID-19 pandemic. The aim of this review is to provide an overview of HypoRT in breast cancer based on prospective randomized trials and discuss the special consideration regarding HypoRT.

Purpose: Specific radiation delivered to tumors by stereotactic radiosurgery (SRS) has become widely used in the treatment of brain metastasis. This study aimed to compare radiation therapy planning and its parameters from SRS using three different modalities: helical tomotherapy (HT), volumetric modulated arc therapy (VMAT), and cone-based linac radiosurgery (Cone-based).

Materials and methods: Each contouring dataset of patents who experienced one to four brain metastasis received SRS in our center was re-planned to create radiation therapy planning in all three treatment systems (HT, VMAT, and Cone-based). The parameters of conformity index (CI), homogeneity index (HI), CI50, and gradient index (CGI) were analyzed to compare the effects of the three techniques. Decision score analysis was used to evaluate the performance on dosimetric and organs-at-risk parameters among the different techniques by applying the Cone-based technique as a benchmark.

Results: A total of 21 patients with 39 lesions were included in this study. The results from the decision score analysis demonstrated statistically identical CI, CI50, and CGI values between Cone-based and VMAT for single lesions. For multiple lesions, VMAT also provided better CI when compared to Cone-based technique while HT exhibited the poorest dosimetric parameters. Moreover, VMAT exhibited the lowest BrainV5Gy value and displayed the shortest beam-on time calculation.

Conclusion: We have conducted a comprehensive comparison of SRS planning approaches. The Cone-based technique revealed the highest HI value, while VMAT provided the best estimated beam-on time value. HT displayed a feasible SRS modality for single lesions, but not for multiple lesions.

Mucoepidermoid carcinoma (MEC) is most common malignancy of minor salivary glands in adults. Pulmonary MEC is extremely uncommon comprising of only 0.1%-0.2% of the primary lung malignancies and <1% of primary bronchial tumors. It is even rarer in children and literature limited to few case reports only. Here we present a case report of a 9-year-old boy diagnosed with primary MEC of trachea along with review of the literature. A 9-year-old male child presented with complaint of dry cough for two years which was later associated with shortness of breath after one year. Bronchoscopic examination revealed a growth arising from right lateral wall of carina occluding 50% of the lumen and detailed histopathological examination revealed it to be a MEC of the trachea. Patient underwent local excision of the tumor with primary anastomosis. In view of positive margins adjuvant radiotherapy of 60 Gy in 30 fractions were given to the tumor bed. Patient tolerated the treatment well and is disease free at 6 months follow-up. Experience with MEC of the trachea in children is limited and optimal treatment protocols have not been defined, with current treatment mainly extrapolated from MEC of the salivary glands.

Purpose: To compare biochemical recurrence-free survival (BRFS) and toxicity outcomes of high dose rate brachytherapy (HDRB) and stereotactic body radiotherapy (SBRT) boost after elective nodal irradiation for high/very high-risk prostate cancer.

Materials and methods: a retrospective analysis was performed in 149 male. In 98 patients, the boost to the prostate was delivered by HDRB as 2 fractions of 10 Gy (EQD2 for α/β = 1.5; 66 Gy) or 1 fraction of 15 Gy (EQD2 for α/β = 1.5; 71 Gy). In 51 male, SBRT was used for the boost delivery (3 fractions of 7 Gy; EQD2Gy for α/β = 1.5; 51 Gy) because brachytherapy equipment was out of order.

Results: In 98 patients that received HDRB boost, 3- and 5-year BRFS were 74.6% and 66.8%. Late grade-II genitourinary toxicity was detected in 27, grade-III in 1 case. Grade-II (maximum) rectal toxicity was diagnosed in nine patients. For 51 male patients that received SBRT boost, 3- and 5-year BRFS was 76.5% and 67.7%. Late grade-II (maximum) genitourinary toxicity was detected in five cases, late grade-II rectal toxicity in four cases. Other three patients developed late grade-III-IV rectal toxicity that required diverting colostomy. SBRT boost was associated with higher maximum dose to 2 cm3 of anterior rectal wall (D2cm³rectum) compared to HDRB: 92% versus 55% of dose to prostate. Severe rectal toxicity was negligible at EQD2 D2cm³rectum <85 Gy and EQD2 D5cm³ rectum <75 Gy.

Conclusion: Our results indicate similar 3- and 5-year BRFS in patients with high/very high-risk prostate cancer who received HDRB or SBRT boost, but SBRT boost is associated with higher rate of severe late rectal toxicity.

Purpose: Intracavitary brachytherapy is one of the important methods of gynecological cancer treatment. The effect of attenuation is not considered in the dose calculation method released by the American Association of Physicists in Medicine (AAPM) Task Group No. 43 Report (TG-43). In this study, the effect of high-dose rate (HDR) brachytherapy applicators on dose distribution was measured using Gafchromic films and well-type ionization chamber.

Materials and methods: A plan created by the treatment planning system was first executed using a well-type ionization chamber with a water equivalent elasto-gel in place for charge collection. Again, same plan was executed using central tandems of various angulations with different diameters of vaginal cylinders and charge collection was measured. For in vitro dose measurements this plan was also executed on tandem and vaginal cylinder assembly with Gafchromic films fixed on the surface of vaginal cylinder.

Results: The results show that the central tandem when used with different vaginal cylinders resulted in increase in effective attenuation of the beam. The central tandem of 300 angulations when used with a 35-mm diameter vaginal cylinder results in maximum attenuation whereas the 0º tandem when used with 20-mm diameter vaginal cylinder results in least attenuation of the beam.

Conclusion: Due to the attenuation by various applicators used in brachytherapy for the treatment of gynecological cancers, it can be concluded that the difference between practical dose and the treatment planning system calculated dose should be considered for the correct estimation of the dose to the target and the organs-at-risk.

Purpose: Ablative treatment of oligometastases has shown survival benefit with certain tumors, although these effects still are to be demonstrated in prostate cancer.

Materials and methods: We analysed the toxicity and clinical control results obtained in patients with bone-only oligometastatic prostate cancer treated with stereotactic ablative radiotherapy (SABR). Retrospective study on patients with metachronous oligoprogression and synchronous de novo bone-only oligometastatic prostate cancer treated with SABR and androgen deprivation therapy.

Results: Treatment schedules varied according to location and organs at risk, with biologically equivalent dose (BED) ≥100 Gy. Fifty-five bone lesions (31 patients) were treated and evaluated for toxicity, local control, progression-free survival (PFS), and overall survival (OS). After a 41-month follow-up, there was minimal acute or chronic toxicity and no G3 toxicity. The local control at 3 and 5 years was 100% and 87.1%, respectively. Median PFS and OS were 43 and 98 months, respectively. The best result in PFS was obtained with BED ≥230 Gy, delaying time to the next systemic therapy by 28.5 months.

Conclusion: The use of SABR in bone oligometastases of prostate cancer is safe with minimal toxicity and excellent results in local control and PFS, delaying the start of the next systemic therapy.