Deep inspiration breath-hold intensity modulated radiation therapy in a large clinical series of 239 left-sided breast cancer patients: a dosimetric analysis of organs at risk doses and clinical feasibility from a single center experience.

OBJECTIVE: To evaluate dose to organs at risk, target coverage and treatment compliance in left-sided breast cancer patients (LSBCP) treated with deep inspiration breath-hold (DIBH) and intensity modulated radiation therapy (IMRT) technique in a contest of daily clinical practice. METHODS: A total of 280 consecutive LSBCP referred for adjuvant radiotherapy were systematically screened for suitability of DIBH technique. 239 were able to comply with the requirement for DIBH. Whole breast or chest wall were irradiated in DIBH, monitored by Varian RPM™ Respiratory Gating System, and two tangential inverse-planned beams with dynamic dose delivery. Dose prescription was 42.4 Gy/16 fractions in 205 patients and 50 Gy/25 fractions in 34. 23 patients received local and nodal treatment. Boost to tumor bed, of 10 Gy/5 fractions was used in 135 patients. Relevant dose metrics for heart, left anterior descending (LAD) coronary artery, lungs, contralateral breast and planning target volume were retrospectively analyzed. RESULTS: The average mean heart dose (MHD) for all patients was 0.94 Gy and mean maximum LAD dose was 13.82 Gy. MHD and LAD maximum dose were significantly higher in patients treated with conventional fractionation whether expressed in absolute dose (1.44 vs 0.85 Gy, p < 0.0005 and 20.78 vs 12.45 Gy, p < 0.0005 respectively) or in equivalent doses of 2 Gy fractionation (0.88 vs 0.52 Gy, p =< 0.0005 and 17.68 vs 10.63 Gy, p = 0.0002 respectively). In 57 patients (23.8%) the maximum LAD dose was >20 Gy. Mean V20 ipsilateral lung dose was 8.5%. Mean doses of contralateral breast and lung were 0.13 Gy and 0.09 Gy respectively. Mean planning target volume V95% coverage was 96.1%. Compliance rate of DIBH technique was 84.5% (239/280). CONCLUSION: DIBH and IMRT in daily clinical practice are feasible in high percentage of unselected patients and allows low levels of irradiation of organs at risk without compromising target coverage. However, despite low MHD a significant proportion of patients receives a maximum LAD dose superior to 20 Gy. ADVANCES IN KNOWLEDGE: The value of MHD used exclusively is not able to describe entirely the risk of late heart toxicity, which can be better evaluated with the joint analysis of the maximum dose to LAD region. The vast majority of LSBCP referred to adjuvant radiotherapy in the setting of routine practice are able to comply with the requirement of DIBH.

Pediatric craniospinal irradiation with conventional technique or helical tomotherapy: impact of age and body volume on integral dose.

PURPOSE: The use of helical tomotherapy (HT) for craniospinal irradiation (CSI) in pediatric patients remains an issue of discussion. In this study, we evaluated the integral dose (ID) to organs at risk (OARs) and to the whole body delivered with conventional 3-dimensional conformal radiotherapy (3D-CRT) and HT for pediatric patients and made a comparison according to different whole body volumes. METHODS: We selected 10 pediatric patients with different body volumes and of different ages undergoing CSI. Plans for 3D-CRT and HT were developed for each patient. The ID to OARs and to the whole body were compared and statistical analyses were performed to determine differences. RESULTS: We noticed that variations of ID depend on the different anatomical location of the organs relatively to the target, with lower ID to OARs opposed to the target and increased ID to lateral organs: ID tomotherapy/3D-CRT ratio was higher in lungs, kidneys, and mammary region, while it was lower in heart, liver, thyroid, and esophagus. The ID of the body increased with large volumes both in HT and in 3D-CRT plans, but in tomotherapy plans ID increased significantly more with large volumes than with small ones. CONCLUSIONS: While there are no differences in using tomotherapy or 3D-CRT with small body volumes, we found a difference with large volumes (≥20,000 mL vs ≤20,000 mL). Therefore, for very small patients, the use of intensity-modulated radiotherapy provided with tomotherapy to reduce the dose to OARs can be reconsidered.

Image guided hypofractionated radiotherapy by helical tomotherapy for prostate carcinoma: toxicity and impact on Nadir PSA.

AIM: To evaluate the toxicity of a hypofractionated schedule for primary radiotherapy (RT) of prostate cancer as well as the value of the nadir PSA (nPSA) and time to nadir PSA (tnPSA) as surrogate efficacy of treatment. MATERIAL AND METHODS: Eighty patients underwent hypofractionated schedule by Helical Tomotherapy (HT). A dose of 70.2 Gy was administered in 27 daily fractions of 2.6 Gy. Acute and late toxicities were graded on the RTOG/EORTC scales. The nPSA and the tnPSA for patients treated with exclusive RT were compared to an equal cohort of 20 patients treated with conventional fractionation and standard conformal radiotherapy. RESULTS: Most of patients (83%) did not develop acute gastrointestinal (GI) toxicity and 50% did not present genitourinary (GU) toxicity. After a median follow-up of 36 months only grade 1 of GU and GI was reported in 6 and 3 patients as late toxicity. Average tnPSA was 30 months. The median value of nPSA after exclusive RT with HT was 0.28 ng/mL and was significantly lower than the median nPSA (0.67 ng/mL) of the conventionally treated cohort (P = 0.02). CONCLUSIONS: Hypofractionated RT schedule with HT for prostate cancer treatment reports very low toxicity and reaches a low level of nPSA that might correlate with good outcomes.

Focus on the actual clinical target volume irradiated with intraoperative radiotherapy for breast cancer.

AIM: Intraoperative radiotherapy (IORT) has been investigated as an exclusive adjuvant treatment option for early-stage breast cancer (BC). We analysed our experience on the technical aspects of this innovative approach in terms of identification of breast volume actually to be treated during IORT. PATIENTS AND METHODS: A total of 315 patients at low risk of breast cancer recurrence underwent IORT as exclusive treatment after breast-conservative surgery. To evaluate the breast volume actually irradiated with IORT, we considered a sample of eight patients, chosen retrospectively as having enough clips to identify the tumour bed and IORT site in computed-tomography (CT). The clinical target volume (CTV) was assessed for each patient with two different methods: the first, cc-IORT, was considered during surgery according to the chosen collimator diameter and glandular thickness, while the second, cc-CT, was evaluated through computed-tomography performed after surgery. The cc-CT CTV was obtained by contouring the cc-IORT on the CT section on the basis of the clips placed by the surgeon on the resection margins. RESULTS: In our experience, the 5-cm (50%) and the 6-cm (36%) diameter collimators have been the ones, used the most. The diameter of the collimator used did not appear to adversely affect the satisfactory aesthetic result. The comparison between CTVs showed that glandular breast volume contoured with CT (cc-CT) appeared to be three fold larger than the target identified at surgery and included in the area of chosen collimator (cc-IORT). CONCLUSION: The actual volume of breast gland irradiated with the IORT procedure appears to be larger than expected. This may be due to the area being prepared for IORT by placing tissue compactly.