Neoadjuvant radio- or chemoradiation (nIRT) therapy is the standard treatment for loco-regional advanced rectal cancer patients of the lower or middle third. Currently, intensity modulated radiation therapy (IMRT) is not the recommended radiation technique even though IMRT has advantages compared to 3D-radiation regarding dose sparing to organs at risk like small bowel and urinary bladder. So far, the benefit of IMRT concerning the anal sphincter complex is not examined. With this study we intended to evaluate the dose distribution on the anal sphincters of rectal cancer patients treated with IMRT in comparison with 3D-techniques. We selected 16 patients for the IMRT-group and 16 patients for the 3D-group with rectal cancer of the middle third who were treated in our institute. All patients received 45 Gy in a chemoradiation protocol. Patients in both groups were matched regarding stage, primary tumor distance to the anal verge and size of the tumor. We delineated the internal and external anal sphincters, the addition of both sphincters and the levator ani muscle in all patients. Subsequently, we evaluated and compared dose parameters of the different sphincters in both groups and analysed the configuration of the isodoses in the area of the caudal radiation field, respectively. Most of the relevant dose parameters of the caudal sphincters (Dmean, Dmedian, V10–V40) were significantly reduced in the IMRT-group compared to the 3D-group. Accordingly, the isodoses at the caudal edge of the target volume in the IMRT group demonstrated a steep dose fall. The levator ani muscle always was included into the planned target volumes and received the full dose in both groups. The modern VMAT-IMRT can significantly reduce the dose to the anal sphincters for rectal cancer patients of the middle third who were treated with conventional chemoradiation therapy.

There are different contouring guidelines for the clinical target volume (CTV) in anal cancer (AC) which vary concerning recommendations for radiation margins in different anatomical regions, especially on inguinal site. PET imaging has become more important in primary staging of AC as a very sensitive method to detect lymph node (LN) metastases. Using PET imaging, we evaluated patterns of LN spread, and examined the differences of the respective contouring guidelines on the basis of our results. We carried out a retrospective study of thirty-seven AC patients treated with chemoradiation (CRT) who underwent FDG-PET imaging for primary staging in our department between 2011 and 2018. Patients showing PET positive LN were included in this analysis. Using a color code, LN metastases of all patients were delineated on a template with “standard anatomy” and were divided indicating whether their location was in- or out-field of the standard CTV as recommended by the Radiation Therapy Oncology Group (RTOG), the Australasian Gastrointestinal Trials Group (AGITG) or the British National Guidance (BNG). Furthermore, a detailed analysis of the location of LN of the inguinal region was performed. Twenty-two out of thirty-seven AC patients with pre-treatment PET imaging had PET positive LN metastases, accumulating to a total of 154 LN. The most commonly affected anatomical region was inguinal (49 LN, 32%). All para-rectal, external/internal iliac, and pre-sacral LN were covered by the recommended CTVs of the three different guidelines. Of forty-nine involved inguinal LN, fourteen (29%), seven (14%) and five (10%) were situated outside of the recommended CTVs by RTOG, AGITG and BNG. Inguinal LN could be located up to 5.7 cm inferiorly to the femoral saphenous junction and 2.8 cm medial or laterally to the big femoral vessels. Pelvis-related, various recommendations are largely consistent, and all LN are covered by the recommended CTVs. LN “misses” appear generally cranially (common iliac or para-aortic) or caudally (inguinal) to the recommended CTVs. The established guidelines differ significantly, particular regarding the inguinal region. Based on our results, we presented our suggestions for CTV definition of the inguinal region. LN involvement of a larger number of patients should be investigated to enable final recommendations.

Introduction: Major national and international oncological societies generally recommend treating a significant proportion of oncological patients in clinical trials to improve therapy strategies for cancer patients. At cancer centers, the recommendation about the appropriate therapy for the individual tumor patient is usually made in interdisciplinary case discussions in multidisciplinary tumor boards (MDT). In this study, we examined the impact of MDTs for the inclusion of patients in therapy trials. Methodology: A prospective, explorative study of the Comprehensive Cancer Center Munich (CCCM) was conducted at both university hospitals in 2019. In the first phase, various MDTs’ case discussions about oncological situations and their decisions regarding possible therapy trials were recorded in a structured manner. In the second phase, the actual inclusion rates of patients in therapy trials and reasons for non-inclusion were examined. Finally, the data of the respective university hospitals were anonymized, pooled and analyzed. Results: A total of 1797 case discussions were reviewed. Therapy recommendations were made in 1527 case presentations. 38 (2.5%) of 1527 patients were already included in a therapy trial at the time of case presentation. The MDTs recommended inclusion of an additional 107 cases (7%), for a therapy trial. Of these patients, 41 were finally enrolled in a therapy trial which resulted in a total recruitment rate of 5.2%. Despite MDTs’ recommendations, 66 patients were not included in a therapy trial. The main reason for non-inclusion was insufficient inclusion or existing exclusion criteria (n = 18, 28%). In 48% of all cases (n = 31), the reason for non-inclusion could not be determined. Conclusion: The potential of MDTs as an instrument for the inclusion of patients in therapy trials is high. To increase the enrollment of patients in oncological therapy trials, structural measures such as the central use of trial administration and MTB software in addition to standardized tumor board discussions must be established to ensure a seamless flow of information about actual recruiting trials and the current status of trial participation of patients.

The cranial border of the target volume (TV) in rectal cancer patients treated with neoadjuvant chemoradiation (nCRT) is mostly defined at the level of L5/S1. However, current studies have shown that relapse cranially of the target volume after neoadjuvant nCRT and surgery is very rare. A reduction of cranial TV margins could be reasonable to reduce toxicity to the organs at risk (OAR). In this study we compared the dose distribution to the OAR for different cranial longitudinal margins using a dose-volume histogram (DVH) analysis. Ten patients with loco regional advanced rectal cancer were analysed retrospectively. All patients were planned for Volumetric Arc Therapy Radiation Therapy (VMAT). Next to the original PTV (PTV0), three new planning target volumes (PTV) were defined for each patient: The PTV0 reduced by 1 cm, 2 cm and 3 cm on cranial extension. For each PTV a treatment plan with a total dose of 50.4 Gy with daily doses of 1.8 Gy was calculated. Dose to the OAR were evaluated and compared. For the bone marrow, the small bowel and the peritoneal space all clinically relevant relative dose parameters (V10-V50) as well as the Dmedian could be significantly reduced with every cranial target volume reduction of 1 cm. For V10 of the peritoneal space the dose could be nearly halved with a 3 cm shortened TV. After TV reduction of 3 cm also for the urinary bladder a significant dose reduction of the Dmedian could be achieved. Considering the very low recurrence rates in the TME and IMRT era, the distribution patterns of these relapses as well as the relevant side effects of nCRT, we would agree with existing recommendations of reduction of the cranial target volume in nCRT treated rectal cancer patients.

Background: Soft tissue sarcomas (STS) are a relatively rare group of malignant tumors. Currently, there is very little published clinical data, especially in the context of curative multimodal therapy with image-guided, conformal, intensity-modulated radiotherapy. Methods: Patients who received preoperative or postoperative intensity-modulated radiotherapy for STS of the extremities or trunk with curative intent were included in this single centre retrospective analysis. A Kaplan–Meier analysis was performed to evaluate survival endpoints. Multivariable proportional hazard models were used to investigate the association between survival endpoints and tumour-, patient-, and treatment-specific characteristics. Results: 86 patients were included in the analysis. The most common histological subtypes were undifferentiated pleomorphic high-grade sarcoma (UPS) (27) and liposarcoma (22). More than two third of the patients received preoperative radiation therapy (72%). During the follow-up period, 39 patients (45%) suffered from some type of relapse, mainly remote (31%). The two-years overall survival rate was 88%. The median DFS was 48 months and the median DMFS was 51 months. Female gender (HR 0.460 (0.217; 0.973)) and histology of liposarcomas compared to UPS proved to be significantly more favorable in terms of DFS (HR 0.327 (0.126; 0.852)). Conclusion: Conformal, intensity-modulated radiotherapy is an effective treatment modality in the preoperative or postoperative management of STS. Especially for the prevention of distant metastases, the establishment of modern systemic therapies or multimodal therapy approaches is necessary.

Background: There are different contouring guidelines for definition of the clinical target volume (CTV) for intensity-modulated radiation therapy (IMRT) of anal cancer (AC). We conducted a planning comparison study to evaluate and compare the dose to relevant organs at risk (OARs) while using different CTV definitions. Methods: Twelve patients with a primary diagnosis of anal cancer, who were treated with primary chemoradiation (CRT), were selected. We generated four guideline-specific CTVs and subsequently planned target volumes (PTVs) on the planning CT scan of each patient. An IMRT plan for volumetric arc therapy (VMAT) was set up for each PTV. Dose parameters of the planned target volume (PTV) and OARs were evaluated and compared, too. Results: The mean volume of the four PTVs ranged from 2138 cc to 2433 cc. The target volumes contoured by the authors based on the recommendations of each group were similar in the pelvis, while they differed significantly in the inguinal region. There were no significant differences between the four target volumes with regard to the dose parameters of the cranially located OARs. Conversely, some dose parameters concerning the genitals and the skin varied significantly among the different guidelines. Conclusion: The four contouring guidelines differ significantly concerning the inguinal region. In order to avoid inguinal recurrence and to protect relevant OARs, further investigations are needed to generate uniform standards for definition of the elective clinical target volume in the inguinal region.