Stereotactic radiation therapy in oligometastatic colorectal cancer: outcome of 102 patients and 150 lesions.

To evaluate the local control (LC), progression free survival (PFS), out-field PFS, overall survival (OS), toxicity and failure predictors of SRT in a series of various sites oligometastatic CRC patients. Patients with oligometastatic CRC disease were analyzed retrospectively. The SRT prescribed dose was dependent on the lesion volume and its location. 102 consecutive oligometastatic CRC patients (150 lesions) were included. They underwent SRT between 2012 and 2015. Median prescription dose was 45 Gy (median dose/fraction was 15 Gy/3 fractions biological equivalent dose (BED10) 112.5 Gy). Median follow-up was 11.4 months. No patients experienced G3 and G4 toxicity. No progression was found in 82% (radiological response at 3 months) and 85% (best radiological response) out of 150 evaluable lesions. At 1 and 2 years: LC was 70% and 55%; OS was 90% and 90%; PFS was 37% and 27%; out-field PFS was 37% and 23% respectively. Progressive disease was correlated with BED10 (better LC when BED10 was ≥ 75 Gy (p < 0.0001)). In multivariate analysis, LC was higher in lesions with a Plpnning target volume (PTV) volume < 42 cm3 and BED10 ≥ 75 Gy. Patients with Karnofsky performance status < 90 showed higher out-field progression. SRT is an effective treatment for patients with oligometastases from CRC. Its low treatment-associated morbidity and acceptable LC make of SRT an option not only in selected cases. Further studies should be focused to clarify which patient subgroup will benefit most from this treatment modality and to define the optimal dose to improve LC while maintaining low toxicity profile.

Ablative stereotactic radiotherapy for oligometastatic colorectal cancer: Systematic review.

BACKGROUND: SBRT is a novel modality in treatment for oligometastatic colorectal cancer. We aimed to perform a systematic review of results of SBRT in maintaining LC (local control) for CRC liver and lung oligometastases. MATERIALS AND METHODS: The review was performed according to PRISMA and PICO guidelines. Database search using keywords: stereotactic, colon, colorectal, cancer, sbrt, sabr returned 457 results. 15 were included in the study. Only cohorts with CRC histology and reported LC were included. RESULTS: For liver LC rates ranged from 50% to 100% after 1 year and 32% to 91% after 2 years. BED range 40.5-262.5 Gy (Gray). For lung LC rates ranged from 62% to 92% after 1 one year and from 53% to 92% after 2 years. BED range 51.3-262.5 Gy. CONCLUSIONS: SBRT of oligometastatic CRC offers high LC with low morbidity and toxicity. It requires more observational studies and randomized trials but available data on clinical efficacy is promising, however not yet matured.

Genital marginal failures after intensity-modulated radiation therapy (IMRT) in squamous cell anal cancer: no higher risk with IMRT when compared to 3DCRT.

Intensity-modulated radiotherapy (IMRT) is considered the preferred option in squamous cell canal cancer (SCAC), delivering high doses to tumor volumes while minimizing dose to surrounding normal tissues. IMRT has steep dose gradients, but the technique is more demanding as deep understanding of target structures is required. To evaluate genital marginal failure in a cohort of patients with non-metastatic SCAC treated either with IMRT or 3DCRT and concurrent chemotherapy, 117 patients with SCAC were evaluated: 64 and 53 patients were treated with IMRT and 3DCRT techniques, respectively. All patients underwent clinical and radiological examination during their follow-up. Tumor response was evaluated with response evaluation criteria in solid tumors v1.1 guideline on regular basis. All patients' data were analyzed, and patients with marginal failure were identified. Concomitant chemotherapy was administered in 97 and 77.4% of patients in the IMRT and 3DCRT groups, respectively. In the IMRT group, the median follow-up was 25 months (range 6-78). Progressive disease was registered in 15.6% of patients; infield recurrence, distant recurrence and both infield recurrence and distant recurrence were identified in 5, 4 and 1 patient, respectively. Two out of 64 patients (3.1%) had marginal failures, localized at vagina/recto-vaginal septum and left perineal region. In the 3DCRT group, the median follow-up was 71.3 months (range 6-194 months). Two out of 53 patients (3.8%) had marginal failures, localized at recto-vaginal septum and perigenital structures. The rate of marginal failures was comparable in IMRT and 3DCRT groups (χ2 test p = 0.85). In this series, the use of IMRT for the treatment of SCAC did not increase the rate of marginal failures offering improved dose conformity to the target. Dose constraints should be applied with caution-particularly in females with involvement of the vagina or the vaginal septum.