Preliminary results of a vaginal constraint for reducing G2 late vaginal complications after postoperative brachytherapy in endometrial cancer: a prospective analysis.

PURPOSE: To evaluate the preliminary results of the use of 68 Gy EQD2(α/ß=3 Gy) as a dose limit to the lowest dose in the most exposed 2 cm3 of the vagina in order to reduce G2 late vaginal problems in postoperative endometrial carcinoma (EC). METHODS: From November 2016 to October 2019, 69 postoperative EC patients receiving vaginal brachytherapy (VBT) ± external beam radiotherapy (EBRT) were prospectively analyzed. The median EBRT dose was 45 Gy (range: 44-50.4 Gy), 1.8-2 Gy/day, 5 fractions(Fr)/week. VBT was administered with the following schedule: 1Fr of 7 Gy after EBRT and 2 daily Fr × 7.5 Gy in exclusive VBT. The dose was prescribed at 0.5 cm from the applicator surface with an active length of 2.5 cm; 56 patients were treated with vaginal cylinders (49-3.5 cm, 6-3 cm, and 1-2.5 cm) and 13 with the colpostat technique. The overall VBT dose was adjusted to meet the vaginal restriction of < 68 Gy EQD2(α/ß=3 Gy) at 2 cm3. Late toxicity was prospectively assessed using RTOG scores for bladder and rectum, and the objective LENT-SOMA criteria for vagina. RESULTS: With a median follow-up of 31.0 months, no vaginal-cuff recurrences were found. Late toxicity: only 1G1(1.4%) rectal toxicity; 21G1(30.4%) and 3G2(4.3%) vaginal complications. Only one (1.4%) of 3 G2 manifested as vaginal shortening. CONCLUSIONS: In postoperative EC patients treated with VBT, only one developed G2 vaginal stenosis with the use of 68 Gy EQD2(α/ß=3 Gy) as a dose constraint. These preliminary results seem to indicate the value of this dose limit for reducing G2 vaginal stenosis. Nonetheless, these findings should be confirmed in a larger number of patients with longer follow-up.

Is one brachytherapy fraction of 7 Gy similar to more fractions after external beam irradiation in postoperative endometrial carcinoma?

PURPOSE: To determine whether brachytherapy with a single hypofractionated dose of 7 Gy provides the similar vaginal-cuff relapses and safety profile in terms of complications compared to schedules of 2 or 3 fractions of lower doses in patients treated previously with external beam irradiation in postoperative endometrial carcinoma. METHODS/MATERIAL: From June 2003 to December 2016, 325 patients were treated with 3 different schedules of high-dose-rate brachytherapy after external beam irradiation for postoperative endometrial carcinoma. The patients were divided into 3 groups: Group-1: 125 patients were treated with 3 fractions of 4-6 Gy per fraction (3 fractions/week) between 2003 and 2008; Group-2: 93 patients were treated with 2 consecutive daily fractions of 5-6 Gy between 2008 and 2011; Group-3: 107 patients received a single fraction of 7 Gy between 2011 and 2016. Bladder and rectum complications were assessed using RTOG scores and with the objective scores of LENT-SOMA for the vagina. STATISTICS: the chi-square test. RESULTS: The mean follow-up of Groups 1, 2 and 3 was 95, 67 and 51 months, respectively. Three patients in Group-1, 2 in Group-2, 1 in Group-3 developed vaginal-cuff relapse (p = 0.68). No differences were found in late toxicity among the three groups. CONCLUSIONS: One single dose of 7 Gy is safe and effective and may be the best treatment schedule with a similar incidence of vaginal-cuff relapses, complications and patient comfort with less hospital attendance.

Are endometrial cancer radiotherapy results age related?

OBJECTIVE: To analyze the impact of age on radiotherapy results based on cancer-specific survival (CSS), vaginal-cuff relapses (VCR) and complications analysis in 438 patients with endometrial carcinoma (EC) receiving postoperative radiotherapy (PRT) divided into three age groups for analysis. MATERIALS AND METHODS: From 2003 to 2015, 438 patients with EC were treated with PRT and divided into three age groups: Group-1: 202 patients < 65 years; Group-2: 210 patients ≥ 65 and < 80 years; Group-3: 26 patients ≥ 80 years. Vaginal toxicity was assessed using the objective LENT-SOMA criteria and RTOG scores were recorded for the rectum, bladder, and small bowel. STATISTICS: Chi square and Student's t tests, Kaplan-Meier survival study for analysis of CSS. RESULTS: The mean follow-up was 5.6 years in Group-1, 5.6 years in Group-2 and 6.3 years in Group-3 (p = 0.38). No differences were found among the groups in distribution of stage, grade, myometrial invasion, Type 1 vs. 2 EC and VLSI (p = 0.97, p = 0.52, p = 0.35, p = 0.48, p = 0.76, respectively). There were no differences in rectal, bladder and vagina late toxicity (p = 0.46, p = 0.17, p = 0.75, respectively). A better CSS at 5 years was found in Group-1 (p = 0.006), and significant differences were found in late severe small bowel toxicity in Group-3 (p = 0.005). VCR was increased in Group-3 (p = 0.017). CONCLUSIONS: Patients ≥ 65 years had a worse outcome in comparison to younger patients. Late vaginal, rectal and bladder toxicities were similar in the three groups, although an increase of severe late small bowel toxicity led to IMRT in patients ≥ 80 years. Further larger studies are needed including quality of life analysis in patients ≥ 80 years.

Vaginal-cuff control and toxicity results of a daily HDR brachytherapy schedule in endometrial cancer patients.

PURPOSE: To analyze the vaginal-cuff local control (VCC) and toxicity in postoperative endometrial carcinoma patients (EC) underwent high-dose-rate brachytherapy (HDR-BT) administered daily. MATERIALS AND METHODS: 154 consecutive patients received postoperative HDR-BT for EC from January 2007 to September 2011. FIGO-staging I-IIIC2 patients were divided into two groups according to risk classification: Group 1 (94/154) included high-risk or advanced disease patients and Group 2 (60/154) included intermediate-risk EC patients. Group 1 underwent external beam irradiation (EBI) plus HDR-BT (2 fractions of 5 Gy) and Group 2 underwent HDR-BT alone (4 fractions of 5 Gy). Toxicity evaluation was done with RTOG scores for bladder and rectum, and the objective criteria of LENT-SOMA for vagina. RESULTS: With a median follow-up of 46.7 months (36.6-61 months) only two patients developed vaginal-cuff recurrence in Group 1 (2.1 %) and none in group 2 (0 %). Early toxicity in Group 1 appeared 5.3 % in rectum, 7.5 % in bladder (G1-G2) and 2.1 % in vagina (G1); late toxicity was present in 7.3 % in rectum (all G1-G2 but 1 G3) and in 27.7 % in vagina (all G1-G2 but one G4). In Group 2, 6.7 % developed acute G1-G2 bladder and 6.6 % acute vaginal (G1-G2) toxicity. No late rectal or bladder toxicity was observed; 21.7 % of G1-G2 presented late problems in vagina. CONCLUSIONS: The present HDR-BT schedule of 2 fractions of 5 Gy after EBI and 4 fractions of 5 Gy administered daily showed excellent results in terms of VCC and toxicity.

Three or four fractions per week in postoperative high-dose-rate brachytherapy for endometrial carcinoma. The long-term results on vaginal relapses and toxicity.

BACKGROUND: High-dose-rate brachytherapy (HDR-BT) is an accepted part of treatment for endometrial carcinoma and is usually performed in 1-2 fractions per week using different total doses and doses per fraction. To reduce the overall treatment time, HDR-BT was administered with a 3-4 days/week schedule. PATIENTS AND METHODS: From June 2003 to December 2008, 164 patients with stage I-IIIc endometrial carcinoma were treated with HDR-BT (4-5 Gy per fraction). The patients were divided into two groups; Group 1 (40/164 patients) was treated with HDR-BT alone (6 fractions; 4 fractions/week) and Group 2 (124/164 patients) was treated with both (External Beam Radiotherapy [EBRT] + HDR-BT: 3 fractions/week). Complications were analyzed using RTOG scores for rectum and bladder and the objective scores of LENT-SOMA for vaginal complications. RESULTS: The mean followup was 48 months. In Group 1, 35 % of patients underwent treatment in ≤10 days and 65 % in >10 days. In Group 2, 53.2 % received treatment in ≤5 days and in 46.8 % in >5 days. Vaginal relapse was observed in only two patients (1.2 %), both having received adjuvant EBRT + HDR-BT. Acute vaginal toxicity appeared in 8.5 % and late vaginal toxicity in 20.7 % of patients with 13.4 % being G1, 6.7 % G2 and only 0.6 % being G4. No statistically significant differences were found in complications in either brachytherapy group regardless of the overall time. CONCLUSION: In our series, three fractions given in 3-5/days after EBRT or six fractions in 10 days, is a safe regimen in terms of complications and local control.

Microbial colonization of Ca-sulfate crusts in the hyperarid core of the Atacama Desert: implications for the search for life on Mars.

The scarcity of liquid water in the hyperarid core of the Atacama Desert makes this region one of the most challenging environments for life on Earth. The low numbers of microbial cells in the soils suggest that within the Atacama Desert lies the dry limit for life on our planet. Here, we show that the Ca-sulfate crusts of this hyperarid core are the habitats of lithobiontic micro-organisms. This microporous, translucent substrate is colonized by epilithic lichens, as well as endolithic free-living algae, fungal hyphae, cyanobacteria and non photosynthetic bacteria. We also report a novel type of endolithic community, "hypoendoliths", colonizing the undermost layer of the crusts. The colonization of gypsum crusts within the hyperarid core appears to be controlled by the moisture regime. Our data shows that the threshold for colonization is crossed within the dry core, with abundant colonization in gypsum crusts at one study site, while crusts at a drier site are virtually devoid of life. We show that the cumulative time in 1 year of relative humidity (RH) above 60% is the best parameter to explain the difference in colonization between both sites. This is supported by controlled humidity experiments, where we show that colonies of endolithic cyanobacteria in the Ca-sulfate crust undergo imbibition process at RH >60%. Assuming that life once arose on Mars, it is conceivable that Martian micro-organisms sought refuge in similar isolated evaporite microenvironments during their last struggle for life as their planet turned arid.

Microbial colonization of halite from the hyper-arid Atacama Desert studied by Raman spectroscopy.

The hyper-arid core of the Atacama Desert (Chile) is the driest place on Earth and is considered a close analogue to the extremely arid conditions on the surface of Mars. Microbial life is very rare in soils of this hyper-arid region, and autotrophic micro-organisms are virtually absent. Instead, photosynthetic micro-organisms have successfully colonized the interior of halite crusts, which are widespread in the Atacama Desert. These endoevaporitic colonies are an example of life that has adapted to the extreme dryness by colonizing the interior of rocks that provide enhanced moisture conditions. As such, these colonies represent a novel example of potential life on Mars. Here, we present non-destructive Raman spectroscopical identification of these colonies and their organic remnants. Spectral signatures revealed the presence of UV-protective biomolecules as well as light-harvesting pigments pointing to photosynthetic activity. Compounds of biogenic origin identified within these rocks differed depending on the origins of specimens from particular areas in the desert, with differing environmental conditions. Our results also demonstrate the capability of Raman spectroscopy to identify biomarkers within rocks that have a strong astrobiological potential.