Definitive high-dose, proton-based radiation for unresected mobile spine and sacral chordomas.

BACKGROUND/PURPOSE: Treatment of spine and sacral chordoma generally involves surgical resection, usually in conjunction with radiation therapy.In certain locations, resection may result in significant neurological dysfunction, so definitive radiation has been used as an alternative to surgery. The purpose of this study is to report the results of high-dose, proton-based definitive radiotherapy for unresected spinal and sacral chordomas. MATERIALS/METHODS: Retrospective review of 67 patients with newly diagnosed, unresected spinal chordomas treated with high-dose definitive, proton-based radiotherapy at our center from 1975 to 2019. RESULTS: Reasons for radiotherapy alone included medical inoperability and/or concern for neurological dysfunction based on spine level or patient choice. Tumor locations included cervical (n = 10), thoracic (n = 1), lumbar (n = 4) spine, and sacrum (n = 52). Median maximal tumor diameter was 7.4 cm (range 1.8-25 cm). Median total dose was 77.4 Gy (RBE) (range 73.8-85.9 Gy RBE). Analysis with median follow-up of 56.2 months (range, 4-171.7 months) showed overall survival of 83.5 % (95%CI: 69.4-91.5%) and 65.9% (95%CI: 47.3-79.3%), disease-free survival of 64% (95%CI: 49.3-75.4) and 44.1% (95%CI: 27.8-59.2%), local control of 81.8% (95%CI: 67.6-90.2%) and 63.6% (95%CI: 44.7-77.5%), and distant control of 77.4% (95%CI: 63.6-86.5%) and 72.5% (95%CI: 55.7-83.8%) at 5 and 8 years respectively. The most common late side effect was insufficiency fracture. CONCLUSION: These results continue to support the use of high-dose definitive radiotherapy for patients with medically inoperable or otherwise unresected mobile spine or sacrococcygeal chordomas. There is a trend towards better disease-free survival with doses > 78 Gy (RBE).

Rectal dose-sparing effect with bioabsorbable spacer placement in carbon ion radiotherapy for sacral chordoma: dosimetric comparison of a simulation study.

It is difficult to treat patients with an inoperable sarcoma adjacent to the gastrointestinal (GI) tract using carbon ion radiotherapy (C-ion RT), owing to the possible development of serious GI toxicities. In such cases, spacer placement may be useful in physically separating the tumor and the GI tract. We aimed to evaluate the usefulness of spacer placement by conducting a simulation study of dosimetric comparison in a patient with sacral chordoma adjacent to the rectum treated with C-ion RT. The sacral chordoma was located in the third to fourth sacral spinal segments, in extensive contact with and compressing the rectum. Conventional C-ion RT was not indicated because the rectal dose would exceed the tolerance dose. Because we chose spacer placement surgery to physically separate the tumor and the rectum before C-ion RT, bioabsorbable spacer sheets were inserted by open surgery. After spacer placement, 67.2 Gy [relative biological effectiveness (RBE)] of C-ion RT was administered. The thickness of the spacer was stable at 13-14 mm during C-ion RT. Comparing the dose-volume histogram (DVH) parameters, Dmax for the rectum was reduced from 67 Gy (RBE) in the no spacer plan (simulation plan) to 45 Gy (RBE) in the spacer placement plan (actual plan) when a prescribed dose was administered to the tumor. Spacer placement was advantageous for irradiating the tumor and the rectum, demonstrated using the DVH parameter analysis.

An easy way to determine bone mineral density and predict pelvic insufficiency fractures in patients treated with radiotherapy for cervical cancer.

PURPOSE: The aim of this study was to investigate whether bone mineral density (BMD) as measured in planning computed tomographies (CTs) by a new method is a risk factor for pelvic insufficiency fractures (PIF) after radio(chemo)therapy (R(C)T) for cervical cancer. METHODS: 62 patients with cervical cancer who received definitive or adjuvant radio(chemo)therapy between 2013 and 2017 were reviewed. The PIF were detected on follow-up magntic resonance imaging (MRI). The MRI of the PIF patients was registered to the planning CT and the PIF contoured. On the contralateral side of the fracture, a mirrored structure of the fracture was generated (mPIF). For the whole sacral bone, three lumbar vertebrae, the first and second sacral vertebrae, and the PIF, we analyzed the BMD (mg/cm3), V50Gy, Dmean, and Dmax. RESULTS: Out of 62 patients, 6 (9.7%) had a fracture. Two out of the 6 patients had a bilateral fracture with only one of them being symptomatic. PIF patients showed a significantly lower BMD in the sacral and the lumbar vertebrae (p < 0.05). The BMD of the contoured PIF, however, when comparing to the mPIF, did not reach significance (p < 0.49). The difference of the V50Gy of the sacrum in the PIF group compared to the other (OTH) patients, i.e. those without PIF, did not reach significance. CONCLUSION: The dose does not seem to have a relevant impact on the incidence of PIF in our patients. One of the predisposing factors for developing PIF after radiotherapy seems to be the low BMD. We presented an easy method to assess the BMD in planning CTs.

Palliative Irradiation of Sacral Metastases: Must the Entire Bone Be Treated?

BACKGROUND AND PURPOSE: The sacrum as radiation target, raises a conceptual question: should the structure be regarded as a single unit or 5 distinct bones. If the entire sacrum must be irradiated there is a higher risk of rectal morbidity. MATERIALS AND METHODS: Images of 53 patients with sacral metastases were reviewed. The extent of sacral involvement was documented. The location of the rectum was recorded relative to the individual sacral bones. RESULTS: In 37.7% only S1 and S2 were involved by metastatic disease. In 41.5% there was metastatic involvement of S1-S3. In 1 patient there was involvement of S5 only. In 10 cases the entire sacrum was infested by metastatic disease. The rectum never extended to the height of S1. In 38% the upper pole of the rectum reached the S3 level. In toto, there were 64.2% where the inferior extension of sacral metastatic involvement did not overlap the upper pole of the rectum. Palliation of pain was achieved in 19/20 patients treated with partial sacral irradiation. CONCLUSIONS: The distal part of the sacrum is rarely involved in the metastatic process. Avoidance of radiation therapy to the lower sacrum simultaneously enables effective palliation and sparing of the adjacent rectum.

Radiation-Induced Insufficiency Fractures After Pelvic Irradiation for Gynecologic Malignancies: A Systematic Review.

PURPOSE: To identify and define the incidence, risk factors, clinical characteristics, and treatment approaches to pelvic insufficiency fractures (PIFs) that develop as a consequence of pelvic radiation therapy for gynecologic malignancies. MATERIALS AND METHODS: A systematic literature review (PubMed and Embase indexed from January 1, 1980, to May 1, 2020) of studies describing PIFs that result from radiation therapy for gynecologic malignancies. A random-effects model weighted by the inverse variance was used to calculate the pooled crude incidence, actuarial incidence, and proportion of symptomatic PIFs, and to evaluate the relationship between PIF incidence and various risk factors. RESULTS: Thirty-eight studies describing PIFs following radiation therapy for gynecologic malignancies were reviewed. A meta-analysis of 6488 patients (37 studies) identified the crude incidence of PIF as 9.4% (95% confidence interval [CI] 6.8%-12.4%), and a meta-analysis of 2131 patients (9 studies) identified the 5-year actuarial incidence of PIF as 15.3% (95% CI 7.5%-25.0%). Factors that significantly correlated with increased risk of PIF development included evidence of osteoporosis (P < .001), postmenopausal state (P < .001), and history of diabetes mellitus (P = .005). Median time to PIF development ranged from 8 to 39 months after radiation therapy with the sacrum being the most frequent location for fracture development (60%). From 18 studies, 58.5% (95% CI 50.6%-66.2%) of PIFs were symptomatic, with pain as the most common presenting symptom of PIFs. Conservative management was used more than bone-directed therapies for treatment of PIFs (85% and 6% of patients, respectively). CONCLUSIONS: PIFs cause significant morbidity in gynecologic cancer patients after radiation therapy. In this systematic review, we discuss the incidence and risk factors associated with PIF development as it relates to the different detection methods, radiation techniques, doses, and gynecologic cancers treated. Additional studies are needed to further define prevention and treatment approaches for insufficiency fractures.

BILATERAL AVASCULAR NECROSIS OF SACRAL LATERAL MASSES AFTER A COMPLETE RADIOLOGICAL RESPONSE OF LOCALLY ADVANCED RECTAL CANCER TREATED WITH NEOADJUVANT CHEMORADIATION THERAPY. CASE REPORT. / BILATERAL'NYY̆ AVASKULIaRNYY̆ NEKROZ LATERAL'NYKh MAS KRYZhIV PRY POVNOMU KLINIKO-RADIOLOGIChNOMU REGRESI PISLIa NEOAD'IuVANTNOÏ KhIMIOPROMENEVOÏ TERAPIÏ MISTsEVO POShYRENOGO DYSTAL'NOGO RAKU PRIaMOÏ KYShKY. KLINIChNYY̆ VYPADOK.

We present a rare case report of a bilateral avascular necrosis of lateral sacral masses in a patient who developed a sustainable complete clinical and radiological response after chemoradiotherapy for locally advanced rectal cancer. It is shown that despite the standardized and precise planning and fractioning for neoadjuvant chemoradiation therapy for locally advanced rectal cancer, the biological effects of ionizing radiation on critical organs can be va- ried both in time of occurrence and in structure. Evaluating the effect of neoadjuvant chemoradiation therapy, one should take into account the possibility of the development of even very rare effects of ionizing radiation on criti- cal organs and include their early detection in the diagnostic algorithm.

Investigation of differences of sacral and vertebral bone mineral densities before and after radiotherapy in patients with locally advanced rectal cancer.

PURPOSE: Radiotherapy is a treatment method performed using ionizing radiation on cancer patients either alone or with surgery and/or chemotherapy. Although modern radiotherapy techniques provide a significant advantage in protecting healthy tissues, it is inevitable that normal tissues are also located in the areas targeted by radiations. In this study, we aimed to examine the bone mineral density changes in bone structures commonly included in the irradiated area such as, L5 vertebra, sacrum, and femur heads, in patients who have received pelvic radiotherapy; and the relationship between these changes with radiation dose. MATERIAL AND METHODS: Patients included in the study had been previously diagnosed with rectal cancer, which were operated or not. Preoperative or postoperative pelvic radiotherapy was planned for all patients. In terms of convenience when comparing with future scans, all densitometry and CT scans were performed with the same devices. Fifteen patients were included in the study. In order to determine the dose of radiation each identified area had taken after radiotherapy, the sacrum, L5 vertebra, bilateral femoral heads, and L1 regions were contoured in the CT scans in which treatment planning was done. Sagittal cross-sectional images were taken advantage of while these regions were being contoured. RESULTS: Bone mineral density was evaluated with CT and dual-energy X-ray absorptiometry before and after the treatment. The regions that have theoretically been exposed to irradiation, such as L5, sacrum, left to right femur were found to have significant difference in terms of bone density. According to CT evaluation, there was a significant decrease in bone intensity of L5, sacrum, left and right femurs. Dual-energy X-ray absorptiometry assessment revealed that the whole of the left femoral head, left femur neck and Ward's region were significantly affected by radiotherapy. However, there was no significant difference in the sacrum and L5 vertebra before and after radiotherapy. CONCLUSION: More accurate results could be achieved if the same study was conducted on a larger patient population, with a longer follow-up period. When the reduction in bone density is at maximum or a cure is likely in a long-term period, bone mineral density could be determined by measurements performed at regular intervals.

Dose optimization strategy of sacrum limitation in cervical cancer intensity modulation radiation therapy planning.

The aim of this study was to investigate the dose optimization strategy for the sacrum to reduce the risk of pelvic insufficiency fracture (PIF).Using a retrospective study design, we analyzed data from 28 patients with cervical cancer who underwent postoperative adjuvant radiotherapy in our department from June 2017 to January 2018. Among these patients, 20 (71.4%) underwent external beam radiation therapy in the pelvic lymphatic drainage area (node-negative patients). Overall, 8 patients (28.6%) underwent radiotherapy in the pelvic lymphatic drainage area with a simultaneous integrated boost (node-positive patients). Furthermore, 20 patients were assigned to 2 groups of plans according to the prescribed doses of 5000 and 4500 cGy/25. Each group had 3 plans according to 3 different dose limit conditions: "pelvic bones and sacrum unlimited," "pelvic bones limited," and "pelvic bones + sacrum limited." The irradiation dose of the sacrum and pelvis was analyzed in three limited optimization models.The planning target volume conformity index and homogeneity index, based on different optimization modes in the 4500 and 5000 cGy plans, showed no significant differences. The D50% and Dmean of the pelvis + sacrum limited mode were significantly lower than those of the pelvic limited mode (P < .001). The dose of the sacrum and pelvis in the 4500 cGy plan in the lymphatic drainage area was significantly lower than that of the 5000 cGy plan (P < .001). In the lymph node boost group, the irradiation dose of the sacrum and pelvis was significantly increased (P ≤ .001).Increasing the limitation of the sacrum, on the basis of pelvic bone limitation, in cervical cancer intensity-modulated radiation therapy can significantly reduce the dose to the sacrum. Compared with the dose of 5000 cGy to the lymphatic drainage area, the dose of 4500 cGy was the largest influencing factor to reduce the dose to the sacrum.

Low dose radiotherapy is associated with local complications but not disease control in sacral chordoma.

BACKGROUND: We reviewed the disease control and complications of the treatment of sacrococcygeal chordoma from four tertiary cancer centers with emphasis on the effects of radiotherapy in surgically treated patients. METHODS: A total of 193 patients with primary sacrococcygeal chordoma from 1990 to 2015 were reviewed. There were 124 males, with a mean age of 59 ± 15 years and a mean follow-up of 7 ± 4 years. Eighty-nine patients received radiotherapy with a mean total dose of 61.8 ± 10.9 Gy. RESULTS: The 10-year disease-free and disease-specific survival was 58% and 72%, respectively. Radiation was not associated with local recurrence (hazard ratio [HR], 1.13; 95% confidence interval [CI], 0.59-2.17; P = 0.71), metastases (HR, 0.93; 95% CI, 0.45-1.91; P = 0.85) or disease-specific survival (HR, 0.96; 95% CI, 0.46-2.00; P = 0.91). Higher doses (≥70 Gy; HR, 0.52; 95% CI, 0.20-1.32; P = 0.17) may be associated with reduced local recurrence. Radiotherapy was associated with wound complications (HR, 2.76; 95% CI, 1.64-4.82;, P < 0.001) and sacral stress fractures (HR, 4.73; 95% CI, 1.88-14.38; P < 0.001). CONCLUSIONS: In this multicenter review, radiotherapy was not associated with tumor outcome but associated with complications. The routine use of radiotherapy with en-bloc resection of sacrococcygeal chordomas should be reconsidered in favor of a selective, individualized approach with a radiation dose of ≥70 Gy.

Risk Factors for Sacral Insufficiency Fractures in Cervical Cancer After Whole Pelvic Radiation Therapy.

AIM: To evaluate the incidence and risk factors of sacral insufficiency fractures (SIFs), particularly dose-volume histogram (DVH) parameters, in patients with cervical cancer after whole pelvic radiation therapy (WPRT). PATIENTS AND METHODS: The medical records of 61 patients with cervical cancer who underwent WPRT were retrospectively reviewed. The cumulative incidence of SIF, as well as the risk factors that could affect its incidence were assessed. RESULTS: Of the 61 patients, 11 (18%) were diagnosed with SIF, as revealed by computed tomography. Multivariate analysis revealed that abnormal body mass index (BMI) (more than 25 kg/m2 or below 18 kg/m2) and administration of five or more chemotherapy cycles were independently associated with SIF. A slight difference was observed in the D50% (the administered dose covering half of the sacrum) between patients with and those without SIF (p=0.052). CONCLUSION: Thus, the D50% of the sacrum should be particularly considered in patients with abnormal BMI and five or more cycles of chemotherapy.

Palliative Radiotherapy as a Treatment for Carcinoma Invasion of the Sacrum: An Observational Case Series Study.

BACKGROUND/AIM: Radiotherapy for carcinoma invasion of the sacrum (CIS) is an alternative treatment to surgery in patients with advanced, inoperable tumors or those not medically eligible for resection of the neoplasm. Herein we present an observational study of patients with imaging-confirmed CIS who were treated non-operatively with radiation. PATIENTS AND METHODS: A retrospective chart review of CIS patients treated with palliative radiotherapy (PR) during a 9-year period (2004-2013) was performed. RESULTS: Six women and 13 men with an average age of 60 years took part in this study. Most patients (84%) exhibited extrasacral metastases. Primary tumors included lung (n=6), colorectal (n=6), breast (n=3), bladder or kidney (n=2), and liver carcinoma or a tumor in an unknown primary site (n=2). The mean follow-up time was 10 months with a 2-year survival rate of 9%. The majority (71%) of symptomatic patients obtained relief from pain following PR. Half of those individuals who were non-ambulatory prior to therapy regained mobility. There were no acute ill-effects or later complications after irradiation. CONCLUSION: Despite the small cohort and poor overall survival rate, non-operative radiation treatment is a beneficial method of palliative care in patients with CIS.

Sacral insufficiency fractures after high-dose carbon-ion based radiotherapy of sacral chordomas.

BACKGROUND: This study aimed to analyse the frequency and clinical relevance of sacral insufficiency fractures (SIFs) after high-dose carbon-ion based irradiation of sacral chordomas. METHODS: A total of 56 patients were included in this retrospective study. Twenty one patients (37%) were treated with definitive radiotherapy (RT), and 35 patients (63%) received postoperative RT using carbon ions, either in combination with photons or as single-modality treatment (median radiation dose 66 Gy RBE, range 60-74 Gy). Follow-up examinations including MRI of the pelvis were performed at 3-monthly intervals in the first year and consecutively at 6-monthly intervals. Median follow-up was 35.5 months (range 2-83). RESULTS: SIFs were diagnosed in 29 patients (52%) after a median follow-up of 11 months (range 1-62 months). Most sacral fractures (79%) occurred within 2 years after RT. For the overall study population, the fracture-free survival probability amounted to values of 0.68 (95% CI, 0.53-0.79) after 1 year, 0.46 (95% CI, 0.31-0.60) after 2 years, and 0.31 (95% CI, 0.16-0.47) after 5 years. Statistical analysis showed no significant difference regarding the fracture rates between patients who received an operation and postoperative RT and patients treated with definitive RT. About one third of the patients with SIFs (34%; 10 of 29 patients) had associated clinical symptoms, most notably pain. All patients with symptomatic fractures required strong analgesics and often intensive pain management. CONCLUSIONS: Sacral fractures after high-dose carbon ion-based RT of sacral chordomas were shown to be a considerable radiogenic late effect, affecting about half of the treated patients. However, only one third of these fractures were clinically symptomatic requiring regular medical care and pain therapy. Further hazard factor analysis in the future with larger patient numbers will possibly enable the identification of high-risk patients for developing SIFs with the ultimate goal to prevent symptomatic fractures.

What Is the Effect of High-dose Radiation on Bone in Patients With Sacral Chordoma? A CT Study.

BACKGROUND: Effects of high-dose radiation using protons and photons on bone are relatively unexplored, but high rates of insufficiency fractures are reported, and the causes of this are incompletely understood. Imaging studies with pre- and postradiation scans can help one understand the effect of radiation on bone. QUESTIONS/PURPOSES: The purpose of this study was to assess the effects of high-dose radiation on the trabecular density of bone in the sacrum using CT-derived Hounsfield units (HU). METHODS: Between 2009 and 2015, we treated 57 patients (older then 18 years) with sacral chordoma. Fourteen (25%) of them were treated with radiation only. The general indication for this approach is inoperability resulting from tumor size. Forty-two (74%) patients were treated with transverse sacral resections and high-dose radiotherapy (using either protons or photons or a combination) before surgery and after surgery. During this time period, our indication for this approach generally was symptomatic sacral chordoma in which resection would prevent further growth and reasonable sacrifice of nerve roots was possible. Of those patients, 21 (50%) had CT scans both before and after radiation treatment. We used HU as a surrogate for bone density. CT uses HU to derive information on tissue and bone quantity. A recent study presented reference HU values for normal (mean 133 ± 38 HU), osteoporotic (101 ± 25 HU), and osteopenic bone (79 ± 32 HU). To adjust for scanning protocol-induced changes in HU, we calculated the ratio between bone inside and outside the radiation field rather than using absolute values. To assess the effect of radiation, we tested whether there was a difference in ratio (sacrum/L1) before and after radiation. A control measurement was performed (L2/L1) and also tested for a difference before and after radiation. Statistical analyses were performed using the paired t-test. RESULTS: The effects of radiation appeared confined to the intended field, because the bone density outside the treated field was not observed to decrease. The ratio of HU (a surrogate for bone density) in L2 relative to L1 did not change after radiotherapy (preradiation mean: 0.979 ± 0.009, postradiation mean: 0.980 ± 0.009, mean difference outside the radiation field: -0.001, 95% confidence interval [CI], -0.009 to 0.007, p = 0.799). The ratio of HU within the radiation field relative to L1 decreased after radiotherapy (preradiation mean: 0.895 ± 0.050, postradiation mean: 0.658 ± 0.050, mean difference inside the radiation field: 0.237, 95% CI, 0.187-0.287, p < 0.001), suggesting the bone density stayed the same outside the radiation field but decreased inside the radiation field. CONCLUSIONS: Trabecular bone density decreased after high-dose radiation therapy in a small group of patients with sacral chordoma. High-dose radiation is increasingly gaining acceptance for treating sacral malignancies; further long-term prospective studies using calibrated CT scanners and preferably bone biopsies are needed. LEVEL OF EVIDENCE: Level IV, therapeutic study.

From radiation osteitis to osteoradionecrosis: incidence and MR morphology of radiation-induced sacral pathologies following pelvic radiotherapy.

OBJECTIVE: To investigate the incidence rate, time-to-onset and recovery, MRI morphology and occurrence of insufficiency fractures in radiation-induced changes in the sacrum following pelvic radiotherapy. MATERIAL AND METHODS: 410 patients with pelvic malignancies treated with radiotherapy were reviewed. Follow-up was 1-124 months (mean 22 months). Serial MRI (average four studies/patient) were analysed using a new semi-quantitative score (Radiation-Induced Sacral Changes=RISC). A size category (I/II/III), a type category for MR signal morphologies (a/b/c) and sacral insufficiency fractures (+/-) were applied. RESULTS: Seventy-two patients (17.6 %) were found to have new pathological signal changes. Radiation osteitis was documented in 83.3 % (60/72, RISC stage a + b), and definite osteonecrosis (stage c) in 12 patients (16.7 %, 12/72). Thirty-one patients (43.1 %) had sacral insufficiency fractures. Initial bone marrow signal changes were found 1-35 months (median 4 months) after radiotherapy. The maximum manifestation of radiation-induced signal changes occurred after 1-35 months (mean 11 months). Fifty-six cases (77.8 %) showed a significant signal recovery within 16.5 months. CONCLUSION: Radiation-induced bone marrow changes appear with a high incidence at the sacrum with an early onset and frequent recovery. The majority presented a pattern of radiation osteitis, whereas osteoradionecrosis was proportionately rare. KEY POINTS: • Radiation-induced sacral bone marrow changes appear frequently (17.6 %) following pelvic radiotherapy. • Insufficiency fractures are common late effects (43 %). • Radiation osteitis develops early (4 mo), with recovery between 16.5 and 39.5 months. • Definite radiological osteoradionecrosis is proportionately rare (3 %). • A 3-stage classification system simplifies and standardizes the morphological disease staging.

Long-Term Bone Marrow Suppression During Postoperative Chemotherapy in Rectal Cancer Patients After Preoperative Chemoradiation Therapy.

PURPOSE/OBJECTIVE(S): To quantify ensuing bone marrow (BM) suppression during postoperative chemotherapy resulting from preoperative chemoradiation (CRT) therapy for rectal cancer. METHODS AND MATERIALS: We retrospectively evaluated 35 patients treated with preoperative CRT followed by postoperative 5-Fluorouracil and oxaliplatin (OxF) chemotherapy for locally advanced rectal cancer. The pelvic bone marrow (PBM) was divided into ilium (IBM), lower pelvis (LPBM), and lumbosacrum (LSBM). Dose volume histograms (DVH) measured the mean doses and percentage of BM volume receiving between 5-40 Gy (i.e.: PBM-V5, LPBM-V5). The Wilcoxon signed rank tests evaluated the differences in absolute hematologic nadirs during neoadjuvant vs. adjuvant treatment. Logistic regressions evaluated the association between dosimetric parameters and ≥ grade 3 hematologic toxicity (HT3) and hematologic event (HE) defined as ≥ grade 2 HT and a dose reduction in OxF. Receiver Operator Characteristic (ROC) curves were constructed to determine optimal threshold values leading to HT3. RESULTS: During OxF chemotherapy, 40.0% (n=14) and 48% (n=17) of rectal cancer patients experienced HT3 and HE, respectively. On multivariable logistic regression, increasing pelvic mean dose (PMD) and lower pelvis mean dose (LPMD) along with increasing PBM-V (25-40), LPBM-V25, and LPBM-V40 were significantly associated with HT3 and/or HE during postoperative chemotherapy. Exceeding ≥36.6 Gy to the PMD and ≥32.6 Gy to the LPMD strongly correlated with causing HT3 during postoperative chemotherapy. CONCLUSIONS: Neoadjuvant RT for rectal cancer has lasting effects on the pelvic BM, which are demonstrable during adjuvant OxF. Sparing of the BM during preoperative CRT can aid in reducing significant hematologic adverse events and aid in tolerance of postoperative chemotherapy.

Sacral Insufficiency Fractures are Common After High-dose Radiation for Sacral Chordomas Treated With or Without Surgery.

BACKGROUND: Surgery with high-dose radiation and high-dose radiation alone for sacral chordomas have shown promising local control rates. However, we have noted frequent sacral insufficiency fractures and perceived this rate to be higher than previously reported. QUESTIONS/PURPOSES: We wished (1) to characterize the incidence of sacral insufficiency fractures in patients with chordomas of the sacrum who received high-dose radiation, and (2) to determine whether patients treated with surgery plus high-dose radiation or high-dose radiation alone are more likely to experience a sacral fracture, and to compare time to fracture in these groups. METHODS: Sixty-two patients who received high-dose radiation for sacral chordomas with (n = 44) or without surgical resection (n = 18) between 1992 and 2013 were included in this retrospective study. At our institution, sacral chordomas generally are treated by preoperative radiotherapy, followed by en bloc resection, and postoperative radiotherapy. Radiation alone, with an intent to cure, is offered to patients who otherwise are not good surgical candidates or patients who elect radiotherapy based on tumor location and the anticipated morbidity after surgery (such as sexual, bowel, or bladder dysfunction). MRI and CT scans were evaluated for evidence of sacral insufficiency fractures. Complete followup was available at a minimum of 2 years (or until fracture or death) for all 18 patients who underwent radiation alone, whereas 14% (six of 44 patients) in the surgery plus radiation group (9% [three of 33] after high sacrectomy and 27% [three of 11] after low sacrectomy) were lost to followup before 2 years. RESULTS: Sacral insufficiency fractures occurred in 29 of the 62 patients (47%). A total of 25 of 33 patients (76%) with high sacrectomy had fractures develop compared with zero of 11 (0%) after low sacrectomy, and four of the 18 patients (22%) who had high-dose radiation alone (p < 0.001). The fracture rate was greater in the high sacrectomy group than in the low sacrectomy group (p < 0.001) and the radiation only group (p < 0.001). There was no difference with the numbers evaluated in fracture probability between patients in the low-sacrectomy group and those treated with radiation alone (p = 0.112). The fracture-free survival probability was 0.99 for the low sacrectomy group at all times as there were no insufficiency fractures in this group; the 1-year fracture-free survival probability was 0.53 (95% CI, 0.35-0.69) after high sacrectomy, 0.83 (95% CI, 0.57-0.94) after radiation alone; the 2-year fracture-free survival probability was 0.36 (95% CI, 0.19-0.52) after high sacrectomy and 0.77 (95% CI, 0.50-0.91) after radiation alone; and the 5-year fracture-free survival probability was 0.14 (95% CI, 0.04-0.30) after high sacrectomy and 0.77 (95% CI, 0.50-0.91) after radiation alone. CONCLUSIONS: Acknowledging the limitations of potential differences in baseline and followup among treatment groups in our study, we found that almost ½ of our patients experienced an insufficiency fracture. We found that the fracture rate was greater in the surgery group compared with the radiation alone group and that high sacrectomy accounted for all fractures in the surgery group. These findings can be used to inform patients and also support the need for further research to elucidate the influence of high-dose radiation on bone quality. LEVEL OF EVIDENCE: Level III, therapeutic study.

Gelfoam embolization or 125I seed implantation may be a more effective treatment than surgical treatment for giant benign sacral neurogenic tumors.

BACKGROUND: The goal of the present study was to assess the effects of computed tomography (CT)-guided iodine-125 (125I) seed implantation or gelatin sponge particle (GSP) embolization on patients with giant benign sacral neurogenic tumors. METHODS: A total of 24 cases with giant sacral neurogenic tumor were performed in a retrospective study between 2000 and 2012. Nineteen cases received surgical resection, and five cases received non-surgical treatment. In surgical group, patients with type III sacral tumor had received a combined anterior-posterior approach and patients with type IV were treated with simple anterior approach. In non-surgical group, CT-guided 125I seed implantation or GSP embolization was applied to occlude vessels. Besides, CT scanning or magnetic resonance imaging was used to assess the size and development of tumors. RESULTS: Two of the five patients were treated three times with GSP embolization, one had received GSP embolization combined with CT-guided 125I seed implantation, one case did not receive any treatment, and one patient was lost to follow-up. Patients in non-surgical group were followed up for 2-8 years. CONCLUSIONS: Our study suggested that CT-guided 125I seed implantation or GSP embolization treatment is very useful to slow down the development of giant benign sacral neurogenic tumors.