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.

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.

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.

Gluteus Maximus Turnover Flap for Sacral Osteomyelitis After Radiation Therapy

Developments in radiation therapy modalities offer alternative treatments for unresectable malignant tumors in the pelvis and trunk. However, poor vascularity as a result of radiation therapy makes the treated lesion susceptible to infection, and there are no established treatments for pelvic osteomyelitis with a large dead space after radiation therapy. The authors report 2 cases of sacral osteomyelitis after radiation therapy that were treated successfully with a gluteus maximus turnover flap. To create the flap, the distal portion of the lower third of the muscle was detached from the trochanter. The distal edge of the flap was turned toward the sacral defect and sewn to the remnant of the sacrum, which filled the dead space with the muscle bulk. A 68-year-old man with a recurrent sacral chordoma was treated with carbon ion radiation therapy; however, a sacral infection developed 5 months later. Debridement and a course of antibiotics could not control the infection and did not induce sufficient formation of granulation tissue in the large and deep dead space. The turnover flap with both gluteus maximus muscles cured the deep-seated infection and closed the wound. A 58-year-old woman had sacral osteoradionecrosis with infection. A turnover flap created with the left gluteus maximus muscle controlled the infection and closed the wound after the first operation, a V-Y flap, failed. This study showed that a gluteus maximus muscle turnover flap effectively controlled infectious lesions with large and deep dead space around the sacrum.

Outcome of long-axis percutaneous sacroplasty for the treatment of sacral insufficiency fractures with a radiofrequency-induced, high-viscosity bone cement

Our goal was to assess the technical results in patients who underwent long-axis sacroplasty for the treatment of sacral insufficiency fractures (SIF) by radiofrequency-induced high-viscosity bone cement augmentation. Twelve patients with bilateral sacral fractures were treated by augmentation with radiofrequency-activated, high-viscosity polymethylmethacrylate (PMMA) bone cement under local anesthesia. CT-guided sacroplasty was performed by using a long-axis approach through a single entry point. Thirty-six vertebrae were treated in 12 sessions under a combination of CT and fluoroscopic guidance using a bilateral access and a cavity-creating osteotome prior to remote-controlled, hydraulically driven cement injection. The visual analogue scale (VAS) score before sacroplasty and at 1 and 3 months after the treatment was obtained. PMMA leaks were evaluated retrospectively using the post-interventional CT. The mean amount of high-viscosity PMMA injected per patient was 7.8 ml. No major adverse events were observed. In the first 4 days after the procedure, the mean VAS score decreased from 8.1 ± 1.9 to mean 3.1 ± 1.2 and was followed by a gradual but continuous decrease throughout the rest of the follow-up period at 24 weeks (mean 2.2 ± 1.1) and 48 weeks (mean 2.1 ± 1.4). CT fluoroscopy-guided sacral augmentation was safe and effective in all 12 patients with osteoporotic SIF.

Relative importance of hip and sacral pain among long-term gynecological cancer survivors treated with pelvic radiotherapy and their relationships to mean absorbed doses

PURPOSE

To investigate the relative importance of patient-reported hip and sacral pain after pelvic radiotherapy (RT) for gynecological cancer and its relationship to the absorbed doses in these organs.

METHODS AND MATERIALS

We used data from a population-based study that included 650 long-term gynecological cancer survivors treated with pelvic RT in the Gothenburg and Stockholm areas in Sweden with a median follow-up of 6 years (range, 2-15) and 344 population controls. Symptoms were assessed through a study-specific postal questionnaire. We also analyzed the hip and sacral dose-volume histogram data for 358 of the survivors.

RESULTS

Of the survivors, one in three reported having or having had hip pain after completing RT. Daily pain when walking was four times as common among the survivors compared to controls. Symptoms increased in frequency with a mean absorbed dose >37.5 Gy. Also, two in five survivors reported pain in the sacrum. Sacral pain also affected their walking ability and tended to increase with a mean absorbed dose >42.5 Gy.

CONCLUSIONS

Long-term survivors of gynecological cancer treated with pelvic RT experience hip and sacral pain when walking. The mean absorbed dose was significantly related to hip pain and was borderline significantly related to sacral pain. Keeping the total mean absorbed hip dose below 37.5 Gy during treatment might lower the occurrence of long-lasting pain. In relation to the controls, the survivors had a lower occurrence of pain and pain-related symptoms from the hips and sacrum compared with what has previously been reported for the pubic bone.

Dosimetric predictors of acute hematologic toxicity in cervical cancer patients treated with concurrent cisplatin and intensity-modulated pelvic radiotherapy

PURPOSE

To identify dosimetric parameters associated with acute hematologic toxicity (HT) and chemotherapy delivery in cervical cancer patients undergoing concurrent chemotherapy and intensity-modulated pelvic radiotherapy.

METHODS AND MATERIALS

We analyzed 37 cervical cancer patients receiving concurrent cisplatin (40 mg/m(2)/wk) and intensity-modulated pelvic radiotherapy. Pelvic bone marrow (BM) was contoured for each patient and divided into three subsites: lumbosacral spine, ilium, and lower pelvis. The volume of each region receiving 10, 20, 30, and > or =40 Gy (V(10), V(20), V(30), and V(40), respectively) was calculated. HT was graded according to the Radiation Therapy Oncology Group system. Multivariate regression models were used to test associations between dosimetric parameters and HT and chemotherapy delivery.

RESULTS

Increased pelvic BM V(10) (BM-V(10)) was associated with an increased Grade 2 or worse leukopenia and neutropenia (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.24-3.53; p = 0.006; and OR, 1.41; 95% CI, 1.02-1.94; p = 0.037, respectively). Patients with BM-V(10) > or =90% had higher rates of Grade 2 or worse leukopenia and neutropenia than did patients with BM-V(10) <90% (11.1% vs. 73.7%, p < 0.01; and 5.6% vs. 31.6%, p = 0.09) and were more likely to have chemotherapy held on univariate (16.7% vs. 47.4%, p = 0.08) and multivariate (OR, 32.2; 95% CI, 1.67-622; p = 0.02) analysis. No associations between HT and V(30) and V(40) were observed. Dosimetric parameters involving the lumbosacral spine and lower pelvis had stronger associations with HT than did those involving the ilium.

CONCLUSION

The volume of pelvic BM receiving low-dose radiation is associated with HT and chemotherapy delivery in cervical cancer patients undergoing concurrent chemoradiotherapy.

The treatment of chronic coccydynia with intrarectal manipulation: a randomized controlled study

STUDY DESIGN

Randomized open study.

OBJECTIVE

To evaluate the efficacy of intrarectal manual treatment of chronic coccydynia; and to determine the factors predictive of a good outcome.

SUMMARY OF BACKGROUND DATA

In 2 open uncontrolled studies, the success rate of intrarectal manipulation of the coccyx was around 25%.

METHODS

Patients were randomized into 2 groups of 51 patients each: 1 group received three sessions of coccygeal manipulation, and the other low-power external physiotherapy. The manual treatment was guided by the findings on stress radiographs. Patients were assessed, at 1 month and 6 months, using a VAS and (modified) McGill Pain, Paris (functional coccydynia impact), and (modified) Dallas Pain questionnaires.

RESULTS

At baseline, the 2 groups were similar regarding all parameters. At 1 month, all the median VAS and questionnaire values were modified by -34.7%, -36.0%, -20.0%, and -33.8%, respectively, in the manipulation group, versus -19.1%, -7.7%, 20.0%, and -15.7%, respectively, in the control (physiotherapy) group (P = 0.09 [borderline], 0.03, 0.02, and 0.02, respectively). Good results were twice as frequent in the manipulation group compared with the control group, at 1 month (36% vs. 20%, P = 0.075) and at 6 months (22% vs. 12%, P = 0.18). The main predictors of a good outcome were stable coccyx, shorter duration, traumatic etiology, and lower score in the affective parts of the McGill and Dallas questionnaires.

CONCLUSIONS

We found a mild effectiveness of intrarectal manipulation in chronic coccydynia.

Perisacral gastrointestinal stromal tumor with intracranial metastasis. Case report

A 68-year-old woman presented with an extremely rare intracranial metastasis from a gastrointestinal stromal tumor (GIST) manifesting as left hemiparesis 2 years after resection of a sacral tumor adjacent to the coccygeal bone. Magnetic resonance imaging revealed an intracranial tumor in the right parietal lobe. Craniotomy was performed to completely remove the tumor. Although the tumor was located extra-axially, only internal carotid angiography showed mass staining. Seven months after surgery, the tumor recurred. Repeat craniotomy was performed to remove the recurrent tumor. Immunohistochemical analysis showed that the tumor cells were positive for c-kit and CD34, and the tumors were identified as intracranial metastasis of GIST. Following the second intracranial surgery, the patient developed severe lower back pain caused by metastatic tumor invading the lumbar spine and ureter. To avoid surgical complications and to reduce tumor volume, imatinib mesylate (Gleevec) was administered. The severe pain was relieved, although the tumor was not reduced. In this case, the extra-axial tumor was fed only by the internal carotid artery.

Evaluation of methods for red marrow dosimetry based on patients undergoing radioimmunotherapy

Red marrow dosimetry is essential during radioimmunotherapy and a reliable method is essential in order to find a measure correlated to the toxic effect observed. The aim of this study was to calculate the absorbed dose to red marrow with different methods for the same patients and to compare the results. Patients diagnosed with B-cell lymphoma were treated with (131)I-labelled monoclonal antibodies (LL2, anti-CD22). Blood samples were collected, scintillation camera images were taken and single probe measurements were carried out at different points in time after administration of the radiopharmaceutical. The absorbed dose to red marrow per unit activity administered was calculated using four varieties of the blood method and from activity quantification in the sacrum in the scintillation camera images. The absorbed dose to the total body per unit activity, sometimes used as a measure for determining the toxic effect in red marrow, was calculated from both the scintillation camera images and the single probe measurements. The results from the different methods of calculating the absorbed dose for the same patient and treatment were compared. The ratio of the maximum and the minimum absorbed dose to red marrow calculated using the four variations of the blood method and the sacrum imaging method for one and the same patient varied between 1.8 and 2.8. The correlation coefficients for all the possible combinations of the dosimetry methods, including total body measurements, varied from 0.51 to 0.99. The results show that the variability of the absorbed dose to the bone marrow is dependent on both method and patient.

Carbon-11-methionine positron emission tomography imaging of chordoma

OBJECTIVE

Chordoma is a rare malignant bone tumor that arises from notochord remnants. This is the first trial to investigate the utility of (11)C-methionine (MET) positron emission tomography (PET) in the imaging of chordoma before and after carbon-ion radiotherapy (CIRT).

DESIGN AND PATIENTS

Fifteen patients with chordoma were investigated with MET-PET before and after CIRT and the findings analyzed visually and quantitatively. Tumor MET uptake was evaluated by tumor-to-nontumor ratio (T/N ratio).

RESULTS

In 12 (80%) patients chordoma was clearly visible in the baseline MET-PET study with a mean T/N ratio of 3.3+/-1.7. The MET uptake decreased significantly to 2.3+/-1.4 after CIRT ( P<0.05). A significant reduction in tumor MET uptake of 24% was observed after CIRT. Fourteen (93%) patients showed no local recurrence after CIRT with a median follow-up time of 20 months.

CONCLUSION

This study has demonstrated that MET-PET is feasible for imaging of chordoma. MET-PET could provide important tumor metabolic information for the therapeutic monitoring of chordoma after CIRT.

Pelvic insufficiency fractures in postmenopausal woman with advanced cervical cancer treated by radiotherapy

PURPOSE

To assess the predisposing factors and clinical characteristics of pelvic insufficiency fractures (PIF) in postmenopausal women with pelvic irradiation.

MATERIAL AND METHODS

A total 335 postmenopausal patients with cervical cancer of the intact uterus treated with radiation therapy between 1983 and 1998 were reviewed. Total external dose was delivered between 45 and 50.4 Gy with parallel opposed anteroposterior portals. Total brachytherapy dose at point A was delivered between 10 and 36 Gy. PIF were diagnosed by bone scintigraphy and confirmed by computed tomography. The cumulative incidence of symptomatic PIF was estimated by actuarial methods. Potential risk factors (age, weight, type II diabetes, delivery, menopause, total external dose, total brachytherapy dose) were assessed.

RESULTS

Fifty-seven (17.0%) of 335 patients were diagnosed as having PIF. Forty-seven patients were symptomatic and ten were asymptomatic. Parameters carrying a significant association with PIF were body weight 49 kg or below (P=0.044) in stepwise logistic regression analysis. The cumulative incidence of symptomatic PIF at 5 years was 17.9% calculated by the Kaplan-Meier method. A body weight of 49 kg or below and more than three deliveries were identified as having a significant effect on symptomatic PIF in univariate analysis (P=0.021, P=0.003, log-rank test) and Cox life table regression analysis (P=0.038, P=0.013). Five patients required narcotic agents and eight patients required hospital admission.

CONCLUSIONS

We should consider reducing the dose contribution to the sacrum and sacroilac joints, without underdosing the tumor, especially in postmenopausal women with many deliveries or low body weight.

Early MR changes in vertebral bone marrow for patients following radiotherapy

Our study aimed to evaluate the vertebral marrow changes in patients following radiotherapy (RT) by measuring the T2 relaxation times before and during RT. We were mostly interested in evaluating early MR marrow changes during RT. Fifteen patients treated by RT for cervical cancer were submitted to MR examination before and during RT (5-23 days of RT). T2 values were calculated for irradiated and non-irradiated tissues (lumbar and sacral vertebral bone marrow, symphysis pubis marrow, and regional muscle). Fourteen patients presented increased T2 values for irradiated vertebral bone marrow (VBM), and 3 patients showed increased T2 values even for non-irradiated VBM. We found T2 variations for VBM as early as in the fifth day of RT for an absorbed dose as small as 9 Gy. Calculated T2 values in irradiated and also in non-irradiated tissues prove very early tissue alterations.

Radiation-induced changes in MR signal intensity and contrast enhancement of lumbosacral vertebrae: do changes occur only inside the radiation therapy field?

PURPOSE

To evaluate temporal changes in signal intensity (SI) and degree of contrast enhancement (CE) of bone marrow in lumbosacral vertebrae inside and outside the radiation therapy (RT) field.

MATERIALS AND METHODS

Twenty-three patients with advanced uterine cervical cancer who were treated with RT were prospectively evaluated. Each patient underwent four dynamic magnetic resonance (MR) studies: before RT, 2 and 4 weeks after initiation of RT, and 4 weeks after completion of RT. SI and CE were calculated in all four studies of each patient.

RESULTS

Bone marrow inside the RT field showed steady and marked increase in precontrast SI and early and transient increase in CE at 2 weeks after initiation of RT followed by progressive and marked decrease in CE at 4 weeks after initiation of RT and 4 weeks after completion of RT. Bone marrow outside the RT field showed slight increase in precontrast SI and steady and moderate decrease in CE to a lesser degree without early increase as seen in bone marrow inside the RT field.

CONCLUSION

RT causes an increase in precontrast SI predominantly in bone marrow inside the RT field. However, a decrease in CE is seen in bone marrow not only inside but also outside the RT field.

[Multi-modality therapy concept in metastatic follicular thyroid carcinoma with hyperthyroidism]

The coincidence of hyperthyroidism and thyroid carcinoma seldom occurs. Only few reports on functionally metastases of thyroid carcinoma have been published. We report a 59-year-old man who underwent subtotal thyroidectomy for toxic nodular goiter. Histological examination revealed a follicular thyroid carcinoma. After thyroidectomy and cervical lymphadenectomy the patient developed a strong hyperthyreosis. Scintigraphy showed strong radioiodine uptake in the sacrum. De-bulking resection of the metastasis followed by high-dose radioiodine treatment was performed. After radioiodine therapy the patient became euthyroid. Treatment of hyperthyreosis in metastatic thyroid cancer requires a multimodal therapeutic concept.

[Bone metastasis versus insufficiency fractures due to pelvic radiotherapy for gynecologic neoplasm]

Five cases of patients with gynecological neoplasm (four cervix carcinoma and one endometrial sarcoma) who underwent pelvic external radiotherapy and intracavitary brachytherapy in whom pathologic pelvic uptake was found in the bone scan are presented. The diagnosis was pelvic insufficiency fractures due to radiotherapy adverse effects on the skeletal system confirmed by CT and by the favorable scintigraphy and clinical outcome. Both bone metastases and insufficiency fractures must be considered in the differential diagnosis of bone pain in irradiated pelvises. The bone scintigraphy detects these insufficiency fractures early and can show a typical symmetric uptake pattern. In asymmetric lesions, the CT and clinical follow-up as well as the scintigraphic evolution of the lesions should confirm the findings of the bone scintigraphies.

Sacral chordoma, gas gangrene and bilateral renal cell carcinomas

The case history is reported of a 59-year-old man with a locally symptomatic sacral chordoma. During treatment with radical radiotherapy, he developed gas gangrene, which proved rapidly fatal. At post-mortem examination there was evidence of local invasion of the rectum by the tumour and extensive gangrenous myonecrosis (gas gangrene) involving the pelvic tissues and left leg. An unexpected finding was the presence of histologically distinct bilateral renal cell carcinomas. Neither gas gangrene nor renal cell cancer has been reported previously in association with sacral chordoma.

Insufficiency fractures of the sacrum in elderly subjects

Elderly patients who develop insufficiency fractures of the sacrum usually have generalized bone loss and/or lesions of the pelvic bones (due to radiation therapy or previous fractures). The sacral fracture occurs either spontaneously or after a trivial traumatic episode. We compared patients admitted for sacral fractures (n = 12) or vertebral crush fractures (n = 56) in an effort to identify risk factors for sacral fractures. We conducted a retrospective review of the medical records of the 12 patients older than 70 years who were admitted to the rheumatology department of the Morvan Hospital between January 1, 1985 and December 31, 1994 for evaluation of a sacral fracture. The onset of symptoms was abrupt in 11 patients and occurred after an unremarkable fall in three. Patients admitted for sacral fractures were significantly more likely to have a positive history for a fracture, femoral surgery, or pelvic radiation therapy than patients admitted for vertebral fractures (58% versus 9%, p = 0.0005). In contrast, levels of calcium, phosphorus, 25-OH vitamin D and 1,25(OH)2 vitamin D were comparable in the two groups after exclusion of those patients with endocrine disorders or a history of calcium and vitamin D supplementation. In conclusion, populations of elderly patients with sacral fractures and crush fractures are comparable and the occurrence of a sacral fracture is dependent on the presence of pelvic and/or femoral osseous abnormalities.

Sacral insufficiency fractures. Spectrum of radiological features

Clinical and radiological features of 22 Chinese patients with sacral insufficiency fractures were reviewed. Twenty-one were postmenopausal women. Other risk factors were external pelvic radiotherapy (eight) and total hip replacement (two). Severe low back pain was the most common presenting complaint. Fractures initially were demonstrated by bone scintigraphy in 21 and computed tomography (CT) in seven patients. Concomitant parasymphyseal and pubic rami fractures were detected in 17 and 10 patients, respectively. Follow-up assessment by CT and bone scintigraphy in five patients showed various stages of fracture healing. Recognition of the radiological patterns of this entity is emphasized.

MRI of occult sacral insufficiency fractures following radiotherapy

Following radiation therapy, marrow abnormalities noted on magnetic resonance imaging (MRI) are frequent and may mimic metastases. Specific radiotherapy changes are usually easily identifiable; however, traumatic lesions cause more interpretive difficulties. We assessed the incidence and MRI characteristics of insufficiency fractures in this population. During a 5-year span (1987-1991), 546 patients received pelvic radiotherapy for primary malignancies. MRI was performed in 25 of these patients at least 3 months after treatment. The mean dose in this group was 53 Gy. These MRI scans were retrospectively reviewed for the appearance of the sacrum with particular attention to the presence of insufficiency fractures. This was correlated with clinical course and scintigraphic findings. Presumed insufficiency fractures on MRI paralleled the sacral side of the sacroiliac joint, enhanced with Gd-DTPA, were most prominent or initially seen anteriorly, and had ill-defined margins on all imaging sequences. The incidence of occult sacral insufficiency fractures was at least 20%. Insufficiency fractures of the sacrum in the post-radiotherapy patient are a relatively frequent occurrence which can mimic metastases. Consideration of this phenomenon and knowledge of differential features may avoid overdiagnosis of osseous metastases.

Vacuum phenomena in insufficiency fractures of the sacrum

OBJECTIVE

Insufficiency fractures of the sacrum are found in women who have undergone radiation therapy to the lower abdomen as well as those suffering from osteoporosis of postmenopausal, steroid-induced, or primary biliary cirrhosis-related origin. Increased uptake in bone scintigraphy and osteolytic changes in these fractures can be misinterpreted as bone metastases, leading to unnecessary biopsies and other procedures in the ensuing search for non-existent primary tumor.

PATIENTS

In eight female patients averaging 69.4 years of age, insufficiency fracture of the sacrum was diagnosed by computed tomography (CT) and bone scintigraphy. Three underwent a total of five MRI examinations. Malignancy was excluded by histology in two patients and follow-up of at least 6 months in the remainder. Retrospective analysis of CT scans of 13 patients with metastases in the sacrum revealed no vacuum phenomena.

RESULTS

In seven of eight patients with insufficiency fracture of the sacrum, vacuum phenomena were shown on CT examination. The gas was localized centrally within the ventral part of the fracture in three patients; gas was located in ten adjacent sacro-iliac joints of six patients.

CONCLUSIONS

The vacuum phenomenon may be an incidental finding in osteoarthritis of the sacro-iliac joint, but it has not been previously recognized in IFS. The presence of intra-articular vacuum phenomena in the sacro-iliac joints in combination with a sacral fracture and vacuum phenomena located within the sacral fracture supports a diagnosis of insufficiency fracture or may indeed be the clue by which this diagnosis is established.

Sacral and pubic insufficiency fractures after irradiation of gynaecological malignancies

The association between radiotherapy and insufficiency fractures of the pelvis has not been well documented. Fractures were detected over a 2-year period in eight postmenopausal women who had previously undergone irradiation for gynaecological malignancies. Six of these patients also had local soft tissue complications, such as rectal bleeding and haematuria, in addition to severe low back, buttock or groin pain, caused by the fractures. Plain radiographs were unhelpful in the detection of sacral insufficiency fractures, but showed the pubic fractures in five patients. Diagnoses of insufficiency fractures were made on bone scintigraphic demonstration of the typical 'H' shaped sacral pattern, or the combination of the partial 'H' pattern together with public uptake. Computed tomography was useful for confirmation of insufficiency fractures in doubtful cases. Recognition of insufficiency fractures helps to avoid the pitfalls of misdiagnosing tumour recurrence or bony metastases.

A cohort study with regard to the risk of haematological malignancies in patients treated with x-rays for benign lesions in the locomotor system. II. Estimation of absorbed dose in the red bone marrow

A cohort study with regard to the risk of haematological malignancies was performed on about 20,000 patients who in 1950-1964 received roentgen treatment for benign conditions in the locomotor system. In order to estimate the mean absorbed red bone marrow dose the treatments were classified as concerning 10 sites (cervical spine, thoracic spine, lumbar spine, sacral region, shoulder, hip, elbow, wrist, knee and ankle). The four last-mentioned sites do not normally contain red bone marrow in adults and their contribution to the mean absorbed dose was regarded as zero. For the other 6 sites random samples consisting of 30 patients for each site were drawn from the cohort. By use of the treatment records and data from the literature on some physical parameters and red bone marrow distribution in normal adult persons, average conversion factors were calculated by which the subscribed surface dose could be converted into mean absorbed dose in red bone marrow. These conversion factors were then applied on the whole cohort and used for stratification of it according to different levels of exposure.

Conservative surgery for giant cell tumors of the sacrum. The role of cryosurgery as a supplement to curettage and partial excision

BACKGROUND

Giant cell tumors (GCTs) of the sacrum are a difficult clinical problem. Wide excision (total sacrectomy) is associated with high morbidity and pelvic/spinal instability. Curettage with or without supplemental radiotherapy is associated with a high recurrence rate. In view of the proven effectiveness of cryosurgery as an adjunct to curettage for extremity GCT, cryosurgery was used for treatment of GCTs of the sacrum.

METHODS

Seven patients with GCTs of the sacrum were treated at our institution by conservative surgery from 1973 to 1992. Four patients presented with recurrent tumors after failing previous radiation treatment (dose, 5040 cGy). Four patients were treated with curettage with cryosurgery and three with limited excision with cryosurgery. In the latter procedure after limited excision of the caudal (below S2) part of the tumor, the upper sacral segments were treated with curettage and cryosurgery. This spared the important upper sacral roots and maintained the skeletal integrity.

RESULTS

At a median follow-up of 12.25 years (range, 2-14.2 years), all patients were disease free. Local recurrence developed in two patients. Both of these underwent repeat curettage and cryosurgery and have since remained disease free. Two patients had positive second look biopsy with microscopic tumor. Both of these were treated with repeat cryosurgery and have remained disease free. Two patient who developed solitary pulmonary metastases, underwent wedge resection and are alive without disease. No patient suffered neurologic deterioration.

CONCLUSION

Conservative surgery (curettage or partial excision) with adjunct of cryosurgery is our preferred technique for the treatment of GCT of the sacrum. Satisfactory local control could be obtained by close observation, second look biopsy and repeat cryosurgery. The chief advantages of this method include preservation of pelvic and spinal continuity, speed and ease of surgical procedure and less potential blood loss. We recommend it over more radical sacrectomy due to low morbidity and less resultant neurologic deficits.

Cervical cancer: application of MR imaging in radiation therapy

PURPOSE

To evaluate magnetic resonance (MR) imaging in the planning of radiation therapy for patients with cervical cancer.

MATERIALS AND METHODS

MR imaging was performed in 15 patients with predominantly advanced cervical carcinomas. Skin markings of the radiation ports were labeled with MR-detectable tubing and beads to assess the adequacy of port placement. Volume and extent of tumor at MR imaging were compared with those at physical and computed tomographic (CT) examinations.

RESULTS

Tumor involvement of normal structures (parametrium, vagina, endometrium) was more extensive at MR imaging than at clinical examination in six patients (40%) and at CT in five patients (33%), resulting in modification of the radiation fields in eight patients (53%). Tumor size was larger on MR images than at clinical examination in 11 patients (73%).

CONCLUSION

MR imaging can depict tumor volume and better delineate the extent of involvement than physical and CT examination. This can be useful for placement of radiation ports, especially when small boost fields are used.

Insufficiency fractures of the sacrum after radiotherapy for gynaecological malignancy

An entity is described which is characterized by low back pain and increased radionuclide uptake in the sacrum at bone scintigraphy in postmenopausal women having received radiotherapy towards the pelvis because of gynaecological malignancy. The findings stimulate bone metastases, but are in all likelihood caused by insufficiency fractures of the sacrum promoted by bone weakness induced by postmenopausal osteoporosis and radiotherapy combined. The increased radionuclide activity has a characteristic appearance which in the fully developed fracture acquires the shape of an 'H'. In plain radiography, changes are absent or subtle. The proper complementary examination is CT, in which the fractures can be visualized and malignant changes excluded. Awareness of this benign entity is important to avoid overdiagnosis of bone metastases.

Radiation induced fractures of sacrum: CT diagnosis

Sacral insufficiency fracture due to bone atrophy may develop as a complication of irradiation of pelvic malignancies. Pain is the presenting symptom and the clinical diagnoses most often considered are recurrence of the original malignancy and metastatic disease. Computed tomography provides the most specific information helpful for the detection of these fractures and for exclusion of recurrent malignancy.