Usefulness of tumor volumetry by magnetic resonance imaging in assessing response to radiation therapy in carcinoma of the uterine cervix

Mid-treatment MRI-based tumor response assessment for tumor recurrence and patient survival in locally advanced adenocarcinoma of the cervix: A retrospective multicenter study of KROG 23-03

OBJECTIVE

To evaluate the significance of response assessment with magnetic resonance imaging (MRI) during chemoradiotherapy (CRT) for outcomes of adenocarcinoma of the cervix.

METHODS

A retrospective analysis of 102 patients diagnosed with FIGO 1B3-IVa cervical adenocarcinoma was conducted. Patients underwent definitive CRT and brachytherapy. Mid-treatment MRI-assessments were used to evaluate tumor response during radiotherapy, focusing on tumor volume reduction rate (TVRR), which was defined as an optimal reduction rate from initial tumor volume for tumor progression. Locoregional recurrence (LRR), distant metastasis (DM), progression-free survival (PFS) and overall survival (OS) rates according to the tumor response were analyzed.

RESULTS

Forty-five (44.1 %) of 102 patients experienced tumor downstaging during CRT, with 72 (70.5 %) demonstrating a complete response on post-treatment MRI three months after radiotherapy. With a median follow-up of 35.5 months, the 3-year PFS and overall OS rates for all patients were 60.0 % and 84.0 %, respectively. LRR and DM rates at 3 years were 25.2 % and 23.3 %, respectively. Patients with TVRR≥81.8 % had significantly longer 3-year PFS (75.4 % vs. 36.2 %, P < 0.001) and OS (93.2 % vs. 69.0 %, P = 0.002) rates than the other patients with TVRR<81.8 %. LRR (10.6 % vs. 45.6 %, P = 0.003) and DM (14.6 % vs. 33.5 %, P = 0.008) rates at 3 years were significantly lower in TVRR≥81.8 % group compared to TVRR<81.8 % group. In the multivariate analysis, positive initial lymph node (hazard ratio [HR], 2.11; confidence interval [CI], 1.25-3.87; P = 0.02] and TVRR (HR, 0.42; CI, 0.19-0.93; P = 0.03) were significantly associated with PFS.

CONCLUSION

Mid-treatment MRI assessment is crucial and higher rates of tumor volume reduction during radiotherapy indicates better prognosis for tumor recurrence and patient survival in cervical adenocarcinoma.

The clinical practice and dosimetric outcome of the manual adaptive planning during definitive radiotherapy for cervical cancer

PROPOSE

To evaluate the advantage of the manual adaptive plans comparing to the scheduled plans, and explored clinical factors predicting patients suitable for adaptive strategy.

METHODS AND MATERIALS

Eighty two patients with weekly online cone-beam computed tomography (CBCT) were enrolled. The re-CT simulation was performed after 15 fractions and a manual adaptive plan was developed if a significant deviation of the planning target volume (PTV) was found. To evaluate the dosimetric benefit, D98, homogeneity index (HI) and conformity index (CI) for the planning target volume (PTV), as well as D2cc of the bowel, bladder, sigmoid and rectum were compared between manual adaptive plans and scheduled ones. The clinical factors influencing target motion during radiotherapy were analyzed by chi-square test and logistic regression analysis.

RESULTS

The CI and HI of the manual adaptive plans were significantly superior to the scheduled ones (P = 0.0002, 0.003, respectively), demonstrating a better dose coverage of the target volume. Compared to the scheduled plans, D98 of the manual adaptive plans increased by 3.3% (P = 0.0002), the average of D2cc to the rectum, bladder decreased 0.358 Gy (P = 0.000034) and 0.240 Gy (P = 0.03), respectively. In addition, the chi-square test demonstrated that age, primary tumor volume, and parametrial infiltration were the clinical factors influencing target motion during radiotherapy. Multivariate analysis further identified the large tumor volume (≥ 50cm3, OR = 3.254, P = 0.039) and parametrial infiltration (OR = 3.376, P = 0.018) as the independent risk factors.

CONCLUSION

We found the most significant organ motion happened after 15 fractions during treatment. The manual adaptive plans improved the dose coverage and decreased the OAR doses. Patients with bulky mass or with parametrial infiltration were highly suggested to adaptive strategy during definitive radiotherapy due to the significant organ motion.

Usefulness of Short-Term Imaging and Squamous Cell Carcinoma Antigen to Early Predict Response to Concurrent Chemoradiotherapy in Patients With Cervical Cancer

OBJECTIVE

The objective is to investigate the factors that can predict early treatment response in patients receiving concurrent chemoradiotherapy (CCRT) for cervical cancer.

METHODS

We assessed clinical factors and treatment response in patients who underwent CCRT for cervical cancer at four time points: initial, 2.5 weeks, 6 weeks after starting CCRT, and 3 months after completing CCRT. The final treatment response was determined by positron emission tomography-computed tomography (PET-CT) 3 months after completion of CCRT. Patients were divided into two groups according to the final treatment response: complete response (CR) group or non-CR group. And the early CCRT response prediction model was developed using stepwise multivariate logistic regression analysis.

RESULTS

Of the 62 patients who underwent CCRT for cervical cancer, 57 patients who completed all 4 time points examinations were included in the analyses and classified as CR (n = 32) and non-CR (n = 25) group. Tumor volume and serum squamous cell carcinoma antigen (SCC Ag) of the initial, 2.5 weeks, and 6 weeks after CCRT were significantly associated with the final treatment response. For the early treatment response prediction model, we selected patient age, tumor volume, and SCC Ag measured at initial and 2.5 weeks of CCRT as variables, and the equation of the final model was yielded. Using a cutoff of 0.433, this model had a sensitivity of 72.0%, a specificity of 84.4%, and a probability of 0.8225 (P < .0001).

CONCLUSION

Short-term (at 2.5 weeks after starting CCRT) measurements of tumor volume and serum SCC Ag were significant predictors of response to CCRT in patients with cervical cancer.

Correlations of UICC tumor stage and tumor regression on T2-weighted MRI sequences during definitive radiotherapy of cervical cancer

BACKGROUND

The purpose of this study is to detect a correlation between the preradiation tumor staging and the relative volumetric regression of the primary tumor through external beam radiation therapy (EBRT).

METHODS

Clinical data of 32 patients with a mean age of 60±12 years treated with primary radiation therapy (RT) of cervical carcinoma were analyzed. Union Internationale Contre le Cancer (UICC) stages were T1 = 4 patients, T2 = 15 patients, T3 = 8 patients, T4 = 5 patients; N1 = 26 patients, N0 = 6 patients; and M0 = 25 patients, M1 = 7 patients. All patients received pelvic magnetic resonance imaging (MRI) before RT as well as during RT. The cervical primary tumor was delineated as gross tumor volume (ptGTV) in T2-weighted MRI sequences. We compared ptGTV reduction by stage, lymph node status, metastatic status, and grading.

RESULTS

Mean ptGTV reduction during RT was 61.4±28.9%. T1 tumors shrank by 88.2±13.4%, T2 by 67.6±28.7%, T3 by 50.8±23.6%, and T4 by 38.7±27.2%. The difference in tumor shrinkage was statistically significant between the lower T stages and the higher T stages (p < 0.05). There was no statistical difference in the mean ptGTV before treatment in the group with lymph node metastases (LNM) (54.1±47.7 cm³) as compared to the group without LNM (76.6±52.2 cm³). Nonetheless, ptGTV shrank significantly differently: by 68.9±25.7% (N1 patients) and by 29.0±17.7% (N0 patients). No significant differences in ptGTV shrinkage were observed in M0 versus M1 and G2 versus G3 tumors.

CONCLUSION

There is a correlation between mean ptGTV reduction during EBRT and tumor stages. Tumors with higher T stages shrank less under radiation treatment, and the ptGTV of N1 patients responded better than that of N0 patients.

Comparative radiological pathological study of biliary intraductal tubulopapillary neoplasm and biliary intraductal papillary mucinous neoplasm

PURPOSE

Biliary tract intraductal tubulopapillary neoplasms (BT-ITPNs) and intraductal papillary mucinous neoplasms (BT-IPMNs) are rare and poorly described. Herein, we examined the magnetic resonance imaging (MRI) features of BT-ITPNs and BT-IPMNs and correlated them with key gross and microscopic pathological findings.

METHODS

We retrospectively identified five patients with definitive pathological findings of BT-ITPN and available diagnostic MRI findings. Key MRI features were correlated to the gross and microscopic pathology and compared to those of BT-IPMNs (19 patients).

RESULTS

All BT-ITPNs showed ductal dilatation and visible intraductal soft tissue with peribiliary liver parenchyma enhancement. One BT-ITPN patient had synchronous lung metastases, and another showed rapid tumor growth rate. The intraductal soft tissue proportion of BT-ITPNs was significantly more than that of BT-IPMNs (p < 0.05). CA-199 level was elevated in 60% of BT-ITPN cases. The overall combined 1-year and 3-year survival rates in the BT-ITPN group was 100% and 40%, and in the BT-IPMN group was 100% and 58%, respectively. A high intraductal soft tissue proportion, a lack of intraluminal mucin, and immunohistochemical absence of MUC5AC are radiological and pathological characteristics that differentiate BT-ITPN from BT-IPMN.

CONCLUSIONS

Although rare, BT-ITPN should be suspected when solid intraductal soft tissue and peribiliary liver parenchyma enhancement are present, particularly if the bile duct upstream and downstream of the lesion have a normal diameter, without mucin. Owing to the aggressive nature of the tumor, recognition of these features may indicate the need for more aggressive treatment in selected patients.

Effect of bladder distension on doses to organs at risk in Pulsed-Dose-Rate 3D image-guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

To evaluate the impact of bladder distension on doses to organs at risk in patients treated with 3D image-guided adaptive pulsed-dose-rate (PDR) brachytherapy (BT) for locally advanced cervical cancer.

METHODS AND MATERIALS

Twenty-two patients who had previously been treated by external beam radiation therapy (EBRT), underwent BT treatment planning to a pelvic MRI (or a CT scan in case of contraindication) after their bladder was filled with 100 cc of physiological saline (full bladder). This was immediately followed by a CT scan after emptying of the bladder. A fusion of these two examinations was conducted, and the dosimetry was duplicated for the study with an empty bladder. Equieffective doses of 2 Gy per fraction from EBRT and BT of bladder/rectum/sigmoid colon/small bowel were compared.

RESULTS

A full bladder condition was found to be non-inferior in terms of the bladder D2cc (a difference of -0.9 Gy; 97.5% CI [-∞; 2.6]), and it resulted in a reduction in the bladder D0.1cc (p = 0.038). Bladder expansion resulted in a significant reduction of maximum doses received by the small bowel, both in terms of the D0.1cc (51.2 Gy vs. 63.4 Gy, p < 0.001) and the D2cc (48.5 Gy vs. 53.6 Gy, p < 0.001). A negative correlation was seen between the difference in the small bowel D2cc and the body mass index; (r = -0.55; p = 0.008). No differences were noted in regard to doses to the rectum and sigmoid colon.

CONCLUSIONS

Bladder distension with 100 cc of physiological saline can reduce maximum doses received by the small bowel without the alteration of the doses received by the other organs at risk during a 3D image-guided adaptive PDR BT for locally advanced cervical cancer. However, the maintenance of a predefined bladder volume is difficult to achieve with PDR BT, whereas it could be easily managed before each session in case of high-dose-rate BT.

Magnetic Resonance Imaging of Gynecological Malignancies: Role in Personalized Management

Gynecological malignancies are a leading cause of mortality and morbidity in women and pose a significant health problem around the world. Currently used staging systems for management of gynecological malignancies have unresolved issues, the most important being recommendations on the use of imaging. Although not mandatory as per the International Federation of Gynecology and Obstetrics recommendations, preoperative cross-sectional imaging is strongly recommended for adequate and optimal management of patients with gynecological malignancies. Standardized disease-specific magnetic resonance imaging protocols help assess disease spread accurately and avoid pitfalls. Multiparametric imaging holds promise as a roadmap to personalized management in gynecological malignancies. In this review, we will highlight the role of magnetic resonance imaging in cervical, endometrial, and ovarian carcinomas.

Implementation of image-guided brachytherapy (IGBT) for patients with uterine cervix cancer: a tumor volume kinetics approach

Purpose

To evaluate tumor shrinking kinetics in order to implement image-guided brachytherapy (IGBT) for the treatment of patients with cervix cancer.

Material and methods

This study has prospectively evaluated tumor shrinking kinetics of thirteen patients with uterine cervix cancer treated with combined chemoradiation. Four high dose rate brachytherapy fractions were delivered during the course of pelvic external beam radiation therapy (EBRT). Magnetic resonance imaging (MRI) exams were acquired at diagnosis (D), first (B1), and third (B3) brachytherapy fractions. Target volumes (GTV and HR-CTV) were calculated by both the ellipsoid formula (VE) and MRI contouring (VC), which were defined by a consensus between at least two radiation oncologists and a pelvic expert radiologist.

Results

Most enrolled patients had squamous cell carcinoma and FIGO stage IIB disease, and initiated brachytherapy after the third week of pelvic external beam radiation. Gross tumor volume volume reduction from diagnostic MRI to B1 represented 61.9% and 75.2% of the initial volume, when measured by VE and VC, respectively. Only a modest volume reduction (15-20%) was observed from B1 to B3.

Conclusions

The most expressive tumor shrinking occurred in the first three weeks of oncological treatment and was in accordance with gynecological examination. These findings may help in IGBT implementation.

Consecutive magnetic resonance imaging during brachytherapy for cervical carcinoma: predictive value of volume measurements with respect to persistent disease and prognosis

BACKGROUND

Cervical cancer is associated with a high yearly mortality. The presence of persistent disease after radiotherapy is a significant predictor of patient survival. The aim of our study was to assess if tumor volume regression measured with MR imaging at the time of brachytherapy can discriminate between patients who eventually will achieve a complete response to radiotherapy from those who will not. The second objective was to evaluate whether tumor volume regression predicts overall treatment failure.

METHODS

MRI was evaluated quantitatively in 35 patients; by means of tumor volumetry on T2-weighted MR images before treatment, at the first BCT application, and at the final BCT. The MR images were independently analyzed by two investigators. As a reference standard histopathologic confirmation of residual tumor and/or clinical exam during follow-up > 1 year were used. Area under the curve were compared, P-values <0.05 were considered significant.

RESULTS

There was a good correlation between volume measurements made by the two observers. A residual tumor volume >9.4 cm(3) at final BCT and tumor volume regression < 77 % of the pre-treatment volume were significantly associated with local residual tumor after completion of therapy (p < 0.02) (AUC, 0.98-1.00). A volume >2.8 cm(3) at final BCT was associated with overall treatment failure (p < 0.03).

CONCLUSION

Our study shows that volume analysis during BCT is a predictive tool for local tumor response and overall treatment outcome. The potential of local response assessment to identify patients at high risk of overall treatment failure is promising.

Onset time of tumor repopulation for cervical cancer: first evidence from clinical data

PURPOSE

Accelerated tumor repopulation has significant implications in low-dose rate (LDR) brachytherapy. Repopulation onset time remains undetermined for cervical cancer. The purpose of this study was to determine the onset time of accelerated repopulation in cervical cancer, using clinical data.

METHODS AND MATERIALS

The linear quadratic (LQ) model extended for tumor repopulation was used to analyze clinical data and magnetic resonance imaging-based three-dimensional tumor volumetric regression data from 80 cervical cancer patients who received external beam radiotherapy (EBRT) and LDR brachytherapy. The LDR dose was converted to EBRT dose in 1.8-Gy fractions by using the LQ formula, and the total dose ranged from 61.4 to 99.7 Gy. Patients were divided into 11 groups according to total dose and treatment time. The tumor control probability (TCP) was calculated for each group. The least χ(2) method was used to fit the TCP data with two free parameters: onset time (T(k)) of accelerated repopulation and number of clonogens (K), while other LQ model parameters were adopted from the literature, due to the limited patient data.

RESULTS

Among the 11 patient groups, TCP varied from 33% to 100% as a function of radiation dose and overall treatment time. Higher dose and shorter treatment duration were associated with higher TCP. Using the LQ model, we achieved the best fit with onset time T(k) of 19 days and K of 139, with uncertainty ranges of (11, 22) days for T(k) and (48, 1822) for K, respectively.

CONCLUSION

This is the first report of accelerated repopulation onset time in cervical cancer, derived directly from clinical data by using the LQ model. Our study verifies the fact that accelerated repopulation does exist in cervical cancer and has a relatively short onset time. Dose escalation may be required to compensate for the effects of tumor repopulation if the radiation therapy course is protracted.

Method of tumor volume evaluation using magnetic resonance imaging for outcome prediction in cervical cancer treated with concurrent chemotherapy and radiotherapy

PURPOSE

To evaluate the patterns of tumor shape and to compare tumor volume derived from simple diameter-based ellipsoid measurement with that derived from tracing the entire tumor contour using region of interest (ROI)-based 3D volumetry with respect to the prediction outcome in cervical cancer patients treated with concurrent chemotherapy and radiotherapy.

MATERIALS AND METHODS

Magnetic resonance imaging was performed in 98 patients with cervical cancer (stage IB-IIIB). The tumor shape was classified into two categories: ellipsoid and non-ellipsoid shape. ROI-based volumetry was derived from each magnetic resonance slice on the work station. For the diameter-based surrogate "ellipsoid volume," the three orthogonal diameters were measured to calculate volume as an ellipsoid.

RESULTS

The more than half of tumor (55.1%) had a non-ellipsoid configuration. The predictions for outcome were consistent between two volume groups, with overall survival of 93.6% and 87.7% for small tumor (<20 mL), 62.9% and 69.1% for intermediate-size tumor (20-39 mL), and 14.5% and 16.7% for large tumors (≥40 mL) using ROI and diameter based measurement, respectively. Disease-free survival was 93.8% and 90.6% for small tumor, 54.3% and 62.7% for intermediate-size tumor, and 13.7% and 10.3% for large tumor using ROI and diameter based method, respectively. Differences in outcome between size groups were statistically significant, and the differences in outcome predicted by the tumor volume by two different methods.

CONCLUSION

Our data suggested that large numbers of cervical cancers are not ellipsoid. However, simple diameter-based tumor volume measurement appears to be useful in comparison with ROI-based volumetry for predicting outcome in cervical cancer patients.

American Brachytherapy Society consensus guidelines for locally advanced carcinoma of the cervix. Part I: general principles

PURPOSE

To develop brachytherapy recommendations covering aspects of pretreatment evaluation, treatment, and dosimetric issues for locally advanced cervical cancer.

METHODS

Members of the American Brachytherapy Society (ABS) with expertise in cervical cancer brachytherapy formulated updated recommendations for locally advanced (Federation of Gynecology and Obstetrics Stages IB2-IVA) cervical cancer based on literature review and clinical experience.

RESULTS

The ABS recommends the use of brachytherapy as a component of the definitive treatment of locally advanced cervical carcinoma. Precise applicator placement is necessary to maximize the probability of achieving local control without major side effects. The ABS recommends a cumulative delivered dose of approximately 80-90Gy for definitive treatment. The dose delivered to point A should be reported for all brachytherapy applications regardless of treatment-planning technique. The ABS also recommends adoption of the Groupe Européen Curiethérapie-European Society of Therapeutic Radiation Oncology (GEC-ESTRO) guidelines for contouring, image-based treatment planning, and dose reporting. Interstitial brachytherapy may be considered for a small proportion of patients whose disease cannot be adequately encompassed by intracavitary application. It should be performed by practitioners with special expertise in these procedures.

CONCLUSIONS

Updated ABS recommendations are provided for brachytherapy for locally advanced cervical cancer. Practitioners and cooperative groups are encouraged to use these recommendations to formulate their clinical practices and to adopt dose-reporting policies that are critical for outcome analysis.

Assessment of response to chemoradiation therapy in rectal cancer using MR volumetry based on diffusion-weighted data sets: a preliminary report

PURPOSE

This study evaluated the feasibility of magnetic resonance (MR) volumetry using a diffusion-weighted data set (V(DWI)) and compared it with conventional T2-weighted volumetry (V(C)) in patients affected by rectal cancer treated with chemoradiation therapy (CHRT).

MATERIALS AND METHODS

Fourteen patients with a biopsy diagnosis of rectal cancer underwent MR examination before and after CHRT. T2-weighted images were used to extrapolate V(C). A diffusion-weighted (DW) sequence was acquired [spin-echo diffusion-weighted echo-planar imaging (SE-DW-EPI)] with a b-value of 800 s/mm(2) and volume (V(DWI)) was calculated by semiautomatic segmentation of tumour hyperintensity. Two radiologists independently assessed volumes and analysed data in order to establish interobserver agreement and compare and correlate volumes to tumour regression grade (TRG), as evaluable at pathological examination of the surgical specimen.

RESULTS

Interobserver agreement was 0.977 [(95% confidence interval (CI) 0.954-0.989) and 0.956 (95% CI 0.905-0.980) for V(C) and V(DWI) and 0.964 (95% CI 0.896-0.988) and 0.271 (95% CI-0.267 to 0.686) between V(C) and V(DWI) before and after CHRT. The correlation between TRG and V(C) and V(DWI) was, respectively, rho = 0.597 (p<0.05) and r(2)=0.156 (p=0.162) and rho=0.847 (p<0.001).

CONCLUSIONS

V(DWI) seems to be a promising tool for assessing response to CHRT in rectal cancer. Further studies on large series of patients are needed to refine the technique and evaluate its potential predictive value.

Recommendations from Gynaecological (GYN) GEC-ESTRO Working Group (IV): Basic principles and parameters for MR imaging within the frame of image based adaptive cervix cancer brachytherapy

The GYN GEC-ESTRO working group issued three parts of recommendations and highlighted the pivotal role of MRI for the successful implementation of 3D image-based cervical cancer brachytherapy (BT). The main advantage of MRI as an imaging modality is its superior soft tissue depiction quality. To exploit the full potential of MRI for the better ability of the radiation oncologist to make the appropriate choice for the BT application technique and to accurately define the target volumes and the organs at risk, certain MR imaging criteria have to be fulfilled. Technical requirements, patient preparation, as well as image acquisition protocols have to be tailored to the needs of 3D image-based BT. The present recommendation is focused on the general principles of MR imaging for 3D image-based BT.

Methods and parameters have been developed and progressively validated from clinical experience from different institutions (IGR, Universities of Vienna, Leuven, Aarhus and Ljubljana) and successfully applied during expert meetings, contouring workshops, as well as within clinical and interobserver studies.

It is useful to perform pelvic MRI scanning prior to radiotherapy (“Pre-RT-MRI examination”) and at the time of BT (“BT MRI examination”) with one MR imager. Both low and high-field imagers, as well as both open and close magnet configurations conform to the requirements of 3D image-based cervical cancer BT. Multiplanar (transversal, sagittal, coronal and oblique image orientation) T2-weighted images obtained with pelvic surface coils are considered as the golden standard for visualisation of the tumour and the critical organs. The use of complementary MRI sequences (e.g. contrast-enhanced T1-weighted or 3D isotropic MRI sequences) is optional. Patient preparation has to be adapted to the needs of BT intervention and MR imaging. It is recommended to visualise and interpret the MR images on dedicated DICOM-viewer workstations, which should also assist the contouring procedure. Choice of imaging parameters and BT equipment is made after taking into account aspects of interaction between imaging and applicator reconstruction, as well as those between imaging, geometry and dose calculation.

In a prospective clinical context, to implement 3D image-based cervical cancer brachytherapy and to take advantage of its full potential, it is essential to successfully meet the MR imaging criteria described in the present recommendations of the GYN GEC-ESTRO working group.

Characterizing at-Risk Voxels by Using Perfusion Magnetic Resonance Imaging for Cervical Cancer during Radiotherapy

The number of voxels with low signal intensity (Low DCE voxels) might be potentially related to treatment failure, which might be associated with the tumor oxygenation status. Our goal was to investigate whether at-risk voxels can be used to predict treatment outcome during radiation therapy for cervical cancer. 80 patients with Stage IB2-IVB cervical cancer were included. Four sequential MRI scans were performed at pre-RT, every 2-2.5 weeks during RT, and post-radiotherapy. 3D volumetric data including tumor regression and tumor perfusion from dynamic contrast enhanced MRI (DCE-MRI) were analyzed. Based on the signal intensity (SI) curves of the DCE-MRI, the low-DCE tumor voxels was obtained for individual patients. The predictive power of low DCE voxels in predicting the treatment outcomes was evaluated by Kaplan-Meier survival analysis. Correlation of low DCE voxels with hemoglobin (Hgb) was checked by Pearson Correlation. The actuarial local control rate and survival rate in the patient group with a small number of low DCE voxels were 89.7% and 76.9%, compared with 75.6% and 51.2% in the patient group with a big number of low DCE voxels for the MRI study #1, and 94.1% and 80.4% compared with 62.1% and 34.5% for the MRI study #2, and 95.7% and 78.7% compared with 63.6% and 42.4% for the MRI study #3, respectively. Low DCE voxels were significantly correlated with Hgb. At-risk voxels can be used to predict the outcomes and help understand tumor heterogeneity of response to RT. The Hgb level and tumor perfusion during RT influence the radioresponsiveness and survival in cervical cancer patients.

No correlation between pretreatment serum CEA levels and tumor volume in locally advanced rectal cancer patients

BACKGROUND

Although serum carcinoembryonic antigen (CEA) levels reflect tumor volume in rectal cancer patients intrapersonally, it is unclear interpersonally. We determined the correlation between pretreatment serum CEA levels and tumor volume.

METHODS

A total of 489 patients with locally advanced primary rectal cancer who underwent preoperative chemoradiotherapy followed by surgery between October 2001 and April 2007 were retrospectively evaluated. CEA levels were measured by chemiluminescent microparticle immunoassay, and magnetic resonance (MR) volumetry was performed using MR data. The correlation between CEA levels and tumor volume was assessed using linear regression analysis and one-way analysis of variance. The prognostic values of CEA levels and tumor volume for survival were evaluated.

RESULTS

There was no significant correlation between CEA levels and tumor volume. The five-year overall survival and disease-free survival were 89.0%, 80.6% and 82.9%, and 72.0%, 70.0% and 60.3% in patients with CEA levels of ≤3 ng/ml, >3-10 ng/ml, and >10 ng/ml, respectively. Tumor volume had no prognostic value for either overall survival or disease-free survival

CONCLUSIONS

Pretreatment serum CEA levels were not correlated with tumor volume. While there was no correlation between tumor volume and survival, there was a positive correlation between CEA levels and survival.

Correlation between tumor size and surveillance of lymph node metastasis for IB and IIA cervical cancer by magnetic resonance images

PURPOSE

To assess the feasibility of preoperative MRI based measurement of tumor size with regard to lymph node (LN) metastasis in early uterine cervical cancer.

MATERIAL AND METHODS

A retrospective review of patients with FIGO stage IB-IIA cervical cancer who underwent lymphadenectomy was performed. Diagnostic accuracy of MRI in detecting LN metastasis and rate of LN recurrence in terms of tumor size (≤4cm versus >4cm) were analyzed. ROC curve analysis was used to determine LN size for differentiating LN metastasis in terms of tumor size. P<0.05 was considered statistically significant.

RESULTS

Of the 200 patients, 45 (22.3%) had LN metastasis. There was no statistical difference between patients-based and region-specific analysis. The patients with tumor size with >4cm revealed higher diagnostic accuracy of MRI in detecting LN metastasis (85.4% versus 50.6%, P=0.023) and rate of LN recurrence (20.0% versus 6.4%, P=0.031) in than those with size with ≤4cm, the differences were statistically significant. Discriminant analysis of LN size for the differentiation of metastasis from non-metastasis resulted in cut-off values (11.8mm; size with >4cm versus 8.3mm; size with ≤4cm) and diagnostic accuracy (84.0% of size with >4cm versus 72.0% of size with ≤4cm).

CONCLUSION

MRI has limited sensitivity, but high specificity in predicting surveillance of LN metastasis in the preoperative early cervical cancer, especially useful tool for patients with tumor size with >4cm.

Prognostic significance of tumor volume in nasopharyngeal carcinoma

OBJECTIVE

To investigate the prognostic significance of primary and residual tumor volume in nasopharyngeal carcinoma.

METHODS

56 patients were included in the study. Diameters of tumors were measured from CT and MR film hardcopies. Diameter-based measurements were computed as an ellipsoid (V=4/3·π·d1·d2·d3) to calculate diameter-based volume. It was investigated whether primary tumor volume provided prognostic information about local regional recurrence free survival (LRRFS), disease free survival (DFS), distant metastasis free survival (DMFS) and overall survival (OS) by monovariant and multivariant analysis. Kaplan-Meier survival analysis method and log-rank test were used to estimate survival analysis (95% confidence interval). Cox regression test was used for two variant and multivariant survival analysis. Statistical Package for Social Sciences (SSSP) 10.0 for Windows programme was used for data analysis.

RESULTS

In the multivariate analysis, in the patients with tumor volume more than 60ml, local regional recurrence more frequently developed. The relationship between tumor volume and local regional recurrence was found significant (p=0.053). In the monovariate analysis, primary tumor volume was found to be a significant predictive value on DFS and DMFS. In the patients with tumor volume below 20ml, DFS was 60%, whereas in the patients with tumor volume above 60ml, DFS was 0% (p=0.007). The prevalence were 68% and 0% in the patients group that had tumor volume below 30ml and above 60ml respectively. DMSF ratios in the patients with primary tumor volume below 20ml and above 60ml were 86.67% and 33.3% respectively. The residual tumor volume (RTV) at first control after treatment was found to be a significant prognostic factor on LRRFS (p=0.03).

CONCLUSION

The foundation of new T staging systems that consists of PTV that was found as an independent prognostic factor alone in multivariate statistical analysis may precede better prediction of prognosis and more appropriate treatment of patients having different prognostic factors. RTV in the first control after treatment was a significant prognostic factor on LRRFS.

Sequential magnetic resonance imaging of cervical cancer: the predictive value of absolute tumor volume and regression ratio measured before, during, and after radiation therapy

BACKGROUND

The objectives of this study were to investigate outcome prediction by measuring absolute tumor volume and regression ratios using serial magnetic resonance imaging (MRI) during radiation therapy (RT) for cervical cancer and to develop algorithms capable of identifying patients at risk of a poor therapeutic outcome.

METHODS

Eighty patients with stage IB2 through IVA cervical cancer underwent 4 MRI scans: before RT (MRI1), during RT at 2 to 2.5 weeks (MRI2) at 4 to 5 weeks (MRI3), and 1 to 2 months after RT (MRI4). The median follow-up was 6.2 years (range, 0.2-9.4 years). Tumor volumes at MRI1, MRI2, MRI3, and MRI4 (V1, V2, V3, and V4, respectively) and tumor regression ratios (V2/V1, V3/V1, and V4/V1) were measured by 3-dimensional volumetry. Predictive metrics based on tumor volume/regression parameters were correlated with ultimate clinical outcomes, including tumor local recurrence (LR) and dying of disease (DOD). Predictive power was evaluated using the Mann-Whitney test, sensitivity/specificity analyses, and Kaplan-Meier analyses.

RESULTS

Both tumor volume and regression ratio were strongly correlated with LR (P=.06, P = 5×10(-4), P=1×10(-6), and P=2×10(-8) for V1, V2, V3, and V4, respectively; and P=7×10(-5), P=1×10(-6), and P=1×10(-8) for V2/V1, V3/V1, and V4/V1, respectively) and DOD (P=.015, P=.004, P=.001, and P=3×10(-4) for V1, V2, V3, and V4, respectively; and P=.03, P=.009, and P=3×10(-4) for V2/V1, V3/V1, and V4/V1, respectively). Algorithms that combined tumor volumes and regression ratios improved predictive power (sensitivity, 61%-89%; specificity, 79%-100%). The strongest predictor, pre-RT volume and regression ratio at MRI3 (V1>40 cm3 and V3/V1>20%, respectively), achieved 89% sensitivity, 87% specificity, and 88% accuracy for LR and achieved 54% sensitivity, 83% specificity, and 73% accuracy for DOD.

CONCLUSIONS

The current results suggested that tumor volume/regression parameters obtained during primary therapy are useful in predicting LR and DOD. Both tumor volume and regression ratio provided important information as early outcome predictors that may guide early intervention for patients with cervical cancer who are at high risk of treatment failure.

Ultra-early predictive assay for treatment failure using functional magnetic resonance imaging and clinical prognostic parameters in cervical cancer

BACKGROUND

The authors prospectively evaluated magnetic resonance imaging (MRI) parameters quantifying heterogeneous perfusion pattern and residual tumor volume early during treatment in cervical cancer, and compared their predictive power for primary tumor recurrence and cancer death with the standard clinical prognostic factors. A novel approach of augmenting the predictive power of clinical prognostic factors with MRI parameters was assessed.

METHODS

Sixty-two cervical cancer patients underwent dynamic contrast-enhanced (DCE) MRI before and during early radiation/chemotherapy (2-2.5 weeks into treatment). Heterogeneous tumor perfusion was analyzed by signal intensity (SI) of each tumor voxel. Poorly perfused tumor regions were quantified as lower 10th percentile of SI (SI[10%]). DCE-MRI and 3-dimensional (3D) tumor volumetry MRI parameters were assessed as predictors of recurrence and cancer death (median follow-up, 4.1 years). Their discriminating capacity was compared with clinical prognostic factors (stage, lymph node status, histology) using sensitivity/specificity and Cox regression analysis.

RESULTS

SI(10%) and 3D volume 2-2.5 weeks into therapy independently predicted disease recurrence (hazard ratio [HR], 2.6; 95% confidence interval [95% CI], 1.0-6.5 [P = .04] and HR, 1.9; 95% CI, 1.1-3.5 [P = .03], respectively) and death (HR, 1.9; 95% CI, 1.0-3.5 [P = .03] and HR, 1.9; 95% CI, 1.2-2.9 [P = .01], respectively), and were superior to clinical prognostic factors. The addition of MRI parameters to clinical prognostic factors increased sensitivity and specificity of clinical prognostic factors from 71% and 51%, respectively, to 100% and 71%, respectively, for predicting recurrence, and from 79% and 54%, respectively, to 93% and 60%, respectively, for predicting death.

CONCLUSIONS

MRI parameters reflecting heterogeneous tumor perfusion and subtle tumor volume change early during radiation/chemotherapy are independent and better predictors of tumor recurrence and death than clinical prognostic factors. The combination of clinical prognostic factors and MRI parameters further improves early prediction of treatment failure and may enable a window of opportunity to alter treatment strategy.

Predicting outcomes in cervical cancer: a kinetic model of tumor regression during radiation therapy

Applications of mathematical modeling can improve outcome predictions of cancer therapy. Here we present a kinetic model incorporating effects of radiosensitivity, tumor repopulation, and dead-cell resolving on the analysis of tumor volume regression data of 80 cervical cancer patients (stages 1B2-IVA) who underwent radiation therapy. Regression rates and derived model parameters correlated significantly with clinical outcome (P < 0.001; median follow-up: 6.2 years). The 6-year local tumor control rate was 87% versus 54% using radiosensitivity (2-Gy surviving fraction S(2) < 0.70 vs. S(2) > or = 0.70) as a predictor (P = 0.001) and 89% vs. 57% using dead-cell resolving time (T(1/2) < 22 days versus T(1/2) > or = 22 days, P < 0.001). The 6-year disease-specific survival was 73% versus 41% with S(2) < 0.70 versus S(2) > or = 0.70 (P = 0.025), and 87% vs. 52% with T(1/2) < 22 days versus T(1/2) > or = 22 days (P = 0.002). Our approach illustrates the promise of volume-based tumor response modeling to improve early outcome predictions that can be used to enable personalized adaptive therapy.

Tumor volume reduction rate measured by magnetic resonance volumetry correlated with pathologic tumor response of preoperative chemoradiotherapy for rectal cancer

PURPOSE

To determine whether the tumor volume reduction rate (TVRR) measured using three-dimensional region-of-interest magnetic resonance volumetry correlates with the pathologic tumor response after preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer.

METHODS AND MATERIALS

The study included 405 patients with locally advanced rectal cancer (cT3-T4) who had undergone preoperative CRT and radical proctectomy. The tumor volume was measured using three-dimensional region-of-interest magnetic resonance volumetry before and after CRT but before surgery. We analyzed the correlation between the TVRR and the pathologic tumor response in terms of downstaging and tumor regression grade (TRG). Downstaging was defined as ypStage 0-I (ypT0-T2N0M0), and the TRG proposed by Dworak et al. was used.

RESULTS

The mean TVRR was 65.0% +/- 22.3%. Downstaging and complete regression occurred in 167 (41.2%) and 58 (14.3%) patients, respectively. The TVRRs according to ypT classification (ypT0-T2 vs. ypT3-T4), ypN classification (ypN0 vs. ypN1-N2), downstaging (ypStage 0-I vs. ypStage II-III), good regression (TRG 3-4 vs. TRG 1-2), and complete regression (TRG 4 vs. TRG 1-3) were all significantly different (p <.05). When the TVRR was categorized into three groups (<60%, 60-80%, and >80%), the rates of ypT0-T2, ypN0, downstaging, and good regression were all significantly greater for patients with a TVRR of >or=60%, as was the complete regression rate for patients with a TVRR >80% (p <.05).

CONCLUSION

The TVRR measured using three-dimensional region-of-interest magnetic resonance volumetry correlated significantly with the pathologic tumor response in terms of downstaging and TRG after preoperative CRT for locally advanced rectal cancer.

Translating response during therapy into ultimate treatment outcome: a personalized 4-dimensional MRI tumor volumetric regression approach in cervical cancer

PURPOSE

To assess individual volumetric tumor regression pattern in cervical cancer during therapy using serial four-dimensional MRI and to define the regression parameters' prognostic value validated with local control and survival correlation.

METHODS AND MATERIALS

One hundred and fifteen patients with Stage IB(2)-IVA cervical cancer treated with radiation therapy (RT) underwent serial MRI before (MRI 1) and during RT, at 2-2.5 weeks (MRI 2, at 20-25 Gy), and at 4-5 weeks (MRI 3, at 40-50 Gy). Eighty patients had a fourth MRI 1-2 months post-RT. Mean follow-up was 5.3 years. Tumor volume was measured by MRI-based three-dimensional volumetry, and plotted as dose(time)/volume regression curves. Volume regression parameters were correlated with local control, disease-specific, and overall survival.

RESULTS

Residual tumor volume, slope, and area under the regression curve correlated significantly with local control and survival. Residual volumes >or=20% at 40-50 Gy were independently associated with inferior 5-year local control (53% vs. 97%, p <0.001) and disease-specific survival rates (50% vs. 72%, p = 0.009) than smaller volumes. Patients with post-RT residual volumes >or=10% had 0% local control and 17% disease-specific survival, compared with 91% and 72% for <10% volume (p <0.001).

CONCLUSION

Using more accurate four-dimensional volumetric regression analysis, tumor response can now be directly translated into individual patients' outcome for clinical application. Our results define two temporal thresholds critically influencing local control and survival. In patients with >or=20% residual volume at 40-50 Gy and >or=10% post-RT, the risk for local failure and death are so high that aggressive intervention may be warranted.

Primary tumor volume of nasopharyngeal carcinoma: significance for recurrence and survival

BACKGROUND

Primary tumor volume (PTV) is known to be a significant prognostic factor in malignant tumor. There have been several studies of nasopharyngeal carcinoma (NPC) relating tumor volume to treatment outcome. Our study was designed to evaluate the effect of PTV on treatment outcomes in NPC treated with radiotherapy (RT)/concurrent chemoradiotherapy (CCRT) or CCRT with adjuvant chemotherapy.

METHODS

We retrospectively reviewed 100 cases with newly diagnosed NPC who were treated with RT/CCRT or CCRT with adjuvant chemotherapy from 2002 to 2006. Magnetic resonance imaging-derived PTV was calculated using the summation-of-area technique. Kaplan-Meier plots and the log-rank test were used to estimate tumor recurrence (locoregional, distant, or both) and overall survival. Cox proportional hazards regression analysis was used to assess the prognostic impact of PTV.

RESULTS

The median PTV was 12.94 mL. PTV remained an independent prognostic factor for distant metastasis (hazard ratio [HR], 1.04; p=0.03), for any relapse (HR, 1.04; p=0.02), and for overall survival (HR, 1.09; p<0.001) in multivariate analysis. In the large tumor volume group (PTV>15 mL), patients' metastasis-free survival rates, with and without adjuvant chemotherapy, were 100% and 68.3%, respectively (p=0.002). Their 3-year recurrence-free survival rates, with and without adjuvant chemotherapy, were 94.1% and 69.6%, respectively (p=0.006). In the small tumor volume group (PTV <or= 15 mL), this phenomenon was not observed.

CONCLUSION

PTV had a close relationship with survival rates and recurrence rates in patients with NPC. The large tumor volume group (PTV>15 mL) was associated with more recurrence and poor survival rate, and it was suggested that these high-risk patients should benefit from CCRT followed by adjuvant chemotherapy.

18-F-fluorodeoxyglucose-positron emission tomography evaluation of early metabolic response during radiation therapy for cervical cancer

PURPOSE

To document changes in cervical tumor (18)-F-fluorodeoxyglocose (FDG) uptake during radiation therapy and to correlate those changes with post-treatment tumor response and survival outcome.

METHODS AND MATERIALS

A total of 36 patients with Stage Ib1 to IIIb cervical cancer were enrolled in an institutional protocol examining the use of fluorodeoxyglucose-positron emission tomography (FDG-PET) for brachytherapy treatment planning. As part of this study, FDG-PET or PET/computed tomograpy (CT) images were obtained before, during, and after the completion of radiation therapy. Tumor metabolic responses were assessed qualitatively and semi-quantitatively by measurement of the maximal standardized uptake value (SUV(max)).

RESULTS

Post-treatment FDG-PET images were obtained for 36 patients in this study. Of the patients, 29 patients had a complete metabolic response on the post-treatment PET, 4 had a partial metabolic response, and 3 had new sites of FDG uptake. Six patients had a complete metabolic response observed during radiation therapy, 26 had a partial metabolic response and 4 had stable or increased tumor metabolic activity. For patients with complete metabolic response during radiation therapy, median time to complete response was 29.5 days (range, 18-43 days). The mean cervical tumor SUV(max) decreased from 11.2 (SD, 6.3; range, 2.1-38.0) pretreatment to 2.4 (SD, 2.7; range, 0-8.8) mid treatment, and 0.5 (SD, 1.7; range, 0-8.3) post-treatment.

CONCLUSIONS

During radiation therapy for cervical cancer, FDG-PET can be used to monitor treatment response. Complete metabolic response during radiation therapy was observed for a subset of patients. Recommendations regarding the optimal timing of FDG-PET during treatment for cervical cancer will require further systematic study.

Sirolimus for angiomyolipoma in tuberous sclerosis complex or lymphangioleiomyomatosis

BACKGROUND

Angiomyolipomas in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis are associated with mutations in tuberous sclerosis genes resulting in constitutive activation of the mammalian target of rapamycin (mTOR). The drug sirolimus suppresses mTOR signaling.

METHODS

We conducted a 24-month, nonrandomized, open-label trial to determine whether sirolimus reduces the angiomyolipoma volume in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. Sirolimus was administered for the first 12 months only. Serial magnetic resonance imaging of angiomyolipomas and brain lesions, computed tomography of lung cysts, and pulmonary-function tests were performed.

RESULTS

Of the 25 patients enrolled, 20 completed the 12-month evaluation, and 18 completed the 24-month evaluation. The mean (+/-SD) angiomyolipoma volume at 12 months was 53.2+/-26.6% of the baseline value (P<0.001) and at 24 months was 85.9+/-28.5% of the baseline value (P=0.005). At 24 months, five patients had a persistent reduction in the angiomyolipoma volume of 30% or more. During the period of sirolimus therapy, among patients with lymphangioleiomyomatosis, the mean forced expiratory volume in 1 second (FEV1) increased by 118+/-330 ml (P=0.06), the forced vital capacity (FVC) increased by 390+/-570 ml (P<0.001), and the residual volume decreased by 439+/-493 ml (P=0.02), as compared with baseline values. One year after sirolimus was discontinued, the FEV1 was 62+/-411 ml above the baseline value, the FVC was 346+/-712 ml above the baseline value, and the residual volume was 333+/-570 ml below the baseline value; cerebral lesions were unchanged. Five patients had six serious adverse events while receiving sirolimus, including diarrhea, pyelonephritis, stomatitis, and respiratory infections.

CONCLUSIONS

Angiomyolipomas regressed somewhat during sirolimus therapy but tended to increase in volume after the therapy was stopped. Some patients with lymphangioleiomyomatosis had improvement in spirometric measurements and gas trapping that persisted after treatment. Suppression of mTOR signaling might constitute an ameliorative treatment in patients with the tuberous sclerosis complex or sporadic lymphangioleiomyomatosis. (ClinicalTrials.gov number, NCT00457808.)

Cervical Cancer Regression Measured Using Weekly Magnetic Resonance Imaging During Fractionated Radiotherapy: Radiobiologic Modeling and Correlation With Tumor Hypoxia

PURPOSE

To measure regression of cancer of the uterine cervix during external beam radiotherapy using magnetic resonance imaging, derive radiobiologic parameters from a mathematical model of tumor regression, and compare these parameters with the pretreatment measurements of tumor hypoxia.

METHODS AND MATERIALS

A total of 27 eligible patients undergoing external beam radiotherapy for cervical cancer underwent weekly magnetic resonance imaging scans. The tumor volume was assessed on each of these scans and the rate of regression plotted. A radiobiologic model was formulated to simulate the effect on tumor regression of the surviving proportion of cells after 2 Gy (SP(2)), the cell clearance constant (clearance of irreparably damaged cells from the tumor [T(c)]), and accelerated repopulation. Nonlinear regression analysis was used to fit the radiobiologic model to the magnetic resonance imaging-derived tumor volumes and to derive the estimates of SP(2) and T(c) for each patient. These were compared to the pretreatment hypoxia measurements.

RESULTS

The initial tumor volume was 8-209 cm(3). The relative reduction in volume during treatment was 0.02-0.79. The simulations using representative values of the independent biologic variables derived from published data showed SP(2) and T(c) to strongly influence the shape of the volume-response curves. Nonlinear regression analysis yielded a median SP(2) of 0.71 and median T(c) of 10 days. Tumors with a high SP(2) >0.71 were significantly more hypoxic at diagnosis (p = 0.02).

CONCLUSION

The results of our study have shown that cervical cancer regresses during external beam radiotherapy, although marked variability is present among patients and is influenced by underlying biologic processes, including cellular sensitivity to radiotherapy and proliferation. Better understanding of the biologic mechanisms might facilitate novel adaptive treatment strategies in future studies.

Primary tumor volume calculation as a predictive factor of prognosis in nasopharyngeal carcinoma

CONCLUSIONS

Primary tumor volume (PTV) has a close relationship with survival rates of patients with nasopharyngeal carcinoma (NPC) who were treated with concurrent chemoradiotherapy (CCRT) or radiotherapy. Besides the current AJCC staging system, measurement of PTV may be needed to predict prognosis of NPC and adjust treatment strategy.

OBJECTIVES

We conducted a retrospective study to elucidate the effect of PTV on treatment outcomes in patients with NPC who were treated with CCRT or radiotherapy.

PATIENTS AND METHODS

A total of 66 patients with newly diagnosed NPC were enrolled in this study. Computed tomography (CT)-derived or magnetic resonance imaging (MRI)-derived PTV was calculated. The correlation between AJCC disease stage, PTV, and disease-specific survival was analyzed. Correlations between different prognostic factors were assessed using a Cox regression model.

RESULTS

The median PTV for the whole series was 12.01 ml (range 1.25-166.58 ml). The median PTV was 3.45 ml in T1 disease, 7.96 ml in T2 disease, 17.95 ml in T3 disease, and 64.73 ml in T4 disease. Disease stage and T stage carried no prognostic significance (p=0.25 and p =0.30, respectively). Four categories of PTV (<12.5 ml, 12.5-25 ml, 25-50 ml and >50 ml) had prognostic significance (p=0.02). Survival analysis demonstrated a significant difference in overall survival with larger tumor volume (risk ratio 5.447; p=0.044).

Inter- and intrafractional tumor and organ movement in patients with cervical cancer undergoing radiotherapy: a cinematic-MRI point-of-interest study

PURPOSE

Internal tumor and organ movement is important when considering intensity-modulated radiotherapy for patients with cancer of the cervix because of the tight margins and steep dose gradients. In this study, the internal movement of the tumor, cervix, and uterus were examined using serial cinematic magnetic resonance imaging scans and point-of-interest analysis.

METHODS AND MATERIALS

Twenty patients with Stage IB-IVA cervical cancer underwent pelvic magnetic resonance imaging before treatment and then weekly during external beam radiotherapy. In each 30-min session, sequential T(2)-sagittal magnetic resonance imaging scans were obtained. The points of interest (cervical os, uterine canal, and uterine fundus) were traced on each image frame, allowing the craniocaudal and anteroposterior displacements to be measured. The mean displacements and trends were analyzed using mixed linear models. Prediction intervals were calculated to determine the internal target margins.

RESULTS

Large interscan motion was found for all three points of interest that was only partially explained by the variations in bladder and rectal filling. The intrascan motion was much smaller. Both inter- and intrascan motion was greatest at the fundus of the uterus, less along the canal, and least at the cervical os. The isotropic internal target margins required to encompass 90% of the interscan motion were 4 cm at the fundus and 1.5 cm at the os. In contrast, smaller margins of 1 cm and 0.45 cm, respectively, were adequate to encompass the intrascan motion alone.

CONCLUSION

Daily soft-tissue imaging with correction for interfractional motion or adaptive replanning will be important if the benefits of intensity-modulated radiotherapy are to be maximized in women with cervical cancer.

Early invasive cervical cancer: tumor delineation by magnetic resonance imaging, computed tomography, and clinical examination, verified by pathologic results, in the ACRIN 6651/GOG 183 Intergroup Study

PURPOSE

To compare magnetic resonance imaging (MRI), computed tomography (CT), and clinical examination for delineating early cervical cancer and for measuring tumor size.

PATIENTS AND METHODS

A 25-center study enrolled 208 patients with biopsy-proven invasive cervical cancer for MRI and CT before attempted curative radical hysterectomy. Each imaging study was interpreted prospectively by one onsite radiologist and retrospectively by four independent offsite radiologists, who were all blinded to surgical, histopathologic, and other imaging findings. Likelihood of cervical stromal and uterine body involvement was rated on a 5-point scale. Tumor size measurements were attempted in three axes. Surgical pathology was the standard of reference.

RESULTS

Neither MRI nor CT was accurate for evaluating cervical stroma. For uterine body involvement, the area under the receiver operating characteristic curve was higher for MRI than for CT for both prospective (0.80 v 0.66, respectively; P = .01) and retrospective (0.68 v 0.57, respectively; P = .02) readings. Retrospective readers could measure diameter by CT in 35% to 73% of patients and by MRI in 79% to 94% of patients. Prospective readers had the highest Spearman correlation coefficient with pathologic measurement for MRI (r(s) = 0.54), followed by CT (r(s) = 0.45) and clinical examination (r(s) = 0.37; P < .0001 for all). Spearman correlation of multiobserver diameter measurements for MRI (r(s) = 0.58; P < .0001) was double that for CT (r(s) = 0.27; P = .03).

CONCLUSION

In patients with cervical cancer, MRI is superior to CT and clinical examination for evaluating uterine body involvement and measuring tumor size, but no method was accurate for evaluating cervical stroma.

Usefulness of MRI volumetric evaluation in patients with squamous cell cancer of the head and neck treated with neoadjuvant chemotherapy

BACKGROUND

The purpose was to evaluate the efficacy of tumor volumetry on MRI as predictive of response to treatment with induction chemotherapy, comparing the results with endoscopy.

METHODS

Fifty patients with advanced squamous cell carcinoma of the head and neck (SSCHN) who underwent MRI volumetry before and after neoadjuvant chemotherapy consisting of docetaxel, cisplatin, and 5-fluorouracil (TPF) were included in this study. The tumor volume was calculated by a slice-by-slice evaluation. With the standard software of a workstation, the area of the tumor was measured slice by slice using manual segmentation. To evaluate the efficacy of MRI volumetry, pretreatment volume was compared with pretreatment remission status as evaluated with endoscopy.

RESULTS

Forty-five (90%) patients demonstrated a tumor downstaging after chemotherapy. Fourteen (28%) patients showed a complete histologic remission (CR), 31 (62%) patients showed a partial remission (PR). Pretreatment tumor volume was significantly different between patients whose tumor completely responded (CR) and those whose tumor did not completely respond or whose disease was stable or was progressive (p = .00023). We defined a threshold for the pretreatment tumor volume in patients with CR, which was equal to 29.71 cc.

CONCLUSION

We propose that MRI tumor volume analyses can be a useful parameter to predict the response to neoadjuvant chemotherapy in SCCHN.

Magnetic resonance–guided interstitial therapy for vaginal recurrence of endometrial cancer

PURPOSE

To evaluate the feasibility and to describe the acute toxicity of a real-time intraoperative magnetic resonance (MR)-image guided interstitial approach to treating vaginal recurrence of endometrial cancer.

METHODS AND MATERIALS

From February 2004 to April 2005, 10 patients with recurrent endometrial cancer underwent MR-guided interstitial brachytherapy. Parameters evaluated included needle placement, dose-volume histograms (DVH), and complications.

RESULTS

Magnetic resonance-image guidance resulted in accurate needle placement. Tumor DVH values included median volume, 47 cc; V100, 89%; V150, 61%; V200, 38%; D90, 71 Gy; and D100, 60 Gy. DVH of organs at risk resulted in a median D2cc of external beam and brachytherapy dose (% of brachytherapy prescription): bladder, 75Gy(3) (88%); rectum, 70Gy(3) (87%); and sigmoid, 56Gy(3) (41%). All patients experienced either a Grade 1 or 2 acute toxicity related to the radiation; only 1 patient had Grade 3 toxicity. No toxicities were attributable to the use of MR guidance.

CONCLUSIONS

Real-time MR guidance during the insertion of interstitial needles reduces the likelihood of an inadvertent insertion of the needles into the bladder and the rectum. Three-dimensional dosimetry allows estimation of the dose to organs at risk. Toxicities are limited.

Serial Therapy-Induced Changes in Tumor Shape in Cervical Cancer and Their Impact on Assessing Tumor Volume and Treatment Response

OBJECTIVE

The purpose of this study was to evaluate the patterns and distribution of tumor shape and its temporal change during radiation therapy (RT) in cervical cancer and the effect of tumor configuration changes on the correlation between region of interest (ROI)-based and diameter-based MRI tumor measurement.

MATERIALS AND METHODS

Serial MRI examinations (T1-weighted and T2-weighted images) were performed in 60 patients (age range, 29-75 years; mean, 53.3 years) with advanced cervical cancer (stages IB2-IVB/recurrent) who were treated with RT at four time points: start of RT, during RT (at 2-2.5 and at 4-5 weeks of RT), and post-RT. Tumor configuration was classified qualitatively into oval, lobulated, and complex based on MR film review. Two methods of tumor volume measurement were compared: ellipsoid computation of three orthogonal diameters (diameter based) and ROI volumetry by delineating the entire tumor volume on the MR workstation (ROI based). Temporal changes of tumor shape and the respective tumor volumes measured by the two methods were analyzed using linear regression analysis.

RESULTS

Most tumors (70%) had a non-oval (lobulated and complex) shape before RT and became increasingly irregular during and after RT: 84% at 2-2.5 weeks of RT (p = 0.037), 86% (p = 0.025) at 4-5 weeks, and 96% post-RT (p = 0.010), compared with 70% pre-RT. Diameter-based and ROI-based measurement correlated well before RT (r = 0.89) but not during RT (r = 0.68 at 2-2.5 weeks, r = 0.67 at 4-5 weeks of RT).

CONCLUSION

Most cervical cancers are not oval in shape pretherapy, and they become increasingly irregular during and after therapy because of nonconcentric tumor shrinkage. ROI-based volumetry, which can optimally measure irregular volumes, may provide better response assessment during treatment than diameter-based measurement.