Radiation dose intensification in pre-operative chemo-radiotherapy for locally advanced rectal cancer (original) (raw)
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Radiation oncology (London, England), 2012
Preoperative radiochemotherapy (RCT) is standard in locally advanced rectal cancer (LARC). Initial data suggest that the tumor's metabolic response, i.e. reduction of its 18 F-FDG uptake compared with the baseline, observed after two weeks of RCT, may correlate with histopathological response. This prospective study evaluated the ability of a very early metabolic response, seen after only one week of RCT, to predict the histopathological response to treatment. Twenty patients with LARC who received standard RCT regimen followed by radical surgery participated in this study. Maximum standardized uptake value (SUV-MAX), measured by PET-CT imaging at baseline and on day 8 of RCT, and the changes in FDG uptake (ΔSUV-MAX), were compared with the histopathological response at surgery. Response was classified by tumor regression grade (TRG) and by achievement of pathological complete response (pCR). Absolute SUV-MAX values at both time points did not correlate with histopathological re...
International Journal of Radiation Oncology Biology Physics, 2004
Methods and Materials: Twenty-five consecutive patients with rectal cancer were included, with tumor stages c T 2-4 N x M 0 , during the period 1997-1999. We prospectively performed two FDG-PET scans in all patients to assess disease stage (1) at initial diagnosis and (2) presurgically, 4 to 5 weeks after protracted chemoradiation. Protracted chemoradiation was carried out during 5-6 weeks with 45-50 Gy, plus concurrent oral tegafur 1200 mg/day or 5-fluorouracil 500 -1000 mg/m 2 administered as a 24-h continuous i.v. infusion on Days 1-4 and 21-25 of the radiotherapy treatment. Tumors were staged with CT in 95% of patients, whereas endorectal ultrasound was used in 90% of patients. Maximum standardized uptake value (SUVmax) was used as the quantitative parameter to estimate the tumor:tissue metabolic ratio. Results: Preoperative chemoradiation significantly decreased the SUVmax: 5.9 (mean SUVmax at initial staging) vs. 2.4 (mean SUVmax after chemoradiation) with p < 0.001. Unknown liver metastases were detected by FDG-PET in 2 patients, in 1 of them with the initial staging FDG-PET scan, and with the restaging FDG-PET scan in the other. After an average follow-up of 39 months, the value of SUVmax >6 allowed us to discriminate for survival at 3 years: 92% vs. 60% (p ؍ 0.04). T downstaging (total 62%) was significantly correlated with SUVmax changes: 1.9 vs. 3.3 (p ؍ 0.03). The degree of rectal cancer response to chemoradiation, established as mic vs. mac categories, was not associated with SUVmax differences (mean values of 2.0 vs. 2.7). Conclusion: Preliminary results observed suggest the potential utility of FDG-PET as a complementary diagnostic procedure in the initial clinical evaluation (8% of unsuspected liver metastases) as well as in the assessment of chemoradiation response (any T downstaged event) of locally advanced rectal cancer. Initial SUVmax might be of prognostic value related to long-term patient outcome.
2013
The role of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) in the staging and radiation treatment planning of locally advanced rectal cancer is ill defined. We studied the role of integrated PET/CT in the staging, radiation treatment planning, and use as an imaging biomarker in rectal cancer patients undergoing multimodality treatment. Thirty-four consecutive patients with T3-4N0-2M0-1 rectal adenocarcinoma underwent FDG-PET/CT scanning for staging and radiation treatment planning. Planned clinical management was compared before and after the addition of PET/CT information. Three radiation oncologists independently delineated CT-based gross tumor volumes (GTVCT) using clinical information and CT imaging data, as well as gradient autosegmented PET/CT-based GTVs (GTVPETCT). The mean GTV, interobserver concordance index (CCI), and proximal and distal margins were compared. The maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV), and dual-time point PET parameters were correlated with clinicopathologic endpoints. Clinical management was altered by PET/CT in 18% (n = 6) of patients with clinical upstaging in 6 patients and radiation treatment planning altered in 5 patients. Of the 30 evaluable preoperative patients, the mean GTVPETCT was significantly smaller than the mean GTVCT volumes: 88.1 versus 102.8 cc (P = .03). PET/CT significantly increased interobserver CCI in contouring GTV compared with CT only-based contouring: 0.56 versus 0.38 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .001). The proximal and distal margins were altered by a mean of 0.4 ± 0.24 cm and -0.25 ± 0.18 cm, respectively. MTV was inversely associated with 2-year progression-free survival (PFS) and overall survival (OS): smaller MTVs (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;33 cc) had superior 2-year PFS (86% vs 60%, P = .04) and OS (100% vs 45%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; .01) compared with larger MTVs (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt;33 cc). SUVmax and dual-time point PET parameters did not correlate with any endpoints. FDG-PET/CT imaging impacts overall clinical management and is useful in the radiation treatment planning of rectal cancer patients by decreasing interobserver variability in contouring target boost volumes. Pretreatment MTV may provide useful prognostic information and requires further study.
Role of 18F-PET-CT to Predict Pathological Response After Neoadjuvant Treatment of Rectal Cancer
2021
Objectives: Neoadjuvant radiochemotherapy (nCRT) is universally considered to be a valid treatment to achieve downstaging, improve local disease control and obtain better resectability in locally advanced rectal cancer (LARC). The aim of this study is to correlate the change in tumor 18F -FDG PET-CT standardized uptake value (SUV) before and after nCRT, in order to obtain an early prediction of pathologic response (pR) achieved in patients with LARC.Data description: We performed a retrospective analysis of patients with LARC diagnosis who underwent curative resection. All patients received nCRT and surgical treatment was carried after 8/12th. All patients underwent a baseline 18F -FDG PET-CT scan within the week prior to the initiation of the treatment (PET-CT SUV1) and a second scan (PET-C T SUV2) within six weeks of the completion of nCRT. Furthermore, we evaluated the prognostic value of 18F -FDG PET-CT in terms of disease free survival (DFS) and overall survival (OS) in patient...
18F FDG PET-CT for EBRT Planning in Inoperable Rectal Carcinoma after Receiving Chemotherapy– A
Bangladesh Journal of Nuclear Medicine, 2018
Colorectal cancer (CRC) is the third most commonly diagnosed cancer in men and the second in women globally. The incidence varies with geographic difference. In Bangladesh, hospital based cancer registry shows rate of CRC in male 10.1%- 12% and in female 3% - 12.0%. The prognosis of the disease and treatment planning depends upon the staging of the disease. Surgery is usually a common way of treatment of rectal cancer except some cases with advanced stage. Radiation therapy, often with chemotherapy, is frequently used in the adjuvant or neoadjuvant setting for the treatment of rectal cancers. External beam radiation therapy (EBRT) is a well practiced method of treatment in the in-operable cases of rectal cancer. 18F FDG PET-CT is a well recognized imaging tool in the pretreatment evaluation of colorectal cancer worldwide. Accurate staging is needed for proper selection of treatment and cost effectiveness. Here, we discussed a case of rectal cancer (stage IV) with post chemotherapy s...
2018
OBJECTIVE To evaluate the prognostic value of 18F-FDG PET/CT in terms of survival in patients with locally advanced rectal cancer (LARC) who had undergone surgery preceded by neoadjuvant chemoradiotherapy (nCRT). Moreover, the existence of correlation between Overall Survival (OS) and Disease Free Survival (DFS) with pathological staging ((y)pTNM and TRG) was evaluated. PATIENTS AND METHODS A total of 58 patients with biopsy-proven of LARC were included. All patients underwent conventional diagnostic/staging procedures to characterize the rectal lesion. The first whole-body 18F-FDG PET/CT was performed 1 week before the beginning of nCRT (baseline scan). The second 18F-FDG PET/CT was scheduled at 5-6 weeks from nCRT completion (post-nCRT scan). Survival was evaluated in 3 different restaging classification systems, based on focusing only on primary lesion (TRG), loco-regional evaluation (ypTNM) and whole-body 18F-FDG PET/CT evaluation (VRA). RESULTS Among the 58 patients at the end ...
International Journal of Radiation Oncology*Biology*Physics, 1997
Purpose: To determine predictive factors and prognostic value of tumor downstaging and tumor sterilization after preoperative RT for rectal cancer. Methods and Materials: Between 1977 and 1994, 167 patients with a histologically proven adenocarcinoma (70 T2, 65 T3, 29 T4, and 3 local recurrences) underwent preoperative RT. Median dose was 44 Gy (5-73 Gy). Surgery was performed in a mean time of 5 weeks after RT. Pathologic specimens have been reviewed by the same pathologist in order to specify the modified Astler Colier chrssification (MAC), and to quantify the residua1 tumor cell density (RTCD). Results: According to the MAC, there was 9 stage 0 (5%), 10 stage A (6%), 103 stage Bl-B3 (62%), and 45 stage Cl-C3 (27%) tumors. Seventeen percent and 56% of the patients who received a dose 244 Gy had respectively a O-A and a B tumor, compared to 4 and 69% in those who received a dose <44 Gy @ = 0.04). Tumor diierentiation and a longer interval before surgery were significantly associated with a more frequent downstaging, and preoperative staging correlated well to the postoperative pathological findings. According to the RTCD, 62 tumors (37%) showed no or only rare foci of residual tumor cells (Group 1); 62 (37%) showed an intermediate RTCD (Group 2); and 43 (26%) a high RTCD (Group 3). No predictive factor of RTCD was statistically significant. In univariate analysis, postoperative staging was a significant prognostic factor, with corresponding 5-year overall survival rates in O-A, B, and C stages of 92,67, and 26% @ < 0.01). RTCD was not a prognostic factor. However, overall and disease-free survival rates for patients with complete pathologic response of 83% at 2 and 5 years suggested a better outcome in this subgroup of patients. Conclusion: The favorable inlluence of higher doses of preoperative RT on pathologic stage has been observed.
BioMed Research International, 2014
This study prospectively assessed 18 F-FDG PET/CT in predicting the response of locally advanced low rectal cancer (LRC) to neoadjuvant chemoradiation (nCRT). Methods. 56 patients treated with chemoradiation underwent two 18 F-FDG PET/CT scans (baseline and 5-6 weeks post-nCRT). 18 F-FDG uptake (SUVmax and SUVmean) and differences between baseline (SUV1) and post-nCRT (SUV2) scans (ΔSUV and RI%) were evaluated. Results were related to the Mandard's TRG and (y)pTNM. Results. 18 F-FDG PET/CT sensitivity, specificity, accuracy, PPV and NPV resulted in 88.6%, 66.7%, 83.92%, 90.7%, and 61.5%. SUV2 resulted in better than SUV1 to predict nCRT response by TRG, with no significant statistical difference between the SUVmax2 and SUVmean2 AUC (0.737 versus 0.736; = 0.928). The same applies to the (y)pTNM (0.798 versus 0.782; = 0.192). In relation to the TRG, RI values had a higher AUC than ΔSUV, with no significant difference between RImax and RImean (0.672 versus 0.695; = 0.292). The same applied to the (y)pTNM (0.742 versus 0.741; = 0.940). In both cases ΔSUV does not appear to be a good predictive tool. Logistic regression confirmed the better predictive role of SUVmax2 for the (y)pTNM (odds ratio = 1.58) and SUVmean2 for the TRG (odds ratio = 1.87). Conclusions. 18 F-FDG PET/CT can evaluate response to nCRT in LRC, even if more studies are required to define the most significant parameter for predicting pathologic tumor changes.