Elective clinical target volumes for conformal therapy in anorectal cancer: a radiation therapy oncology group consensus panel contouring atlas

Dose-volume parameters of MRI-based active bone marrow predict hematologic toxicity of chemoradiotherapy for rectal cancer

Purpose

Magnetic resonance imaging (MRI) is routinely used for locoregional staging of rectal cancer and offers promise for the prediction of hematologic toxicity. The present study compares the clinical utility of MRI-based active bone marrow (BMact) delineation with that of CT-based bone marrow total (BMtot) delineation for predicting hematologic toxicity.

Methods

A prospective cohort study was performed. Eligible patients had stage II/III rectal cancer and qualified for preoperative chemoradiotherapy. The BMact areas on T1-weighted MRI were contoured. The impact of the dose–volume parameters of BMact/BMtot and clinical data on hematologic toxicity were assessed. Basic endpoints were the occurrence of grade 3/4 hematologic toxicity and peripheral blood parameters reaching a nadir. Linear regression models were generated for the nadirs and receiver operating characteristic (ROC) curves for the occurrence of grade 3/4 hematologic toxicity.

Results

Thirty-five patients were enrolled. Women presented higher dose–volume parameters of BMact, BMtot, and lymphocyte nadir (ALCnadir%) than men. Models for the prediction of ALCnadir% (V5-V20BMtot, V5-V30BMact) and platelet nadir (PLTnadir%; V5-V10BMtot, V5-V20BMact) were statistically significant. In the ROC curves, a baseline lymphocyte level of 1.81 × 10³/ml was adopted as the cutoff for predicting grade 3/4 lymphopenia, with specificity of 77.8% and sensitivity of 73.1%. The multivariate linear regression model for ALCnadir% had R² = 0.53, p = 0.038. In the tenth step of selection, V5BMact (p = 0.002) and gender (p = 0.019) remained. The multivariate linear regression model for PLTnadir% had R² = 0.20, p = 0.34. In the sixth step of selection, V15BMact remained (p = 0.026).

Conclusion

The dose–volume parameters of BMact serve as better predictors of ALCnadir% and PLTnadir% than BMtot.

Adding Boost to Standard Neoadjuvant Radiation for Rectal Cancer Improves Likelihood of Complete Response

BACKGROUND

Pathologic tumor response is a prognostic factor for survival in patients with rectal cancer. Standard neoadjuvant radiation (nRT) dosing for locally advanced rectal cancer ranges from 4500 to 5400 centigray (cGy), but it is unknown if tumor regression differs as a consequence adding a boost to the tumor bed.

METHODS

The National Cancer Database (NCDB) 2006-2016 was used to identify patients 18 years of age and older with clinical stage II and III rectal cancer who received pelvic nRT dosed between 4500 and 5400 cGy. Standard nRT dose (no boost, NB) and dose with boost (DWB) were defined respectively as 4500 and 5040-5400 cGy. Complete pathologic response (pCR) was defined as postoperative pathologic stage of zero. A multivariate logistic regression was performed to evaluate the association between radiation dosing and pCR.

RESULTS

The study cohort was 28,841 patients; the majority received DWB 22,701 (78.7%), while 6140 (21.3%) received NB. pCR was achieved in 3135 (14.4%) patients. On multivariate analysis, patients who received NB were significantly less likely to have complete tumor response (OR 1.41, 95% CI 1.2-1.66, p < 0.001). Other factors significantly associated with pCR included insurance, facility type, tumor characteristics, clinical stage, and time between radiation and surgery.

CONCLUSIONS

This is the first investigation demonstrating that standard dose neoadjuvant radiation for rectal cancer was associated with a lower likelihood of pCR compared with standard dose with boost. Past studies demonstrate that rectal cancer patient survival is strongly correlated with pCR. Prospective trials should focus on examining neoadjuvant radiation dosing to evaluate if DWB improves outcomes.

Short-course versus long-course neoadjuvant chemoradiotherapy in patients with rectal cancer: preliminary results of a randomized controlled trial

Purpose

Colorectal cancer is becoming an increasing concern in the middle-aged population of Iran. This study aimed to compare the preliminary results of short-course and long-course neoadjuvant chemoradiotherapy treatment for rectal cancer patients.

Materials and Methods

In this clinical trial we recruited patients with rectal adenocarcinoma located from 5 cm to 15 cm above the anal verge. Patients in group I (short-course) received three-dimensional conformational radiotherapy with a dose of 25 Gy/5 fractions in 1 week plus concurrent XELOX regimen (capecitabine 625 mg/m² from day 1–5 twice daily and oxaliplatin 50 mg/m² on day 1 once daily). Patients in group II (long-course) received a total dose of 50–50.4 Gy/25–28 fractions for 5 to 5.5 weeks plus capecitabine 825 mg/m² twice daily. Both groups underwent consolidation chemotherapy followed by delayed surgery at least 8 weeks after radiotherapy completion. The pathological response was assessed with tumor regression grade.

Results

In this preliminary report on complications and pathological response, 66 patients were randomized into two study groups. Mean duration of radiotherapy in groups I and II was 5 ± 1 days (range, 5 to 8 days) and 38 ± 6 days (range, 30 to 58 days). The median follow-up was 18 months. Pathological complete response was achieved in 32.3% and 23.1% of patients in the short-course and long-course groups, respectively (p = 0.558). Overall, acute grade 3 or higher treatment-related toxicities occurred in 24.2% and 22.2% of patients in group I and II, respectively (p = 0.551). No acute grade 4 or 5 adverse events were observed in either group except one grade 4 hematologic toxicity that was seen in group II. Within one month of surgery, no significant difference was seen regarding grade ≥3 postoperative complications (p = 0.333).

Conclusion

For patients with rectal cancer located at least 5 cm above the anal verge, short-course radiotherapy with concurrent and consolidation chemotherapy and delayed surgery is not different in terms of acute toxicity, postoperative morbidity, complete resection, and pathological response compared to long-course chemoradiotherapy.

Patterns of recurrence in anal cancer: a detailed analysis

Background

Anal cancer is a rare disease, which might be the reason for the “one size fits all” approach still used for radiotherapy target contouring. To refine and individualize future guidelines, detailed and contemporary pattern of recurrence studies are needed.

Methods

Consecutive anal cancer patients, all treated with curative intent intensity-modulated radiotherapy (IMRT), were retrospectively studied (n = 170). Data was extracted from medical records and radiological images. Radiotherapy planning CT’s and treatment plans were reviewed, and recurrences were mapped and categorized according to radiation dose.

Results

The mean dose to the primary tumor was 59.0 Gy. With a median follow-up of 50 months (range 14–117 months), 5-year anal cancer specific survival was 86.1%. Only 1 of 20 local recurrences was located outside the high dose (CTVT) volume. More patients experienced a distant recurrence (n = 34; 20.0%) than a locoregional recurrence (n = 24; 14.1%). Seven patients (4.2%) had a common iliac and/or para-aortic (CI/PA) recurrence. External iliac lymph node involvement (P = 0.04), and metastases in ≥3 inguinal or pelvic lymph node regions (P = 0.02) were associated with a 15–18% risk of CI/PA recurrence. Following chemoradiotherapy, 6 patients with recurrent or primary metastatic CI/PA lymph nodes were free of recurrence at last follow-up. The overall rate of ano-inguinal lymphatic drainage (AILD) recurrence was 2 of 170 (1.2%), and among patients with inguinal metastases at initial diagnosis it was 2 of 65 (3.1%).

Conclusions

We conclude that other measures than increased margins around the primary tumor are needed to improve local control. Furthermore, metastatic CI/PA lymph nodes, either at initial diagnosis or in the recurrent setting, should be considered potentially curable. Patients with certain patterns of metastatic pelvic lymph nodes might be at an increased risk of harboring tumor cells also in the CI/PA lymph nodes.

Re-irradiation for recurrent rectal cancer - a single-center experience

Background: There is no clear consensus on the use of re-irradiation (reRT) in the management of locally recurrent rectal cancer (LRRC). The aim of the present study was to investigate all reRT administered for rectal cancer at a large referral institution and to evaluate patient outcomes and toxicity.Material and methods: All patients with rectal cancer were identified who had received previous pelvic radiotherapy (RT) and underwent reRT during 2006-2016. Medical records and RT details of the primary tumor treatments and rectal cancer recurrence treatments were registered, including details on reRT, chemotherapy, surgery, adverse events, and long-term outcomes.Results: Of 77 patients who received ReRT, 67 had previously received pelvic RT for rectal cancer and were administered reRT for LRRC. Re-irradiation doses were 30.0-45.0 Gy, most often given as hyperfractionated RT in 1.2-1.5 Gy fractions twice daily with concomitant capecitabine. The median time since initial RT was 29 months (range, 13-174 months). Of 36 patients considered as potentially resectable, 20 underwent surgery for LRRC within 3 months after reRT. Operated patients had better 3-year overall survival (OS) (62%) compared to those who were not operated (16%; HR 0.32, p = .001). The median gross tumor volume (GTV) was 107 cm³, and 3-year OS was significantly better in patients with GTV <107 cm³ (44%) compared to patients with GTV ≥107 cm³ (21%; HR 0.52, p = .03).Conclusion: Three-year survival was significantly better for patients who underwent surgery after reRT or who had small tumor volume. Prospective clinical trials are recommended for further improvements in patient selection, outcomes, and toxicity assessment.

The importance of mesorectum motion in determining PTV margins in rectal cancer patients treated with neoadjuvant radiotherapy

New precision radiotherapy (RT) techniques reduce the uncertainties in localizing soft and moving tumors. However, there are still many uncontrollable internal organ movements. In our study, patients who underwent neoadjuvant chemoradiotherapy (NA-CRT) for rectal cancer were evaluated to determine inter-fraction mesorectum motion and dosimetric changes. Fourteen patients treated with NA-CRT for rectal cancer between 2014 and 2016 were included in the analysis. The mesorectum and clinical target volume (CTV) were delineated on planning computed tomography (CT) and cone-beam CT (CB-CT) scans. After planning with a volumetric modulated arc therapy (VMAT) plan, re-planning was performed on all CB-CTs. Finally, the volumetric and dosimetric changes of PTV and mesorectum were evaluated in all CB-CTs compared with the initial CT and VMAT plans. The geometrical center of mesorectum volume in CB-CTs had moved 1 (0.2-6.6), 1.6 (0.2-3.8) and 1.6 (0-4.9) mm in the x, y and z-axis respectively compared with the initial CT. The dosimetric parameters of PTV including D2, D95 and D98 on CB-CT showed a median 47.19 (46.70-47.80), 45.05 (44.18-45.68) and 44.69 (43.83-45.48) Gy and median 1% (1-2), 0% (0-2) and 1% (0-2) dosimetric change compared with the initial VMAT plan. In our study, we have shown that the mesorectum has moved up to 20 mm in the lateral and anterior-posterior direction and almost 10 mm in the superior/inferior direction during RT, causing a median of ~2% change in dosimetric parameters. Therefore, these movements must be considered in determining PTV margins to avoid dosimetric changes.

What is the Best Way to Plan Rectum Three-Dimensional Conformal Radiotherapy in Prone Position-Classic Anatomical Landmark, Three Dimensional Fitting the Planning Target Volume, or Volumetric Modulated Arc?

BACKGROUND

Traditionally, rectal cancer radiation therapy uses bony landmark fields to cover common lymphatic drainage sites, including the internal iliac, presacral, and perirectal lymph nodes. We aimed to investigate if bony landmark borders sufficiently cover the internal iliac nodes and to compare tumor volume and normal tissue avoidance using classic bony landmarks (c3DCRT), contoured elective clinical target volume (f3DCRT), and volumetric modulated arc therapy (VMAT) planning in locally advanced rectal cancer.

METHODS

Computed tomography datasets of 11 patients with locally advanced rectal cancer who had completed treatment in the prone position on a bellyboard in c3DCRT technique. The elective clinical target volumes and organs at risk were contoured, and a f3DCRT VMAT plan generated for all patients. Planning target volume, gross tumor volume, and normal tissue dose limits were evaluated.

RESULTS

The mean planning target volume 95% coverages were significantly lower for c3DCRT plans, and the lymph node coverage was better for f3DCRT. No differences were found in PTV coverages between f3DCRT and volumetric modulated arc therapy plans. No significant differences among all techniques were found for organs-at-risk constraints. The bladder dosage was higher in the VMAT plan. The c3DCRT technique missed coverage of the internal iliac lymph nodes and exposed smaller bowel, compared with the other methods.

DISCUSSION AND CONCLUSION

Tumor volume coverage was improved by f3DCRT planning, without significant differences in doses to critical structures compared with c3DCRT and was noninferior to VMAT planning. It is recommended that f3DCRT be used in routine clinical practice in radiotherapy treatments for locally advanced rectal cancer.

Dosimetric comparison of organs at risk using different contouring guidelines for definition of the clinical target volume in anal cancer

Background

There are different contouring guidelines for definition of the clinical target volume (CTV) for intensity-modulated radiation therapy (IMRT) of anal cancer (AC). We conducted a planning comparison study to evaluate and compare the dose to relevant organs at risk (OARs) while using different CTV definitions.

Methods

Twelve patients with a primary diagnosis of anal cancer, who were treated with primary chemoradiation (CRT), were selected. We generated four guideline-specific CTVs and subsequently planned target volumes (PTVs) on the planning CT scan of each patient. An IMRT plan for volumetric arc therapy (VMAT) was set up for each PTV. Dose parameters of the planned target volume (PTV) and OARs were evaluated and compared, too.

Results

The mean volume of the four PTVs ranged from 2138 cc to 2433 cc. The target volumes contoured by the authors based on the recommendations of each group were similar in the pelvis, while they differed significantly in the inguinal region. There were no significant differences between the four target volumes with regard to the dose parameters of the cranially located OARs. Conversely, some dose parameters concerning the genitals and the skin varied significantly among the different guidelines.

Conclusion

The four contouring guidelines differ significantly concerning the inguinal region. In order to avoid inguinal recurrence and to protect relevant OARs, further investigations are needed to generate uniform standards for definition of the elective clinical target volume in the inguinal region.

Long-term follow-up experience in anal canal cancer treated with Intensity-Modulated Radiation Therapy: Clinical outcomes, patterns of relapse and predictors of failure

BACKGROUND AND PURPOSE

To assess the long-term outcomes of patients with squamous cell carcinoma of the anal canal (SCCAC) treated with Intensity-Modulated Radiation Therapy (IMRT).

MATERIAL AND METHODS

From 2007 to 2015, 193 patients were treated by IMRT for SCCAC. Radiotherapy delivered 45 Gy in 1.8 Gy daily-fractions to the primary tumor and elective nodal areas, immediately followed by a boost of 14.4-20 Gy to the primary tumor and involved nodes. Concurrent chemotherapy with 5-FU-mitomycin (MMC) or cisplatin was added for locally advanced tumors. Survivals were estimated by Kaplan-Meier method. Locoregional (LR) relapses were precisely assessed. Prognostic factors were evaluated by uni- and multivariate analyses. Late toxicity was scored according to the Common Toxicity Criteria for Adverse Events v4.0.

RESULTS

Median follow-up was 70 months (range, 1-131). Forty-nine men (25%) and 144 women (75%) were analyzed. Median age was 62 years. Tumor stages were I, II, III and IV in 7%, 24%, 63% and 6% of cases, respectively. Chemotherapy was delivered in 167 patients (87%), mainly MMC (80%). Five-year OS, DFS, CFS and LR control rates were 74%, 68%, 66% and 85%, respectively. Forty-one patients (21%) had a relapse: 22 were LR, mostly in-field (68%). Predictors for LR failure were exclusive radiotherapy, chemotherapy lacking MMC and treatment breaks >3 days. Overall late toxicity ≥grade 2 occurred in 43% of patients, with 24% grade 3 and one case of grade 4 (hematuria).

CONCLUSION

CRT with IMRT assures excellent local control in locally advanced SCCAC with manageable long-term toxicity. Multicentric prospective trials are required to reinforce those results.

Automatic Delineation of the Clinical Target Volume in Rectal Cancer for Radiation Therapy using Three-dimensional Fully Convolutional Neural Networks

Accurate, robust, and fast delineation of the clinical target volume (CTV) for the use in radiotherapy of rectal cancer (RC) is highly sought-after. Convolutional neural networks (CNNs) have proven themselves very effective in various segmentation tasks on medical images. Despite this, their application in CTV delineation is not yet fully explored. This study uses the three-dimensional fully convolutional neural network architecture called V-net for CTV delineation. The West China Hospital (Chengdu, China) provided this study with 120 annotated CT scans. For improved performance and to battle data scarcity, the available scans were augmented. Trained on 100 CT-scans for 20 hours and tested on 20 previously unseen CT-scans the network achieved a mean dice similarity coefficient (DSC) of 0.90 and a mean delineation time per CTV of 0.60 seconds. The proposed method is compared with two other state-of-the-art CNNs and is shown to be superior.

Outcomes after intensity-modulated compared with 3-dimensional conformal radiotherapy with chemotherapy for squamous cell carcinoma of the anal canal

Purpose

We report our institution's treatment techniques, disease outcomes, and complication rates after radiotherapy for the management of anal canal carcinoma with intensity-modulated radiotherapy (imrt) and concurrent chemotherapy relative to prior cases managed with 3-dimensional conformal radiotherapy (3D-crt).

Methods

In a retrospective review of the medical records of 21 patients diagnosed with biopsy-proven stage i (23%), stage ii (27%), or stage iii (50%) squamous-cell carcinoma of the anal canal treated with curative chemotherapy and imrt between July 2009 and December 2014, patient outcomes were determined. Results for patients treated with 3D-crt by the same group were previously reported. The median initial radiation dose to the pelvic and inguinal nodes at risk was 45 Gy (range: 36-50.4 Gy), and the median total dose, including local anal canal primary tumour boost, was 59.4 Gy (range: 41.4-61.2 Gy). Patients received those doses over a median of 32 fractions (range: 23-34 fractions). Chemotherapy consisted of 2 cycles of concurrent fluorouracil-cisplatin (45%) or fluorouracil-mitomycin C (55%).

Results

Median follow-up was 3.1 years (range: 0.38-6.4 years). The mean includes a patient who died of septic shock at 38 days. The 3-year rates of overall survival, metastasis-free survival, locoregional control, and colostomy-free survival were 95%, 100%, 100%, and 100% respectively. No patients underwent abdominoperitoneal resection after chemoradiotherapy or required diverting colostomy during or after treatment. Those outcomes compare favourably with the previously published series that used 3D-crt with or without brachytherapy in treating anal canal cancers. Of the 21 patients in the present series, 10 (48%) experienced acute grade 3, 4, or 5 toxicities related to treatment.

Conclusions

The recommended use of imrt with concurrent chemotherapy as an improvement over 3D-crt for management of anal canal carcinoma achieves a high probability of local control and colostomy-free survival without excessive risk for acute or late treatment-related toxicities.

High-dose-rate vs. low-dose-rate interstitial brachytherapy boost for anal canal cancers

PURPOSE

The purpose of this study was to analyze and compare clinical outcomes of low-dose-rate (LDR) and high-dose-rate (HDR) interstitial brachytherapy boost (ISBT) after EBRT or radio chemotherapy for the treatment of anal canal cancers.

METHODS AND MATERIALS

One hundred patients with anal canal cancers were treated at our institution by ISBT [LDR (n = 50); HDR (n = 50)]. Chronic toxicity rates, local control, disease-free survival, overall survival, and colostomy-free survival of the two different dose-rate brachytherapy modalities were analyzed and compared.

RESULTS

With a median followup of 42.2 months (95% CI, [34.5-48.8]), 9 (9% [4.8-16.2%]) local recurrences were observed, 4 (8% [3.2-18.8%]) in LDR vs. 5 (10% [4.4-21.4%]) in HDR group (odds ratio [OR] = 1.28 [0.32-5.07], p = 0.73). The 5-year rate of local control for the entire population was 90% [81-95%], 93% [79-98%] vs. 86% [69-94%] for LDR and HDR, respectively (p = 0.38). The 5-year disease-free survival rate for all patients was 82% [71-90%], 88% [73-95%] vs. 72% [44-88%] for LDR and HDR, respectively (p = 0.21). The 5-year overall survival rate for global population was 94% [84-98%], with no significant differences between LDR (97% [79-100%]) and HDR (93% [80-98%]) (p = 0.27). The 5-year colostomy-free survival rate was 92% [83-96%], respectively, 95% [83-99%] vs. 86% [69-94%] for LDR and HDR (p = 0.21). Significant differences were found in terms of chronic toxicity rates, with 28 (56% [42.3-68.8%]) patients concerned in low-dose-rate brachytherapy vs. 17 (34% [22.4-47.9%]) in high-dose-rate brachytherapy (OR = 0.40 [0.18-0.91], p = 0.03).

CONCLUSIONS

Local recurrence rates were comparable between both groups; HDR brachytherapy seem to have a better toxicity profile. Our data confirmed the finding that HDR can be used to safely administer ISBT without increasing chronic toxicity.

[Anal channel cancer: customization of dose, volume and breaching]

The conservative treatment of squamous cell carcinoma of anal canal by irradiation is recommended as first indication. Despite its rarity, significant improvements were obtained by retrospective or prospective clinical studies these 20 past years, evaluating concomitant chemotherapy and IMRT. Nevertheless, the individualisation of the treatment, over dose distribution, has poor data available. Fractionation remains classic (1.8-2.0Gy/Fr), but the optimal dose level remains under discussion. The strategy concerning the volumes and doses for the prophylactic volumes remains under discussion. This paper will describe the data published, and the recommendations of working Groups, and the main options under evaluation. To conclude, today only the absence of gap is recommended, the benefit of a one-step schedule reducing the treatment time, then increasing local control and survival, but personalised schedules remain under investigation.

mARC preoperative rectal cancer treatments vs. 3D conformal radiotherapy. A dose distribution comparative study

PURPOSE

mARC (modulated arc) is the arc therapy technique provided by Siemens. The present study analyses the dose distributions and treatment times corresponding to preoperative rectal cancer mARC treatments. The results are compared to those corresponding to 3D-CRT plans.

METHODS

The plans of 30 patients, each having one mARC and one 3D-CRT plan, were evaluated. Every plan was calculated on a sequential two-phase treatment scheme with prescription doses of 45 Gy in the initial phase and 5.4 Gy in the boost phase. Dosimetric parameters and mean DVHs corresponding to the PTVs and OARs were assessed for both techniques.

RESULTS

All mARC plans were considered valid for treatment and yielded a highly significant improvement in the CI over 3D-CRT plans (p <0.001). They also showed statistically significant advantage on the parameters D98%, D95% and D2% of the high dose PTV. Regarding the OARs, mARC plans showed reductions in the mean dose of 3.5 Gy in the bladder and greater than 4 Gy in the femoral heads. Considering the small bowel, the mARC plans resulted in a 2.7 Gy mean reduction in the mean dose and lower irradiated volumes over the entire dose range.

CONCLUSIONS

Arc therapy plans with the mARC technique for preoperative rectal cancer treatment in a sequential two-phase treatment scheme provide important advantages in the PTVs and OARs. mARC plans show superior protection of the femoral heads, bladder and small bowel, similar to the results found with other more widespread arc therapy techniques.

Excluding the ischiorectal fossa irradiation during neoadjuvant chemoradiotherapy with intensity-modulated radiotherapy followed by abdominoperineal resection decreases perineal complications in patients with lower rectal cancer

BACKGROUND

The aim of this study was to explore the impact of including or excluding the ischiorectal fossa (IRF) within the clinical target volume during neoadjuvant chemoradiotherapy (NCRT) using intensity modulated radiotherapy, in locally advanced lower rectal cancer (LALRC).

METHODS

We retrospectively analysed the data of 220 LALRC patients who received NCRT followed by abdominoperineal resection between January 2009 and January 2015. Six patients were excluded because of loss to follow-up, 90 patients received IRF irradiation (IRF group) while 124 patients did not (NIRF group). Survival, patterns of recurrence, and treatment toxicities were compared between the two groups.

RESULTS

Overall, patient/treatment variables were well balanced except for surgical technique. Perineal wound complications in the IRF and NIRF groups, were 40.0 and 24.2%, respectively (p = 0.010); corresponding 3-year perineal recurrence rates, local recurrence free survival, overall survival, and distant relapse free survival were 4.4% vs. 2.4% (p = 0.670), 88.1% vs. 95.0% (p = 0.079), 82.6% vs. 88.4% (p = 0.087), and 61.9% vs. 81.0% (p = 0.026), respectively. Multivariate analyses demonstrated the following factors to be significantly related to perineal wound complications: irradiation of the IRF (odds ratio [OR] 2.892, p = 0.002), anaemia (OR 3.776, p = 0.010), operation duration > 180 min (OR 2.486, p = 0.007), and interval between radiotherapy and surgery > 8 weeks (OR 2.400, p = 0.010).

CONCLUSIONS

Exclusion of the IRF from the clinical target volume during NCRT using intensity-modulated radiotherapy in LALRC could lower the incidence of perineal wound complications after abdominoperineal resection, without compromising oncological outcomes.

Intensity-modulated radiotherapy at high-volume centers improves survival in patients with esophageal adenocarcinoma receiving trimodality therapy

The standard of care trimodality therapy for resectable locally advanced esophageal adenocarcinoma is complex and necessitates multidisciplinary care and expertise. In this work, it is hypothesized that facility clinical volume and utilization of intensity-modulated radiotherapy (IMRT) may influence outcomes. The National Cancer Data Base was queried for patients with cT1-4-N0-3 M0 esophageal adenocarcinoma undergoing trimodality therapy from 2004 to 2013 (n = 2445). All patients received chemoradiation followed by esophagectomy at a Commission on Cancer facility. The facility volume was categorized into tertiles: high-volume centers (HVCs) in the highest 25th percentile of cases per year, intermediate-volume centers (IVCs) with the next highest 25th percentile of cases, and low- and very low-volume centers (LVCs) in the lowest 50th percentile. Overall survival (OS) was estimated using Kaplan-Meier methods and Cox proportional hazard regression. Propensity score matching to balance patient characteristics between volume centers was performed. Subgroup analysis was done comparing IMRT versus 3D conformal radiotherapy. The median follow-up was 26 months. Treatment at an HVC (hazard ratio 0.63, 95% CI 0.49-0.81, P < 0.001) was found to be independently associated with improved overall survival in multivariable analysis. Three-year OS was 58.4%, 46.2%, and 47.5% for HVCs, IVCs, and LVCs, respectively (P < 0.001). Patients at HVCs were more likely to receive IMRT over 3D chemoradiation (CRT; OR 3.45, 95% CI 2.4-5.0, P < 0.001). Patients treated using IMRT at HVCs had improved OS compared to those treated at IVCs or LVCs (HR 0.68, 95% CI 0.52-0.90, P < 0.01), while patients treated with 3D CRT at HVCs had no survival advantage over those at IVCs or LVCs (P = 0.28). Patients with locally advanced esophageal adenocarcinoma treated with IMRT and at HVCs appear to have improved survival.

Have we achieved adequate recommendations for target volume definitions in anal cancer? A PET imaging based patterns of failure analysis in the context of established contouring guidelines

Background

There are different contouring guidelines for the clinical target volume (CTV) in anal cancer (AC) which vary concerning recommendations for radiation margins in different anatomical regions, especially on inguinal site. PET imaging has become more important in primary staging of AC as a very sensitive method to detect lymph node (LN) metastases. Using PET imaging, we evaluated patterns of LN spread, and examined the differences of the respective contouring guidelines on the basis of our results.

Methods

We carried out a retrospective study of thirty-seven AC patients treated with chemoradiation (CRT) who underwent FDG-PET imaging for primary staging in our department between 2011 and 2018. Patients showing PET positive LN were included in this analysis. Using a color code, LN metastases of all patients were delineated on a template with “standard anatomy” and were divided indicating whether their location was in- or out-field of the standard CTV as recommended by the Radiation Therapy Oncology Group (RTOG), the Australasian Gastrointestinal Trials Group (AGITG) or the British National Guidance (BNG). Furthermore, a detailed analysis of the location of LN of the inguinal region was performed.

Results

Twenty-two out of thirty-seven AC patients with pre-treatment PET imaging had PET positive LN metastases, accumulating to a total of 154 LN. The most commonly affected anatomical region was inguinal (49 LN, 32%). All para-rectal, external/internal iliac, and pre-sacral LN were covered by the recommended CTVs of the three different guidelines. Of forty-nine involved inguinal LN, fourteen (29%), seven (14%) and five (10%) were situated outside of the recommended CTVs by RTOG, AGITG and BNG. Inguinal LN could be located up to 5.7 cm inferiorly to the femoral saphenous junction and 2.8 cm medial or laterally to the big femoral vessels.

Conclusion

Pelvis-related, various recommendations are largely consistent, and all LN are covered by the recommended CTVs. LN “misses” appear generally cranially (common iliac or para-aortic) or caudally (inguinal) to the recommended CTVs. The established guidelines differ significantly, particular regarding the inguinal region. Based on our results, we presented our suggestions for CTV definition of the inguinal region. LN involvement of a larger number of patients should be investigated to enable final recommendations.

18F-FDG PET Predicts Hematologic Toxicity in Patients with Locally Advanced Anal Cancer Treated With Chemoradiation

Purpose

Hematologic toxicity (HT) during chemoradiation therapy (CRT) for anal cancer can lead to treatment breaks that compromise efficacy. We hypothesized that CRT-induced HT correlates with changes in active bone marrow (ABM) characterized by pre-/post-CRT positron emission tomography (PET)/computed tomography.

Methods and materials

Data from 36 patients with anal cancer who were treated with 18F-fluorodeoxyglucose PET/computed tomography scans 2 weeks before and 6 to 16 weeks after CRT were analyzed. Complete blood counts with differential within 2 weeks from, weekly during, and 2 week after treatment were obtained. HT was defined as baseline complete blood count change to nadir and posttreatment recovery. Total bone marrow was segmented into 2 subregions: lumbosacral (LS) pelvis (L5 vertebrae, sacrum, and coccyx) and lower pelvis (LP) (ilium, femoral head/neck, and greater and lesser trochanter). PET ABM was characterized as the volume having standard uptake value (SUV) greater than the mean uptake of unirradiated extrapelvic bone marrow. PET variables of pre-/post-CRT and HT predictors were analyzed by linear regression.

Results

Average pelvic ABM was significantly reduced from 52% to 41% in pre- to post-CRT PET scans for all patients (P = .0012). Regional analysis indicated significant post-CRT reduction of LS-ABM (P < .0001) and LP-ABM (P = .006). Linear regression analysis identified post-CRT SUVmean, differential ΔSUVmean, and ΔABM as correlating significantly with pre- and posttreatment HT. ΔWBC linearly correlated with ΔABM of LS and LP pelvis (P = .033 and P = .028, respectively). Dosimetrically, ABM was sensitive to higher radiation doses (>50 Gy) in terms of acute hematologic ΔWBC (P = .021) and ΔANC(P = .028). HT increased with increasing volume of ABM receiving 40 Gy. The results also suggest that ABM V40 Gy ≤ 20% to 25% may significantly reduce the risk of HT.

Conclusions

HT was significantly associated with ΔABM in patients with anal cancer who were treated with CRT. LS-ABM was a robust surrogate for evaluating CRT-induced HT. Our results suggest implementation of ABM dosimetric constraints, V40 Gy ≤ 20-25%, may significantly reduce HT and lead to decreased treatment delays associated with clinical outcomes.

Positron emission tomography with computed tomography imaging (PET/CT) for the radiotherapy planning definition of the biological target volume: PART 2

AIM

Positron Emission Tomography with Computed Tomography (PET/CT) has been proven to be useful in the definition of Radiotherapy (RT) target volume. In this regard, the present expert review summarizes existing data for pancreas, prostate, gynecological and rectum/anal cancer.

METHODS

A comprehensive search of published original article was made, based on SCOPUS and PubMed database, selecting the paper that evaluated the role of PET/CT in the definition of RT volume.

RESULTS

FDG-PET has an important and promising role for pancreatic cancer. Choline PET/CT could be useful for identifying high-risk volumes for prostate cancer; while PSMA PET/CT is still under evaluation. FDG PET/CT in gynecological cancers has been shown to impact external-beam RT planning. The role of FDG-PET for Gross Tumor volume identification is crucial, representing a useful and powerful tool for anal and rectal cancer.

CONCLUSION

Taken together, molecular and functional imaging approaches offer a major step to individualize radiotherapeutic approach.

Anti-epidermal growth factor receptor therapy in combination with chemoradiotherapy for the treatment of locally advanced anal canal carcinoma: Results of a phase I dose-escalation study with panitumumab (FFCD 0904)

BACKGROUND AND PURPOSE

Standard treatment of epidermoid anal cancer is 5-fluorouracil (5FU) and mitomycin C (MMC) based chemoradiotherapy (CRT). This phase I study aims to evaluate the addition of panitumumab (Pmab) to CRT and to determine the maximum tolerated dose (MTD) of Pmab and 5-FU in combination with CRT.

MATERIALS AND METHODS

Immunocompetent patients with locally advanced tumour without metastases (Stage T2, T3 or T4, whatever N stage; Stage N1-N3 whatever T stage) followed two RT periods (45 Gy in 5 weeks and 20 Gy in 2 weeks, separated by a 2-week break) with concomitant CT sessions of 5FU/MMC at RT weeks 1, 5 and 8. Pmab was administered on RT weeks 1, 3, 5, 8 and 10 according to a predefined dose escalation schedule.

RESULTS

Ten patients were enroled. One was excluded due to unmet dose constraints respect. Three patients received dose level (DL) 0 (Pmab 3 mg/kg + 5FU 600 mg/m²/day) and six received DL-1 (Pmab 3 mg/kg + 5FU 400 mg/m²/day). Dose-limiting toxicities occurred in all patients at DL 0 and 2 at DL-1. Most common grade 3-4 toxicities observed at DL 0 were haematologic (100%), dermatitis (67%), and anaemia (67%). No death occurred. Four months after ending CRT, five and two patients had a local complete response and a partial response, respectively. One patient had a colostomy with abdomino-perineal amputation due to a tumour recurrence.

CONCLUSIONS

The MTD is 5FU at 400 mg/m²/day, MMC at 10 mg/m² and Pmab at 3 mg/kg. The effect of the MTD on tumour response is evaluated in the phase 2 study.

Induction Chemotherapy Reduces Patient-reported Toxicities During Neoadjuvant Chemoradiation with Intensity Modulated Radiotherapy for Rectal Cancer

BACKGROUND

Initial treatment with either neoadjuvant chemoradiation (CRT) or induction FOLFOX (5-Fluorouracil, leucovorin, and oxaliplatin) chemotherapy followed by CRT is considered standard treatment for locally advanced rectal cancer. We compared patient-reported outcomes (PRO) during CRT in patients who had received induction chemotherapy versus those who did not.

PATIENTS AND METHODS

We reviewed records of patients with locally advanced rectal cancer who were treated with CRT between September 2009 and October 2014, and who had completed ≥ 4 PRO assessments during treatment. Clinician- and patient-reported toxicities were collected each week during treatment. We fit binomial generalized linear models to maximum toxicity scores across all patients' visits.

RESULTS

Of 123 patients with ≥ 4 PRO assessments, 87 (71%) patients reported a clinically meaningful PRO score of 3 or higher for diarrhea, and 91 (74%) patients reported a PRO score of ≥ 3 for urgency, during 1 or more weeks of treatment, corresponding to 'very frequent' or worse. Of 116 patients who had also completed ≥ 4 clinician-reported assessments for descriptive analysis, clinically significant diarrhea (Common Terminology Criteria for Adverse Events grade ≥ 2) was reported in 9% of patients, and grade 2 proctitis and cystitis were reported in 20% and 4%, respectively. Eighty-four (68%) patients had undergone induction chemotherapy prior to CRT. Patients who received induction chemotherapy had 68% lower odds of experiencing significant urgency (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.11-0.95; P = .04), 76% lower odds of bleeding (OR, 0.24; 95% CI, 0.1-0.62; P < .01), and 75% lower odds of tenesmus (OR, 0.25; 95% CI, 0.11-0.6; P < .01) versus those treated with upfront CRT.

CONCLUSION

Based on PROs, a high proportion of patients experienced clinically significant symptoms during pelvic CRT, with diarrhea and urgency being most commonly reported. This appears to be under-reported on clinician-reported assessments. Delivery of induction chemotherapy was associated with lower odds of experiencing urgency, bleeding, and tenesmus on PROs during subsequent CRT, with no significant impact on diarrhea and rectal pain.

Neoadjuvant chemoradiotherapy delivered with helical tomotherapy under daily image guidance for rectal cancer patients: efficacy and safety in a large, multi-institutional series

Purpose

Helical tomotherapy (HT) has been recently introduced in the neoadjuvant treatment of locally advanced rectal cancer. Aim of this study is to report the toxicity and local control rates of a large series of locally advanced rectal cancer patients treated with neoadjuvant chemotherapy and HT under daily image guidance followed by surgery.

Methods

Data from 117 locally advanced rectal cancer patients treated at two Swiss Radiotherapy departments were collected and analyzed. Radiotherapy consisted of 45 Gy (1.8 Gy/fraction, 5 fractions/week delivered in 5 weeks) to the regional pelvic lymph nodes. Seventy patients also received a simultaneous integrated boost (SIB) up to 50 Gy to the tumor and involved nodes (2 Gy/fraction, 5 fractions/week delivered in 5 weeks). Chemotherapy consisted of capecitabine 825 mg/m², twice daily, during the irradiation days. After a median interval of 59 days [95% confidence interval (CI) 53–65 days), all patients underwent surgery.

Results

Median follow-up was 45 months (range 4–90 months). The overall rate of acute grade 2–4 toxicity was 18.8% (n = 22). Four patients (3.4%) presented a grade 3 dermatitis (n = 1) or diarrhea (n = 3), and 1 (0.8%) demonstrated grade 4 rectal toxicity. No patients presented with grade ≥ 3 hematologic toxicity. Six patients (5.1%) had late grade 3 gastrointestinal toxicity. The 4-year local control rate was 88.4% (95% CI 87.5–88.5%).

Conclusions

Neoadjuvant chemoradiotherapy delivered with HT under daily image guidance is well tolerated and shows a high 4-year local control rates.

Anal Cancer in the Era of Dose Painted Intensity Modulated Radiation Therapy: Implications for Regional Nodal Therapy

Since the initial development of 5-fluorouracil and mitomycin as a standard of care platform for definitive anal cancer chemoradiotherapy, multiple studies have evaluated the optimal chemotherapy regimen, and radiotherapy technique. Refinements in treatment technique have taken place during an era of improved diagnostic imaging, including incorporation of FDG-PET, with implications for a possible stage migration effect. This has introduced an opportunity to develop stage-specific recommendations for primary tumor, involved nodal, and elective nodal irradiation dose. Elective nodal irradiation remains standard given the low rates of elective nodal failure with current practice, although may be subject to evolving controversy for patients with early stage disease. In this review, development of the current standard of care for anal cancer chemoradiotherapy is reviewed in the context of modern staging and dose-painted radiotherapy treatment techniques.

An in-silico quality assurance study of contouring target volumes in thoracic tumors within a cooperative group setting

•

We aimed at quantifying inter-observer Pancoast tumors delineation variability.

•

Experts’ delineations were used to define ground truth.

•

Other observers’ delineations were compared against ground truth.

•

High degree of variability was noted for most target volumes except GTV_P.

•

This unveils potentials for protocol modification for future IMRT studies.

Introduction

Target delineation variability is a significant technical impediment in multi-institutional trials which employ intensity modulated radiotherapy (IMRT), as there is a real potential for clinically meaningful variances that can impact the outcomes in clinical trials. The goal of this study is to determine the variability of target delineation among participants from different institutions as part of Southwest Oncology Group (SWOG) Radiotherapy Committee’s multi-institutional in-silico quality assurance study in patients with Pancoast tumors as a “dry run” for trial implementation.

Methods

CT simulation scans were acquired from four patients with Pancoast tumor. Two patients had simulation 4D-CT and FDG-FDG PET-CT while two patients had 3D-CT and FDG-FDG PET-CT. Seventeen SWOG-affiliated physicians independently delineated target volumes defined as gross primary and nodal tumor volumes (GTV_P & GTV_N), clinical target volume (CTV), and planning target volume (PTV).

Six board-certified thoracic radiation oncologists were designated as the ‘Experts’ for this study. Their delineations were used to create a simultaneous truth and performance level estimation (STAPLE) contours using ADMIRE software (Elekta AB, Sweden 2017). Individual participants’ contours were then compared with Experts’ STAPLE contours.

Results

When compared to the Experts’ STAPLE, GTV_P had the best agreement among all participants, while GTV_N showed the lowest agreement among all participants. There were no statistically significant differences in all studied parameters for all TVs for cases with 4D-CT versus cases with 3D-CT simulation scans.

Conclusions

High degree of inter-observer variation was noted for all target volume except for GTV_P, unveiling potentials for protocol modification for subsequent clinically meaningful improvement in target definition. Various similarity indices exist that can be used to guide multi-institutional radiotherapy delineation QA credentialing.

A systematic review and meta-analysis of pT2 rectal cancer spread and recurrence pattern: Implications for target design in radiation therapy for organ preservation

BACKGROUND

There are no guidelines on clinical target volume (CTV) delineation for cT2 rectal cancer treated with organ preservation.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed to determine the extent of distal mesorectal (DMS) and distal intramural spread (DIS), the risk of lateral lymph node (LLN) metastases in pT2 tumours, and regional recurrence pattern after organ preservation.

RESULTS

The rate of DMS > 1 cm was 1.9% (95% CI: 0.4-5.4%), maximum extent: 1.3 cm. The rate of DIS > 0.5 cm was 4.7% (95% CI: 1.3-11.5%), maximum extent: 0.8 cm. The rate of LLN metastases was 8.2% (95% CI: 6.7-9.9%) for tumours below or at peritoneal reflexion and 0% for higher tumours. Regional nodal recurrences alone were recorded in 1.0% (95% CI: 0.5-1.7%) of patients after watch-and-wait and in 2.1% (95% CI: 1.2-3.4%) after preoperative radiotherapy and local excision. Thus, the following rules for CTV delineation are proposed: caudal border 1.5 cm from the tumour to account for DMS or 1 cm to account for DIS, whichever is more caudal; cranial border at S2/S3 interspace; inclusion of LLN for tumours at or below peritoneal reflexion. A planning study was performed in eight patients to compare dose-volume parameters obtained using these rules to that obtained using current guidelines for advanced cancers. The proposed rules led to a mean 18% relative reduction of planning target volume, which resulted in better sparing of organs-at-risk.

CONCLUSION

This meta-analysis suggests a smaller CTV for cT2 tumours than the current guidelines designed for advanced cancers.

The Management and Prevention of Anal Squamous Cell Carcinoma

Our aim is to discuss the current established management of care and associated prevention strategies of anal squamous cell carcinoma (SCCA). In general, the development of SCCA is commonly linked to a prior history of HPV. Unfortunately, HPV vaccination continues to be underutilized in the United States versus other countries. Increased acknowledgment of the importance of HPV vaccination as an anticancer vaccine should be encouraged. The present standard of care is primary chemoradiotherapy (CRT), which results in a high level of disease control for small, early-stage SCCA. More advanced cancers still fare poorly with this treatment, and the disease relapses locoregionally in the majority of cases (30%-50% of patients), resulting in an abdominoperineal resection. Current treatment recommendations are associated with substantial morbidity; alternative radiation doses and/or novel combinations of agents with CRT are needed to improve quality of life and oncologic outcomes. Cytotoxic chemotherapy remains the standard of care for treatment-naïve patients with metastatic disease, with a possible new treatment paradigm of carboplatin/weekly paclitaxel. In addition, immune checkpoint inhibition appears to have a promising role in the setting of patients with refractory disease. Several clinical trials with immunotherapeutic and vaccine approaches for locally advanced and metastatic anal cancer are ongoing, as are HPV-agnostic umbrella trials. Whenever possible, clinical trial enrollment is always encouraged for further therapeutic development in the setting of a rare cancer, given the potentially substantial global impact for other HPV-associated malignancies.

Radiation-induced injury on surgical margins: a clue to anastomotic leakage after rectal-cancer resection with neoadjuvant chemoradiotherapy?

Background

Few studies on anastomotic condition after rectal-cancer resection and its effect on anastomotic leakage (AL) are available up to now. This study aimed to investigate potential radiation-induced injury left on surgical margins of anterior resection after neoadjuvant chemoradiotherapy (nCRT) and its association with AL.

Methods

We retrospectively identified 161 consecutive patients who underwent anterior resection with nCRT, neoadjuvant chemotherapy without radiation (nCT) or no neoadjuvant therapy between 2014 and 2015. Tissue samples of resection margins were assessed using a specific histopathological score and microvessel density in submucosa. Propensity score matching was used to balance the baseline characteristics. Association between AL and histopathological features was analysed.

Results

AL occurred in 13 of 54 patients undergoing nCRT, 5 of 48 patients undergoing nCT and 7 of 59 patients without neoadjuvant therapy. Comparisons after matching showed median (range) histopathological scores as follows: 3 (0–8) vs 0 (0–3) vs 0 (0–2) for the proximal margin (P < 0.001); 4 (2–9) vs 0 (0–4) vs 0 (0–3) for the distal margin (P < 0.001). Correspondingly, mean (SD) microvessel densities were as follows: 21.7 (7.9) vs 27.2 (8.6) vs 27.3 (9.4) for the proximal margin (P = 0.003); 18.1 (9.3) vs 25.2 (12.9) vs 24.9 (7.4) for the distal margin (P < 0.001). Among patients undergoing nCRT, AL was associated with increased histopathological score (P = 0.003) and decreased microvessel density (P = 0.004) on the proximal margin.

Conclusions

Surgical margins of rectal-cancer resection are exposed to certain radiation-induced injury after nCRT. AL is associated with aggravated radiation damage on the proximal margin.

Impact of VMAT-IMRT compared to 3D conformal radiotherapy on anal sphincter dose distribution in neoadjuvant chemoradiation of rectal cancer

Background

Neoadjuvant radio- or chemoradiation (nIRT) therapy is the standard treatment for loco-regional advanced rectal cancer patients of the lower or middle third. Currently, intensity modulated radiation therapy (IMRT) is not the recommended radiation technique even though IMRT has advantages compared to 3D-radiation regarding dose sparing to organs at risk like small bowel and urinary bladder. So far, the benefit of IMRT concerning the anal sphincter complex is not examined. With this study we intended to evaluate the dose distribution on the anal sphincters of rectal cancer patients treated with IMRT in comparison with 3D-techniques.

Methods

We selected 16 patients for the IMRT-group and 16 patients for the 3D-group with rectal cancer of the middle third who were treated in our institute. All patients received 45 Gy in a chemoradiation protocol. Patients in both groups were matched regarding stage, primary tumor distance to the anal verge and size of the tumor. We delineated the internal and external anal sphincters, the addition of both sphincters and the levator ani muscle in all patients. Subsequently, we evaluated and compared dose parameters of the different sphincters in both groups and analysed the configuration of the isodoses in the area of the caudal radiation field, respectively.

Results

Most of the relevant dose parameters of the caudal sphincters (Dmean, Dmedian, V10–V40) were significantly reduced in the IMRT-group compared to the 3D-group. Accordingly, the isodoses at the caudal edge of the target volume in the IMRT group demonstrated a steep dose fall. The levator ani muscle always was included into the planned target volumes and received the full dose in both groups.

Conclusions

The modern VMAT-IMRT can significantly reduce the dose to the anal sphincters for rectal cancer patients of the middle third who were treated with conventional chemoradiation therapy.

Dosimetric comparison of different radiation techniques (IMRT vs. 3-dimensional) of the "true" (deep) ano-inguinal lymphatic drainage of anal cancer patients

Introduction

The ano-inguinal lymphatic drainage (AILD) is located in the subcutaneous adipose tissue of the proximal medial thigh. Currently, there are no recommendations for an inclusion of the ‘true’ AILD in the clinical target volume (CTV) of definitive chemoradiation for anal cancer patients. To estimate the relevance of inguinal recurrence, we compared the incidental dose to the AILD in anal cancer (AC) patients who were treated either with Volumetric Arc Therapy – Intensity Modulated Radiation Therapy (VMAT-IMRT) or conventional 3D-radiation technique.

Methods

One VMAT-IMRT-plans and one 3D-plans were calculated on the same target volumes and identical dose prescription in ten patients. We defined the volume of the AILD on the planning CT-scans based on the information of new fluorescence methods. Furthermore, we defined several anatomical subvolumes of interest inside the AILD. We examined and compared absolute and relative dosimetric parameters of the AILD and different anatomical subunits.

Results

The Dmean of the AILD was 40 Gy in the 3D-group and 38 Gy in the IMRT-group. Dmean and Dmedian as well as the V30Gy of the AILD and all subvolumes of the caudal AILD were significant higher using 3D-RT compared to IMRT. Even though the absolute differences were small, in the caudal aspect of the ano-inguinal lymphatic drainage the V30Gy could be more than 10% less with VMAT-IMRT.

Conclusions

3D-RT was slightly superior to IMRT in terms of dose coverage of the AILD. However, the absolute differences were very small. Some relevant caudal parts of the AILD received an insufficient dose for treating potential micrometastases. Particularly in high-risk situations, this may lead to inguinal recurrence and therefore the true deep AILD should be included into the target volume in high risk patients.

Quality Control of Radiation Delivery for Lower Gastrointestinal Cancers

OPINION STATEMENT

Assessing the quality of health care delivered is a priority across medical specialties, but it is particularly critical for radiation oncology, a field with rapid introduction of new technologies and treatment paradigms. Deviation from acceptable standards can lead to delivery of inferior therapies and medical errors that can directly compromise patient clinical outcome, thus leading to disparities in quality of care. Professional oncologic specialty societies often take ownership of standardizing best practices by issuing evidence-based disease-specific consensus guidelines. They also inform quality indicators that are set as requirements for accreditation, maintenance of certification, and reimbursement. Cooperative groups also create benchmarks for quality radiation therapy through design of clinical protocols that set standard-of-care treatment practices. Pelvic radiotherapy for colorectal and anal cancers has undergone a significant transformation in radiation planning and delivery including increased complexity in contour segmentation with a transition from three-dimensional to intensity-modulated radiation therapy (IMRT). Compliance with quality metrics proposed in national consensus guidelines and participation in clinical trials help keep practicing radiation oncologists up-to-date with advances in our field and well-trained to provide safe and effective high-value care.

Dosimetric analysis and comparison of reduced longitudinal cranial margins of VMAT-IMRT of rectal cancer

Background

The cranial border of the target volume (TV) in rectal cancer patients treated with neoadjuvant chemoradiation (nCRT) is mostly defined at the level of L5/S1. However, current studies have shown that relapse cranially of the target volume after neoadjuvant nCRT and surgery is very rare. A reduction of cranial TV margins could be reasonable to reduce toxicity to the organs at risk (OAR). In this study we compared the dose distribution to the OAR for different cranial longitudinal margins using a dose-volume histogram (DVH) analysis.

Methods

Ten patients with loco regional advanced rectal cancer were analysed retrospectively. All patients were planned for Volumetric Arc Therapy Radiation Therapy (VMAT). Next to the original PTV (PTV0), three new planning target volumes (PTV) were defined for each patient: The PTV0 reduced by 1 cm, 2 cm and 3 cm on cranial extension. For each PTV a treatment plan with a total dose of 50.4 Gy with daily doses of 1.8 Gy was calculated. Dose to the OAR were evaluated and compared.

Results

For the bone marrow, the small bowel and the peritoneal space all clinically relevant relative dose parameters (V10-V50) as well as the Dmedian could be significantly reduced with every cranial target volume reduction of 1 cm. For V10 of the peritoneal space the dose could be nearly halved with a 3 cm shortened TV. After TV reduction of 3 cm also for the urinary bladder a significant dose reduction of the Dmedian could be achieved.

Conclusions

Considering the very low recurrence rates in the TME and IMRT era, the distribution patterns of these relapses as well as the relevant side effects of nCRT, we would agree with existing recommendations of reduction of the cranial target volume in nCRT treated rectal cancer patients.

Management of locally advanced anal canal carcinoma with intensity-modulated radiotherapy and concurrent chemotherapy

The best curative option for locally advanced (stages II-III) squamous-cell carcinomas of the anal canal (SCCAC) is concurrent chemo-radiotherapy delivering 36-45 Gy to the prophylactic planning target volume with an additional boost of 14-20 Gy to the gross tumor volume with or without a gap-period between these two sequences. Although 3-dimensional conformal radiotherapy led to suboptimal tumor coverage because of field junctions, this modality remains a standard of care. Recently, intensity-modulated radiotherapy (IMRT) techniques improved tumor coverage while decreasing doses delivered to organs at risk. Sparing healthy tissues results in fewer severe acute toxicities. Consequently, IMRT could potentially avoid a gap-period that may increase the risk of local failure. Furthermore, these modalities reduce severe late toxicities of the gastrointestinal tract as well as better functional conservation of anorectal sphincter. This report aims to critically review contemporary trends in the management of locally advanced SCCAC using IMRT and concurrent chemotherapy.

Neoadjuvant PET and MRI-based intensity modulated radiotherapy leads to less toxicity and improved pathologic response rates in locally advanced rectal cancer

Background

Neoadjuvant chemoradiation (NeoCRT) is standard of care for the treatment of locally advanced rectal cancer (LARC). Contemporary radiation techniques and pre-treatment imaging may impact toxicities and pathologic response (PR). Herein we compare intensity modulated radiotherapy (IMRT) and advanced pre-treatment imaging in the neoadjuvant treatment of LARC and resulting impact on toxicities and pathologic outcomes relative to 3 dimensional conformal radiotherapy (3DCRT).

Methods

LARC patients treated at 4 large academic centers in the US from 2007-2016 were reviewed. Patients received 5-FU-based NeoCRT concurrently with IMRT or 3DCRT. PR was recorded as none, partial, or complete. Common terminology for adverse events version 4 was used to grade toxicities. Toxicity rates were compared using Chi-square analysis. Multivariable models were fit adjusting for age, gender, pre-tx CT to identify independent predictors of PR and toxicity.

Results

A total of 128 patients were analyzed: 60.1% male and 39.8% female, median age 57.7 years (range, 31-85 years). Clinical characteristics were similar across RT groups. The outcome of partial and complete PR was similar for IMRT and 3DCRT (48.1%, 23.1% vs. 31.7%, 23.3%), respectively. After adjusting for gender, age, and pre-RT chemotherapy type, IMRT and pretreatment PET and/or MRI imaging was significantly associated with increased odds for complete and partial response (OR =2.95, 95% CI: 1.21-7.25, P=0.018; OR =14.70, 95% CI: 3.69-58.78, P<0.0001). Additionally, IMRT was associated with reduced rates of dehydration, dermatitis, rectal pain, rectal bleeding, and diverting ostomy (P<0.05). Overall rates of grade 2 and higher toxicities were significantly reduced in IMRT vs. 3DCRT after adjusting for confounders (OR =0.27, 95% CI: 0.08-0.87).

Conclusions

NeoCRT IMRT with pretreatment PET and/or MRI for LARC leads to reduced acute toxicities and improved PR compared to 3DCRT. Given the challenges associated with prospective validation of these data, IMRT with pretreatment PET and/or MRI should be considered standard treatment for LARC.

Toxicity, Tolerability, and Compliance of Concurrent Capecitabine or 5-Fluorouracil in Radical Management of Anal Cancer With Single-dose Mitomycin-C and Intensity Modulated Radiation Therapy: Evaluation of a National Cohort

PURPOSE

Chemoradiation therapy (CRT) with mitomycin C (MMC) and 5-fluorouracil (5-FU) is established as the standard of care for the radical treatment of patients with anal squamous cell carcinoma (ASCC). The use of the oral fluoropyrimidine-derivative capecitabine is emerging as an alternative to 5-FU despite limited evidence of its tolerability and toxicity.

METHODS AND MATERIALS

A national cohort evaluation of ASCC management within the United Kingdom National Health Service was undertaken from February to July 2015. The toxicity rates were prospectively recorded. For the present analysis, we report data from ASCC patients who underwent intensity modulated RT and a single dose of MMC with either 5-FU (5-FU/MMC) or capecitabine (capecitabine/MMC). All were treated with radical intent and intensity modulated radiation therapy (IMRT) was delivered in accordance with UK guidance.

RESULTS

Of the 242 patients received from 40 centers across the United Kingdom, 147 met the inclusion criteria; 52 of whom were treated with capecitabine/MMC and 95 with 5-FU/MMC. No treatment-related deaths and no overall difference were found in the proportion of patients experiencing any grade ≥3 toxicity between the capecitabine and 5-FU groups (45% vs 55%; P = .35). However, significantly fewer patients in the capecitabine/MMC group experienced grade 3 hematologic toxicity (4% vs 27%; P = .001). A lower proportion of patients completed their planned chemotherapy course in the capecitabine cohort, although this did not reach statistical significance (81% vs 90%; P = .21). The median RT duration was 38 days (interquartile range 38-39) for both groups. No difference was found in the 1-year oncologic outcomes.

CONCLUSIONS

Capecitabine/MMC resulted in similar levels of grade 3/4 toxicity overall compared with 5-FU/MMC as CRT for ASCC, although differences were found in the patterns of observed toxicities, with less hematologic toxicity with capecitabine. Further studies of capecitabine/MMC are required to understand the acute toxicity profile and long-term oncologic outcomes of this combination with intensity modulated RT for ASCC.

Definitive chemoradiotherapy for anal canal cancer: single-center experience

BACKGROUND

Chemoradiotherapy (CRT) is a standard treatment for anal canal cancer although many patients with anal canal cancer undergo surgery in Japan. The efficacy of CRT for anal canal cancer was evaluated retrospectively.

METHODS

Medical charts of 13 patients with anal canal cancer treated by definitive CRT from October 2004 to May 2016 were reviewed. Twelve patients had squamous cell carcinoma and one had adeno-squamous carcinoma. PET/CT simulation was performed in nine patients. The median total dose was 59.4 Gy (range 57.6-63.4 Gy) with fractions of 1.8-2.0 Gy. Ten patients received chemotherapy with mitomycin C (10 mg/m²) and fluorouracil (5-FU) (800 mg/m² over 4 days) in weeks 1 and 5, while two patients were treated with cisplatin (40 mg) and 5-FU (750 mg over 5 days) in weeks 1 and 5. One elderly patient received radiotherapy (RT) alone.

RESULTS

All 13 patients were alive after a median follow-up period of 102 months (range 16-121 months). Local failure only occurred in the patient with adeno-squamous cell carcinoma, while there was no loco-regional recurrence or distant metastasis in the other 12 patients. The 5-year loco-regional control rate (LRC) and 5-year overall survival rate (OS) were 92% and 100%, respectively. Acute toxicities of ≥ grade 3 were observed in six patients (46%), mainly being dermatitis around the anal verge, and late toxicity of ≥ grade 3 occurred in one patient.

CONCLUSION

CRT for squamous cell carcinoma of the anal canal achieved good LRC and OS with acceptable toxicities.

A Definitive IMRT-SIB with Concomitant Chemotherapy for Synchronous Locally Advanced Anal Canal Cancer and Prostate Cancer

Currently, there are no specific recommendations regarding the management of the synchronous tumours due to the lack of either specific guidelines or individuals' clinical experiences relative to these clinical situations. In the presence of a locally advanced double primary tumour and with the lymph node metastases in addition, from the radiotherapeutical point of view, it must be challenging to manage this complicated situation that requires a more delicate treatment planning, due to higher doses prescribed to greater volumes concomitantly with the chemotherapy. A 68-year-old Caucasian male with a synchronous intermediate-risk prostate adenocarcinoma and locally advanced anal canal carcinoma underwent IMRT-SIB with concomitant chemotherapy at our institute. Two years after the treatment, the restaging CT and MRI scan showed no evidence of the disease and the patient reported no significant gastrointestinal or genitourinary toxicity. Our experience is unique, since it is the first report on using the IMRT-SIB technique simultaneously with chemotherapy in the management of the synchronous prostate and anal canal carcinomas. Therefore, we find it important to provide the current literature with the results from our experience which show good feasibility, efficacy, and tolerability of the definitive concomitant IMRT-SIB-chemotherapy for the synchronous anal canal cancer and prostate cancer.

How Histopathologic Tumor Extent and Patterns of Recurrence Data Inform the Development of Radiation Therapy Treatment Volumes in Solid Malignancies

The ability to deliver highly conformal radiation therapy using intensity-modulated radiation therapy and particle therapy provides for new opportunities to improve patient outcomes by reducing treatment-related morbidities following radiation therapy. By reducing the volume of normal tissue exposed to radiation therapy (RT), while also allowing for the opportunity to escalate the dose of RT delivered to the tumor, use of conformal RT delivery should also provide the possibility of expanding the therapeutic index of radiotherapy. However, the ability to safely and confidently deliver conformal RT is largely dependent on our ability to clearly define the clinical target volume for radiation therapy, which requires an in-depth knowledge of histopathologic extent of different tumor types, as well as patterns of recurrence data. In this article, we provide a comprehensive review of the histopathologic and radiographic data that provide the basis for evidence-based guidelines for clinical tumor volume delineation.

Variability of clinical target volume delineation for rectal cancer patients planned for neoadjuvant radiotherapy with the aid of the platform Anatom-e

Objective

Delineation of treatment volumes is a major source of uncertainties in radiotherapy (RT). This is also true for rectal cancer patients undergoing neoadjuvant RT, with a potential impact on treatment quality. We investigated the role of the digital platform Anatom-e (Anatom-e Information Sytems Ltd., Houston, Texas) in increasing the compliance to follow a specific treatment protocol in a multicentric setting.

Materials and methods

Two clinical cases of locally advanced rectal cancer were chosen. Participants were instructed to follow the 2009 Radiation Therapy Oncology Group consensus atlas and asked to manually segment clinical target volumes (CTVs), for both patient 1 and 2, on day 1 with and without the use of Anatom-e. After one week (day 2), the same radiation oncologist contoured again, with and without Anatom-e, the same CT series. Intraobserver (Intra-OV) and interobserver (Inter-OV) variability were evaluated with the Dice similarity coefficient (DSC), the Hausdorff distance (HD) and mean distance to agreement (MDA).

Results

For clinical case 1, no significant difference was found for Intra-OV and Inter-OV. For clinical case 2, no significant difference was found for Intra-OV but a statistically significant difference was found for Inter-OV in DSC when using or not the platform. Mean DCS was 0.65 (SD: ±0.64; range: 0.58-0.79) for day 1 vs reference volume without Anatom-e and 0.72 (SD: ±0.39; range: 0.67-0.77) (p = 0.03) with it. Mean MDA was lower with Anatom-e (3.61; SD: ±1.33; range: 2.85-4.78) than without (4.14; SD: ±2.97; range: 2.18-5.21), with no statistical significance (p = 0.21) The use of Anatom-e decreased the SD from 2.97 to 1.33. Mean HD was lower with Anatom-e (26.06; SD: ±2.05; range: 24.08-32.62), with no statistical significance (p = 0.14) compared to that without (31.39; SD: ±1.31; range: 26.14-48.72).

Conclusions

The use of Anatom-e decreased the Inter-OV in the CTV delineation process for locally advanced rectal cancer with complex disease presentation planned for neoadjuvant RT. This system may be potentially helpful in increasing the compliance to follow shared guidelines and protocols.

Dosimetric quantification of the incidental irradiation of the 'true' (deep) ano-inguinal lymphatic drainage of anal cancer patients not described in conventional contouring guidelines

INTRODUCTION

The ano-inguinal lymphatic drainage (AILD) is located in the subcutaneous adipose tissue of the proximal medial thigh. Findings from fluorescence methods give us new information about anatomical conditions of the AILD. Current contouring guidelines do not advise the inclusion of the 'true' AILD into the clinical target volume (CTV). Aim of this work was the retrospective analysis of the incidental dose to the AILD in an anal cancer (AC) patient cohort who underwent definitive chemoradiation (CRT) therapy with Volumetric Arc Therapy - Intensity Modulated Radiation Therapy (VMAT-IMRT).

METHODS

VMAT-IMRT plans of 15 AC patients were analyzed. Based on findings from new fluorescence methods we created a new volume, the expected AILD. The examined dosimetric parameters were the minimal, maximal and mean dose and V10-V50 that were delivered to the AILD, respectively.

RESULTS

The median volume of AILD was 1047 cm³. Mean D_min, D_max and D_mean were 7.5 Gy, 58.9 Gy and 40.8 Gy for AILD. The clinical relevant dose of 30.0 Gray covered in mean 76% of the volume of the AILD, respectively.

CONCLUSIONS

Only 76% of the AILD-volume received at least an expected required treatment dose of 30 Gy incidentally. Concerning the low number of loco-regional relapses in AC patients after definitive CRT one has to balance increased side effects against a rigid oncological-anatomical interpretation of the local lymphatic drainage by including the AILD into the standard CTV.

Neoadjuvant therapy and subsequent treatment in rectal cancer: balance between oncological and functional outcomes

Current practice of neoadjuvant therapy and total mesorectal excision (TME) in rectal cancer bears the weakness in systemic disease control and long-term functional outcomes. With increasing concerns of the balance between cure and quality of life, new strategies are developed to better oncological outcomes at least cost of function damage. Attractive options to adjust neoadjuvant modality include escalation of radiotherapy, intensification of chemotherapy, and chemoradiotherapy with consolidation or full-course chemotherapy. Subsequently, organ-preserving strategies have gained the popularity. Surgical or nonsurgical approaches that spare the rectum are used as possible alternatives for radical surgery, though high-quality TME remains the last resort to offer reliable local disease control. This review discusses new strategies of neoadjuvant therapy and subsequent management, with a specific focus on the balance between oncological and functional outcomes.

Evolution and Management of Treatment-Related Toxicity in Anal Cancer

Over the past several decades, clinical trials have demonstrated improved disease-related outcomes in the definitive treatment of anal cancer. Although treatment with radiation and concurrent chemotherapy results in high rates of cure, significant acute and late toxicities are seen. This review focuses on the evolution of treatment-related toxicity for anal cancer. Management of these adverse effects is reviewed, as are future directions in anal cancer treatment and their impact on toxicity.

Hybrid Tri-Co-60 MRI radiotherapy for locally advanced rectal cancer: An in silico evaluation

•

Tri-Co-60 MRI radiotherapy (RT) is feasible in locally advanced rectal cancer.

•

Larger volumes of normal tissue receive low-moderate doses in Tri-Co-60 MRI RT.

•

Further studies on functional imaging applications and LinacMRI approach are needed.

•

Tri-Co-60 MRI might represent a safe irradiation technique for pelvic tumors.

Introduction

Aim of this paper is to investigate the plan quality of a tri-Co-60 MRI-Hybrid system for intensity-modulated radiation therapy (IMRT) in patients affected by locally advanced rectal cancer (LARC) undergoing neo-adjuvant radiotherapy.

Materials and methods

Ten consecutive LARC patients were selected. Tri-Co-60 step and shoot IMRT plans were generated simulating the presence of the magnetic field (B_on) or not (B_off) with the dedicated treatment planning system (TPS).

The total planned dose was 45 Gy in 25 fractions to the mesorectum and the pelvic nodes (planning target volume 2, PTV2) and 55 Gy to the tumor and correspondent mesorectum (PTV1) through simultaneous integrated boost (SIB). Tri-Co-60 IMRT plans were compared with Volumetric Modulated Arc Therapy (VMAT) and IMRT plans for Linear Accelerator (Linac).

Results

B_on and B_off tri-Co-60 IMRT plans showed no relevant differences. Mean values of PTV1 and PTV2 receiving at least 95% of the D_p (V_95%) were higher than 95% in all treatment plans. All plans met the V_105% constraint for the PTV1. Mean values of V_105% for the PTV2 were 14.8, 5.0, and 7.3% respectively for tri-Co-60, VMAT and IMRT. Mean Wu’s HI values were similar in all plans (7.4–7.8%). All plans met the V_45Gy constraint for small bowel, but mean V_45Gy value was higher with tri-Co-60.

Bladder irradiation was comparable and always lower than the chosen D max 65 Gy constraint.

Mean values of V_5Gy and V_20Gy to the body and median skin doses were higher with tri-Co-60 plans.

Discussion

Treatment plans with Tri-Co-60 step and shoot IMRT met the dose-volume objectives in patients with LARC. Nevertheless, a larger volume of normal tissue received low-moderate doses when compared with Linac based VMAT and IMRT.

Positron emission tomography and computed tomographic (PET/CT) imaging for radiation therapy planning in anal cancer: A systematic review and meta-analysis

To improve the accuracy of chemoradiation therapy in anal cancer patients PET/CT is frequently used in the planning of radiation therapy. A systematic review was performed to assess impact on survival, quality of life, symptom score, change in target definition and treatment intention. Systematic literature searches were conducted in Medline, EMBASE, the Cochrane Library, and Centre for Reviews and Dissemination. Ten cross-sectional studies were identified. No data were available on survival or quality of life. The summary estimate of the proportion of patients in which PET/CT had an impact on the target definition, was 23% (95% CI 16;33). The corresponding summary estimate of a change in treatment intent from curative to palliative was 3% (95% CI 2;6). Almost one in four patients had a change in target definition, which supports the use of PET/CT in radiation therapy planning, but the consequence regarding survival and quality of life is still uncertain.