Postoperative IMRT Research Articles

Patterns of failure for recurrent head and neck squamous cell carcinoma treated with salvage surgery and postoperative IMRT reirradiation

Purpose/ObjectivesThe purpose of this study was to evaluate patterns of locoregional recurrence (LRR) after surgical salvage and adjuvant reirradiation with IMRT for recurrent head and neck squamous cell cancer (HNSCC). Materials/MethodsPatterns of LRR for 61 patients treated consecutively between 2003 and 2014 who received post-operative IMRT reirradiation to ≥ 60 Gy for recurrent HNSCC were determined by 2 methods: 1) physician classification via visual comparison of post-radiotherapy imaging to reirradiation plans; and 2) using deformable image registration (DIR). Those without evaluable CT planning image data were excluded. All recurrences were verified by biopsy or radiological progression. Failures were defined as in-field, marginal, or out-of-field. Logistic regression analyses were performed to identify predictors for LRR. ResultsA total of 55 patients were eligible for analysis and 23 (42 %) had documented LRR after reirradiation. Location of recurrent disease prior to salvage surgery (lymphatic vs. mucosal) was the most significant predictor of LRR after post-operative reirradiation with salvage rate of 67 % for lymphatic vs. 33 % for mucosal sites (p = 0.037). Physician classification of LRR yielded 14 (61 %) in-field failures, 3 (13 %) marginal failures, and 6 (26 %) out-of-field failures, while DIR yielded 10 (44 %) in-field failures, 4 (17 %) marginal failures, and 9 (39 %) out-of-field failures. Most failures (57 %) occurred within the original site of recurrence or first echelon lymphatic drainage. Of patients who had a free flap placed during salvage surgery, 56 % of failures occurred within 1 cm of the surgical flap. ConclusionOur study highlights the role of DIR in enhancing the accuracy and consistency of POF analysis. Compared to traditional visual inspection, DIR reduces interobserver variability and provides more nuanced insights into dose-specific and spatial parameters of locoregional recurrences. Additionally, the study identifies the location of the initial recurrence as a key predictor of subsequent locoregional recurrence after salvage surgery and re-IMRT.

PD-0961 Postoperative IMRT Radiotherapy in resected NSCLC patients: a multicentre retrospective analysis

PD-0961 Postoperative IMRT Radiotherapy in resected NSCLC patients: a multicentre retrospective analysis

Rates of osteoradionecrosis in resected oral cavity cancer reconstructed with free tissue transfer in the intensity-modulated radiotherapy era.

Resected oral cavity carcinoma defects are often reconstructed with osteocutaneous or soft-tissue free flaps, but risk of osteoradionecrosis (ORN) is unknown. This retrospective study included oral cavity carcinoma treated with free-tissue reconstruction and postoperative IMRT between 2000 and 2019. Risk-regression assessed risk factors for grade ≥2 ORN. One hundred fifty-five patients (51% male, 28% current smokers, mean age 62 ± 11 years) were included. Median follow-up was 32.6months (range, 1.0-190.6). Thirty-eight (25%) patients had fibular free flap for mandibular reconstruction, whereas 117 (76%) had soft-tissue reconstruction. Grade ≥2 ORN occurred in 14 (9.0%) patients, at a median 9.8months (range, 2.4-61.5) after IMRT. Post-radiation teeth extraction was significantly associated with ORN. One-year and 10-year ORN rates were 5.2% and 10%, respectively. ORN risk was comparable between osteocutaneous and soft-tissue reconstruction for resected oral cavity carcinoma. Osteocutaneous flaps can be safely performed with no excess concern for mandibular ORN.

Postoperative radiotherapy with modern techniques does not improve survival for operable stage IIIA-N2 non–small cell lung cancer

ObjectivesThis study aims to evaluate whether postoperative radiotherapy using newer techniques (intensity-modulated radiotherapy [IMRT]) is associated with improved survival for patients with stage IIIA-N2 non–small cell lung cancer (NSCLC) who underwent complete resection. MethodsThe overall survival of patients with stage IIIA-N2 NSCLC who received postoperative IMRT versus no postoperative IMRT following induction chemotherapy and lobectomy in the National Cancer Database from 2010-2018 was assessed via Kaplan-Meier analysis, Cox proportional hazards analysis and propensity score-matched analysis. Additional survival analyses were also conducted in patients with completely resected stage IIIA-pN2 NSCLC who had upfront lobectomy (without induction therapy) followed by adjuvant chemotherapy alone or adjuvant chemotherapy with postoperative IMRT. Only patients receiving IMRT, which is a newer, more conformal radiotherapy technique, were included. Patients with positive surgical margins were excluded. ResultsA total of 3203 patients with stage IIA-N2 NSCLC who underwent lobectomy were included. Five hundred eighty-eight (18.4%) patients underwent induction chemotherapy followed by lobectomy, and 2615 (82%) underwent lobectomy followed by chemotherapy. In unadjusted, multivariable-adjusted, and propensity score--matched analyses, there were no significant differences in overall survival between the patients who also received postoperative IMRT versus those who did not. ConclusionsIn this national analysis, the use of postoperative IMRT was not associated with improved survival in patients with completely resected stage IIIA-N2 NSCLC with or without induction chemotherapy.

Relapse patterns and radiation dose exposure in IDH wild-type glioblastoma at first radiographic recurrence following chemoradiation

PurposeTo quantify the radiation dose distribution and lesion morphometry (shape) at baseline, prior to chemoradiation, and at the time of radiographic recurrence in patients with glioblastoma (GBM).MethodsThe IMRT dose distribution, location of the center of mass, sphericity, and solidity of the contrast enhancing tumor at baseline and the time of tumor recurrence was quantified in 48 IDH wild-type GBM who underwent postoperative IMRT (2 Gy daily for total of 60 Gy) with concomitant and adjuvant temozolomide.ResultsAverage radiation dose within enhancing tumor at baseline and recurrence was ≥ 60 Gy. Centroid location of the enhancing tumor shifted an average of 11.3 mm at the time of recurrence with respect to pre-IMRT location. A positive correlation was observed between change in centroid location and PFS in MGMT methylated patients (P = 0.0007) and Cox multivariate regression confirmed centroid distance from baseline was associated with PFS when accounting for clinical factors (P = 0.0189). Lesion solidity was higher at recurrence compared to baseline (P = 0.0118). Tumors that progressed > 12 weeks after IMRT were significantly more spherical (P = 0.0094).ConclusionMost GBMs recur local within therapeutic IMRT doses; however, tumors with longer PFS occurred further from the original tumor location and were more solid and/or nodular.

Low Cardiopulmonary Toxicity With Use of IMRT When Delivering Postoperative Radiation Therapy (PORT) in Patients With NSCLC

The role of PORT for patients with resected stage IIIA (N2) NSCLC is controversial. Recently, the Phase III LungART trial reported a significant improvement in mediastinal control with PORT but failed to show an overall survival (OS) benefit, due in part to cardiopulmonary (CP) toxicity (7% early and 20% late grade (G) 3-5). However, LungART employed 3D conformal radiotherapy (3D-CRT) in 90% of patients as well as elective treatment of mediastinal nodal stations. We evaluated the risk of CP toxicity associated with use of postoperative IMRT for this population.We conducted a retrospective study of consecutive patients with NSCLC treated with postoperative IMRT between 2008 and 2019. Patients were eligible if they were found to have incidental pN2 or an R1/2 resection. Targets of PORT for pN2 were bronchial stump, ipsilateral hilum, and involved mediastinal station(s). The primary objective was incidence of CTCAE (v4) G3+ CP toxicities. Secondary objectives were major adverse cardiac events (MACE), defined as cardiac death, myocardial infarction, coronary revascularization or hospitalization due to heart failure; disease-free survival (DFS); and OS. Cumulative incidence and Kaplan-Meier method were used as appropriate.73 patients received PORT with IMRT. Median follow-up was 54 months. Median age at diagnosis was 65 years (range 36 - 81); 33 patients (45%) had pre-existing cardiovascular disease and 48 (65.8%) were current/former smokers. 50 patients had pN2 disease and 23 patients had R1/R2 resection. Among patients with pN2, the median number of involved mediastinal nodes was 1 (range 1 - 12). All patients with pN2 and 70% of patients with R1/R2 resection received chemotherapy, the majority of which was sequential (n = 52, 71.2%). Median RT dose was 54 Gy (range 45 - 66 Gy) in 27 fractions for patients with pN2 and 59.4 Gy (range 45 - 66 Gy) in 30 fractions for patients with R1/R2 resection. 3-year cumulative incidence of G3+ CP toxicity was 2.7%, with an overall incidence of 6.8% (5 events in 73 patients). The rate of G3+ CP toxicity in patients with pN2 was 8%. Three patients developed ≥1 MACE: one died of a cardiac arrest and two underwent coronary revascularization. Two of these patients had a history of coronary artery disease. Two episodes of G3+ toxicity involved valve replacements in patients with pre-existing valvular disease. 3-year DFS was 51.4% (95% CL 46.9 - 55.1%). Two patients with pN2 developed mediastinal failures. 3-year OS was 62.3% (95% CL 50.2 - 74.4%).PORT for pN2 NSCLC using IMRT and no elective nodal irradiation is associated with a low rate of G3+ CP toxicity in patients with pN2, comparable to the chemotherapy only arm of the LungART trial. Our data suggest that highly conformal radiation techniques should be prospectively assessed for their potential to translate the known local control benefit of PORT into a survival advantage.

Identification of Salivary Gland Tumors (SGT) at Risk for Local or Distant Recurrence After Postoperative Radiation Therapy (PORT) With or Without Systemic Therapy (ST) Using Clinical Risk Grouping

To identify risk groups and patterns of recurrence after curative treatment of primary SGT treated with PORT +/- ST.We retrospectively identified consecutive pts with stage I-IVA SGT, excluding adenoid cystic carcinoma (ca), treated with curative-intent surgery and postoperative IMRT with or without radiosensitizing chemotherapy from 12/2008-02/2020 at a tertiary care center. Pts were classified into clinical risk groups based on histologic diagnoses and pathologic features: (1) low-risk = morphologically low grade (LG) tumors (e.g. acinic cell, secretory, LG mucoepidermoid (MEC), epithelial-myoepithelial, basal cell adenocarcinoma), pN0, without lymphovascular invasion (LVI) or perineural invasion (PNI), including minimally invasive/non-invasive carcinoma ex-pleomorphic adenoma (CXPA); (2) intermediate-risk = intermediate grade morphology (e.g. grade 2 MEC) or LG morphology with PNI or LVI or pN+; (3) high-risk = high grade histology (e.g. salivary duct, high-grade MEC, poorly differentiated ca including invasive CXPA). Kaplan Meier estimates were used for recurrence-free survival (RFS) and univariable predictors.72 pts were included. Median age at surgery was 59.6 years [interquartile range (IQR) 49.7,67.7 yrs]. Sites were: 86% parotid (n = 62), 8% submandibular (n = 6), 4% minor salivary (n = 3), and 1% unknown primary. SGT were classified into clinical risk groups: 26% low (n = 19), 25% intermediate (n = 18), and 49% high-risk (n = 35). Concurrent chemotherapy (CRT) was given to 3% of low-risk (n = 1), 13% of intermediate risk (n = 4), and 71% of high-risk pts (n = 25). Regimens included carboplatin + paclitaxel, cisplatin, and concurrent/adjuvant trastuzumab (in 10 pts with HER2-positive SGT). With a median follow-up of 40.5 months, 2-year OS was 95% (85-98%); there were 11 recurrences (9 distant metastasis (DM), 2 in-field local failure (LF) both in pts with gross residual after surgery), with 82% (9 of 11) having received CRT. All recurrences were in the high-risk group with 2-year RFS of 73% (54%-85%) and 2-year cumulative incidence of DM 21% and LF 6%. Factors associated with RFS included positive margins (P = 0.004) and low-neck positive lymph nodes (level III/IV/V vs. level I/II, P = 0.04). Thirteen pts (18%) had targeted genomic sequencing (4 with recurrence); common mutations included TP53 (n = 4), HRAS (n = 3), NFKBIZ (n = 3), and PIK3CA (n = 3). Mutations in NF1 (n = 3) and HNFA1 (n = 2) were observed only in pts that recurred.DM are the primary mode of recurrence in pts with resected SGT treated with PORT +/- ST and occurred only in high-risk pts. After randomized trials like RTOG 1008 determine the added benefit of chemo to PORT, DM is likely to remain an unmet need. Further studies incorporating molecular characterization of high-grade SGT may identify potentially actionable targets to prevent distant recurrence.

Impact of a fiducial marker based ART strategy on margins in postoperative IMRT of gynecological tumors

PurposeTo investigate the potential of an offline Adaptive Radiotherapy (ART) strategy, based on the interfractional vagina motion (IVM) measured using fiducial markers (FM) during an initial number of fractions, on the CTV to PTV margins in post-operative gynecological patients. Materials and methodsIn 18 patients, treated post-operatively for gynecological tumors, the systematic residual IVM was quantified after simulating an offline ART procedure, utilizing the average IVM measured with FM for a varying initial numbers of fractions to find the optimal moment to adapt the treatment plan and a threshold for selecting patients for replanning. Clinical margins for a zero, 2 and 5 mm threshold based strategy were calculated to assess the possible margin reduction. ResultsApplying an ART strategy based on the average IVM of the initial 5 fractions reduces the systematic IVM significantly (P < 0.025), allowing a reduction of the clinical margin of 3 mm (20%) in the CC direction and 2 mm (13%) in the AP direction. A 2 mm threshold for selecting patients for replanning shows no difference in the reduction of the clinical margin, but reduces the workload with 12%. ConclusionAn ART strategy based on adapting on the average IVM during the initial 5 fractions of treatment provides an opportunity to reduce the CTV to PTV margins in postoperative gynecological tumors. To keep the workload in balance with the best achievable margin reduction, a threshold for selecting patients for plan adaptation is recommended.

PO-1044: Postoperative hypofractionated Image-Guided IMRT concomitant to chemotherapy in biliary tract cancer

PO-1044: Postoperative hypofractionated Image-Guided IMRT concomitant to chemotherapy in biliary tract cancer

The Contribution of Intensity-Modulated Radiotherapy after Non-curative Intent Surgery for Head and Neck Adenoid Cystic Carcinoma

Incomplete surgery (gross total resection, near total resection, and subtotal resection) of head and neck adenoid cystic carcinoma (HNACC) is controversially considered as an unfavorable prognostic factor as to curative intent surgery (CIS). However, in Intensity-Modulated Radiotherapy (RT) era, after planed incomplete surgery (PIS), intensified RT or RT with concurrent chemotherapy (CCT) may contribute to tumor control and survival. Thus, we investigated the contribution of IMRT after PIS on local control and survival in HNACC. Retrospective review was performed for 170 consecutive patients with HNACC treated with curative postoperative IMRT with or without concurrent chemotherapy, between 2015 and 2018, after PIS (n = 102) or CIS (n = 68). All plan target volumes were designed to including the primary tumor and related cranial nerve pathway. Patients with other malignant tumors or distant metastasis were excluded. Among the 170 patients (98 women and 72 men; median age, 53 years), the median follow-up time was 27.8 (range, 9.6-59.1) months. The estimated 3-year local-regional recurrence-free survival (LRRFS) rate, progression-free survival (PFS) rate, overall survival (OS) rate, and distant metastasis-free survival (DMFS) rate were 92.4% (95%CI: 87.3-95.9), 74.7% (95%CI: 67.5-81.0), 98.5% (95%CI: 94.9-99.6), and 76.0% (95%CI: 68.7-82.1), respectively. Patients with high grade, Ki-67≥10%, Stage III-IV, extra-nodal extension (ENE), perineural invasion (PNI) and positive margin was associated with worse PFS (p<0.0001, p = 0.002, p = 0.003, and p = 0.0004, p = 0.042, and p = 0.021, respectively). The baseline and treatment characteristics were equally distributed between PIS and CIS group, except that there were more patients with positive margin and received RT dose≥66 Gy in PIS group (p = 0.000 and p = 0.000). There was no difference in LRRFS, DFS, OS, and DMFS between two groups, both in stage I-II and Stage III-IV (p = 0.280, p = 0.371, p = 0.752, and p = 0.549, respectively). Among patients with high grade, Ki-67≥10%, ENE or PNI, there was also no difference in PFS between two groups. Among patients received radiation dose<66Gy, PIS group patients had significant worse PFS (p = 0.029), while among patients without any CCT, PIS group patients had marginal significant worse PFS (p = 0.067). In IMRT era, PIS does not compromise oncologic treatment, even in patients with worse prognostic factors; however, Doses of ≥66 Gy or CCT might be essential. This strategy warrants further evaluation in prospective randomized trials with longer follow-up.

Evaluation and prediction of pelvic dose in postoperative IMRT for cervical cancer

Objective To evaluate and predict the pelvic dose by analyzing two pelvic contour definitions and identify the influencing factors of the pelvic dose in postoperative IMRT for cervical cancer, aiming to provide reference for postoperative pelvis-sparing IMRT for cervical cancer. Methods Sixty cervical cancer patients receiving postoperative IMRT with unrestricted pelvic dose were selected. Two sets of pelvic contours (pelvic anatomy and pelvic Mell) were delineated as per the anatomical and Mell methods. The dose relationship between two methods was analyzed after redesigning the treatment plan by limiting dose of pelvic anatomy. The correlation analysis was performed by Pearson’s correlation method. The factors affecting the pelvic anatomy dose were identified by Logistic multivariate regression analysis and a dose prediction model was subsequently established. Results The volumes of pelvic anatomy and pelvic Mell were 925.82 cm3 and 1141.20 cm3(P=0.000). There was a significant correlation between them (r>0.622, P=0.000). The dose of pelvic anatomy was significantly higher than that of pelvic Mell. The relationship of V10, V20 and V30 between them was y=-8+ 1.01x, y=-13+ 1.05x and y=-4+ 0.9x, respectively. The dose limits of pelvic Mell recommended by literatures(V10<90%, V20<75%, V30<60%) were translated into V10<97%, V20<83% and V30<70%, respectively. The pelvic anatomy dose was significantly reduced after dose limiting. The V10, V20, V30 and Dmean were significantly decreased by 3.64%, 12.69%, 12.02% and 6.93%(P=0.000, 0.000, 0.000), respectively. Multivariate analysis showed that the overlapping volume of pelvic anatomy within PTV was an independent influencing factor of pelvic anatomy dose (P<0.05). Patients with a relative overlapping volume of less than 18% could easily meet the dose limiting requirement. Conclusions Both two pelvic contour definitions can be applied in postoperative pelvis-sparing IMRT for cervical cancer. Use of pelvic dose limiting can significantly reduce the IMRT dose. The overlapping volume of the pelvis within PTV is an independent influencing factor of pelvic dose. Patients whose overlapping volume within the PTV relative to pelvis is less than 18% can easily meet the dose limiting requirement. Key words: Cervical cancer/intensity-modulated radiotherapy; Pelvis; Dosimetry

Adjuvant Bone-Marrow Sparing IMRT in Endometrial Cancer Patients Treated with Sequential Chemotherapy- Does it Help with Completion Rate?

Postoperative pelvic IMRT has been shown to have decreased rates of myelosuppression in patients with gynecologic cancers treated with concurrent chemoradiation therapy, when compared to conventional 3D-CRT. However, there is limited data on how marrow sparing IMRT might impact tolerance in the setting of full-dose sequential chemotherapy and extended-field radiotherapy. A retrospective analysis of 158 patients with endometrial cancer treated with adjuvant sequential chemoradiation therapy with marrow sparing IMRT from 2008-2018 was performed. 146 of 158 patients received pre-IMRT chemotherapy, with 14 of 158 receiving post-IMRT chemotherapy. 63 patients were treated with extended field IMRT to include para-aortic lymph nodes, while 95 were treated with pelvic field IMRT including the entire common iliac region. Bone marrow was defined dosimetrically as the pelvic bone, bilateral femoral heads, and lower lumbosacral spine, with goal bone marrow V20 Gy < 80%. Myelosuppressive events were categorized using RTOG criteria. Linear regression analysis was used to assess for correlation between myelosuppression events and bone marrow dose. 157 of 158 (99.4%) patients completed EBRT as prescribed, with 1 discontinuing treatment due to acute GI toxicity. Median EBRT treatment time was 35 days (range 32-60 days). Total EBRT treatment time was 40 days or more in 17 patients (11%), with 4 patients having prolonged EBRT treatment time attributable to myelosuppression (range 42-57 days). All 158 patients had CBCs during treatment (median 4, range 1-8). Results for myelosuppressive events are detailed in the table below. Bone marrow V20 <80% was met in 118/158 (75%) of patients. Median bone marrow mean dose was 29.1 Gy (range 19.4-35.8 Gy). Median bone marrow V20 Gy was 73.9% (range 47.1-91.0%). Linear regression analysis did not reveal statistically significant associations between V20 Gy or mean bone marrow dose with grade 2 myelosuppression events. Grade 3 myelosuppression were rare events, with 2% incidence in pelvic field IMRT and 5% incidence in extended field IMRT. This is the largest series with marrow sparing IMRT in patients with endometrial cancer treated with sequential chemoradiation therapy, showing very low rates of grade III myelosuppression and 99.4% completion rate, with few treatment interruptions. With our goal bone marrow V20 Gy <80% dose met in the majority of patients, we were unable to determine a statistically significant relationship between myelosuppression events and V20 Gy or mean bone marrow dose.Abstract 2808; Table 1Grade 2 Anemia (Hgb<9.5-7.5)Grade 3 Anemia (Hgb <7.5)Grade 2 Neutropenia (ANC <1500-1000)Grade 3 Neutropenia (ANC <1000)Grade 2 Thrombocytopenia (PLT<75-50)Grade 3 Thrombocytopenia (PLT<50)Any Myelosuppression EventAny Grade 3 EventFrequency (n=158)20/158 (13%)0/158 (0%)33/158 (21%)4/158 (3%)8/158 (5%)1/158 (1%)53/158 (34%)5/158 (3%) Open table in a new tab

Disease-Free Survival Benefit of Radiotherapy Following Narrow-Margin Hepatectomy in Patients with Hepatocellular Carcinoma

To evaluate the effect of postoperative radiotherapy on the prognosis and recurrent patterns of hepatocellular carcinoma (HCC) patients with narrow-margin hepatectomy. From July 2007 to October 2016, a total of 234 patients with narrow-margin (<1.0 cm) hepatectomy were recruited in this study. Of which, 76 patients (Group A) eligible for inclusion in Phase II study were received postoperative radiotherapy, and the rest 158 patients were assigned to Group B. Kaplan-Meier survival analysis was performed to identify the association between postoperative radiotherapy and clinical outcomes of HCC patients with narrow-margin hepatectomy. Propensity score-matched (PSM) analysis was used to balance the differences in the basic clinical characteristics between Groups. Before PSM, the overall survival (OS) between Group A and Group B was not significantly different (P=0.2062), and the 1-year, 3-year and 5-year OS rate for the Group A and Group B were 98.6%, 89.0% and 72.6% versus 92.5%, 80.5% and 72.7%, respectively. While the disease-free survival (DFS) was significantly higher in Group A than in Group B (P=0.0337), and the 1-year, 3-year and 5-year DFS rate for the Group A and Group B were 88.0%, 71.3% and 60.2% versus 77.9%, 62.3% and 48.8%, respectively. After PSM, the OS between Group A and Group B were marginally different (P=0.0739), and the 1-year, 3-year and 5-year OS rate were 98.6%, 89.0% and 72.6% versus 88.0%, 76.8% and 66.9%, respectively. The DFS values were still significantly higher in Group A than in Group B (P=0.0076), and the 1-year, 3-year and 5-year DFS rate were 88.0%, 71.3% and 60.2% versus 73.4%, 55.6% and 43.2%, respectively. Before PSM, the surgical margin recurrence, single recurrence beyond the margin, and diffuse recurrence rates in Group A were 0% (0), 23.4% (18) and 5.3% (4) versus 5.1% (8), 12% (19), 13.9% (22) in Group B (P=0.009), respectively. There were no significant difference in extrahepatic recurrence rates (P=0.826), the early recurrence (less than 18 months after surgery) and late recurrence (more than 18 months after surgery) rates (P=0.104)．After PSM, regarding the patterns of margin recurrence, single recurrence beyond the margin or diffuse recurrence, the patients who had undergone postoperative IMRT still showed a significantly lower intrahepatic recurrence than those who did not undergo treatment (P=0.009). Postoperative radiotherapy has a significant DFS benefit for patients with narrow-margin hepatectomy. Long-term follow up and prospective studies with larger patient cohorts are needed to confirm OS benefit.

EP-1185 QOL for HPV+ SCC of the oropharynx treated with transoral laser microsurgery and postoperative IMRT

EP-1185 QOL for HPV+ SCC of the oropharynx treated with transoral laser microsurgery and postoperative IMRT

PO-147 Functional outcome of postoperative IMRT after laryngeal conservative surgery

PO-147 Functional outcome of postoperative IMRT after laryngeal conservative surgery

Intenzitet modulisana radioterapija u postoperativnom lečenju karcinoma grlića materice

Introduction: Postoperative radiotherapy in patients with cervical cancer significantly reduces the risk of loco-regional disease relapse, but at the same time is associated with increased toxicity at surrounding healthy organs and tissues. The occurrence of toxicity can significantly reduce the patient's quality of life, despite the complete remission of the disease. Aim: In this review article, we present modern radiotherapy technique-intensity modulated radiotherapy (IMRT), its advantages and disadvantages. Significant number of studies documented the results of postoperative IMRT role in treatment of cervical cancer, in reducing acute and late toxicity. Conclusions: Compared to previously used modalities of irradiation, IMRT is a complex ra-diotherapy technique-technically and time-consuming-which achieves escalation of the dose in the target volume, with better organ risk management, while decrease the frequency of acute and chronic complications and improve the quality of life after treatment. Of particular importance is the IMRT in postoperative approach in patients with a good prognosis.

Selectively sparing the submandibular gland when level Ib lymph nodes are included in the radiation target volume: An initial safety analysis of a novel planning objective

BackgroundSubmandibular gland (SMG) metastases are extremely rare in head and neck cancer, even in the presence of level Ib lymph node (LN) involvement. In recent years, we have contoured the SMG and specifically attempted to limit its dose exposure even in patients in whom the level Ib LN station is targeted. This study reports our preliminary feasibility and safety experience with selective submandibular gland sparing. MethodsPatients with squamous cell cancer (SCC) of the oral cavity or oropharynx with T1-2, N0-3, M0 disease in whom at least a single level Ib lymph node region was included in the target volume were identified. All patients were treated from 2009 to 2014 with definitive or postoperative IMRT with or without chemotherapy. Patients with recurrent disease, previous radiation or treated palliatively were excluded. ResultsA total of 174 patients met criteria for inclusion. Among the 185 level Ib LN stations that were deliberately targeted in the clinical treatment volume, 32 submandibular glands were contoured, excluded from the target volume and avoided during treatment planning. Mean dose to the spared SMG were reduced by 12% (66.6 Gy vs. 58.9 Gy, p < .001). None of these patients experienced any level 1b LN failures. ConclusionSelective sparing of the submandibular gland when targeting the level 1b nodes in oral cavity and oropharynx cancer is feasible, reduces the mean dose to submandibular glands and does not result in increased level 1b nodal failure rates. Additional studies with larger cohorts are needed to validate this preliminary observation.

Local Regional Patterns of Failure Following Postoperative IMRT for Anaplastic Thyroid Cancer

Local Regional Patterns of Failure Following Postoperative IMRT for Anaplastic Thyroid Cancer

Patterns of locoregional failure following post-operative intensity-modulated radiotherapy to oral cavity cancer: quantitative spatial and dosimetric analysis using a deformable image registration workflow

BackgroundWe sought to identify spatial/dosimetric patterns of failure for oral cavity cancer patients receiving post-operative IMRT (PO-IMRT).MethodsTwo hundred eighty-nine OCC patients receiving PO-IMRT were retrospectively reviewed from 2000 to 2012. Diagnostic CT documenting recurrence (rCT) was co-registered with planning CT (pCT) using a validated deformable image registration software. Manually segmented recurrent gross disease (rGTV) was deformed to co-registered pCTs. Mapped rGTVs were compared dosimetrically to planned dose and spatially to planning target volumes using centroid-based approaches. Failures types were classified using combined spatial/dosimetric criteria: A (central high-dose), B (peripheral high-dose), C (central intermediate/low-dose), D (peripheral intermediate/low-dose), and E (extraneous-dose).ResultsFifty-four patients with recurrence were analyzed; 26 local recurrence, 19 regional recurrence, and 9 both local and regional recurrence. Median time to recurrence was 4 months (range 0–71). Median rGTVs volume was 3.7 cm3 (IQR 1.4–10.6). For spatial and dosimetric analysis of the patterns of failure, 30 patients (55.5%) were classified as type A (central high-dose). Non-central high dose failures were distributed as follows: 2 (3.7%) type B, 10 (18.5%) type C, 1 (1.8%) type D, and 9 (16.7%) type E. Non-IMRT failure in the matching low-neck field was seen in two patients. No failures were noted at the IMRT-supraclavicular field match-line.ConclusionsApproximately half of patients with local/regional failure had non-central high dose recurrence. Peripheral high dose misses were uncommon reflecting adequate delineation and dose delivery. Future strategies are needed to reduce types C and E failures.

Outcomes of oral cavity cancer patients treated with surgery followed by postoperative intensity modulated radiation therapy

ObjectivesAlthough treatment paradigms have not changed significantly, radiotherapy, surgery, and imaging techniques have improved, leading us to investigate oncologic and survival outcomes for oral cavity squamous cell cancer (OCSCC) patients treated with surgery followed by postoperative IMRT. Material and methodsRecords of patients with pathological diagnosis of OCSCC treated between 2000 and 2012 were retrospectively reviewed. Patients’ demographic, disease, and treatment criteria were extracted. Kaplan-Meier method was used to calculate survival curves. ResultsTwo hundred eighty-nine patients were analyzed. Median follow-up was 35months. Two hundred sixty-eight had neck dissections (93%), of which 66% had nodal involvement, and 51% of those positive dissections had extracapsular extension. Forty patients received induction chemotherapy and 107 received concurrent chemotherapy. Median dose to high risk clinical target volume was 60Gy/30 fractions. The 5-year locoregional control and overall survival rates were 76% and 57%, respectively. Tumors with >1.5cm depth of invasion had significantly higher risk of local failure compared with ≤1.5cm (p<0.001). In multivariate analysis, positive and no neck dissection (p=0.01), positive lymphovascular invasion (p=0.006) and >1.5cm depth of invasion (p=0.003) were independent predictors of poorer survival. ConclusionsDisease outcomes were consistent with historical data and did not appear compromised by the use of IMRT.