BACKGROUND:We prospectively assessed acute and late toxicity in post-operative oral cavity squamous cell carcinoma (PO-OCSCC) treated with adjuvant dysphagia optimized intensity-modulated radiotherapy (Do-IMRT) versus standard IMRT (S-IMRT).MATERIAL AND METHODS:Fifty-six patients of PO-SCC without indications of concurrent chemotherapy were alternatively allocated to adjuvant Do-IMRT (n = 28) versus S-IMRT (n = 28) arms. High- and low-risk planning target volume received 60 and 54 Gy, respectively, in 30 fractions over 6 weeks. Dysphagia aspiration-related structures (DARS) were contoured in both arms. While dosimetric constraints were given in Do-IMRT arm, doses to DARS were only observed without dose constraints in S-IMRT arm. Acute and late toxicity were assessed by common terminology criteria for adverse events (CTCAE) v5.0 and RTOG criteria, respectively.RESULTS:The primary site of disease was buccal mucosa (64% vs. 53%) and oral tongue (21% vs. 32%), in Do-IMRT and S-IMRT, respectively. The mean doses to DARS was significantly less with Do-IMRT (all p < 0.001) as compared to S-IMRT. Median follow-up was 24.2 months. Grade ≥2 oral pain was less in the Do-IMRT arm (50% vs. 78.6%, p = 0.05). Grade ≥2 late dysphagia at 2 years were significantly less in Do-IMRT arm (0% vs. 17.9%, p = 0.016). Two-year locoregional control was 89.2% in Do-IMRT and 78.5% in S-IMRT (p = 0.261).CONCLUSION:DARS can be spared in PO-OCSCC patients treated with Do-IMRT without compromising coverage of the target volumes. Limiting doses to DARS leads to lesser acute and late toxicity without compromising locoregional control.

Objective:To compare volumetric modulated arc therapy (VMAT) with simultaneous tumor bed boost (dpSIB-VMAT) to the whole breast and regional nodal irradiation (RNI) against standard three-dimensional conformal radiotherapy plus RNI with sequential tumor bed boost (3D-CRT-seqB). Methods:Thirty patients who underwent breast cancer surgery (BCS) with axillary lymph node dissection (ALND) were enrolled. Two plans were generated for each case: (1) dpSIB-VMAT, and (2) 3D-CRT-seqB plans. Planning target volume (PTV)-Breast and PTV-Nodes were prescribed at a dose of 50 Gy in 25 fractions in both plans. PTV-Boost was prescribed at a dose of 60 Gy in 25 fractions simultaneously in the dpSIB-VMAT plans, whereas it was planned sequentially in the 3D-CRT-seqB plans at 10 Gy in 5 fractions. Dosimetric parameters were compared between the two plans. Results:Both plans achieved the target coverage. Dmean of the heart was lower with dpSIB-VMAT in left-sided cases (7.17 ± 0.66 Gy vs. 10.12 ± 2.91 Gy; t = 4.02; p = 0.001). Ipsilateral mean lung dose (15.87 ± 1.40 Gy vs. 19.82 ± 3.20 Gy; t = 6.30; p<0.001) was significantly lower but mean doses of the contralateral breast (4.30 ± 1.76 Gy vs. 1.48 ± 0.76 Gy; t = -7.84; p<0.001), contralateral lung (3.86 ± 1.21 Gy vs. 0.96 ± 0.25 Gy; t = -13.13; p<0.001) and esophagus (13.11 ± 2.63 Gy vs. 10.32 ± 3.56 Gy; t = -6.65; p<0.001) were relatively higher with dpSIB-VMAT. Conclusion:Dosimetrically, dpSIB-VMAT reduced doses to the ipsilateral lung and heart (in left breast but not right breast cases) compared to 3D-CRT-seqB plans for adequate target coverage.

Prophylactic EFRT with concurrent chemotherapy using IMRT technique yielded excellent short term clinical outcomes with acceptable toxicity profiles. Longer follow up will elucidate late toxicity and long-term clinical outcomes.

155 Background: The paradigm of locally advanced (T3/4; T1-4N1-2) rectal cancers (LARC) requires an intensified treatment for better pathological outcomes. Treatment intensification may be done by radiation dose escalation of long course neoadjuvant chemoradiation therapy (NACRT) by image guided Intensity Modulated Radiation Therapy (IG-IMRT) to increase downstaging with potentially higher local control rates. We aimed to analyze the efficacy and safety of NACRT with dose escalated IG-IMRT in LARC. Methods: 20 patients of LARC were recruited in this prospective interventional phase-II study treated by IG-IMRT with 45 Gray/25 fractions to elective nodal volumes and concomitant boost of 55 Gray/25 fractions to gross primary and nodal disease with concurrent capecitabine (825 mg/m2 twice a day on radiation days). All were planned to undergo definitive surgery 6-8 weeks post completion of NACRT with Total mesorectal excision by Low anterior resection (LAR) or Abdominoperineal resection (APR) followed by 6-8 cycles of adjuvant chemotherapy. Post operative response assessment was assessed by Modified Ryan’s scheme for regression and by tumor downstaging. Primary end point was acute toxicity assessment and secondary end points were pathological complete response (pCR) and loco-regional control (LRC). Results: Of 20 patients, 18 underwent definitive surgery and received full course adjuvant chemotherapy (90%). Median follow up was 15.1 months. 2 patients refused surgery, had complete clinical response (cCR) on assessment and were on follow up. Tumor downstaging was achieved in 14 (77.7%) patients and nodal downstaging was achieved in 15/18 (83.3%) patients. In 4 patients (22.2%) pCR was achieved and overall complete response (OCR defined as pCR and nearCR, including 2 patients with cCR) in 10 patients (50%). 4 patients planned for APR underwent LAR achieving a sphincter preservation rate of 22%. Grade 3 toxicities were observed in 2 patients which resolved on first follow up. No Grade 4 acute toxicities were reported. No loco-regional relapses were found and all patients are disease free at the time of last follow up. Conclusions: Dose escalation with IG-IMRT offers higher rates of pCR and OCR with acceptable toxicity profile and excellent short term locoregional control. [Table: see text]

Purpose:We aimed to assess the toxicity profile and clinical outcome in patients with locally advanced cervical cancer (LACC) treated with a combination of image-guided intensity-modulated radiation therapy (IG-IMRT) and image-guided brachytherapy (IGBT).Material and methods:25 LACC patients were recruited in this single-arm prospective study. Whole pelvis IG-IMRT was delivered (45 Gy with simultaneously integrated nodal boost of 55 Gy in 25 fractions), with concurrent weekly cisplatin (40 mg/m2). Patients received IGBT of 7 Gy each in 4 fractions to high-risk clinical target volume (HR-CTV). First fraction was done under MRI, and subsequent fractions were performed under CT guidance. Primary endpoint was acute toxicity, and secondary endpoints were 2-year loco-regional control and late toxicity.Results:The median age was 52 years, and FIGO 2018 stage distribution was IIA2, IIB, IIIB, and IIIC1 in 12%, 40%, 20%, and 28% patients, respectively. All patients received concurrent chemotherapy with median number of 5 cycles (range, 4-5 cycles). Grade 1 and 2 diarrhea, and grade 1 cystitis was reported in 4 (16%), 3 (12%), and 2 (8%) patients, respectively. Grade 1 and 2 anemia, and grade 1 and 2 dermatitis were observed in 3 (12%) and 2 (8%), and 3 (12%) and 3 (12%) patients, respectively. No patient reported grade 3-4 acute toxicity. At median follow-up of 29.5 months (range, 25-37 months), late grade 1 bladder toxicity was observed in 1 (4%) patient. Loco-regional control at 1 and 2 years were 96% and 92%, respectively.Conclusions:The combination of IG-IMRT and IGBT yielded excellent outcomes in terms of acute toxicity and loco-regional control.

AbstractIntroduction:Dosimetric advantages of volumetric-modulated arc therapy (VMAT) over three-dimensional conformal radiotherapy (3D-CRT) are not established in a head-on comparison of a uniform group of locally advanced carcinoma of the cervix (LACC). Therefore, we conducted a dosimetric comparison of these two techniques in LACC patients.Materials and methods:Computed tomography (CT) data of histologically proven de novo LACC, including Stage IIB–IIIB and earlier stages deemed inoperable, were included in this prospective observational dosimetric study. Planning was initially done by 3D-CRT technique (dose of 45–50·4 Gy @ 1·8–2 Gy/# was used in the actual treatment), followed by VMAT planning and appropriate dosimetric comparisons were done in 39 cases.Results:For planning target volume coverage, D95, D98 and D100 (p < 0·0001 for all parameters) and V95 and V100 (p = 0·002 and <0·0001, respectively) were significantly improved with VMAT. The conformity index (CI) was significantly better with VMAT (p = 0·03), while 3D-CRT had a significantly better homogeneity index (HI)(p = 0·003). Dose to the urinary bladder was significantly reduced with VMAT compared to 3D-CRT for V20–V50, except V10. The doses to the rectum and abdominal cavity were significantly reduced with VMAT compared to 3D-CRT plans for all parameters (V10–V50). The number of organs at risks (OARs) for which constraints were met was higher with VMAT plans than with 3D-CRT plans, with at least four out of the five OARs protected in 46·1 versus 5·1% and all constraints achieved in 15·4% versus none.Conclusion:We conclude that in dosimetric terms, VMAT is superior to 3D-CRT for LACC.

Purpose/Objective(s)We aim to evaluate the role of neoadjuvant chemotherapy followed by hypofractionated radiotherapy in locally advanced unresectable OCSCC in terms of acute toxicity and efficacy.Materials/Methods10 patients with locally advanced (T4a-T4b and N0 or N1-N2) inoperable OCSCC with good performance status were recruited in this single arm prospective study between December 2020-january 2022. All patients received 2 cycles of NACT (paclitaxel 175 mg /m2 on D-1, cisplatin 75 mg / m2 on D1 and D2 in divided doses) every three weekly followed by Hypofractionated Radiotherapy (RT), delivered by 3-dimensional conformal radiotherapy plan with a dose of 55Gray (Gy) in 22 fractions at 2.5Gy per fraction delivered 5 days a week in two phases. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and response was evaluated by WHO response criteria. The primary and secondary endpoints were clinical response rate and acute toxicity, respectively. Statistical analysis was done using statistical software.ResultsAll patients received 2 cycles of NACT. Median RT dose was 55Gy. overall treatment time (OTT) was 98 days (95-120). Median Duration of follow up was 10 months (8-13 months). Patients' characteristics are summarized in table 1. All the patients completed their treatment as per protocol. Weekly assessment of toxicity was done and recorded during radiotherapy. Patients having dysphagia (grade >2) was 40% (4) and patients having dysphagia (grade ≤ 2) was 60% (6). Patients having oral mucositis (grade >2) was 50% (5) and those having (grade ≤ 2) was 50% (5). Radiation dermatitis more than grade 2 was not observed in any patient. No patient developed grade-4 radiation toxicity. All patients were regularly followed up for response assessment both clinically and radiologically. At median follow up of 10 month, 20% (2) patients had complete response (CR), 70% (7) patients had partial response (PR) and 10% (1) had progressive disease (PD).ConclusionNeoadjuvant chemotherapy followed by hypofractionated radiotherapy in locally advanced unresectable OCSCC shows acceptable acute radiation toxicity and good efficacy. We aim to evaluate the role of neoadjuvant chemotherapy followed by hypofractionated radiotherapy in locally advanced unresectable OCSCC in terms of acute toxicity and efficacy. 10 patients with locally advanced (T4a-T4b and N0 or N1-N2) inoperable OCSCC with good performance status were recruited in this single arm prospective study between December 2020-january 2022. All patients received 2 cycles of NACT (paclitaxel 175 mg /m2 on D-1, cisplatin 75 mg / m2 on D1 and D2 in divided doses) every three weekly followed by Hypofractionated Radiotherapy (RT), delivered by 3-dimensional conformal radiotherapy plan with a dose of 55Gray (Gy) in 22 fractions at 2.5Gy per fraction delivered 5 days a week in two phases. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and response was evaluated by WHO response criteria. The primary and secondary endpoints were clinical response rate and acute toxicity, respectively. Statistical analysis was done using statistical software. All patients received 2 cycles of NACT. Median RT dose was 55Gy. overall treatment time (OTT) was 98 days (95-120). Median Duration of follow up was 10 months (8-13 months). Patients' characteristics are summarized in table 1. All the patients completed their treatment as per protocol. Weekly assessment of toxicity was done and recorded during radiotherapy. Patients having dysphagia (grade >2) was 40% (4) and patients having dysphagia (grade ≤ 2) was 60% (6). Patients having oral mucositis (grade >2) was 50% (5) and those having (grade ≤ 2) was 50% (5). Radiation dermatitis more than grade 2 was not observed in any patient. No patient developed grade-4 radiation toxicity. All patients were regularly followed up for response assessment both clinically and radiologically. At median follow up of 10 month, 20% (2) patients had complete response (CR), 70% (7) patients had partial response (PR) and 10% (1) had progressive disease (PD). Neoadjuvant chemotherapy followed by hypofractionated radiotherapy in locally advanced unresectable OCSCC shows acceptable acute radiation toxicity and good efficacy.

Objective:To evaluate efficacy and late toxicity of intensity-modulated radiotherapy with simultaneous integrated boost (IMRT-SIB) in definitive management of head-and-neck cancers. Methods:In this prospective interventional study, histological proven squamous cell carcinoma of oropharynx, hypopharynx, or larynx with stage T1-3 N0-3 M0 who were not candidates for concurrent chemotherapy were treated with IMRT-SIB with radical intent. Doses prescribed for IMRT-SIB to meet the clinical needs of nodal volumes were either SIB-66 schedule 66 Gray (Gy) prescribed to high risk (HR) planned target volume (PTV), 60 (Gy) to intermediate risk (IR) PTV and 54 Gy to low risk (LR) PTV in 30 fractions or SIB-70 schedule 70 Gy to PTV-HR, 59.4 Gy to PTV-IR and 56 Gy to PTV-LR in 33 fractions. Result:Forty-five patients were included. Forty-two patients were treated with SIB-66 schedule and three patients with SIB-70 schedule. The median follow-up period was 21 (6-68) months. There was residual disease in three patients. Recurrence was observed in 24 patients. Most recurrences were in HR volume (n = 19) and three patients had distant failure. Estimated 2-year locoregional control, disease-free survival, and overall survival were 55.55%, 49.7%, and 51.1%, respectively. Grade 3 late skin toxicity, subcutaneous fibrosis, and xerostomia were observed in three patients. Conclusions:Efficacy and late toxicity of IMRT-SIB observed in our study suggest it as a suitable treatment option for patients who are not fit for chemoradiation.

Purpose/Objective(s)To determine the efficacy of pure modestly accelerated fractionated radiotherapy (PM-ART) in postoperative setting in patients of squamous cell carcinoma of oral cavity (OCSCC) in terms of Locoregional control (LRC), Overall survival (OS), and Disease-free survival (DFS).Materials/Methods40 post-operative OCSCC patients with one or more high risk features (pT3 or higher, close margins, DOI >10 mm, lymphovascular invasion, perineural invasion, >1 node positive, extra capsular extension) were treated between May 2015 and July 2016 with adjuvant PM-ART alone (60Gy in 30 fractions @ 2Gy per fraction; 6 fractions per week, over 5 weeks by three-dimensional conformal technique on a linear accelerator). Primary endpoint of the present study was to evaluate the efficacy of PM-ART and secondary endpoint was late toxicity assessment.Results40 patients were followed up till July 2021 of which four were lost to follow up. At a Median follow up of 45.5 months (range 4-70 months), 3-year LRC was 75%. Out of 40 patients, 17 patients had expired at the time of analysis of which 3 deaths occurred due to other competing causes after the completion of RT. DFS rate at 3 years was 64.8% and median DFS was 64.2 months; 3-year OS rate was 59%, and median OS was not yet reached. 23 patients were available for evaluation of late toxicity at the time of analysis. Xerostomia and subcutaneous fibrosis were the main late toxicities observed as follows – xerostomia grade 2 in 2 patients (9%), grade 1 in 11 patients (48%), subcutaneous fibrosis grade 2 was seen in 2 patients (9%), and grade 1 in 12 patients (52%). There was no grade 3 or higher late toxicities recorded.ConclusionIntensification of treatment by using PM-ART (6 fractions per week) was found to have good locoregional control rates and survival outcomes with acceptable late toxicities and needs to be evaluated in the context of randomized controlled trials to validate the findings.

Adjuvant HYPO-RT with RT-TMZ is well tolerated in terms of acute toxicity and may be a good alternative to reduce overall treatment time and counteract tumor repopulation in PO- GBM. Further follow up of our study cohort will elucidate the clinical outcome of patients treated with this HYPO-RT approach.

Introduction: Irradiation to the conserved breast consists of whole breast radiotherapy (WBRT) followed by tumour bed boost. Seroma in the tumor bed is a commonly observed side effects after breast-preservation, which can alter the shape of breast during WBRT and also lead to tumour bed shrinkage during boost irradiation, causing larger volumes of normal tissue irradiated. The aim was to evaluate the change in the lumpectomy cavity volumes before and after WBRT. Materials and Methods: Thirty-three patients with demonstrable lumpectomy cavity after breast conservation surgery (BCS) were included in the study. CT simulation of the breast was performed twice, initially before the start of WBRT and then 2 days prior to completion of WBRT. WBRT was delivered after contouring breast and lumpectomy volumes guided by the presence of surgical clips, seroma, and other surgical changes. Change in volume of lumpectomy cavity was analysed by Students’ paired T-test. Results: The volume reduction in the lumpectomy cavity was noted in 97% of patients (32/33). The change in lumpectomy cavity volume decreased by a mean value of 34.59% (range 0 - 72%) (p < 0.0001). The mean change in breast volume was 8.44% (range, -2.44 to 10.12%) (p - 0.394). Age, weight, location of tumour, T stage, breast volume, lumpectomy cavity volume, presence of clips and pre-radiation chemotherapy were not significantly associated with volume reduction of the lumpectomy cavity. Conclusion: The results of this study have shown that a significant volume reduction of the lumpectomy cavity after WBRT.

Introduction: Conventional Whole Pelvic Radiotherapy (WPRT) is associated with significant morbidity, especially haematological and Gastrointestinal (GI), which increases further with concurrent chemotherapy. Various studies have shown a clinical benefit of pelvic Intensity Modulated Radiotherapy (IMRT) but included a significant number of patients with intact cervix and uterus. Aim: The primary aim of the study was to record the toxicities of IMRT and the secondary aim to detect its tolerance. Materials and Methods: This was a phase 2, single arm cohort study, conducted from August 2015 to October 2018 at Dr. Ram Manohar Lohia Institute of Medical Sciences, Lucknow, Uttar Pradesh, India, including a total of 30 patients (23 cervical and seven endometrial cancer) who had undergone a total hysterectomy and required adjuvant pelvic irradiation. These patients were treated with pelvic IMRT using a dose of 45-50.4 Gray (Gy) at 1.8-2 Gy per fraction given as five fractions per week with/without concurrent chemotherapy (using injection cisplatin 35-40 mg/m(2) per week) as per indications. Acute toxicities were recorded at weekly intervals during the treatment followed by the assessment of late toxicities at the time of each follow-up visits using Radiation Therapy Oncology Group (RTOG) radiation morbidity criteria. All outcomes were measured from the time of the start of radiotherapy to the time of acute event. Acute and late toxicities were assessed according to RTOG radiation morbidity criteria. Survival analysis was done using the Kaplan-Meier method. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) (IBM Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp.). Results: Out of 30 patients, the highest grades of acute toxicities for skin, Lower Gastrointestinal (LGI), Genitourinary (GU), and haematological toxicities were grade 1, 2, 2 and 2, occurring in 11 (36.7%), 9 (30%), 4 (13.4%), and 1 (3.4%) of the cases, respectively. No late skin and GU toxicities were observed. Maximum late LGI toxicity was grade 1, occurring in 6.67% of the cases. Five (out of 30) patients developed treatment failures (two distant and three local). At a median follow- up of 35 months, the three year Progression Free Survival (PFS) and Overall Survival (OS) were 83.3% (all stages included). Conclusion: Considering acute and late adverse events in the form of skin, LGI, GU, and haematological toxicities, IMRT is well tolerated and has an acceptable toxicity profile even in the setting of an aggressive trimodality approach.

Limiting the radiation dose to dysphagia aspiration related structures (DARS) may reduce toxicities in patients of oral cavity squamous cell carcinoma (OCSCC) treated with adjuvant radiotherapy. We analyzed acute toxicity in patients of OCSCC treated with adjuvant intensity modulated radiation therapy (IMRT) reducing the dose of radiation received by DARS: dysphagia optimized IMRT (Do-IMRT) and compared it with standard IMRT (S-IMRT: without dose constraints to DARS). Fifty OCSCC patients between 18-70 years of age were randomized in this prospective study to receive either adjuvant Do-IMRT or S-IMRT. None received concurrent chemoradiotherapy. Target volume was divided into high, intermediate and low risk areas receiving doses in the range of 60-66 Gy, 54-58 Gy, 51-56 Gy in 30-33 fractions over 6-6.5 weeks, respectively. In addition to the conventional organs at risk, dose constraints were given to DARS in Do-IMRT arm. The primary end point was acute toxicity evaluated by common terminology criteria for adverse events (CTCAE) version 5.0. Each arm had 25 patients. Median age was 46.5 years (range 28-74 years). Patient characteristics were balanced between two groups. Buccal mucosa: Tongue: other primary were seen in 72% vs. 48%:12% vs. 36%: 16% vs. 16% respectively in Do-IMRT vs. S-IMRT. Similarly, T1:T2:T3:T4 were 8% vs. 4%: 60% vs. 40%: 24% vs. 32%: 8% vs. 24%; N0:N1:N2 were 68% vs. 48%: 16% vs. 36%: 16% vs. 16% in Do-IMRT vs. S-IMRT arm. respectively. Lymphovascular invasion and peri-neural invasion were observed in 20% vs. 36% and 20% vs. 12% respectively in Do-IMRT vs. S-IMRT. There was a statistically significant difference in the mean doses to DARS in Do-IMRT vs. S-IMRT arm without compromising PTV coverage (Table 1). Grade 3 dysphagia was significantly lower in the Do-IMRT vs. S-IMRT group (0% vs. 16%; p = 0.067). Do-IMRT significantly delivers lesser doses to DARS as compared to S-IMRT and trended to lesser acute grade ≥3 dysphagia and grade ≥2 oral pain compared to S-IMRT. Longer follow up and correlation of late toxicities would better define the role of Do-IMRT compared to S-IMRT in post-operative OCSCC patients.Abstract 3845; Rest is summarized in Table 1Dosimetric AnalysisDo-IMRT (Mean ± SD)S-IMRT (Mean ± SD)P valuePTV-HR V9597.86±1.1797.57±1.530.463PTV-IR V9599.03±1.3198.59±1.280.402PTV-LR V9598.82±1.6198.92±1.120.809Superior constrictor43.24±7.1652.33±6.66<0.001Middle Constrictor40.33±5.9352.86±5.59<0.001Inferior Constrictor29.05±9.9248.76±7.10<0.001Supraglottic Larynx40.06±5.4253.86±5.60<0.001Glottic Larynx31.76±9.3747.54±7.51<0.001Cricopharyngeus33.77±11.9446.48±7.54<0.001Cervical esophagus22.12±15.2532.18±12.780.015Acute toxicityDo-IMRTS-IMRTp-valueDysphagia Grade ≥287%100%0.102Oral mucositis Grade ≥330.4%44%0.252Pharyngeal mucositis Grade ≥30%12%0.133Oral pain Grade ≥252.2%76%0.077Oropharyngeal pain Grade ≥256.5%72%0.207 Open table in a new tab

Incorporation of neo-adjuvant chemotherapy (NACT) in addition to neoadjuvant long course chemoradiotherapy (NACTRT) is being evaluated in several prospective trials. This approach is supposed to have better downstaging of tumors and may have better pathological complete response (pCR) rates. In this prospective study we evaluated pCR rates and short-term clinical outcome in locally advanced rectal cancer (LARC) patients treated with 2cycles of NACT followed by NACTRT and then surgery. Between Jan 2018-July 2019, 25 patients of LARC were treated with 2 cycles of oxaliplatin (130 mg/m2) on D1 and capecitabine (1000mg/m2) from D1-D14 in two divided doses, 3 weekly) followed by NACTRT(50.4Gy in 28 fractions over 5.5 weeks with concurrent capecitabine 825 mg/m2 on radiation days) and then all the patient underwent total mesorectal excision by either abdominal perineal resection (APR) or low anterior resection(LAR). pCR was defined as no remnant tumor at primary or regional lymph nodes in post-operative specimen. Male:female ratio was 2:1 and median age was 40 years (range 18-65). Median distance from anal verge was 3.5 cm (range 0.5-7 cm) and length of disease was 6 cm (range 3.2-15 cm). Patient characteristics are summarized in Table 1. All patients completed NACT and NACTRT as intended. Median time between completion of radiotherapy to surgery was 7 weeks (range 6-9 weeks). Eighteen (72%) patients underwent APR and 7(28%) had low anterior resection (LAR). Six (24%) patients had pCR and 9 (36%) had involved circumferential resection margins. Median number of adjuvant chemotherapy cycles were 6 (range 1 to 6 cycle). At a median follow-up of 14.4 months, crude locoregional control and distant metastasis-free rates were 100% and 80%, respectively. NACT followed by NACTRT in locally advanced rectal cancer is associated with pCR rates in approximately one fourth of the patients. Longer follow up would help discern the clinical outcome better and a prospective trial with larger sample size is warranted in this regard.Abstract 3545; TablePatient characteristicsn = 25Obstruction3 (12%)cT2:T3: T41:22:2cN0:N1: N215:7:3Pre op diversion colostomy5(20%)Lymphovascular Invasion15 (60%)Perineural Invasion10 (40%)Extranodal extension7 (28%)pT0:T2: T3:T46:3:9:7pN0:N1: N211:9:5 Open table in a new tab