Comparative retrospective analysis of locoregional recurrence in unselected breast cancer patients treated with conventional versus hypofractionated radiotherapy at a tertiary cancer center?

BACKGROUND: Role of hypofractionated radiotherapy (HFRT) in early breast cancer is established; comparatively, there are limited data for HFRT in locally advanced breast cancer (LABC). We report the impact of HFRT in unselected breast cancer patients in comparison with historically treated patients with conventional fractionated radiotherapy (CFRT). PATIENTS AND METHODS: Records of 463 breast cancer patients treated between January 09 and July 13 with CFRT (50 Gy/25 fr) or HFRT (42.4 Gy in 16 fractions or 40 Gy in 15 fractions) in two sequential periods were retrospectively reviewed. The analysis was done in August 2018. The primary endpoint was to compare the differences in locoregional recurrence rate. RESULTS: Of the 463 patients, 209 received CFRT and 254 received HFRT. The median age was 48 years (interquartile range: 40-56), premenopausal (CFRT: 23% vs. HFRT 39%, P = 0.005). The most common pathology was infiltrating ductal carcinoma (81%) with Grade III tumors (45%), estrogen receptor (+) was seen in 44%, triple-negative breast cancer in 34%, and Her2Neu (3+) were seen in 27%. Two hundred and fifty-four patients (54.5%) had undergone breast-conserving surgery (BCS) and 209 patients (45%) modified radical mastectomy (MRM). Nodal radiotherapy was delivered in 76% versus 64% in patients receiving CFRT versus HFRT, respectively (P = 0.005). With a median follow-up of 46 months in CFRT and 57 months in HFRT, 9/209 (4.3%) patients in CFRT and 7/254 (2.7%) in HFRT had locoregional relapse (LRR). The 4 years#39; actuarial local recurrence-free survival (LRFS) in CFRT versus HFRT was 95% versus 97% (P = 0.37). The mean estimated LRFS (local relapse-free survival) for CFRT is 113.4 months and for HFRT 94.2 months (P = 0.3). CONCLUSIONS: The risk of local recurrence among patients of breast cancer treated with HFRT after BCS or MRM was not worse when compared to CFRT.

Comparing Setup Errors Using Portal Imaging in Patients With Gynecologic Cancers by Two Methods of Alignment.

AIMS: Alignment tattoos on a lax abdomen contribute to misalignment of patients undergoing abdomino-pelvic radiotherapy (RT). The present study was undertaken to assess setup reproducibility in gynecologic cancer patients positioned identically but aligned for treatment to machine isocenter by two different ways. MATERIALS AND METHODS: A prospective study in 35 women treated with radical RT for gynecologic malignancy was undertaken. A RT planning contrast-enhanced computed tomography scan in the supine position using an foot and ankle positioning device was done, and three reference points tattooed on the reference plane, anteriorly at the mons pubis and one on each side laterally at a fixed table top-to-vertical height of 10 cm, whereas a fourth point was tattooed at the xiphoid in the anterior midline. Patients were aligned using either a field center, that is, conventional method (Arm I, n = 18) or by a new setup isocenter (Arm II, n = 17) defined by a cranial offset of 4 cm to the reference plane for daily treatment. Anterior and right lateral digitally reconstructed radiograph setup fields were created at the treatment isocenters and compared with orthogonal megavoltage portal images (PI) taken during initial 3 days of RT and subsequently twice weekly. Setup deviations-rotations and translations were analysed in mediolateral (ML), craniocaudal, and anteroposterior direction. No online and offline corrections were performed. Population systematic error and random error were calculated and planning target volume margins required were estimated using van Herk's formula. RESULTS: Arm I had 209 PI while Arm II had 188 PI. Patients in arm II had a lesser systematic error in the ML direction. Patients with large pelvic girth (>95 cm) were susceptible for greater movements during treatment, more so in Arm I, major shifts (>5 mm) with respect to Arm II in the ML direction (37% vs. 22%, P = .001). A larger planning target volume expansion was required in Arm I (1.6 cm) compared with Arm II (0.9 cm). The margin expansion required from clinical target volume in anteroposterior direction was about 0.6 cm and about a cm in the craniocaudal direction in both the arm. CONCLUSIONS: Alignment of patient with anterior tattoo at the relatively immobile portion of lower abdomen (mons pubis) Arm II (setup) is superior to a more cranial location over the flabby abdomen during radiation treatment.

Comparative assessment of late toxicity in patients of carcinoma cervix treated by radiotherapy versus chemo-radiotherapy - Minimum 5 years follow up.

BACKGROUND: A randomised trial was carried out comparing chemo-radiation (CTRT) vs. radiotherapy (RT) in patients of carcinoma cervix and showed similar rates of pelvic disease control, disease free survival and overall survival. Late toxicity is presented. METHODS: Between December 2000 and July 2006, 180 patients of carcinoma cervix were randomly assigned to RT + weekly cisplatin (n = 94) or RT alone (n = 86). Late toxicity was prospectively scored using RTOG criteria in 156 evaluable patients, 79 and 77 respectively and is presented as crude incidence for rectum, bladder, small intestine, vagina, skin and bone and also as actuarial incidence for rectum and bladder. RESULTS: The median follow up of surviving patients was 10.4 years (minimum - 6.5 years). Crude incidence, CTRT vs. RT, of late toxicities were: rectal (7.5% vs. 5%, p = 0.22), bladder (15% vs. 10.4%, p = 0.76), small bowel (3% vs. 1.2%, p = 0.51), vagina (25% vs. 35%, p = 0.35) while the actuarial risk of grades 3-5 rectal and bladder toxicities by 5 years were 13% vs. 10% (p = 0.698) and 16% vs. 14.8% (p = 0.783) respectively. Bladder toxicity appeared later then rectal toxicity (median 49.4 vs. 21.4 months). Severe bone toxicity (fractures) were higher in the CTRT arm, 5% vs. 0%, p = 0.018. On multivariate analysis vaginal involvement (p = 0.016) and bulky tumor (p = 0.020) were associated with severe vaginal morbidity while rectal point dose > 80% (p = 0.040) was associated with a higher incidence of rectal toxicity. CONCLUSION: Bone toxicity was significantly increased by addition of CT to RT and patients continued to experience toxicity at longer periods of follow up albeit disease free.

Influence of jaw tracking in intensity-modulated and volumetric-modulated arc radiotherapy for head and neck cancers: a dosimetric study.

PURPOSE: To Study the dosimetric advantage of the Jaw tracking technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) for Head and Neck Cancers. MATERIALS AND METHODS: We retrospectively selected 10 previously treated head and neck cancer patients stage (T1/T2, N1, M0) in this study. All the patients were planned for IMRT and VMAT with simultaneous integrated boost technique. IMRT and VMAT plans were performed with jaw tracking (JT) and with static jaw (SJ) technique by keeping the same constraints and priorities for a particular patient. Target conformity, dose to the critical structures and low dose volumes were recorded and analyzed for IMRT and VMAT plans with and without JT for all the patients. RESULTS: The conformity index average of all patients followed by standard deviation ([Formula: see text] ± [Formula: see text]) of the JT-IMRT, SJ-IMRT, JT-VMAT, and SJ-VMAT were 1.72 ± 0.56, 1.67 ± 0.57, 1.83 ± 0.65, and 1.85 ± 0.64, and homogeneity index were 0.059 ± 0.05, 0.064 ± 0.05, 0.064 ± 0.04, and 0.064 ± 0.05. JT-IMRT shows significant mean reduction in right parotid and left parotid shows of 7.64% (p < 0.001) and 7.45% (p < 0.001) compare to SJ-IMRT. JT-IMRT plans also shows considerable dose reduction to thyroid, inferior constrictors, spinal cord and brainstem compared to the SJ-IMRT plans. CONCLUSION: Significant dose reductions were observed for critical structure in the JT-IMRT compared to SJ-IMRT technique. In JT-VMAT plans dose reduction to the critical structure were not significant compared to the SJ-IMRT due to relatively lesser monitor units.

Dosimetric verification of gated delivery of electron beams using a 2D ion chamber array.

The purpose of this study was to compare the dosimetric characteristics; such as beam output, symmetry and flatness between gated and non-gated electron beams. Dosimetric verification of gated delivery was carried for all electron beams available on Varian CL 2100CD medical linear accelerator. Measurements were conducted for three dose rates (100 MU/min, 300 MU/min and 600 MU/min) and two respiratory motions (breathing period of 4s and 8s). Real-time position management (RPM) system was used for the gated deliveries. Flatness and symmetry values were measured using Imatrixx 2D ion chamber array device and the beam output was measured using plane parallel ion chamber. These detector systems were placed over QUASAR motion platform which was programmed to simulate the respiratory motion of target. The dosimetric characteristics of gated deliveries were compared with non-gated deliveries. The flatness and symmetry of all the evaluated electron energies did not differ by more than 0.7 % with respect to corresponding non-gated deliveries. The beam output variation of gated electron beam was less than 0.6 % for all electron energies except for 16 MeV (1.4 %). Based on the results of this study, it can be concluded that Varian CL2100 CD is well suitable for gated delivery of non-dynamic electron beams.

Outcomes of adjuvant chemoradiation and predictors of survival after extended cholecystectomy in gall bladder carcinoma: a single institution experience from an endemic region.

PURPOSE: The purpose of the study was to analyse outcomes with adjuvant concurrent chemoradiotherapy (cCRT) followed by adjuvant chemotherapy (AC) in radically resected gall bladder carcinoma (GBC) in Indian patients. METHODS AND MATERIALS: We retrospectively reviewed the records of GBC patients who received adjuvant cCRT after extended cholecystectomy (EC) between January 2007 and December 2011. Patterns of recurrence, disease-free survival (DFS), overall survival (OS) and adverse prognostic factors were evaluated. RESULTS: Thirty-two patients were analysed. At a median follow-up of 53 months, 40 % of patients had recurrence either locoregionally (12 %) or had distant metastases (28 %). The 5-year OS and DFS was 25 % and 53 %, respectively. When prognostic factors were evaluated, the median OS was 51 versus 23 months for node-negative (n = 8) versus node-positive disease (n = 24), not reached versus 34 months for stage 2 (n = 4) versus for stage 3 (n = 28), 46 versus 23 months for R0 (n = 11) versus R1 resection (n = 21), 51 versus 12 months (p = 0.15) for well-differentiated (n = 16) versus poorly differentiated tumours (n = 8), and 10 versus 51 months for lymphovascular invasion presence (n = 4) versus absence (n = 28) (p = 0.01). CONCLUSION: Outcome in Indian patients with cCRT followed by AC is similar to that reported in the literature. Adjuvant cCRT followed by AC improves outcomes in patients with R1 and node-positive disease. Advanced stage, nodal positivity, poor differentiation, presence of perineural invasion and lymphovascular invasion are adverse prognostic features. Further research is required with treatment intensification in patients with adverse prognostic factors to improve outcome.

Dosimetric effect of multileaf collimator leaf width in intensity-modulated radiotherapy delivery techniques for small- and large-volume targets.

The purpose of this study was to evaluate the dosimetric effect of the leaf width of a multileaf collimator (MLC) in intensity-modulated radiotherapy (IMRT) delivery techniques for small- and large-volume targets. We retrospectively selected previously treated 5 intracranial and 5 head-neck patients for this study to represent small- (range, 18.37-72.75 cc; mean, 42.99 cc) and large-volume (range, 312.31-472.84 cc; mean, 361.14 cc) targets. A 6-MV photon beam data was configured for Brianlab m3 (3 mm), Varian Millennium 120 (5 mm) and Millennium 80 (10 mm) MLCs in the Eclipse treatment-planning system. Sliding window and step-shoot IMRT plans were generated for intracranial patients using all the above-mentioned MLCs; but due to the field size limitation of Brainlab MLC, we used only 5-mm and 10-mm MLCs in the head-and-neck patients. Target conformity, dose to the critical organs and dose to normal tissues were recorded and evaluated. Although the 3-mm MLC resulted in better target conformity (mean difference of 7.7% over 5-mm MLC and 12.7% over 10-mm MLC) over other MLCs for small-volume targets, it increased the total monitor units of the plans. No appreciable differences in terms of target conformity, organ at risk and normal-tissue sparing were observed between the 5-mm and 10-mm MLCs for large-volume targets. The effect of MLC leaf width was not quantifiably different in sliding window and step and shoot techniques. In addition, we observed that there was no additional benefit to the sliding-window (SW) technique when compared to the step-shoot (SS) technique as a result of reduction of MLC leaf width.

Changes in salivary flow rates in head and neck cancer after chemoradiotherapy.

BACKGROUND: Changes in salivary flow rate were studied in head and neck (H and N) cancer patients who, after receiving moderately accelerated radiotherapy (RT) and concurrent chemotherapy (CT), were free of disease at 1 year. MATERIALS AND METHODS: Between July 2003 and July 2005, saliva estimation was performed for 36 patients of locally advanced (AJCC stages III and IV) squamous cell carcinoma of the H and N. RT, moderately accelerated (70 Gy/35 fx/6 weeks) along with concurrent weekly cisplatin at 35 mg/m 2 (capped at 50 mg) with standard hydration and anti-emetic cover, was planned using conventional planning on telecobalt or 6 MV photons. The saliva flow rate was estimated for 5 min at rest (unstimulated) and after using lemon drops (stimulated) for the next 5 min at baseline (pre-treatment), 3, 6 and 12 months following treatment. RESULTS: The median follow-up of this study was 29 months. Compared with baseline, by 3 months, a significant reduction in unstimulated (0.35 ml/min and 0.10 ml/min) and stimulated (0.97 ml/min and 0.28 ml/min) salivary flow rate was observed, respectively. This continued to decrease further till 6 months (0.06 ml/min and 0.17 ml/min) and, by 12 months, a minimal and non-significant recovery was observed in both unstimulated (0.08 ml/min) and stimulated salivary flow rates (0.22 ml/min), respectively. CONCLUSIONS: Salivary flow rates fall to a fourth of the baseline value with the above CT + RT protocol, with minimal recovery at 12 months following completion of treatment.

Electron beam therapy at extended SSDs: an analysis of output correction factors for a Mitsubishi linear accelerator.

The effects of extended source-to-surface distance (SSD) on the electron beam dose profiles were evaluated for various electron beam energies--6, 9, 12, 15 and 20 MeV-and the accuracy of various output correction methods was analysed on a Mitsubishi linear accelerator using a radiation field analyser (RFA). The dose fall-off region of the central axis depth-dose curves was nearly independent for SSDs up to 120 cm where as in the build-up region, a marginal reduction of surface dose was observed, particularly for lower energies and for smaller field sizes. Effective SSDs and virtual source distances were evaluated for field sizes ranging from 5 x 5 to 15 x 15 cm2 for various energies. Curve fitting was done with the measured outputs with various equations and coefficients were evaluated. The accuracy of the derived output correction factors by effective SSD, virtual source distance and curve-fit methods was assessed by evaluating correlation coefficients between the calculated and the measured values. The correlation coefficient was best with the linear-quadratic equation followed by the effective SSD method and the virtual source method. The output correction based on the linear-quadratic equation showed the best estimate of electron beam output at extended SSDs with an accuracy well within +/- 1%. The rapid reduction of dose due to the applicator-scattered component at d(max) point with an extended SSD was significant for the 5 x 5 cm2 applicator and lower energies.