Modified Radical Mastectomy for Contralateral Breast Cancer

Modified Radical Mastectomy for Contra sidelong Breast cancerAbstractBreast cancer is the most common malignance in women worldwide. With improving survival figures and early rapper cancer detection, give-and-take link up broad term adverse effects of radioactivity have manufacture a concern. Contralateral breast cancer c every last(predicate)able to scatter send out of light from during radiotherapy of ghoulish breast is one of them. This prospective clinical think over was conducted to appreciate the sexually transmitted disease received by the contralateral breast and equate the different techniques which influence this paneling. It was found that in post mastectomy uncomplainings, discussion with telecobalt mesial tangential flying field contribute more battery-acid to contralateral breast compared to supraclavicular field and lateral tangential fields. The mean pane received by contralateral breast during ir shaft of chest wall was 168.29 cGy which 3.36 com ponent of the electropositive drug.Key Words contralateral breast drug, breast malignancy, thermoluminescent disc, scattered beamIntroductionBreast cancer is the most common malignancy among the women worldwide. 1 With amend survival figures collectable to early breast cancer detection and multimodality treatment, long term adverse effects in the form of second malignancy of contralateral breast (CLB) has become a concern. In patients getting radiotherapy to the affected breast, CLB also receives radiation in the form of scattered radiation due to scattered from primary. Second malignancy is a late protraction of radiation appearing at an interval of 10-15 years. 2, 3, 4, 5, 6, 7 Since breast is highly radiosensitive structure this treat to CLB is a major concern especially in younger women and patients with longer life expectancy. Although radiation induced malignancy is a stochastic effect but the intensity increases linearly with increase in dit. 8 Studies have metric C LB social disease on phantom and patients and have observe that the superman to CLB is more for medial tangential (MT) than supraclavicular field (SCL) field and lateral tangential (LT) field. In our centre 22% of female patients are scurvy from breast cancer and majority of them belong to low socio economic spot and presented with advanced disease. In the present study we measure the dit to CLB in patients receiving radiotherapy following modified radical mastectomy (MRM). The radiation drug to CLB were measured with the help of CaSO4 Dy thermoluminescent discs (TLD). The TLD are highly sensitivity and can measure even very small doses.Materials and methodsMeasurement of CLB was done in 25 patients undergoing for EBRT by cobalt teletherapy machine (THERATRON 780 C and E) following MRM. Precalibrated TLD (9mm13mm) were displace on the surface of CLB. Total three discs were placed one at the bosom and other vertically on either side of nipple 3 cm apart. We tried our best to place the TLD on the same part to each one time. Skin tattooing was done to demarcate the exact position at the first sitting and this was apply subsequently to replicate the position. After delivery of radiation dose for a particular field the discs were removed and some other set of three discs were placed for next reading. In this way get along six discs were employ daily, three for SCL field and three for MT or LT field as MT and LT fields were tempered on utility(a) days and SCL field was treated daily. For MT and LT fields breast strobile was used for half beam block. Total dose delivered was 50 Gy in 25 fractions, 2 Gy per fraction, 5 fractions per week in 5 weeks. The unfastened TLD were stored in radiation free zone and the readings were taken after 24 hours and within 7 days after exposure because after sevener days the TLD start to loose electrons. The scattered dose received by TLD were measured on NUCLEONIX TL 10091 TLD reader. After one set of measurement, the discs were annealed by heating 400 degree celcius and then used for next measurement. For each patient, measurements were carried out at first week, third week and last week, chalk up three times during the course of treatment.Statistical Analysis pie-eyed dose calculation received by CLB.Total dose received by CLB, this was calculated by multiplication of mean dose to number of fractions.The office of radiation dose received by CLB with respect to the bring down dose to diseased breast (Total dose 100 / prescribed dose to diseased breast).We also stratified data based on gauntry travel at which EBRT was delivered (50 degree and 50 degree).The statistical software SPSS strain 20.0 was used for the data analysis.ResultsThe age wise distribution of patients and the mean dose received by CLB is shown in table 1. 19 out of 25 patients in our study were 50 years or younger. 52% patients had go forth sided breast cancer. Table 2 shows the part of SCL, MT and LT field dose wit h the gantry angle at which the radiation dose was delivered. Total dose received by CLB varies from 1.22% to 5.82% of the prescribed dose of 50 Gy to the affected breast. Mean total dose received by CLB was 105.55 cGy with MT field followed by SCL field, (33.96 cGy) and LT field (28.97 cGy) as shown in table 2. This data shows that the maximum contribution of dose to CLB was with MT field followed by SCL field and LT field. Mean dose with all three fields received by CLB was 168.48 cGy with SD 62.23 which corresponds to 3.36% of prescribed dose to affected breast. 11 patients were treated on cobalt unit with gantry angle 50 degree having 3.00% contribution of CLB dose (table 3). 14 patients treated with gantry angle 50 degree had 3.79% contribution of CLB dose (p=0.199). The mean, median value and range were 3.66, 3.34 and 4.60 respectively.DiscussionIt is well known that exposure to ionizing radiation causes carcinogenesis in healthy tissues. Although it is a stochastic effect having no threshold dose but the intensity increases with increase in radiation dose. CLB must be considered as an organ at risk during radiotherapy planning for treatment of cancer breast. Many previous studies conducted to calculate the dose received by CLB, were based on patients, phantom or treatment planning system.Boice et al analyzed the record of 41109 patients of cancer breast and they found the mean CLB dose was 2.82 Gy. 9 They also hypothesized that there was increased relative risk of CLB malignancy due to exposure to ionization given to diseased breast. The relative risk was 1.19 for all patients, however the relative risk was more (1.49) for younger patients who were less than 45 years old. In our study, the maximum dose received by CLB in women below 40 years which was 3.93 percentage (196.437 cGy) of prescribed dose. The minimal dose was received in patients who were above 60 years of age (1.96 %) (97.875 cGy). The practical reason could be the increased laxity of b reast tissues in honest-to-god women cause more lateral shifting of CLB away from the radiation at the time of exposure.Half beam block technique is routinely used while irradiating the breast with tangential beams. 10, 11 Kelly et al measured CLB dose on Alderson Rando phantom using TLD with four different techniques of breast cancer treatment using 6 MV photon beam on linear accelerator. 12 The used half beam block with asymmetrical jaws, custom blocks and symmetrical collimator jaw. some other technique used was isocentric method with non divergent posterior border. They discovered highest dose to CLB in MT field with wedge. In our study radiation was delivered using half beam block with breast cone. The dose to CLB was maximum with MT field because in half block beam, the breast cone is placed near to surface of breast which cause increased dose due to secondary collimator scattering.Bhatnagar et al compared dose to CLB during EBRT to chest wall irradiation using convention al tangential technique and intensity modulated radiotherapy (IMRT). 13 They observed 20 percentage reduction of dose to CLB using IMRT.According to a study by Chougule, the average contralateral nipple dose was 152.5-254.75 cGy and the percentage was 3.05-6.05% for a dose of 5000 cGy in 25 fractions for post mastectomy breast cancer. 14 In our study, the measured mean contralateral nipple dose on was 171.88 cGy (55.5-303.80 cGy) which accounts to 3.47% (1.11%-6.07%) of prescribed dose (table 2). Dose to CLB were higher for dose calculated at the train of nipple as compared to dose received by whole CLB. This may be due to TLD at level of nipple being close to the radiation source. According to Rankel et al with high gantry angle the beam will be closer to the surface leading higher dose to the CLB. 15 In this study, it was found that with gantry angle 50, more dose was delivered to the CLB though the difference is not statistically significant (p=0.199).ConclusionIn our patient cohort, higher inadvertent CLB dose was delivered in younger patients with MT field overall, dose being 3.36 percentage of prescribed dose.