A model to predict the risk of lethal nasopharyngeal necrosis after re-irradiation with intensity-modulated radiotherapy in nasopharyngeal carcinoma patients

Background:For patients with nasopharyngeal carcinoma(NPC) who undergo re-irradiation with intensity-modulated radiotherapy(IMRT),lethal nasopharyngeal necrosis(LNN) is a severe late adverse event.The purpose of this study was to identify risk factors for LNN and develop a model to predict LNN after radical re-irradiation with IMRT in patients with recurrent NPC.Methods:Patients who underwent radical re-irradiation with IMRT for locally recurrent NPC between March 2001 and December 2011 and who had no evidence of distant metastasis were included in this study.Clinical characteristics,including recurrent carcinoma conditions and dosimetric features,were evaluated as candidate risk factors for LNN.Logistic regression analysis was used to identify independent risk factors and construct the predictive scoring model.Results:Among 228 patients enrolled in this study,204 were at risk of developing LNN based on risk analysis.Of the 204 patients treated,31(15.2%) developed LNN.Logistic regression analysis showed that female sex(P = 0.008),necrosis before re-irradiation(P = 0.008),accumulated total prescription dose to the gross tumor volume(GTV) ≥ 145.5 Gy(P = 0.043),and recurrent tumor volume >25.38 cm3(P = 0.009) were independent risk factors for LNN.A model to predict LNN was then constructed that included these four independent risk factors.Conclusions:A model that includes sex,necrosis before re-irradiation,accumulated total prescription dose to GTV,and recurrent tumor volume can effectively predict the risk of developing LNN in NPC patients who undergo radical re-irradiation with IMRT.

The Effect of Absorbed Dose to Organs at Risk Following Craniospinal Irradiation Using Different Radiotherapy Techniques

Introduction: In medulloblastoma patients craniospinal irradiation is an important element the treatment. Our study aimed to evaluate the effect of absorbed dose to organs at risk using the hybrid intensity-modulated radiation therapy (IMRT) versus three-dimensional conformal radiotherapy (3DCRT) for craniospinal irradiation (CSI) in average risk medulloblastoma patients. Materials and Methods: In this study, thirteen medulloblastoma patients were included. The prescribed total dose to the planning target volume (PTV) was 23, 40 Gy in 13 fractions. Two radiotherapy techniques, three dimensional conformal radiotherapy (3DCRT) and hybrid intensity modulated radiotherapy (IMRT) were used to treat these patients. The coverage of the Target was evaluated using the D mean, D95%, D2%, D98% and V95%. Other parameters were also compared such as Integral dose (ID), Homogeneity index (HI) and doses to the organs at risk (OARs). Results: There was no significant difference in the mean dose received by the PTV-Brain or the dose received by 95% and 98% of PTV volume using the two techniques. For PTV-Spine, the percentage volume receiving 95% of the total dose increased significantly in the hybrid IMRT technique compared to the conformal technique. So, hybrid IMRT plan achieved the best coverage for PTV spine. Lower dose for OAR was delivered by 3DCRT, except the heart and thyroid, hybrid IMRT achieved better sparing. All plans resulted in the same dose homogeneity index (DHI) for PTV-Brain. For PTV-Spine, hybrid IMRT technique achieved better dose homogeneity compared to 3DCRT technique (1.09 vs. 1.12;p > 0.05). Conclusions: hybrid IMRT technique can be realized on conformal technique because it achieved better dose coverage for the (PTV) and organ at risk (OAR). 3DCRT reduced mean dose to most OARS, except the heart and thyroid. Therefore, the hybrid IMRT technique may be a CSI treatment alternative to 3DCRT.

Comparison of Mathematical Equations Applicable to Tolerance of Total Body Irradiation in Humans and Decay of Isotopes, Uranium and Thorium: Differences and Similarity

A clear and exact quantitative relationship between dose of total body irradiation and mortality in humans is still not known because of lack of human data that would enable us to determine LD50 for humans in total body irradiation. Analysis of human data has been primarily from radiation accidents, radiotherapy and the atomic bomb victims. The author published the general mathematical equations of LD50 constructed on the basis of data presented by Cerveny, MacVittie and Young, employing the probacent formula model. In this study, the author compared the equations of tolerance of total body irradiation and decay of isotopes, uranium and thorium. Differences and similarity in these equations of the two groups are presented. The significance of similarity is specially described.

Mammographic Findings Associated with Accelerated Partial Breast Irradiation Using Single Fraction Intraoperative Radiotherapy

Purpose: To evaluate the mammographic findings of women treated with accelerated partial breast irradiation (APBI) using single-fraction intraoperative radiotherapy (IORT). Materials/Methods: Women ≥ 40 years of age with unifocal invasive or intraductal carcinoma ≤ 2.5 cm on physical examination, mammography, and ultrasound were enrolled on an APBI trial using single fraction IORT. Post-treatment mammographic imaging was obtained at 6 months, 1 year, and then annually. Results: Between 12/02 and 6/04, 17 women underwent IORT at the time of lumpectomy (median age = 60 years;range = 40 - 83). The initial post-IORT mammogram showed increased density at the lumpectomy site in 11 patients (65%), while six patients (35%) had architectural distortion in the area of the irradiated tissue. Fifteen patients (88%) had numerous punctate, benign-appearing calcifications corresponding to the irradiated region. There was focal skin thickening near the incision in 13 patients (76%). At a median of 67 months, architectural distortion had stabilized and the benign-appearing calcifications remained stable in number and character. Eight patients (47%) had mammographic findings consistent with fat necrosis, ranging in size from 0.5 - 4 cm. Conclusions: After lumpectomy and IORT, mammographic changes include increased density and benign appearing calcifications in the irradiated region with focal skin thickening. These changes appear to stabilize over time and are consistent with post-treatment changes. These changes are important to identify in order to characterize benign changes from recurrent tumor.

The effects of three-dimensional conformal radiotherapy combined with whole brain irradiation on brain metastases

Objective： To observe the recently therapeutic effects and toxicity of three-dimensional conformal radiotherapy combined with whole brain irradiation for patients with brain metastasis. Methods： 33 cases were treated by whole brain irradiation at first, the dose of which was 36-40 Gy （18-20 f）. Then three-dimensional conformal radiotherapy was added to the focus with a total dose of 20-25 Gy, whose fractionated dose was 2-5 Gy/time, 5 times/week or 3 times/week. Results： Within 1 month after radiotherapy, according to imaging of the brain, the CR of all patients was 45.5%, PR 36.4%, NC 15.1%, and PD 3%. For the 32 cases with neural symptoms before radiation, the CR of the symptoms was 40.6% and PR 59.4%. All patients gained different increases in KPS grade. By the end of the follow-up period, there were 22 deaths with the mean survival time up to 9.3 months. Conclusion： Three-dimensional conformal radiotherapy combined with whole brain irradiation can not only effectively control brain metastases and improve life quality, but also tends to prolong survival time.

Exosome-mediated cellular crosstalk within the tumor microenvironment upon irradiation

Radiotherapy is one of the most effective treatment methods for various solid tumors.Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in cancer development and treatment responsiveness.Exosomes,initially considered as"garbage bins"for unwanted from cells,are now understood to perform a variety of functions in interactions within the tumor microenvironment.Exosome-mediated regulation processes are rebuilt under the irradiation stimuli,because the exosome production,uptake,and contents are markedly modified by irradiation.In turn,irradiation-modified exosomes may modulate the cell response to irradiation through feedback regulation.Here,we review current knowledge and discuss the roles of exosome-mediated interactions between cells under radiotherapy conditions.

Establishment and validation of a method for cell irradiation in 96-well and 6-well plates using a linear accelerator

To establish and validate a method for cell irradiation in 96-well and 6-well plates using a linear accelerator, three irradiation methods(G0 B0 F40,G0 B1.5 F40, and G180 B1.5 F40) were designed to irradiate cell culture plasticware simulated with RW3 slab phantom and polystyrene. The difference between the actual physical measured dose and the preset dose was compared among the three methods under the preparatory conditions of 2, 4, 6, 8, and 10 Gy. MDA-MB-231 cells were analyzed by using a cell proliferation assay and a clonogenic assay to verify the difference between the three cell irradiation methods on cell radiosensitivity. For each preset dose, the difference between the actual measured dose and the preset dose was the lowest for Method G0 B1.5 F40, the second lowest for Method G180 B1.5 F40, and the maximum for Method GOB0 F40. The ranges of the differences were-0.28 to 0.02%,-2.17 to-1.80%, and-4.92 to-4.55%, and 0.31 to-0.12%,-3.42 to-2.86%, and-7.31 to-6.92%,respectively, for 96-well and 6-well plates. The cell culture experiments proved that Method G0 B1.5 F40 was an accurate, effective, simple, and practical irradiation method. The most accurate and effective cell irradiation method should always be used, as it will reduce dose differences and instability factors and provide improved accuracy and comparability for laboratories researching cellular radiosensitivity.

STEREOTACTIC IRRADIATION OF LUNG CANCER

Objective: To investigate the best stereotactic irradiation (STI) technique in treatment of small lung tumors, using dose-volume statistics. Methods: Dose-volume histogram (DVH) of the study phantom consisting of CT using the software of FOCUS-3D planning system. The beam was a 6MV X-ray from a Varian 2300C. The analysis data of Dose-volume statistics was from the technique used for: (1) 2–12 arcs; (2) 20°–45° separation angle of arcs; (3) 80°–160° of gantry rotation. Then we studied the difference of DVH with various irradiation techniques and the influence of target positions and field size by calculated to the distribution of dose from 20%–90% of the six targets in the lung with 3×3 cm2, 4×4 cm2 and 5×5 cm2 field size. Results: The volume irradiated pulmonary tissue was the smallest using a six non-coplanar 120° arcs with 30° separation between arcs in the hypothetical set up, the non-coplanar SRI was superiority than conventional one’s. The six targets were chosen in the right lung, the volume was the largest in geometric center and was decreased in hilus, bottom, anterior chest wall, lateral wall and apex of the lung in such an order. The DVH had significant change with an increasing field size. Conclusion: the irradiation damage of normal pulmonary tissue was the lowest using the six non-coplanar 120° arcs with a 30° separation between arcs by <5×5 cm2 field and the position of target was not a restricting factor.

A Comparison of Gamma Irradiation Response Models of Bovine Blood, Liver and Kidney Tissues at Radiofrequency

This study is aimed at identifying gamma irradiated response of bovine blood, liver and kidney tissues at radiofrequency. For this purpose, impedence meter (Booton 7200) working in conjunction with signal generators (Loadster, SG416013 and Harris G857993) and improvised parallel plate dielectric cells constructed in line with the method of Laogun et al., (2005) were used to obtain the dielectric spread parameter gamma radiation α, of blood, liver and kidney tissues exposed to gamma irradiation dose range of 1.0 - 85.0 Gy. The dielectric spread parameter α gives the extent of damage induced in an irradiated tissue. Results of this work revealed that at 0 - 50 MHz frequency range, Kidney tissues displayed higher sensitive, followed Liver tissues and lasted the bovine blood between 0 - 60 Gy but reversed for blood and liver at 85 Gy. At 0 - 100 kHz frequency range liver tissue is more venerable to radiation injuries between gamma irradiation dose range of 0 - 20 Gy while between 43 - 85 Gy the Kidney’s sensitivity is the highest followed by blood and liver tissues. This implies that the liver tissues are less liable to radiation injuries at radiofrequency. A comparison of the linear, exponential and polynomial models using Akaike Information Criteria (AIC) revealed that linear models were the most suitable models for describing the effect of gamma radiation on the dielectric dispersion properties of bovine tissues at low and high radiofrequencies. This implies that the response of the investigated tissues increases linearly with gamma irradiation dose.

Sentinel-Node-Driven Personalized Radiation Techniques Ranging from Partial Breast Irradiation to Regional Nodal Radiation after Breast-Conserving Surgery

Background: Breast-conserving surgery (BCS) followed by whole breast irradiation (WBI) has become the standard of care for treating patients with early-stage breast cancer. Recently, various radiation techniques followed by BCS have been reported. We have been investigating “personalized radiotherapy after BCS” ranging from accelerated partial breast irradiation (APBI) to WBI with regional nodal irradiation (RNI) based on the axillary node status. In this study, we compared different cohorts that received personalized radiotherapy. Method: Of 317 consecutive patients who underwent BCS followed by radiotherapy since November 2007, 187 who received APBI and 122 who received WBI were analyzed. Results: The local-only recurrence rate was 1.1% in the APBI group and 3.3% in the WBI group, and the regional-only recurrence rate was 1.1% for APBI and 0.8% for WBI. Conclusions: The clinical efficacy of APBI for local control after BCS was comparable to that of WBI ± RNI. Although this study was based on a small number of patients with a short follow-up period, the feasibility of breast-conserving therapy using multicatheter brachytherapy to achieve acceptable clinical outcomes was demonstrated.

Advance of prophylactic cranial irradiation in lung cancer

Brain metastases in patients with lung cancer are a devastating problem with profound impact on survival. Prophylactic cranial irradiation has been discussed as an option to reduce the risk of brain metastases. This report provides an extensive review of the current evidence from non-randomized and randomized trials regarding the use of prophylactic cranial irradiation in lung cancer.

Current role of modern radiotherapy techniques in the management of breast cancer

Breast cancer is the most common type of malignancy in females. Advances in systemic therapies and radiotherapy(RT) provided long survival rates in breast cancer patients. RT has a major role in the management of breast cancer. During the past 15 years several developments took place in the field of imaging and irradiation techniques, intensity modulated RT, hypofractionation and partial-breast irradiation. Currently, improvements in the RT technology allow us a subsequent decrease in the treatment-related complications such as fibrosis and long-term cardiac toxicity while improving the loco-regional control rates and cosmetic results. Thus, it is crucial that modern radiotherapy techniques should be carried out with maximum care and efficiency. Several randomized trials provided evidence for the feasibility of modern radiotherapy techniques in the management of breast cancer. However, the role of modern radiotherapy techniques in the management of breast cancer will continue to be defined by the mature results of randomized trials. Current review will provide an up-to-date evidence based data on the role of modern radiotherapy techniques in the management of breast cancer.

New insights for pelvic radiation disease treatment:Multipotent stromal cell is a promise mainstay treatment for the restoration of abdominopelvic severe chronic damages induced by radiotherapy

Radiotherapy may induce irreversible damage on healthy tissues surrounding the tumor. It has been reported that the majority of patients receiving pelvic radiation therapy show early or late tissue reactions of graded severity as radiotherapy affects not only the targeted tumor cells but also the surrounding healthy tissues. The late adverse effects of pelvic radiotherapy concern 5% to 10% of them, which could be life threatening. However, a clear medical consensus concerning the clinical management of such healthy tissue sequelae does not exist. Although no pharmacologic interventions have yet been proven to efficiently mitigate radiotherapy severe side effects, few preclinical researches show the potential of combined and sequential pharmacological treatments to prevent the onset of tissue damage. Our group has demonstrated in preclinical animal models that systemic mesenchymal stromal cell(MSC) injection is a promising approach for the medical management of gastrointestinal disorder after irradiation. We have shown that MSCs migrate to damaged tissues and restore gut functions after irradiation.We carefully studied side effects of stem cell injection for further application in patients. We have shown that clinical status of four patients suffering from severe pelvic side effects resulting from an over-dosage was improved following MSC injection in a compationnal situation.

Cage-like radiotherapy system for noncoplanar radiotherapy

The aim of this study was to design a cage-like radiotherapy system(CRTS)to further promote the clinical application of noncoplanar radiotherapy.The CRTS comprises two stands,two O-rings,several arc girders,an X-ray head,an imaging subsystem,and a treatment couch.The X-ray head rotates with O-rings around the patient’s body and slides along the arc girder.Compared with the C-arm linear accelerator(C-Linac),the clinically available spatial irradiation angle ranges(SIARs)of the CRTS for the head,chest,and abdomen were 33%,63.6%,and 62.6%larger,respectively.Moreover,according to a preliminary planning comparison based on the dose distribution simulation method,the CRTS achieved much better protection of normal tissue than the C-Linac.Furthermore,the CRTS enabled accurate noncoplanar irradiation without movement of the body being irradiated,allowed automatic control of the movements of different parts without risk of collisions,and provided continuous radiation over an angle that considerably exceeded a full turn.These advantages make CRTS very promising for noncoplanar radiotherapy.

PhaseⅠ/Ⅱtrial evaluating concurrent carbon-ion radiotherapy plus chemotherapy for salvage treatment of locally recurrent nasopharyngeal carcinoma

Background: After deinitive chemoradiotherapy for non-metastatic nasopharyngeal carcinoma(NPC), more than 10% of patients will experience a local recurrence. Salvage treatments present signiicant challenges for locally recurrent NPC. Surgery, stereotactic ablative body radiotherapy, and brachytherapy have been used to treat locally recurrent NPC. However, only patients with small-volume tumors can beneit from these treatments. Re-irradiation with X-ray—based intensity-modulated radiotherapy(IMXT) has been more widely used for salvage treatment of locally recurrent NPC with a large tumor burden, but over-irradiation to the surrounding normal tissues has been shown to cause frequent and severe toxicities. Furthermore, locally recurrent NPC represents a clinical entity that is more radioresistant than its primary counterpart. Due to the inherent physical advantages of heavy-particle therapy, precise dose delivery to the target volume(s), without exposing the surrounding organs at risk to extra doses, is highly feasible with carbon-ion radiotherapy(CIRT). In addition, CIRT is a high linear energy transfer(LET) radiation and provides an increased relative biological efectiveness compared with photon and proton radiotherapy. Our prior work showed that CIRT alone to 57.5 Gy E(gray equivalent), at 2.5 Gy E per daily fraction, was well tolerated in patients who were previously treated for NPC with a deinitive dose of IMXT. The short-term response rates at 3–6 months were also acceptable. However, no patients were treated with concurrent chemotherapy. Whether the addition of concurrent chemotherapy to CIRT can beneit locally recurrent NPC patients over CIRT alone has never been addressed. It is possible that the beneits of high-LET CIRT may make radiosensitizing chemotherapy unnecessary. We therefore implemented a phase I/II clinical trial to address these questions and present our methodology and results.Methods and design: The maximal tolerated dose(MTD) of re-treatment using raster-scanning CIRT plus concurrent cisplatin will be determined in the phase I, dose-escalating stage of this study. CIRT dose escalation from 52.5 to 65 Gy E(2.5 Gy E × 21–26 fractions) will be delivered, with the primary endpoints being acute and subacute toxicities. Eicacy in terms of overall survival(OS) and local progression-free survival of patients after concurrent chemotherapy plus CIRT at the determined MTD will then be studied in the phase II stage of the trial. We hypothesize that CIRT plus chemotherapy can improve the 2-year OS rate from the historical 50% to at least 70%.Conclusions: Re-treatment of locally recurrent NPC using photon radiation techniques, including IMXT, provides moderate eicacy but causes potentially severe toxicities. Improved outcomes in terms of eicacy and toxicity proile are expected with CIRT plus chemotherapy. However, the MTD of CIRT used concurrently with cisplatin-based chemotherapy for locally recurrent NPC remains to be determined. In addition, whether the addition of chemotherapy to CIRT is needed remains unknown. These questions will be evaluated in the dose-escalating phase I and randomized phase II trials.

Biological effects of human lung cells MRC-5 in CBCT positioning for image-guided radiotherapy

Image-guided radiotherapy(IGRT) provides precise positioning for the tumor target, but it may bring extra irradiation dose in the target positioning with a cone beam CT(CBCT) which has been increasingly used in IGRT. In this work, we focused on biological effects of the low-dose irradiation in IGRT, which have not been considered so far. Primary human fibroblasts cells from the lung and MRC-5 were irradiated by a CBCT. DNA doublestrand breaks(c-H2 AX foci) and micronucleus frequency of the irradiated samples were analyzed. Compared to the control, the c-H2 AX foci yields of the samples irradiated to 16 m Gy increased significantly, and the micronuclei rate of the samples irradiated for 3 days increased notably. The dose by imaging guidance device can be genotoxic to normal tissue cells, suggesting a potential risk of a secondary cancer. The effects, if confirmed by clinical studies,should be considered prudentially in designing IGRT treatment plans for the radiosensitive population, especially for children.

Postoperative Radiotherapy in Bladder Cancer Patients: 5-Year Institutional Experience of National Cancer Institute, Cairo University

Purpose: Adjuvant radiation therapy could reduce loco regional failure, but currently has no defined role because of previously reported morbidity. NCI-Cairo routine work is to give adjuvant PORT for locally advanced bladder carcinoma patients. The aim of this work is to re-evaluate this protocol regarding its effect on prognosis and complications. Patients and Method: A retrospective study included 208 patients with pathologically proven bladder cancer who presented to the NCI, Cairo University from 2007-2011. All of them underwent RC with bilateral PLND followed by conventional post-operative radiotherapy in 2 - 6 weeks after surgery for 5000 cGy in 25 fractions, over 5 weeks using 2D technique. Analysis of data from their files was done for the treatment results, prognostic factors and complications. Results: Three years overall survival (OS) and disease free survival (DFS) for the whole group was ~60%, and 54% respectively in favour of the female gender, non-smokers, Squamous cell carcinoma patients, low grade tumours (grade 1 and 2) negative margins, N0, pT2b and early stage group showed the best prognoses. The 3 years metastases free survival (MFS) was ~71%. Only four factors showed a significant relation with the MFS which were the grade, LN status, T-stage and group staging. The local recurrence rate (LRC) at 2 years for the whole group was ~95% and 94% at 3 years. Only surgical margin status and extent of LN dissection had a significant impact on the LRC. Conclusions: Adjuvant radiotherapy shows sustained improvement in the loco regional control, and should be recommended for patients with locally advanced disease especially those with less than 10 dissected lymph nodes and those with positive margins.

Neoadjuvant Radiotherapy in Stage I Cancer of the Lower Rectum

Introduction: The mortality rate in cancer of the lower rectum is related to the incidence of local recurrence, in the first 5 years. For stage I tumors, local excision has being increasingly used, but recent studies showed a higher incidence rate of local recurrence. Therefore, preoperative radiotherapy should be considered even for these tumors, as an attempt to prevent recurrence and provide cure. Objective: To show the effectiveness of neoadjuvant radiotherapy in stage I cancer of the lower rectum of a cohort population. Materials and Method: A cohort study in a prospective database was made with a total of 75 patients considered as stage I cancer of the lower rectum. Preoperative long course of 4500 cG radiotherapy was performed in this selected group of patients and followed up for a minimum period of five years. Results: Stage I/TI group had 27 patients. All of them presented complete response to the treatment and did not need to be submitted to surgery. Five years follow up with no recurrence. The stage I/TII group had 48 patients. After neoadjuvant radiotherapy, 8 patients had to be submitted to surgery for persistent tumor. All were submitted to full total local excision (FTLE), but anatomopathological examination showed no residual cancer. Conclusion: Preoperative long course of 4500 cG irradiation, not only reduced the local recurrence and mortality rate in lower rectal cancer, but also reduced indication for surgery in patients with stage I cancer of the lower rectum.

Radiotherapy to the Left Breast with 3DCRT, IMRT or VMAT: International Medical Center Experience

Radiation therapy after conservative breast surgery is an integral part of the treatment of early breast cancer. The aim of radiotherapy is to achieve the best coverage of the Planning Target Volume (PTV), while reducing the dose to the Organs at Risk (OAR). Such goals are not always achievable with the conformal three dimensions plans (3DCRT). Recently, radiation oncologist uses Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Therapy (VMAT) for irradiating the breast. In this study, we compared 3DCRT, IMRT and VMAT for left breast cancer patients in terms of PTV coverage, OAR. We also revised the different dose distribution in 1) different breast volume categories, 2) nodal irradiation versus breast only, and 3) boost versus no boost. Results: The routinely reported dose constrains for the ipsilateral lung and for the heart were not significantly different on comparing the three techniques. While for the contralateral lung, the difference in mean dose was in favor of 3DCRT. In large breast volume, 3DCRT provided a lower Max dose to the contralateral lung and the lowest mean dose to the contralateral breast when compared to IMRT p < 0. 046. In case of no nodal irradiation, the contralateral breast mean dose was lower in 3DCRT in comparison to IMRT and VMAT p < 0.037. When boost dose was given, 3DCRT plans had produced a lower Max dose to the contralateral lung p < 0.017. Conclusion: The three techniques (3DCRT, IMRT, and VMAT) can meet the clinical dosimetry demands of radiotherapy for left breast cancer after conservative surgery, as long as the routinely OARs only (heart and ipsilateral lung) are reported. Our study showed that 3CDRT can provide a lower dose to the contralateral organs (breast and lung), specially, in case of large breast volumes, no nodal irradiation and when a boost is given.

Adjuvant Therapy on Cancer of the Lower Rectum. Evaluation of the Effects of Preoperative Radiotherapy on the Prognosis of Patients with Cancer of the Lower Rectum

Aims: The prognosis on treatment of the cancer of the rectum has not changed in the last fifty years. Survival rates of 50 to 55% seems immutable in several published series. The main cause for those results is the high incidence of recurrence, either local or widespread. Local recurrence is directly related to the number of undifferentiated cells and to the grade of wall invasion. Widespread recurrence depends specifically on the lymphatic and vascular spreading. So any kind of treatment that would diminish the number of undifferentiated cells and the size or the tumor wall penetration would certainly decrease the local recurrence rate, lengthening the interval free from cancer and, perhaps, modifying the long term survival rate. Between 1978 and 2009, a total of 538 patients with adenocarcinoma of the lower rectum (from the pectinate line to 10 cm above) were treated by preoperative radiotherapy. Methodology: The same protocol was used in all the patients – 400 cGy, 200 cGy/day, during 4 consecutive weeks (anterior and posterior pelvic fields) by means of a Linear Megavoltage Accelerator (25 MeV). Surgery was performed 2 months after completion of the radiotherapy. Results: Statistical analysis of the whole group showed that preoperative radiotherapy does decrease frequency of undifferentiated cells. Moreover, the incidence of local recurrence diminished after irradiation by 3.4%. Preoperative radiotherapy reduces tumor volume (ERUS) and wall invasion, as well as the mortality rate due to local recurrence (2.4%) and alters long-term survival rate (80.1%). Conclusion: Preoperative radiotherapy is really effective in reducing the number of undifferentiated cells and in diminishing the tumor volume and the carcinomatous infiltration of the rectal wall.