Comparison Of Therapeutic Effects Between Three-dimensional Conformal/intensity Modulated Radiotherapy (IMRT) Combined With Chemotherapy And Chemotherapy Alone

Objectives: Rectal cancer is a common malignant tumor, whose maintherapy is surgery. Despite of development of surgical technique, the5-yearoverall survival rate is still about50%, and local recurrence and distantmetastasis are main causes of treatment failure. It has been testified thatpostoperative adjuvant radiochemotherapy is a standard mean to rectal cancer.However, there are still some problems about it. All classical studies arecompleted based on conventional radiotherapy. With the improvement ofradiotherapy technology, whether accurate radiotherapy such as three-dimensional conformal/intensity modulated radiotherapy (IMRT) used canenhance local control rate and lower toxic reactions? Which patients areoptimum benefited villagers?226cases with stage II and stage III rectalcancer are retrospectively analyzed, and effects of TNM stage, adjuvantradiochemotherapy and chemotherapy, concurrent and sequentialradiochemotherapy, interval between surgery and radiotherapy, cycles ofchemotherapy on local recurrence, overall survival (OS) and disease freesurvival (DFS) are also analyzed. Meanwhile, their prognostic factors areanalyzed as well. To investigate side effect of three-dimensionalconformal/IMRT used for preventional irradiation on pelvic cavity, in order tofurther understand the local recurrence, survival conditions and side effects oftreatment, and Provide a theoretical basis for making a more scientific andreasonable therapeutic scheme.Methods:226rectal cancer cases after resection in the fourth hospital ofHebei medical university from June2006to December2010, including51cases in II stage, and175cases in III stage, according to PTNM.116casesunderwent adjuvant chemotherapy, and110cases underwent adjuvant radiochemotherapy. The total dose was45⁵4Gy (median50Gy), including88cases underwent three-dimensional conformal radiation, and22casesunderwent IMRT. The total cycles of chemotherapy was2⁸(median4).191cases received FOLFOX chemotherapy,24cases received LF,11casesreceived xelox orally. The median follow-up was30months. Effects of TNMstage, adjuvant radiochemotherapy and chemotherapy, concurrent andsequential radiochemotherapy, interval between surgery and radiotherapy,cycles of chemotherapy on local recurrence, OS and DFS were analyzed, andfurther to exlore the prognostic factors for rectal cancer with II^III stages.Results:1Treatment status: The1-,2-,3-year local recurrent rates and distantmetastasis were9.8%,20.7%,22.8%, and15.2%,31.2%,39.4%respectively.The1-,2-,3-year OS and DFS were94.4%,71.7%,61.5%, and78.8%,59.8%,53.1%respectively. I^II grades of gastrointestinal reaction occurred in59.3%cases, and I^II grades of hematological reaction in46.9%, no III gradeoccurred. The incidence of gastrointestinal and hematological reaction in casesunderwent postoperative radiochemotherapy was78.2%and64.5%, whichwere higher than those underwent chemotherapy (χ²=31.683, P=0.000andχ²=26.786, P=0.004). Radiation enteritis occurred in20.9%cases underwentpostoperative radiochemotherapy, including I grade (8.2%) and II grade(9.1%). Radiocystitis occurred in10%, including I grade (8.2%) and II grade(1.8%).2The1-,2-,3-year local recurrent rates and distant metastasis between T₂and T₃had no significant difference (χ²=1.014, P=0.314and χ²=2.295,P=0.130), but OS was higher (χ²=4.278, P=0.039).3The1-,2-,3-year local recurrent rates, OS and DFS had significantdifference (χ²=14.599, P=0.001, χ²=47.196, P=0.000, and χ²=38.885,P=0.000). With N stage raised, local recurrent rates enhanced, and OS andDFS lowered.4The1-,2-,3-year local recurrent rates of cases in II stage were lower thanthose in III stage (P=0.000), while OS and DFS higher (P=0.000, P=0.000). 5The1-,2-,3-year local recurrent rates of cases underwent postoperativeradiochemotherapy were3.8%,10.5%and10.5%, which were lower thanthose underwent postoperative chemotherapy (P=0.001). The1-,2-,3-year OSwere94.2%,76%,70.7and95.6%,68.4%,53.3, and1-,2-,3-year DFS were81.9%,60%,54.1%and76%,59.2%and52.3%, respectively, which had nosignificant difference (P=0.059, P=0.608), but there was prolong trend aboutOS.6Cycles of chemotherapy: The1-,2-,3-year local recurrent rates of caseswith cycle≥4were lower than those with cycle＜4(χ²=4.631, P=0.031), andOS and DFS were higher (χ²=5.306, P=0.021and χ²=3.941, P=0.047).7The1-,2-,3-year local recurrent rates, OS, and DFS of cases whose intervalbetween surgery and radiation≤30days,31⁶0days and＞60days had nosignificant difference (χ²=1.126, P=0.557, χ²=3.831, P=0.147, and χ²=4.051,P=0.132).8The1-,2-,3-year local recurrent rates, OS, and DFS of cases underwentconcurrent or sequential radiochemotherapy had no significant difference(χ²=0.000, P=0.992, χ²=1.596, P=0.207, and χ²=0.230, P=0.631).9The1-,2-,3-year OS and DFS in cases in II stage underwentradiochemotherapy or chemotherapy had no significant difference (χ²=0.058,P=0.810, and χ²=3.356, P=0.067). The1-,2-,3-year local recurrent rates were3.8%,13%and13%, which were lower than those underwent chemotherapy(χ²=13.230, P=0.000). The1-,2-,3-year OS were higher (χ²=3.875, P=0.047),but the1-,2-,3-year DFS had no significant difference (χ²=1.632, P=0.201).10Multivariate analysis: Metastatic lymph node number and adjuvanttreatment modality were independent prognostic factors for local recurrence ofrectal cancer after surgery; Invasive depth and metastatic lymph node numberwere independent prognostic factors for OS; Metastatic lymph node numberwere independent prognostic factors for DFS.Conclusions:1Postoperative radiochemotherapy can lower local recurrent rate, andincrease OS, so it is optimum choice for patients in III stage. 2Local recurrent rate in II a stage is low, and postoperativeradiochemotherapy is not helpful to it, and postoperative chemotherapy isrecommended for this stage.3Gastrointestinal and hematological reactions were higher in casesunderwent radiochemotherapy than those underwent chemotherapy alone.4Interval between surgery and radiation, concurrent or sequentialradiochemotherapy has no difference for local control and survival.5Cycles of chemotherapy have effect on local control and survival. If cyclesare insufficient, they are both Poor.6Three-dimensional conformal/IMRT used for preventional irradiation onpelvic cavity can lower pelvic recurrence, meanwhile, radiocystitis andradiation enteritis are also lowered.7Metastatic lymph node number and adjuvant treatment modality wereindependent prognostic factors for local recurrence of rectal cancer aftersurgery; Invasive depth and metastatic lymph node number were independentprognostic factors for OS; Metastatic lymph node number were independentprognostic factors for DFS.