ANTICANCER RESEARCH 26: (2006)

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1 Clinical Impact of Adjuvant Chemotherapy on Patients with Stage III Colorectal Cancer: l-lv/5fu Chemotherapy as a Modified RPMI Regimen is an Independent Prognostic Factor for Survival TSUKASA HOTTA, KATSUNARI TAKIFUJI, KAZUO ARII, SHOZO YOKOYAMA, KENJI MATSUDA, TAKASHI HIGASHIGUCHI, TOSHIJI TOMINAGA, YOSHIMASA OKU and HIROKI YAMAUE Second Department of Surgery, Wakayama Medical University, School of Medicine, Wakayama, Japan Abstract. Background: Patients with stage III colorectal cancer have a substantial risk of microscopic metastatic disease at the time of resection. Treatment with leucovorin (LV)/5-Fluorouracil (5FU) has been demonstrated to be effective for advanced colorectal cancer; however, the clinical impact of l-lv/5fu is still unclear. l-lv/5fu for patients with stage III colorectal cancer may play an important role, as an adjuvant chemotherapy, in improving survival. Patients and Methods: The clinicopathological features of 36 patients receiving adjuvant l-lv/54 administration and 16 not, univariate analysis of potential predictors of overall survival and disease-free survival, relative risk of overall survival and disease-free survival by multivariate analysis and the occurrence of chemotherapy-induced toxic effects were studied in 52 patients with stage III colorectal cancer, including 30 with rectal and 22 with colon cancer, who had undergone surgery. Results: No significant differences were found in the clinicopathological features of the 2 groups. On univariate analysis, there were no significant differences in overall survival in either group; disease-free survival in patients with adjuvant l-lv/5fu was longer than that in patients without it (p<0.001). Moreover, multivariate analysis demonstrated that l-lv/5fu adjuvant chemotherapy was an independent prognostic factor in terms of disease-free survival (p=0.001; RR, ; 95% CI, ). Conclusion: l-lv/5fu adjuvant chemotherapy in patients with stage III colorectal cancer is important as an independent prognostic factor in terms of disease-free survival. Correspondence to: Hiroki Yamaue, MD, Second Department of Surgery, Wakayama Medical University, School of Medicine, 811-1, Kimiidera, Wakayama , Japan. Tel: , Fax: , yamaue-h@wakayama-med.ac.jp Key Words: Colorectal cancer, adjuvant chemotherapy, l-lv/5fu. Recently, technical advances have made it easier to perform colorectal surgery with a reduction in the operative mortality rate (1, 2). On the other hand, one of the major problems confronted in the treatment of colorectal cancer is chemoresistance. 5-Fluorouracil (5FU) is an active drug currently available for this disease, its action being potentiated when it is combined with folinic acid, which acts as a precursor to the folate cofactor for thymidylate synthetase (3). Indeed, several current trials are attempting to determine the role of folinic acid in 5FU regimens (4). One of these regimens is the weekly administration of leucovorin (LV; folinic acid, citrovorum factor) plus 5FU for 6 weeks, at 2-week intervals. This method is called the Roswell Park Memorial Institute (RPMI) regimen (5-7) and has been adopted in Japan. LV is available generally as a mixture of l and d diastereoisomers in equal proportions. Of these 2 isomers, only the l-form is thought to be biologically active (8, 9). On the other hand, l-lv has been shown to be clinically equivalent to the same dose of the racemic leucovorin (d,l-lv) in its antitumor activity against advanced and metastatic colorectal cancer in prospective randomized trials (10, 11). The single most important determinant of prognosis in patients with cancer of the colon and rectum is lymph node involvement. Adjuvant chemotherapy has been shown to improve survival in patients with locoregional nodal metastases (1). Though many authors have reported the clinical efficacy of LV/5FU chemotherapy in patients with colorectal cancer using racemic leucovorin (d,l-lv), that of l-lv/5fu adjuvant chemotherapy has not been fully clarified. This is the first preliminary evaluation of l-lv/5fu adjuvant chemotherapy for stage III colorectal cancer to have been reported /2006 $

2 Patients and Methods Patients. Fifty-two patients with stage III colorectal cancer, who had undergone surgery at Wakayama Medical University Hospital, Japan, between 2001 and 2003, were enrolled in this study. The data on these patients was collected and followed-up on from 2001 to Thirty patients had rectal cancer and 22 had colon cancer, including: 1 cecum, 3 ascending, 9 transverse, 1 descending and 8 sigmoid colon. The TNM clinical stage III was defined according to the UICC classification of malignant tumors (12). A curative resection of the rectum and colon had been performed with a lymphadenectomy from along the rectal or large intestinal wall to around the main feeding artery. In all patients with rectal cancer, a total mesorectal excision had been performed in this study. One course of adjuvant chemotherapy consisted of the weekly administration of l-lv and 5FU for 6 weeks, at 2-week intervals. During the chemotherapy, l-lv (Wyeth Co., Tokyo, Japan) 250 mg/m 2 was drip intravenously infused for 2 hours and 5FU (Kyowa Hakko, Tokyo, Japan) 600 mg/m 2 was given as a single intravenous injection 1 hour after the start of l-lv administration. This regimen is a modified RPMI regimen because of the administration of l-lv alone, compared with use of d,l-lv in the original RPMI regimen (5-7). In patients with N1 lymph node metastasis, 3 courses of l-lv/5fu adjuvant chemotherapy were administered, whereas in patients with N2 lymph node metastasis, 6 courses were administered. The WHO performance status of the patients in this study was 0 or 1, with l-lv/5fu adjuvant chemotherapy being offered to all. Thirty-six patients agreed to this adjuvant regimen, but 16 patients rejected it because of the high medical cost, or due to their own or family s wishes. For the 16 patients without l-lv/5fu adjuvant chemotherapy, uracil-tegafur (UFT) (Taiho Pharmaceutical Co., Ltd., Tokyo, Japan) (250 mg of tegafur m 2 /day) in the form of 100-mg capsules (100 mg of tegafur plus 224 mg of uracil) was taken orally after meals twice daily. A comparative analysis was conducted between the cases treated with l-lv/5fu adjuvant chemotherapy and those not. Age, gender, WHO performance status, primary lesion, histopathological type, depth of invasion, lymph node metastasis, lymphatic invasion, venous invasion and l-lv/5fu administration as adjuvant chemotherapy were chosen as prognostic factors. The ages of the patients ranged from 39 to 83 years (median: 65) and they were categorized into those <65 and those 65 years old. The depths of invasion were defined as: T1, tumor invasion of submucosa; T2, muscularis propria; T3, subserosa or tumor penetration of serosa; and T4, tumor invasion of adjacent structures. Lymph node metastasis was also defined as: N1, metastasis in 1 to 3 regional lymph nodes; and N2, metastasis in 4 or more regional lymph nodes. Patient follow-up. The range, mean and median follow-up periods of all patients in this study were 12 to 40 months, 23 months and 22 months, respectively. Those follow-up periods of patients with l-lv/5fu adjuvant chemotherapy were 12 to 40 months, 22 months and 21 months, respectively. The follow-up periods of those patients not receiving l-lv/5fu were 16 to 37 months, 25 months and 24 months, respectively. Statistical analysis. The statistical analysis was performed with Stat View-J ver. 5.0 using a Windows XP operating system. Significant differences in the clinicopathological features of the patients were determined by a Chi-squared test or Fisher's exact Figure 1. Overall survival curve by the Kaplan-Meier method. l-lv/5fu (+), patients with the administration of l-lv/5fu. l-lv/5fu ( ), patients without the administration of l-lv/5fu. A) Overall survival curve in all patients. The median survival time was 34 months. The 1-, 2- and 3- year survival rates were 100%, 91.0% and 45.5%, respectively. B) Overall survival curve comparing patients with and without the l-lv/5fu administration. No significant differences were shown (p=0.104). test. The overall survival rate and disease-free survival rate for prognostic factors were estimated by the Kaplan-Meier method and univariate analysis of significance for each factor was evaluated by a log-rank test. The multivariate analysis of the overall and disease-free survival times was performed using Cox s proportional hazards model. A p value of less than 0.05 was considered statistically significant. Results Clinicopathological features of patients and univariate analysis of predictors for survival. The overall survival and diseasefree survival curves for all patients are shown in Figures 1A and 2A, respectively. 1426

3 Hotta et al: Clinical Impact of l-lv/5fu Adjuvant Chemotherapy on Patients with Stage III Colorectal Cancer Table I. Clinicopathological features of patients receiving or not l-lv/5fu administration. Variable l-lv/5fu administration P Yes (n=36) No (n=16) Age (yr) <65 15 (41.7%) 9 (56.3%) (58.3%) 7 (43.7%) Gender Male 22 (61.1%) 9 (56.3%) Female 14 (38.9%) 7 (43.7%) WHO performance status (66.7%) 10 (62.5%) 1 12 (33.3%) 6 (37.5%) Primary lesion Colon 15 (41.7%) 7 (43.7%) Rectum 21 (58.3%) 9 (56.3%) Histopathological type Well-differentiated 25 (69.4%) 10 (62.5%) Other type 11 (30.6%) 6 (37.5%) Depth of invasion T (94.4%) 15 (93.8%) T4 2 (5.6%) 1 (6.2%) Lymph node metastasis N1 21 (58.3%) 12 (75.0%) N2 15 (41.7%) 4 (25.0%) Lymphatic invasion Mild 25 (69.4%) 9 (56.3%) Strong 11 (30.6%) 7 (43.7%) Venous invasion Mild 26 (72.2%) 9 (56.3%) Strong 10 (27.8%) 7 (43.7%) Figure 2. Disease-free survival curve by the Kaplan-Meier method. A) Disease-free survival curve in all patients. The 1-, 2-, and 2.5- year diseasefree survival rates were 82.7%, 73.0% and 58.4%, respectively. B) Diseasefree survival curves of patients with and without the l-lv/5fu administration. Significant differences were shown (p<0.001). In histopathological type, well-differentiated means well-differentiated adenocarcinoma, and other type means moderately-differentiated, poorly-differentiated, or mucinous adenocarcinoma. Depth of invasion of T1, T2, T3 and T4 means tumor invasion of submucosa, that of muscularis propria, that of subserosa or tumor penetration of serosa, and tumor invasion of adjacent structures, respectively. N1 = metastasis in 1 to 3 regional lymph nodes; N2 = metastasis in 4 or more regional lymph nodes. Lymphatic invasion of mild and strong means no or minimal lymphatic invasion and moderate or marked lymphatic invasion, respectively. Venous invasion of mild and strong means no or minimal venous invasion and moderate or severe venous invasion, respectively. The clinicopathological features including age, gender and performance status were analyzed, but no significant differences were determined between the 2 groups (Table I). Neither were any significant differences in overall survival determined for any of the variables (Table II). Moreover, the overall survival curves of the patients in the 2 administration groups were not significantly different (Figure 1B). The disease-free survival of patients receiving l-lv/fu, however, was significantly longer (p<0.001) (Table III). Moreover, the disease-free survival curves showed significant differences (Figure 2B). Overall and disease-free survival by multivariate analysis. The relative overall survival and disease-free survival was analyzed using Cox s proportional hazards model. Neither l-lv/5fu administration or any other factor had an impact on overall survival (Table IV). l-lv/5fu treatment was identified as an independent prognostic factor in patients with stage III colorectal cancer in terms of disease-free survival; the disease-free survival times in patients with this treatment were longer than those in patients receiving other adjuvant chemotherapy (p=0.001; RR, ; 95% CI, ) (Table V). 1427

4 Table II. Univariate analysis of potential predictors of survival. Variable Overall survival (%) P 1-year 2-year 3-year Age (yr) <65 (n=24) (n=28) Gender Male (n=31) Female (n=21) WHO performance status (n=34) (n=18) Primary lesion Colon (n=22) Rectum (n=30) Histopathological type Well-differentiated (n=35) Other type (n=17) Depth of invasion T1-3 (n=49) T4 (n=3) Lymph node metastasis N1 (n=33) N2 (n=19) Lymphatic invasion Mild (n=34) Strong (n=18) Venous invasion Mild (n=35) Strong (n=17) l-lv/5fu administration Yes (n=36) No (n=16) Well-differentiated = well-differentiated adenocarcinoma. T1, tumor invasion of submucosa; T2, muscularis propria; T3, subserosa or tumor penetration of serosa; T4, tumor invasion of adjacent structures. N1 = metastasis in 1 to 3 regional lymph nodes; N2 = metastasis in 4 or more regional lymph nodes. Lymphatic invasion: mild means no or minimal lymphatic invasion and strong means moderate or marked lymphatic invasion. Venous invasion: mild means no or minimal venous invasion and strong means moderate or severe venous invasion. Occurrence of chemotherapy-induced toxic effects during l-lv/5fu treatment. Toxicity was recorded according to the National Cancer Institute Common Toxicity Criteria (NCI-CTC), version 2.0. The incidences of grade 3-4 leucopenia, neutropenia and diarrhea were 2.8%, 2.8% and 5.6%, respectively (Table VI). Two patients received granulocyte colony-stimulating factor and 4 patients needed a 20% dose reduction of 5FU until the improvement of grade 3 toxicity. One patient with grade 3 diarrhea required a short-term hospital stay. There were no chemotherapy-related deaths. Table III. Univariate analysis of potential predictors of disease-free survival. Variable Disease-free survival (%) P 1-year 2-year 2.5-year Age (yr) <65 (n=24) (n=28) Gender Male (n=31) Female (n=21) WHO performance status (n=34) (n=18) Primary lesion Colon (n=22) Rectum (n=30) Histopathological type Well-differentiated (n=35) Other type (n=17) Depth of invasion T1-3 (n=49) T4 (n=3) Lymph node metastasis N1 (n=33) N2 (n=19) Lymphatic invasion Mild (n=34) Strong (n=18) Venous invasion Mild (n=35) Strong (n=17) l-lv/5fu administration <0.001 Yes (n=36) No (n=16) Discussion Colorectal cancer is one of the most common causes of malignancy-related death in the United States, Japan and most European countries (1, 2, 13). Prior to 1990, there was considerable doubt regarding the role of adjuvant chemotherapy for the treatment of colorectal cancer. Overall, adjuvant chemotherapy failed to significantly improve survival (13). Looking back at historical controls from the era prior to chemotherapy, a roughly 40% to 50% cure rate for stage III colorectal cancer patients was seen with surgery alone, indicating that slightly more than half of patients did, in fact, have microscopic metastatic disease at the time of resection (14). 5FU is the active drug currently available for colorectal cancer and an enhanced clinical efficacy of 5FU can be obtained as a result of its biochemical modulation by leucovorin (LV; folinic acid, citrovorum factor) (8). 1428

5 Hotta et al: Clinical Impact of l-lv/5fu Adjuvant Chemotherapy on Patients with Stage III Colorectal Cancer Table IV. Relative risk of overall survival by multivariate analysis using Cox s proportional hazards model. Variable Relative 95% confidence P risk interval Age (yr) < Gender Male 1 Female WHO performance status Primary lesion Colon Rectum 1 Histopathological type Well-differentiated 1 Other type Depth of invasion T T4 1 Lymph node metastasis N N2 1 Lymphatic invasion Mild Strong 1 Venous invasion Mild Strong 1 l-lv/5fu administration Yes 1 No Table V. Relative risk of disease-free survival by multivariate analysis using Cox s proportional hazards model. Variable Relative 95% confidence P risk interval Age (yr) < Gender Male 1 Female WHO performance status Primary lesion Colon Rectum 1 Histopathological type Well-differentiated 1 Other type Depth of invasion T T4 1 Lymph node metastasis N N2 1 Lymphatic invasion Mild Strong 1 Venous invasion Mild Strong 1 l-lv/5fu administration Yes 1 No Globally, 3 administration methods of 5FU and LV have been demonstrated. One is the weekly administration of LV/5FU for 6 weeks, at 2-week intervals. During the chemotherapy, LV is administered with a drip intravenous infusion for 2 hours, and 5FU is given with a single intravenous infusion, 1 hour after the start of LV administration. This method is called the Roswell Park Memorial Institute (RPMI) regimen (5-7), and has been adopted in Japan. In a randomized phase III trial comparing 5FU/LV RPMI regimens in patients with advanced and metastatic colorectal cancer with other regimens, the response rate of treatment with 5FU/LV was significantly higher than those of 5FU/methoxtrate(MTX) and 5FU ( %, 5.0%, %, respectively) without an improvement in median survival time (6, 7). Administration of LV/5FU for 5 consecutive days has been demonstrated. LV/5FU is given by rapid intravenous infusion on days 1-5, every 4 weeks. In patients with advanced colorectal cancer, the response rates of treatment with a 5FU/ low-dose LV regimen (Mayo regimen) and a 5FU/ high-dose LV regimen (Machover regimen) were significantly higher than that of 5FU/MTX (42.0%, 31.0%, 14.0%, respectively). The median survival time in the Mayo regimen was significantly higher than that of 5FU/MTX (12.7 months, 8.4 months, respectively) (15). In Japan, physicians usually advocate the RPMI regimen; we modified this regimen to l-lv /5FU. The formulation of LV used in preclinical and clinical studies consists of a mixture of equal parts of 2 diastereomers differing in chirality at the C-6 carbon of the pteridine ring. The unnatural isomer (d-lv), however, is not inert. In vitro studies of l-lv have shown similar effects at half doses when compared with racemic LV (d,l-lv). On the other hand, l-lv has been shown to be clinically equivalent to the same dose of d,l-lv in its antitumor activity against colorectal cancer in prospective randomized trials (10, 11). The RPMI regimen was based on d,l-lv, while this study employed l-lv. 1429

6 Table VI. Occurrence of chemotherapy-induced toxic effects during l-lv/5fu treatment. NCI-CTC grade (%) NCI-CTC grade (n) Anemia Leucopenia Neutropenia Thrombocytopenia Bilirubinemia Increase of sgot or sgpt Anorexia Nausea NA Vomiting Diarrhea Stomatitis Dyspepsia NA NA Tearing NA Alopecia NA NA Pigmentation changes NA NA Hand-foot skin reaction NA Nail changes NA NA Fatigue NCI-CTC, National Cancer Institute Common Toxicity Criteria (version 2.0). NA, not applicable. SGOT, serum glutamic oxaloacetic transaminase. SGPT, serum glutamic pyruvic transaminase. We evaluated the data of patients who underwent surgery between 2001 and 2003 and who were followed-up in 2004, because of the standardized surgical techniques in those periods, such as the perfection of the total mesorectal excision in all rectal cancer patients or in the technique and extension of lymphadenectomy. We clarified that an adjuvant chemotherapy by l-lv/5fu in patients with stage III colorectal cancer was important as an independent prognostic factor in terms of disease-free survival. In our study, the incidence of grade 3-4 leucopenia, neutropenia and diarrhea were 2.8%, 2.8% and 5.6%, respectively. These were not life-threatening. The incidence of myelosuppression in our study was less than those of previous studies (16-19). On the other hand, the incidence of diarrhea in our study was almost the same as that of a de Grammont regimen (16, 19) and less than that of a Mayo regimen (17, 18). Irinotecan, oxaliplatin and oral fluoropyrimidines, such as UFT, capecitabine and S-1, are widely advocated globally as effective agents for colorectal cancer (2, 20-22). The response rate, median survival time and progressionfree survival of a bolus 5FU and LV Mayo regimen plus infusion irinotecan (IFL regimen or Saltz regimen) was superior to those of a bolus 5FU and LV Mayo regimen (39.0% vs. 21.0%, 14.8 months vs months, 7.0 months vs. 4.3 months, respectively) (22). On the other hand, Saltz et al. recently reported in a randomized phase III study of IFL versus RPMI LV/5FU after a curative resection for stage III colon cancer, that IFL should not be used, because IFL, as compared to LV/5FU, was associated with a greater degree of neutropenia, neutropenic fever and death on treatment, with no associated clinical benefit, such as an improvement of overall survival or a failure-free survival (23). Oxaliplatin, trans-l-1,2-diminocyclohexane oxalatoplatinum, a platinum-based drug, forms cross-linking adducts, thus blocking DNA replication and transcription. In vitro oxaliplatin inhibits colorectal tumor cell lines resistant to cisplatin and carboplatin (24). The response rates of oxaliplatin as single agent for colorectal cancer patients were from 20% to 24% (25, 26). Consequently, an infusion of 5FU and an LV de Gramont regimen plus infusion oxaliplatin (FOLFOX regimen) has been developed (27-30). In Japan, treatment with oxaliplatin is not approved. Oral chemotherapy, including capecitabine, has major advantages over intravenously administered treatment in terms of pharmacoeconomic considerations and patient preferences, because oral treatment can be administered on an out-patient basis (2, 31, 32). Oral chemotherapy may be adopted as the adjuvant chemotherapy for colorectal cancer globally in the near future, although currently in Japan, the use of capecitabine for patients with colorectal cancer is not approved. 1430

7 Hotta et al: Clinical Impact of l-lv/5fu Adjuvant Chemotherapy on Patients with Stage III Colorectal Cancer Cetuximab and bevacizumab are chimeric monoclonal antibodies that specifically bind to the epidermal growth factor receptor and vascular endothelial growth factor with high affinity, respectively. Recently, some reports demonstrated that chemotherapy in combination with cetuximab or bevacizumab was effective for patients with advanced colorectal cancer (33, 34), although neither agent is approved in Japan, for patients with colorectal cancer. In our study, a modified RPMI regimen, approved in Japan for colorectal cancer, resulted in milder side-effects and an improvement in disease-free survival. Moreover, the weekly and short-term administration of l-lv and 5FU in this regimen makes out-patient treatment possible. Therefore, this regimen may contribute, not only to the clinical benefit but also to a better quality of life. 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