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Neoadjuvant chemotherapy for breast cancer determined by chemosensitivity assay achieves better tumor response
Biomedicine & Pharmacotherapy 61 (2007) 562e565 www.elsevier.com/locate/biopha
Neoadjuvant chemotherapy for breast cancer determined by chemosensitivity assay achieves better tumor response Gregory I.S.K. Lau, Wings T.Y. Loo, Louis W.C. Chow* UNIMED Medical Institute, Hong Kong Available online 17 September 2007
Abstract Background: Neoadjuvant chemotherapy can potentially reduce tumor size and help downstage the tumor before definitive operation was performed. However, it was not possible to tell whether the patient would respond to the regimen until given. This difficulty can be overcome by testing the susceptibility of a sample of cancer cells in vitro: a ‘‘patient-tailored approach’’. In this pilot study, we attempt to demonstrate an improved response by this ‘‘patient-tailored’’ approach over standard regimen. Materials and methods: The study included 36 women with moderately advanced local breast cancer larger than 2 cm in diameter. Twelve were allocated to receive a standard regimen of 5-fluorouracil, epirubicin and cyclophosphamide (FEC) preoperatively as controls, and 24 were given the most suitable regimen according to testing; the options were FEC, cyclophosphamide, methotrexate and 5-fluorouracil (CMF), 5-fluorouracil, adriamycin and mitomycin C (FAM) and paclitaxel alone. The cell activities of drug-treated solid tumors were compared to controls with a highly sensitive ATP bioluminescence assay. Patients received chemotherapy according to sensitivity results and the tumor area clinically measured before and after chemotherapy. Results: Sensitivity-directed treatment helped patients achieve a higher rate of complete clinical response (10/24 vs. 0/12), larger mean reduction in tumor area (75% vs. 26%), and 25% pathological complete response (pCR). The paclitaxel subgroup achieved 80% (pCR). Conclusion: It is a useful in vitro assay to provide a reference of the particular patient who received treatment according to her sensitivity result. It may improve pathologic complete response, clinical tumor response and lead to less extensive surgery. Ó 2007 Elsevier Masson SAS. All rights reserved. Keywords: ATP bioluminescence; Chemosensitivity assay; Clinical trial; Evidence-based medicine; Solid tumor
1. Introduction Breast cancer incidence rates have been increasing steadily worldwide for the past few decades, but the mortality rates have remained either stable or decreased in many countries, due to advances in breast cancer detection techniques and treatment approaches [1e3]. However, even with newer drugs that induce a better response and have fewer side effects, the issue of determining the best chemotherapy regimen still remains. The same type and grade of cancer in different patients can respond differently to the same regimen [4,5]. In this study, we
* Corresponding author. UNIMED Medical Institute, 10/F, 72 Gloucester Road, Wanchai, Hong Kong. Tel.: þ852 2861 0286; fax: þ852 2861 1386. E-mail address: [email protected] (L.W.C. Chow). 0753-3322/$ - see front matter Ó 2007 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.biopha.2007.08.013
demonstrate the feasibility of using an in vitro assay to choose the optimum neoadjuvant chemotherapy regimen for patients with breast cancer, improving response and allowing a more conservative surgical approach. We chose ATP bioluminescence assays to measure and have been reported to be highly sensitive [6e14], and we attempted to increase the accuracy by double-beam spectrophotometry measurement of the DNA concentration to account for the slight variation in tissue sample size. 2. Materials and methods Patient recruitment: The study, conducted between 2004 and 2006, included women with breast cancer who fulfilled the following entry criteria: age younger than 70 years, tumor clinically larger than 2 cm in diameter, Karnofsky score
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
greater than 70, and no contraindications to chemotherapy. More than half (56%) of the 36 patients were aged between 40 and 49 years, 18% were aged between 50 and 59 years, and 21% were at least 60 years. At the time of diagnosis, 58% of patients had a grade 2 tumor and 36% had a grade 3 tumor. A total of 71% of patients were positive for oestrogen receptor, 66% were positive for progesterone receptor, and 48% were positive for c-erb-B2 (Table 1). The 36 patients were divided into two groups: a group of 12 patients receiving a standard treatment of FEC (5-fluorouracil, epirubicin, cyclophosphamide), and a group of 24 patients receiving the most suitable chemotherapy according to results obtained from in vitro testing (see Tissue culture system); the options were FEC, CMF (cyclophosphamide, methotrexate, 5fluorouracil), FAM (5-fluorouracil, adriamycin, mitomycin C), Table 1 Patient demographics between standard treatment (FECx3) and chemosensitivitydirected treatment Parameters of measurement
Standard treatment (FECx3)
Age Range: 43e60, mean: 2 Regimen received CMF FAM FEC 12 (100%) Docetaxel Tumor size 2e5 cm 7 (58%) >5 cm 5 (42%) Mean 4.8 cm Tumor grade I 1 (8%) II 8 (67%) III 2 (17%) Unk. Oestrogen receptor (ER) 4 (33%) þ 1 (8%) þþ 4 (33%) þþþ 3 (25%) Unk. Progesterone receptor (PR) 4 (33%) þ 3 (25%) þþ 3 (25%) þþþ 2 (17%) Unk. c-erb-B2 6 (50%) þ 2 (16%) þþ 0 (0%) þþþ 4 (33%) Unk. Ductal carcinoma in situ (DCIS) Yes 7 (58%) No 5 (42%) Unk. Lymphovascular permeation (LVP) Yes 4 (33%) No 8 (67%) Unk. Unk.: information missing.
Chemosensitivity-directed treatment Range 36e67, mean: 49 2 5 12 5
(8%) (21%) (5%) (21%)
9 (38%) >15 (63%) 6.3 cm 1 10 9 4
(4%) (42%) (38%) (17%)
6 4 4 9 1
(25%) (17%) (17%) (38%) (4%)
8 4 5 6 1
(33%) (17%) (21%) (25%) (4%)
11 3 3 4 3
(46%) (13%) (13%) (17%) (13%)
13 (54%) 10 (42%) 1 (4%) 16 (67%) 7 (29%) 1 (4%)
563
and paclitaxel alone. FEC, CMF, and FAM were given for three cycles; paclitaxel was given for six. There were no significant differences between the groups in age, tumor grading, lymphovascular permeation, or oestrogen, progesterone, or c-erb-B2 receptor status. Tissue culture system: We used a three-dimensional tissue culture system for our assay. Fresh breast cancer tissue was collected in a sterilized bottle containing 0.9% normal saline. The specimens were washed three times with Dulbecco’s Phosphate Buffered Saline (PBS) (Invitrogen, CA, USA). A portion of the specimen was taken for histological grading and tumor marker evaluation. The remaining specimens were cut into 1-mm three pieces and placed onto 1 cm collagen sponge cubes (Gelfoam absorbable gelatine sterile sponge, USP, Pharmacia & Upjohn, MI, USA) that had been presoaked in culture medium for 24 h. (Dulbecco’s Modified Eagle Medium (DMEM) (Invitrogen, CA, USA), 10% Foetal Bovine Serum (FBS) (Invitrogen, CA, USA), 100 U/mL penicillin, 100 mg/mL streptomycin; filtered through Steritop 0.22 mm vacuum filter (Millipore, MA, USA.)) Culture medium contained chemotherapy drugs at peak plasma concentration, with three repeats. The tissue-gel pieces were then transferred into six-well plates, and the same culture medium was added until 0.2 mm below the upper horizontal surface of the collagen sponge cube. The plates were then put in a humidified incubator (NuAire, MN, USA) with an atmosphere of 5% CO2 at 37 C for 24 h. The solid tumors were transferred to microcentrifuge tubes and 0.5 mL cell lysis reagent added to the tissues. Cell lysis was accelerated by a sonicator (Sonics & Materials, Inc. Danbury, CT, USA) at one pulse for every 2 s, with 5% amplitude for 1 min. There was a 10-s binding period preceded by amalgamation of 50 mL of samples and 50 mL luciferase reagent as prepared by the assay kit. The absorbance value of the samples was read by TD-20/20 Luminometer (Turner Designs, CA, USA) at 420 nm wavelength. By using the ATP standard provided by the kit (Roche, Germany), the bioluminescence was measured, and is an indirect measure of ATP. Sensitivity to a chemotherapy drug was defined as a reduction in tumor activity by at least 50% from control. The best chemotherapy regimen was the one with the greatest number of components to which samples were sensitive, and patients underwent chemotherapy at three-week intervals. The percentage inhibition (%INH) was calculated as follows:
%INH ¼
CL Test 100% CL
where CL: control without drug and Test: samples with corresponding drugs. Clinical response was measured using callipers and a modified International Union Against Cancer (UICC) classification system was used to grade the response into the following three categories: no response (<50% tumor area reduction), partial response (incomplete response but >50% reduction in tumor area), and complete response (clinically non-palpable).
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
564
In addition, the tumors after excision were examined pathologically to detect any pathological complete response (pCR), meaning no residual tumor or only ductal carcinoma in situ. Statistical significance of the above tests was analyzed by SPSS (12.0 USA) One-Way ANOVA.
3. Results Overall, 10 of the 36 patients (28%) achieved a complete clinical response. All these patients belonged to the group of 24 patients who received treatment directed by the in vitro chemosensitivity test, giving a complete response rate of 42% for this group. There were 12 partial responses: 10 in the chemosensitivity-directed group and two in the standard-regimen group. Ten of 12 (83%) patients were non-responders in the standard treatment group, but only four of 24 (17%) in the chemosensitivity-directed group (Table 2). The mean reduction in tumor area was 75% for the chemosensitivity-directed group and 26% for the standard-regimen group, median was 84% decrease and 24% decrease, respectively ( p < 0.001; Fig. 1). When different regimens were compared (Fig. 2), clinical response was significantly better among patients who received FEC after sensitivity tests (mean reduction, 76%; range, 48e 100%) than those who received FEC without sensitivity testing (mean reduction, 26%; range, 29% increase to 86% reduction) ( p < 0.001). Patients who received paclitaxel after sensitivity testing achieved the best clinical results: the mean response was an 80% reduction in tumor area. The clinical response for patients receiving FAM after sensitivity testing was also consistently high: 80% (4/5) of them showed a partial response, with a mean reduction in tumor area of 82%. Of all patients who received chemosensitivity-directed therapy, 25% (6/24) patients showed no evidence of invasive or in situ carcinoma on pathological examination of an excised specimen. Patients receiving paclitaxel achieved a pCR rate of 80% (4/5). All patients received surgery. Thirty-one patients underwent modified radical mastectomy (MRM), three underwent wide local excision (WLE), and one received radiofrequency ablation (RFA) and one received simple lumpectomy. Ten patients showed no evidence of lymph node metastasis on pathological examination; seven of these patients had received chemosensitivity-directed treatment. The 36 patients are currently undergoing follow-up to obtain survival data (current
Fig. 1. The percentage change in tumor area after neoadjuvant chemotherapy, according to whether in vitro chemosensitivity testing was used.
range of survival, 33e62 weeks). Two patients in the nonchemosensitivity-directed control group developed distant metastasis: one developed bone metastasis and the other liver and lung metastasis. 4. Discussion Achieving pCR is a strong independent predictor for diseasefree and overall survival for patients with breast cancer [15]. In our study, the pCR rate for sensitivity-directed neoadjuvant chemotherapy was 25% overall and 80% for the subgroup receiving paclitaxel, which we find extremely encouraging. The overall
Table 2 Clinical response and pathological response between standard treatment (FECx3) and chemosensitivity-directed treatment Parameters of measurement
Standard treatment (FECx3)
Chemosensitivity-directed treatment
No response Partial response Complete response Pathologic complete response Range of percentage change in tumor size(%)
10 (83%) 2 (17%) 0 0
4 10 4 6
94 to þ29 (mean: 26)
100 to þ17 (mean: 76)
(17%) (42%) (17%) (25%) Fig. 2. The percentage change in tumor area after neoadjuvant chemotherapy, according to regimen.
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
pCR rate is in line with results from large reported series such as the NSABP B-27 (13e26% pCR) [15]. However, most of our patients only received three cycles of neoadjuvant chemotherapy compared to the eight cycles given by the NSABP B-27 study. Three cycles are much fewer than the current standards. Moreover, the dosage of epirubicin given at that time was 75 mg/m2 instead of the currently recommended 100 mg/m2. By adopting more recent regimens and in vitro sensitivity testing, we hope to further raise the overall pCR rate to values similar to our paclitaxel-receiving subgroup. Our pilot study has demonstrated the feasibility of using an in vitro sensitivity test to give patients their own ‘‘tailored therapy’’. By improving protocols and expanding our patient base, we hope that we can show distinctively increased pCR rates, with the ultimate goal of improving patients’ quality-of-life. Acknowledgements We would like to thank the S.K. Yee Medical Foundation for its generous financial support (Project number: 204217). The funding source had no role in data collection, data analysis, data interpretation, or writing of the report. References [1] Parkin DM, Whelan SL, Ferlay J, Storm H. Cancer incidence in five continents, vol. IeVIII. IARC, Lyon: Cancer Base; 2005. No. 7. [2] Althuis MD, Dozier JM, Anderson WF, Devesa SS, Brinton LA. Global trends in breast cancer incidence and mortality 1973e1997. Int J Epidemiol 2005;34:405e12. [3] Parkin DM, Bray F, Ferlay J, Pisani P. Global cancer statistics. CA Cancer J Clin 2002;2005(55):74e108. [4] Undevia SD, Gomez-Abuin G, Ratain MJ. Pharmacokinetic variability of anticancer agents. Nat Rev Cancer 2005;5:447e58.
565
[5] de Jonge ME, Huitema AD, Schellens JH, Rodenhuis S, Beijnen JH. Individualised cancer chemotherapy: strategies and performance of prospective studies on therapeutic drug monitoring with dose adaptation: a review. Clin Pharmacokinet 2005;44:147e73. [6] Kurbacher CM, Grecu OM, Stier U, Gilster TJ, Janat MM, Untch M, et al. ATP chemosensitivity testing in ovarian and breast cancer: early clinical trials. Recent Results Cancer Res 2003;161:221e30. [7] Mollgard L, Tidefelt U, Sundman-Engberg B, Lofgren C, Paul C. In vitro chemosensitivity testing in acute non lymphocytic leukemia using the bioluminescence ATP assay. Leuk Res 2000;24:445e52. [8] Furukawa T, Kubota T, Tanino H, Oura S, Yuasa S, Murate H, et al. Chemosensitivity of breast cancer lymph node metastasis compared to the primary tumor from individual patients tested in the histoculture drug response assay. Anticancer Res 2000;20:3657e8. [9] Tanigawa N, Kitaoka A, Yamakawa M, Tanisaka K, Kobayashi H. In vitro chemosensitivity testing of human tumors by collagen gel droplet culture and image analysis. Anticancer Res 1996;16:1925e30. [10] Cree IA, Pazzagli M, Mini E, Mazzei T, Hunter EM, Sutherland LA, et al. Methotrexate chemosensitivity by ATP luminescence in human leukemia cell lines and in breast cancer primary cultures: comparison of the TCA100 assay with a clonogenic assay. Anticancer Drugs 1995;6:398e404. [11] Rhedin AS, Tidefelt U, Jonsson K, Lundin A, Paul C. Comparison of a bioluminescence assay with differential staining cytotoxicity for cytostatic drug testing in vitro in human leukemic cells. Leuk Res 1993;17: 271e6. [12] Bellamy WT. Prediction of response to drug therapy of cancer. A review of in vitro assays. Drugs 1992;44:690e708. [13] Nguyen HN, Sevin BU, Averette HE, Perras J, Donato D, Penalver M. The use of ATP bioluminescence assays in selecting a drug screen panel for chemosensitivity testing of uterine cancer cell lines. Gynecol Oncol 1992;45:185e91. [14] Kretschmar M, Nichterlein T, Kuntz P, Hof H. Rapid detection of susceptibility to fluconazole in Candida species by a bioluminescence assay of intracellular ATP. Diagn Microbiol Infect Dis 1996;25:117e21. [15] Bear HD, Anderson S, Brown A, Smith R, Mamounas EP, Fisher B, et al. The effect on tumor response of adding sequential preoperative paclitaxel to preoperative doxorubicin and cyclophosphamide: preliminary results from National Surgical Adjuvant Breast and Bowel Project Protocol B-27. J Clin Oncol 2003;21:4165e74.
Neoadjuvant chemotherapy for breast cancer determined by chemosensitivity assay achieves better tumor response Gregory I.S.K. Lau, Wings T.Y. Loo, Louis W.C. Chow* UNIMED Medical Institute, Hong Kong Available online 17 September 2007
Abstract Background: Neoadjuvant chemotherapy can potentially reduce tumor size and help downstage the tumor before definitive operation was performed. However, it was not possible to tell whether the patient would respond to the regimen until given. This difficulty can be overcome by testing the susceptibility of a sample of cancer cells in vitro: a ‘‘patient-tailored approach’’. In this pilot study, we attempt to demonstrate an improved response by this ‘‘patient-tailored’’ approach over standard regimen. Materials and methods: The study included 36 women with moderately advanced local breast cancer larger than 2 cm in diameter. Twelve were allocated to receive a standard regimen of 5-fluorouracil, epirubicin and cyclophosphamide (FEC) preoperatively as controls, and 24 were given the most suitable regimen according to testing; the options were FEC, cyclophosphamide, methotrexate and 5-fluorouracil (CMF), 5-fluorouracil, adriamycin and mitomycin C (FAM) and paclitaxel alone. The cell activities of drug-treated solid tumors were compared to controls with a highly sensitive ATP bioluminescence assay. Patients received chemotherapy according to sensitivity results and the tumor area clinically measured before and after chemotherapy. Results: Sensitivity-directed treatment helped patients achieve a higher rate of complete clinical response (10/24 vs. 0/12), larger mean reduction in tumor area (75% vs. 26%), and 25% pathological complete response (pCR). The paclitaxel subgroup achieved 80% (pCR). Conclusion: It is a useful in vitro assay to provide a reference of the particular patient who received treatment according to her sensitivity result. It may improve pathologic complete response, clinical tumor response and lead to less extensive surgery. Ó 2007 Elsevier Masson SAS. All rights reserved. Keywords: ATP bioluminescence; Chemosensitivity assay; Clinical trial; Evidence-based medicine; Solid tumor
1. Introduction Breast cancer incidence rates have been increasing steadily worldwide for the past few decades, but the mortality rates have remained either stable or decreased in many countries, due to advances in breast cancer detection techniques and treatment approaches [1e3]. However, even with newer drugs that induce a better response and have fewer side effects, the issue of determining the best chemotherapy regimen still remains. The same type and grade of cancer in different patients can respond differently to the same regimen [4,5]. In this study, we
* Corresponding author. UNIMED Medical Institute, 10/F, 72 Gloucester Road, Wanchai, Hong Kong. Tel.: þ852 2861 0286; fax: þ852 2861 1386. E-mail address: [email protected] (L.W.C. Chow). 0753-3322/$ - see front matter Ó 2007 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.biopha.2007.08.013
demonstrate the feasibility of using an in vitro assay to choose the optimum neoadjuvant chemotherapy regimen for patients with breast cancer, improving response and allowing a more conservative surgical approach. We chose ATP bioluminescence assays to measure and have been reported to be highly sensitive [6e14], and we attempted to increase the accuracy by double-beam spectrophotometry measurement of the DNA concentration to account for the slight variation in tissue sample size. 2. Materials and methods Patient recruitment: The study, conducted between 2004 and 2006, included women with breast cancer who fulfilled the following entry criteria: age younger than 70 years, tumor clinically larger than 2 cm in diameter, Karnofsky score
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
greater than 70, and no contraindications to chemotherapy. More than half (56%) of the 36 patients were aged between 40 and 49 years, 18% were aged between 50 and 59 years, and 21% were at least 60 years. At the time of diagnosis, 58% of patients had a grade 2 tumor and 36% had a grade 3 tumor. A total of 71% of patients were positive for oestrogen receptor, 66% were positive for progesterone receptor, and 48% were positive for c-erb-B2 (Table 1). The 36 patients were divided into two groups: a group of 12 patients receiving a standard treatment of FEC (5-fluorouracil, epirubicin, cyclophosphamide), and a group of 24 patients receiving the most suitable chemotherapy according to results obtained from in vitro testing (see Tissue culture system); the options were FEC, CMF (cyclophosphamide, methotrexate, 5fluorouracil), FAM (5-fluorouracil, adriamycin, mitomycin C), Table 1 Patient demographics between standard treatment (FECx3) and chemosensitivitydirected treatment Parameters of measurement
Standard treatment (FECx3)
Age Range: 43e60, mean: 2 Regimen received CMF FAM FEC 12 (100%) Docetaxel Tumor size 2e5 cm 7 (58%) >5 cm 5 (42%) Mean 4.8 cm Tumor grade I 1 (8%) II 8 (67%) III 2 (17%) Unk. Oestrogen receptor (ER) 4 (33%) þ 1 (8%) þþ 4 (33%) þþþ 3 (25%) Unk. Progesterone receptor (PR) 4 (33%) þ 3 (25%) þþ 3 (25%) þþþ 2 (17%) Unk. c-erb-B2 6 (50%) þ 2 (16%) þþ 0 (0%) þþþ 4 (33%) Unk. Ductal carcinoma in situ (DCIS) Yes 7 (58%) No 5 (42%) Unk. Lymphovascular permeation (LVP) Yes 4 (33%) No 8 (67%) Unk. Unk.: information missing.
Chemosensitivity-directed treatment Range 36e67, mean: 49 2 5 12 5
(8%) (21%) (5%) (21%)
9 (38%) >15 (63%) 6.3 cm 1 10 9 4
(4%) (42%) (38%) (17%)
6 4 4 9 1
(25%) (17%) (17%) (38%) (4%)
8 4 5 6 1
(33%) (17%) (21%) (25%) (4%)
11 3 3 4 3
(46%) (13%) (13%) (17%) (13%)
13 (54%) 10 (42%) 1 (4%) 16 (67%) 7 (29%) 1 (4%)
563
and paclitaxel alone. FEC, CMF, and FAM were given for three cycles; paclitaxel was given for six. There were no significant differences between the groups in age, tumor grading, lymphovascular permeation, or oestrogen, progesterone, or c-erb-B2 receptor status. Tissue culture system: We used a three-dimensional tissue culture system for our assay. Fresh breast cancer tissue was collected in a sterilized bottle containing 0.9% normal saline. The specimens were washed three times with Dulbecco’s Phosphate Buffered Saline (PBS) (Invitrogen, CA, USA). A portion of the specimen was taken for histological grading and tumor marker evaluation. The remaining specimens were cut into 1-mm three pieces and placed onto 1 cm collagen sponge cubes (Gelfoam absorbable gelatine sterile sponge, USP, Pharmacia & Upjohn, MI, USA) that had been presoaked in culture medium for 24 h. (Dulbecco’s Modified Eagle Medium (DMEM) (Invitrogen, CA, USA), 10% Foetal Bovine Serum (FBS) (Invitrogen, CA, USA), 100 U/mL penicillin, 100 mg/mL streptomycin; filtered through Steritop 0.22 mm vacuum filter (Millipore, MA, USA.)) Culture medium contained chemotherapy drugs at peak plasma concentration, with three repeats. The tissue-gel pieces were then transferred into six-well plates, and the same culture medium was added until 0.2 mm below the upper horizontal surface of the collagen sponge cube. The plates were then put in a humidified incubator (NuAire, MN, USA) with an atmosphere of 5% CO2 at 37 C for 24 h. The solid tumors were transferred to microcentrifuge tubes and 0.5 mL cell lysis reagent added to the tissues. Cell lysis was accelerated by a sonicator (Sonics & Materials, Inc. Danbury, CT, USA) at one pulse for every 2 s, with 5% amplitude for 1 min. There was a 10-s binding period preceded by amalgamation of 50 mL of samples and 50 mL luciferase reagent as prepared by the assay kit. The absorbance value of the samples was read by TD-20/20 Luminometer (Turner Designs, CA, USA) at 420 nm wavelength. By using the ATP standard provided by the kit (Roche, Germany), the bioluminescence was measured, and is an indirect measure of ATP. Sensitivity to a chemotherapy drug was defined as a reduction in tumor activity by at least 50% from control. The best chemotherapy regimen was the one with the greatest number of components to which samples were sensitive, and patients underwent chemotherapy at three-week intervals. The percentage inhibition (%INH) was calculated as follows:
%INH ¼
CL Test 100% CL
where CL: control without drug and Test: samples with corresponding drugs. Clinical response was measured using callipers and a modified International Union Against Cancer (UICC) classification system was used to grade the response into the following three categories: no response (<50% tumor area reduction), partial response (incomplete response but >50% reduction in tumor area), and complete response (clinically non-palpable).
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
564
In addition, the tumors after excision were examined pathologically to detect any pathological complete response (pCR), meaning no residual tumor or only ductal carcinoma in situ. Statistical significance of the above tests was analyzed by SPSS (12.0 USA) One-Way ANOVA.
3. Results Overall, 10 of the 36 patients (28%) achieved a complete clinical response. All these patients belonged to the group of 24 patients who received treatment directed by the in vitro chemosensitivity test, giving a complete response rate of 42% for this group. There were 12 partial responses: 10 in the chemosensitivity-directed group and two in the standard-regimen group. Ten of 12 (83%) patients were non-responders in the standard treatment group, but only four of 24 (17%) in the chemosensitivity-directed group (Table 2). The mean reduction in tumor area was 75% for the chemosensitivity-directed group and 26% for the standard-regimen group, median was 84% decrease and 24% decrease, respectively ( p < 0.001; Fig. 1). When different regimens were compared (Fig. 2), clinical response was significantly better among patients who received FEC after sensitivity tests (mean reduction, 76%; range, 48e 100%) than those who received FEC without sensitivity testing (mean reduction, 26%; range, 29% increase to 86% reduction) ( p < 0.001). Patients who received paclitaxel after sensitivity testing achieved the best clinical results: the mean response was an 80% reduction in tumor area. The clinical response for patients receiving FAM after sensitivity testing was also consistently high: 80% (4/5) of them showed a partial response, with a mean reduction in tumor area of 82%. Of all patients who received chemosensitivity-directed therapy, 25% (6/24) patients showed no evidence of invasive or in situ carcinoma on pathological examination of an excised specimen. Patients receiving paclitaxel achieved a pCR rate of 80% (4/5). All patients received surgery. Thirty-one patients underwent modified radical mastectomy (MRM), three underwent wide local excision (WLE), and one received radiofrequency ablation (RFA) and one received simple lumpectomy. Ten patients showed no evidence of lymph node metastasis on pathological examination; seven of these patients had received chemosensitivity-directed treatment. The 36 patients are currently undergoing follow-up to obtain survival data (current
Fig. 1. The percentage change in tumor area after neoadjuvant chemotherapy, according to whether in vitro chemosensitivity testing was used.
range of survival, 33e62 weeks). Two patients in the nonchemosensitivity-directed control group developed distant metastasis: one developed bone metastasis and the other liver and lung metastasis. 4. Discussion Achieving pCR is a strong independent predictor for diseasefree and overall survival for patients with breast cancer [15]. In our study, the pCR rate for sensitivity-directed neoadjuvant chemotherapy was 25% overall and 80% for the subgroup receiving paclitaxel, which we find extremely encouraging. The overall
Table 2 Clinical response and pathological response between standard treatment (FECx3) and chemosensitivity-directed treatment Parameters of measurement
Standard treatment (FECx3)
Chemosensitivity-directed treatment
No response Partial response Complete response Pathologic complete response Range of percentage change in tumor size(%)
10 (83%) 2 (17%) 0 0
4 10 4 6
94 to þ29 (mean: 26)
100 to þ17 (mean: 76)
(17%) (42%) (17%) (25%) Fig. 2. The percentage change in tumor area after neoadjuvant chemotherapy, according to regimen.
G.I.S.K. Lau et al. / Biomedicine & Pharmacotherapy 61 (2007) 562e565
pCR rate is in line with results from large reported series such as the NSABP B-27 (13e26% pCR) [15]. However, most of our patients only received three cycles of neoadjuvant chemotherapy compared to the eight cycles given by the NSABP B-27 study. Three cycles are much fewer than the current standards. Moreover, the dosage of epirubicin given at that time was 75 mg/m2 instead of the currently recommended 100 mg/m2. By adopting more recent regimens and in vitro sensitivity testing, we hope to further raise the overall pCR rate to values similar to our paclitaxel-receiving subgroup. Our pilot study has demonstrated the feasibility of using an in vitro sensitivity test to give patients their own ‘‘tailored therapy’’. By improving protocols and expanding our patient base, we hope that we can show distinctively increased pCR rates, with the ultimate goal of improving patients’ quality-of-life. Acknowledgements We would like to thank the S.K. Yee Medical Foundation for its generous financial support (Project number: 204217). The funding source had no role in data collection, data analysis, data interpretation, or writing of the report. References [1] Parkin DM, Whelan SL, Ferlay J, Storm H. Cancer incidence in five continents, vol. IeVIII. IARC, Lyon: Cancer Base; 2005. No. 7. [2] Althuis MD, Dozier JM, Anderson WF, Devesa SS, Brinton LA. Global trends in breast cancer incidence and mortality 1973e1997. Int J Epidemiol 2005;34:405e12. [3] Parkin DM, Bray F, Ferlay J, Pisani P. Global cancer statistics. CA Cancer J Clin 2002;2005(55):74e108. [4] Undevia SD, Gomez-Abuin G, Ratain MJ. Pharmacokinetic variability of anticancer agents. Nat Rev Cancer 2005;5:447e58.
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