Kohji Enomoto

Clinicopathologic Characteristics and Prognosis of Breast Cancer Patients Associated with Pregnancy and Lactation: Analysis of Case-Control Study in Japan

Clinicopathologic characteristics and prognosis of breast cancer patients associated with pregnancy and lactation were clarified by means of a case‐control study of matched non‐pregnant and non‐lactating patients with breast cancer. From 18 institutions in Japan, a total of 192 subjects with breast cancer diagnosed during pregnancy (72 cases) and lactation (120 cases) were collected between 1970 and 1988, accounting for 0.76% of all breast cancer patients. The duration of symptoms was longer and tumor size was larger in the study subjects. Although the disease‐free interval was longer than that in the control patients, the survival time was shorter. There was no characteristic difference in histologic type. Vascular invasion and lymph node metastasis were found more frequently in the subjects. The positive rates of estrogen receptor and progesterone receptor were lower in the subjects. The 5‐ and 10‐year survival rates of the study patients were 65% and 55%, respectively, and these survivals were significantly lower than those of the control (P < 0.001). The survival rates were poorer in the subjects, in accordance with stage and lymph node metastasis. The results suggest that most of the patients with breast cancer diagnosed during pregnancy and lactation are in a more advanced stage because of a delay in detection and diagnosis, and hence have unfavorable prognosis. Therefore, it is important to diagnose and treat early for improvement of prognosis in patients with breast cancer during pregnancy and lactation.

Tumor growth rate and prognosis of breast cancer mainly detected by mass screening.

To investigate the relationship between the tumor growth rate of the primary breast cancer and its prognosis, records for 122 breast cancer patients in 9 hospitals in Japan were retrospectively reviewed. These records contained at least two measurements of the same tumor mass in the breast. So the growth rate was estimated from these measurements taken at different points in time. The doubling time of the breast tumors showed an approximately log‐normal distribution. The geometric mean of doubling times for all cases was 174 days. The solid‐tubular histologic type of carcinoma had the shortest geometric mean of doubling time (126 days), the scirrhous carcinoma had the second shortest one (205 days), and the papillotubular carcinoma had the longest one (252 days). The patients with shorter doubling time of tumor tended to have a poorer prognosis. The Cox multiple regression analysis showed that the tumor growth rate was related significantly with survival, after adjusting for other covariates such as clinical stage, lymph node metastasis, age of patient, histological type, and year of treatment.

Progression of human breast cancers to the metastatic state is linked to genotypes of catechol-O-methyltransferase

There is increasing evidence that catecholestrogens may contribute to the development of breast cancer. Specifically, inactivation of catecholestrogens may prevent the genesis and arrest the progression of the disease. Catechol-O-methyltransferase (COMT), Glutathione S-transferase (GST) M1 and GSTP1 are responsible for the detoxification of catecholestrogens, and are polymorphic in the human population. In this study, a PCR-based restriction fragment length polymorphism analysis was performed to determine genotypes of the COMT, GSTM1 and GSTP1 genes. We investigated the relationship between the germline polymorphism of these genes and clinico-pathological characteristics in 140 patients with breast cancer. Among 73 patients with the low activity COMT allele, 49 (67%) had regional lymph node metastasis. On the other hand, only 27 (40%) of 67 patients without the low activity allele had lymph node metastasis. The COMT genotype was significantly associated with clinical stage and the extent of regional lymph node metastasis of breast cancer (P<0.05). However, polymorphisms of the GSTM1 and GSTP1 gene were not associated with clinico-pathological factors. Our findings suggest that the allele encoding for low activity COMT may contribute to the progression of breast cancer.

Mass Screening for Breast Cancer: Comparison of the Clinical Stages and Prognosis of Breast Cancer Detected by Mass Screening and in Out-patient Clinics

To establish the criteria for assessing the life‐prolonging effect of mass screening for breast cancer, clinical stage and prognosis of breast cancer detected by mass screening in 11 regions of Japan were compared with those for matched patients in out‐patient clinics. A total of 728 patients detected by mass screening and 1,450 found in the out‐patient clinics were reviewed. The stage of the disease was Tis or I in 40.9% of the patients detected by mass screening, and 28.7% of those found in the out‐patient clinics. In contrast, stage III was found in 9.3% and 14.6%, respectively, indicating that early stages were significantly more common in the patients detected by mass screening. The overall survival curve for the patients detected by mass screening was compared with that for those found in the out‐patient clinics. The 5‐year survival rate was significantly higher in the patients detected by mass screening (91.7% vs. 85.6%; P<0.01), while the 10‐year survival rate was slightly higher in the same group of patients, but the difference from the other group was not significant (80.5% vs. 78.1%). Women who had conducted breast self‐examination (BSE) showed a higher survival rate than those who had not conducted BSE.

Frozen-section-guided breast-conserving surgery: implications of diagnosis by frozen section as a guide to determining the extent of resection.

This study was conducted to analyze retrospectively the results of performing sector resection on 56 breasts in 54 patients with breast cancer. The glands were resected with a 2-cm tumor-free margin on both lateral sides and the distal side, and with more than a 3-cm tumor-free margin on the nipple side. The frequency of positive resection margins for the cancer cells was 7/56 (12.5%) on the nipple side and 12/46 (26.1%) on the lateral sides, with an overall frequency of 15/56 (26.8%). There were positive resected margins for cancer cells on both the nipple and lateral sides in 4/46 patients (9%) Assuming the equivocal margins were positive for cancer cells, an accurate diagnosis by frozen section examination was made in 51 of the 56 operations (91.1%). Additional resection of the margins was performed in all 20 cases of a positive resected margin for cancer cells according to the diagnosis by frozen section. Thereafter, the resected margins became negative in 13 cases (65%), but remained positive in 7 cases (35%). These results show that performing diagnosis by frozen section of the surgical margins is an effective guide to resecting tumors adequately.

The Effect of Breast Self‐examination on Early Detection and Survival

To investigate the effect of breast self‐examination (BSE), we compared the stages, survival, and the risk of death for 355 patients with breast cancer detected by BSE with those for 1,327 patients with breast cancer detected by chance. The early stages of the disease were found to be more common among the symptomatic breast cancer patients detected by BSE than those by chance. The 5‐year overall survival rate was 94.4% for the symptomatic patients detected by BSE, and was significantly higher by 8.7% than that (85.7%) for patients detected by chance (P< 0.001). The 10‐year survival rate was 81.6% for patients detected by BSE, and 76.6% for cases detected by chance (the difference was not significant). The overall difference between the two survival curves was statistically significant by the Iogrank test (P<0.01). A multivariate analysis using the Cox proportional hazards model showed that the risk of death for patients detected by BSE was smaller by 0.570 times than that for patients detected by chance, which was statistically significant (P< 0.05). The effect of biases inherent to BSE in the survival analysis cannot be controlled completely even after conducting multivariate analysis. These results suggest that BSE may contribute to the reduction of the risk of death through early detection of breast cancer. However, further examination should be conducted by other methods to obtain conclusive evidence.

Preoperative evaluation of the chemosensitivity of breast cancer by means of double phase99mTc-MIBI scintimammography

The chemosensitivity of breast cancer is important for its management, but it is difficult to evaluate preoperatively. Tc-99m hexakis-2-methoxyisobutylisonitrile (MIBI) scintimammography has been reported to indicate the expression of P-glycoprotein, which is one factor concerned with multidrug resistance. We developed a chemosensitivity assay by using surgical specimens to investigate whether99mTc-MIBI scintimammography findings before the operation are related to chemosensitivity according to our assay. Fifteen patients with primary breast cancer were enrolled into the study. Early and delayed images were obtained at 10 and 120 minutes after intravenous injection of99mTc-MIBI, respectively. Regions of interest were placed on the tumors and the contralateral healthy breasts in each patient to estimate99mTc-MIBI uptake in the tumor, and retention indices were then calculated to assess the washout of99mTc-MIBI. Chemosensitivity assay was performed by incubating surgical specimens with anticancer agents such as doxorubicin, epirubicin, pinorubicin, mitomycin C, cisplatin and 5-fluorouracil.99mTc-MIBI washout on scintimammography was successfully related to inhibition ratios on chemosensitivity tests when compared with99mTc-MIBI uptake by the tumor. In particular, high correlation coefficients were obtained between the retention index of99mTc-MIBI and the inhibition ratios of doxorubicin (r = 0.75), epirubicin (r = 0.60) and pinorubicin (r = 0.62), but poor correlation was found for mitomycin C (r = 0.44) and cisplatin (r = 0.31). Our results indicate that the retention index of99mTc-MIBI is closely correlated to chemosensitivity to anthracyclines, suggesting that double-phase scintimammography allows preoperative prediction of chemosensitivity of breast cancer.

The Role of Contrast-Enhanced High Resolution MRI in the Surgical Planning of Breast Cancer.

The role of contrast-enhanced high resolution MRI for planning surgery in breast cancer was evaluated. Of 72 patients examined, 57 patients had invasive ductal carcinoma, 2 had mucinous carcinoma, 1 had medullary carcinoma, 7 had invasive lobular carcinoma, 2 had ductal carcinoma in situ (DCIS) and 3 had Paget’s disease. A 1.5 T Signa imager (GE Medical Systems, Milwaukee, WI) was used with a dedicated breast coil. The pulse sequence based on RARE (rapid acquisition with relaxation enhancement) was used with a fat suppression technique. After examining both breasts, the affected breast alone was examined with Gd enhancement. Linear and/or spotty enhancement on MRI was considered to suggest DCIS or intraductal spread in the area surrounding the invasive cancer. Of 72 patients, 50 showed linear and/or spotty enhancement on MRI and 41 of those 50 patients had DCIS or intraductal spread. In contrast, 22 of 72 patients were considered to have little or no intraductal spread on MRI and 17 of the 22 patients had no or little intraductal spread on pathological examination. The sensitivity, specificity and accuracy for detecting intraductal spread on MRI were 89%, 82% and 81%, respectively. Discrepancies in the estimated extent of intraductal spread were less than 2 cm in 90% of the patients according to pathological mapping. High resolution MRI was considered useful in detecting intraductal spread and in estimating its extent, however, larger study using precise correlation with pathology is necessary.

Epidermal growth factor receptor-dependent cytotoxicity for human squamous carcinoma cell lines of a conjugate composed of human EGF and RNase 1

Recombinant human ribonuclease 1 (RNase 1) was chemically linked to recombinant human epidermal growth factor (EGF). The EGF-RNase conjugate showed dose-dependent cytotoxicity for EGF receptor-overexpressing A431 and TE-8 human squamous carcinoma cells with an IC50 of 2 x 10(-7)M and 10(-6)M, respectively, whereas the IC50 of RNase alone was almost 10(-4)M. An unconjugated mixture of EGF and RNase had no greater effect than RNase alone. The conjugate showed no detectable cytotoxicity against EGF receptor-deficient small cell lung cancer cells (H69). Addition of excess EGF in the medium protected A431 cells from the EGF-RNase conjugate cytotoxicity. The cytotoxicity of the EGF-RNase conjugate was positively correlated with the EGF receptor numbers of each cell line. The chimeric toxin composed of only human proteins might be a more useful anti-cancer agent with less immunogenicity than the conventional chimeric toxins.

Comparison of chemotherapy with or without medroxyprogesterone acetate for advanced or recurrent breast cancer.

The usefulness of CAF [cyclophosphamide (CPA)/doxorubicin (ADR)/5-fluorouracil (5-FU)] + medroxyprogesterone acetate (MPA) therapy for advanced/recurrent breast cancer was studied in a randomised trial at 56 institutions. Patients received CAF therapy [CPA: 100 mg, orally, days 1-14; ADR: 30 mg/m2, intravenously (i.v.), days 1 and 8; 5-FU: 500 mg/m2, i.v., days 1 and 8) in arm I, or CAF + MPA therapy (CAF + MPA 1200 mg, daily) in arm II. The response rate was significantly higher (P = 0.041) in arm II (53.5%, 46/86) than arm I (36.6%, 30/82). The response rate by tumour site was significantly higher for lymph node and bone lesions in arm II. Partial response duration and overall response duration were significantly longer in arm II. Incidences of anorexia and nausea/vomiting were significantly higher in arm I but in arm II, moon face, oedema and vaginal bleeding were significantly higher. Many patients in arm II demonstrated improvement in performance status and weight loss, suggesting a beneficial effect of MPA. The chemoendocrine therapy with CAF + MPA appears to be more beneficial than CAF alone in the treatment of advanced/recurrent breast cancer.