Bilateral Wilms' tumor: long-term survival and some epidemiological features.

Sixty-seven children with a bilateral Wilms' tumor (BWT) who were registered to the International Society of Pediatric Oncology (SIOP) nephroblastoma trial and studies 1, 2, and 5, conducted between 1971 and 1980, were analyzed. The overall 10-year survival was 64%. While most deaths due to tumor occurred within 3 years after diagnosis of bilateral disease, five patients died after 3 years (20%), three with synchronous and two with metachronous BWT. The survival rates for the 42 children with synchronous BWT (follow-up time, 6 1/2 to 14 years) and the 25 children with metachronous BWT (follow-up time, 5 to 13 years) were 69% and 56%, respectively. Due to an improvement in the synchronous group, overall survival improved over the years: 47%, 72%, and 70%, in SIOP 1, 2, and 5, respectively. Age at diagnosis and most advanced tumor stage affected prognosis. Children presenting a tumor manifestation before the age of 2 years had better prognosis than older children. This difference is significant in synchronous BWT. Prognosis for children with local stage 1 or 2 was better than for those with local stage 3. Median age at initial presentation in BWT was lower than in unilateral nephroblastoma and lower in metachronous BWT than in synchronous BWT. Young children presenting with unilateral nephroblastoma should have a careful follow-up of the contralateral kidney for at least the next 3 1/2 years, as most contralateral tumors will develop during this period.

Effectiveness of preoperative chemotherapy in Wilms' tumor: results of an International Society of Paediatric Oncology (SIOP) clinical trial.

The results of a controlled clinical trial of preoperative radiotherapy compared to chemotherapy in patients with nephroblastoma are presented. Of 397 histologically proven cases of Wilms' tumor registered at 34 centers between January 1977 and July 1979, 164 were eligible for the trial and were randomized to receive preoperative radiotherapy and chemotherapy (group R, 76 patients) or preoperative chemotherapy (group C, 88 patients). The results were evaluated in terms of the number of surgical tumor ruptures and of local tumor extent at pathologic examination, reflecting the effectiveness of the preoperative treatment. Survival and recurrence-free survival in the two treatment groups were also taken into account. The stage distribution was comparable in the two groups, with 52% stage I tumors in group R, and 43% in group C. Significant changes in the pathologic pattern were more frequent in group R than in group C (53% versus 17%). From these data it is concluded that preoperative chemotherapy is as good as preoperative radiotherapy in terms of prevention of tumor rupture. In addition, it was shown that 43% of an unselected population of patients with Wilms' tumor could be treated without any radiotherapy when chemotherapy had been given preoperatively.

Results of the Sixth International Society of Pediatric Oncology Wilms' Tumor Trial and Study: a risk-adapted therapeutic approach in Wilms' tumor.

PURPOSE: The Sixth International Society of Pediatric Oncology study (SIOP6) concerned Wilms' tumor with favorable histology, preoperatively treated to obtain a high rate of stage I patients, and sought to reduce treatment for patients with stage I and stage II negative nodes (IIN0) tumors and to find better therapy to prevent relapses in stage II positive nodes (IIN1) and stage III patients. PATIENTS AND METHODS: Eligible patients (N = 509) had received four weekly doses of vincristine (VCR) and two courses of dactinomycin (AMD) preoperatively and were assigned after surgery, according to stage and lymph node involvement, to three different prognostic groups, which were to be randomized. Stage I patients (n = 303) received VCR and AMD either for 17 weeks (S) or 38 weeks (L). Stage IIN0 patients (n = 123) received either 20 Gy irradiation (R+) or no irradiation (R-) and received VCR and AMD for 38 weeks. Stage IIN1 and III patients (n = 83) received intensified VCR and AMD (INTVCR) versus VCR, AMD, and Adriamycin (ADRIA; Doxorubicin Farmitalia Carbo Erba, Rueil, Malmaison, France; doxorubicin). Assessment criteria were 2-year disease-free survival (DFS) and 5-year survival (SURV) percentages. A stopping rule was added that took into account abdominal recurrences for the stage IIN0 trial. RESULT: A 52% rate of stage I tumors was obtained, with a low rate of ruptures (7%). The 2-year DFS and 5-year SURV rates according to the different therapeutic groups were stage I, 92% versus 88% (equivalent) and 95% versus 92% for S and L, respectively; stage IIN0, 72% versus 78% (stage equivalent) and 88% versus 85% for R+ and R-, respectively; and stage IIN1 and stage III, 49% versus 74% (P < .029) and 77% versus 80% for INTVCR and ADRIA, respectively, which results in an 82% DFS and 89% SURV rate for the entire trial population. However, six abdominal metastases observed during the first year of follow-up (FU) in the R- group versus none in the R+ group resulted in discontinuation of the stage IIN0 trial. CONCLUSION: Risk-adapted therapy to limit risk of sequelae is possible. More intensive chemotherapy is necessary to prevent abdominal recurrences in nonirradiated stage IIN0 patients treated preoperatively. A three-drug protocol is necessary in stage IIN1 and stage III patients.

Second cancer risk following testicular cancer: a follow-up study of 1,909 patients.

PURPOSE: Improved survival in testicular cancer has been accompanied by concern about long-term side effects of therapy. We assessed the evolution of second cancer (SC) risk over a prolonged follow-up period, which has been rarely studied in large patient series. PATIENTS AND METHODS: We estimated the risk of SCs in 1,909 patients with testicular cancer diagnosed in the Netherlands from 1971 to 1985. Complete medical information was obtained up to at least January 1988 for 92% of patients. Median follow-up was 7.7 years. For 89% of second tumors the diagnosis was confirmed through review of histologic slides; for an additional 8%, the diagnosis was verified by pathology reports only. RESULTS: Seventy-eight patients developed a SC 1 year or more after start of treatment, as compared with 47.6 expected on the basis of incidence rates in the general population (relative risk [RR], 1.6; 95% confidence interval [CI], 1.3 to 2.1). The mean 15-year actuarial risk of all SCs was 9.8% (95% CI, 7.5% to 12.8%). Significantly increased RRs were observed for all gastrointestinal cancers combined (RR, 2.6; 95% CI, 1.7 to 3.9), stomach cancer (RR, 3.7; 95% CI, 1.8 to 6.8), contralateral testicular cancer (CLTC) (RR, 35.7; 95% CI, 21.8 to 55.2), and leukemia (RR, 5.1; 95% CI, 1.4 to 13.0). Patients who had received irradiation to the paraaortic lymph nodes and who survived testicular cancer for more than 5 years were at particularly high risk of developing stomach cancer (RR, 6.9; 95% CI, 3.3 to 12.7). The median interval between the diagnosis of testicular cancer and stomach cancer was 12.4 years. Patients treated with chemotherapy (CT) did not experience an increase in SCs in general. Indeed, CT-treated patients, as compared with those who received radiotherapy (RT), or surgery alone, had significantly reduced risk of CLTC. This finding might be attributed to an eradicating effect of CT on carcinoma in situ or subclinical CLTC. The excess risk of leukemia was not found to be clearly related to CT. CONCLUSION: Testicular cancer patients who receive RT experience elevated risk of gastrointestinal tumors. CT does not seem to increase SC risk and may even decrease the risk of a CLTC. Following testicular cancer, the 15-year actuarial risk of all SCs is only about half the risk experienced by patients with Hodgkin's disease.

Metastatic ovarian or colonic cancer: a clinical challenge.

Clinical problems arise when histology is unable to differentiate between an ovarian carcinoma infiltrating into the rectosigmoid region and a colonic cancer with ovarian metastases. To evaluate the discriminative value of immunohistochemistry we studied four groups: (A) ovarian carcinoma (n = 21), (B) ovarian carcinoma with sigmoid stenosis (n = 18), (C) colonic carcinoma (n = 20) and (D) a group in which the differential diagnosis was a problem (n = 19). Paraffin sections stained with a panel of monoclonal antibodies revealed specific patterns: in group A and B a negative Parlam-4 and positive OC-125; in group C the opposite; in group D the 'colonic' pattern in 15 cases, and the 'ovarian' pattern in only 2. The clinical diagnosis in group D during follow-up was ovarian carcinoma in 7, colonic carcinoma in 8, double tumour in 1 and still unknown in 3. This was based on high levels of serum tumour markers such as carcinoembryonic antigen (n = 5) and CA-125 (n = 4), laparotomy (n = 4), autopsy (n = 1), barium enema and/or endoscopy (n = 5). The response to chemotherapy in group D was extremely poor.

Ewing's sarcoma of the pelvis: changes over 25 years in treatment and results.

The pelvic localisations of Ewing's sarcoma have the worst prognosis due to large size at diagnosis, frequent distant metastases, radiosensitive organs next to the tumour and difficult surgery. The purpose of the present study was to analyse treatment results over a period of 25 years and to investigate the impact of newer chemotherapy schedules, improved radiotherapy techniques and newer surgical methods on the prognosis. 35 children and young adults were identified from 1967 to 1994 for whom diagnosis, presentation, performed treatment and outcome were available. Tumour size, as measured from CT scans, response to chemotherapy and radiotherapy target volume, could be reviewed in the later years. Actuarial 5-year survival for the whole group was 31% and for the 24 non-metastatic patients 40%, with a disease-free interval of 19%. Tumour size could be measured in 27 patients and ranged from 36 to 1540 cm3. There were 12 local recurrences, 1 in the 4 patients treated with surgery. After 1983, 9 out of 17 irradiated patients developed local failure. 3 patients had adequate fields and one a close field which did not cover completely the prechemotherapy extent and 3 of these recurred. All 4 patients with stable disease after neoadjuvant CT failed locally, not withstanding high-dose radiotherapy. The mean length of neoadjuvant CT tended to be shorter in patients without local relapse. There was no significant difference in survival before and after 1983.

Abdominal recurrences in Wilms' tumours: a report from the SIOP Wilms' tumour trials and studies.

The Wilms' tumour trials and studies conducted from 1971 to 1980 registered 1042 patients. Of these, 82 patients developed an abdominal recurrence. Particulars of these were studied. Half of the recurrences occurred in stage III patients. Often several untoward prognostic factors could be identified, such as large tumour size, difficult operation, incomplete excision, peritoneal adhesions or metastases, tumour extending to renal vein or vena cava. A tumour rupture increases the chance for an abdominal recurrence, especially if appropriate radiotherapy is not given. In many of these cases, postoperative radiotherapy seems to have been insufficiently tailored to the operative findings. For stage III cases, a careful discussion between surgeon, radiotherapist, and pathologist should lead to the optimal radiotherapy field size and dose for each individual patient, so that the risk of abdominal recurrence can be reduced.

Histopathological classification of childhood rhabdomyosarcomas: relationship with clinical parameters and prognosis.

To define a useful and prognostically relevant classification system for rhabdomyosarcomas (RMSs), tissue sections of 113 well-documented, protocol-treated cases were retrieved from the files of the Emma Kinderziekenhuis Amsterdam, the Netherlands, and reclassified by a panel of pediatric pathologists. The following subtypes were recognized: embryonal RMS (n = 66), alveolar RMS (including the solid variant) (n = 16), botryoid RMS (n = 11), embryonal sarcoma (n = 6), and spindle cell RMS (n = 5). Nine cases were classified as RMS not otherwise specified (NOS). The above-mentioned histopathological subtypes correlated significantly with survival (P = .005) in patients with nonparameningeal tumors. Indeed, the best prognosis was observed in patients with spindle cell RMS, embryonal sarcoma, and botryoid RMS (10-year survival rates of 80% to 86%). Patients with embryonal RMS had an intermediate prognosis (10-year survival rate of 55%) and patients with alveolar RMS fared poorly (10-year survival rate of 9%). Survival rate was poor in patients with a localized parameningeal tumor, irrespective of histopathological subtype (10-year survival rate of 33%). Furthermore, this study confirmed the known impact on prognosis of localization (P = .008) and tumor node metastasis (TNM) stage (P = .0005). Classification of RMS subtypes proved to be fairly well reproducible (kappa ranging from 0.47 to 0.85 and percentage of concordance ranging from 50% to 85%). The best agreement was noted in botryoid RMS and the worst in embryonal sarcoma. However, improvement of agreement was noted for the latter subtype during the consecutive classification sessions. In summary, this study shows the strong prognostic value of histopathological subtypes and parameningeal tumor localization.

Morphometric data to FIGO stage and histological type and grade for prognosis of ovarian tumours.

The prognostic value of using histological typing, grading, and morphology, in addition to clinical staging, was assessed in 98 cases of invasive ovarian cancer of the common epithelial types (serous, mucinous, and endometrial). All of these cases had at least five years of follow up. When regression analysis was used, the International Federation of Gynaecology and Obstetrics' (FIGO) staging system was the best indicator for prognosis. Analysis of a combination of morphometric features was the second best indicator, being especially useful for the those patients with stage I disease. Variables that indicated a relatively poor prognostic outcome were mitotic index above 30; volume percentage epithelium above 65%; shortest nuclear axis above a mean of 1 X 1 micrometers. Histological typing of ovarian tumours was of limited value; mucinous tumours have a somewhat better prognosis than serous tumours, but the prognostic value of typing alone was found to be limited. Qualitative histological grading was useful, but the prognostic value of morphometric grading was better. Measurement of morphological features with an interactive computer program is simple and can be done by a pathologist or a technician: in future it is likely that such automated systems of measurement will improve the objectivity of tissue analysis.

Quantitative morphometry of squamous cell hyperplasia of the larynx.

The histopathological diagnosis of squamous cell hyperplasia of the larynx is very subjective. Since morphometry is highly reproducible, this method was applied to routine processed slides of 45 such lesions to assess objectively the epithelial characteristics. In each case measurements of nuclei of 50 cells in the basal, intermediate, and superficial cell layers were carried out. The data were analysed statistically. The findings suggest that quantitative morphometry may be helpful for the histopathological classification of squamous cell hyperplasia of the laryngeal mucosa.

Prognostic importance of DNA flow cytometric variables in rhabdomyosarcomas.

AIM: To determine whether DNA ploidy patterns and S phase fraction offer prognostic information in patients with rhabdomyosarcoma (RMS). METHODS: DNA flow cytometry was performed on formalin fixed, paraffin wax embedded samples from primary tumours, and metastatic deposits or recurrences in 70 patients. DNA histogram analysis was done using a semi-automated cell cycle analysis program. RESULTS: Of the 70 primary tumours, 23 were DNA diploid, 32 DNA aneuploid, eight DNA multiploid, and seven DNA tetraploid. The prognosis for DNA aneuploid patterns was favourable, intermediate within the group of DNA tetraploid tumours and poor among patients with DNA diploid and DNA multiploid tumours (p = 0.009). In multivariate analysis (Cox regression model) DNA ploidy was an important independent prognostic factor, along with TNM stage, localisation, and histopathological classification. Ten out of 32 patients with a high S phase fraction (> 15%) with primary RMS achieved long term survival in contrast to 20 out of 29 patients with a low S phase fraction (< or = 15%) (p = 0.008). In 24 cases the DNA ploidy of cases of relapse was analysed. Of the 15 cases, in which stem line changes had occurred, 13 died of disease. No stem line changes were noted in nine cases and in this group four patients died of disease (p = 0.02). CONCLUSIONS: Assessment of DNA ploidy and S phase fraction in primary RMS and evaluation of stem line changes in cases of relapse are important variables in predicting prognosis.

Endodermal sinus tumor of the vagina: radiation therapy and progeny.

BACKGROUND: Extraovarian endodermal sinus tumor generally originates in the vagina or cervix of young girls. Some 50 cases are known, all younger than 3 years of age. Many were treated with outdated regimens, and there are 5-year survival data on only nine of them. We describe a curative outcome of primary radiation only. CASE: A 40-year-old woman had a history of localized endodermal sinus tumor of the vagina, stage I, treated by brachytherapy at the age of 6 months. Radiation had a severe impact upon the later functioning of her pelvic organs, with marked deformity of the pelvic floor, vagina, urethra, and bones of the pelvic outlet. She conceived by homologous insemination at the age of 34. Delivery was by cesarean at 31.5 weeks' gestation. CONCLUSION: Current forms of management give preference to limited excisional surgery and multi-agent chemotherapy, analogous to that used for the treatment of endodermal sinus tumor of the ovary. This is the first report of a patient treated by radium needles and the only known patient who had a subsequent pregnancy.

A cytogenetic study of Wilms' tumor.

Cytogenetic studies were attempted on a sample of 33 Wilms' tumors using short- and long-term tissue culture techniques; most were studied after 2-13 wk in vitro. Abnormal karyotypes were found in 11 tumors, 10 of which had been treated previously with radiotherapy and/or chemotherapy. Insufficient growth of 17 tumors prevented cytogenetic analysis, and in 5 only normal karyotypes were found. Of the 11 tumors with abnormalities, 9 had modes within the diploid range, 1 was hypertriploid, and 1 showed hypodiploid variation. Except for chromosome #5, all chromosomes were involved in structural and numeric changes. Three tumors showed variation in the short arm of chromosome #11, and abnormalities of chromosomes #1, #3, #7, #9, #10, and #14 occurred in more than one tumor. A predisposition to Wilms' tumor is associated with a constitutional deletion of 11p13. From the present study, it is apparent that a similar cytogenetic change may play a primary role in the development of Wilms' tumor in normal individuals.

Carcinoma of the uterine cervix stage I and IIA: results of surgical treatment: complications, recurrence and survival.

Between 1967 and 1981, 213 patients with carcinoma of the uterine cervix Stage I and IIA underwent an abdominovaginal radical hysterectomy with transperitoneal lymphadenectomy. In 1987 the overall 5-year survival rate was 87.5% and the 10-year survival 85%. Recurrences were seen in 29 patients (13.7%). Lymph node metastases occurred in 39 patients (18%). Five-year survival decreased from 94% without positive nodes to 65% with positive nodes. The median blood loss was 2100 cc. Fistulas were seen in 6.7% of the patients. Long-term voiding problems were encountered in 40.8%. In 25% of the women intercourse was impeded postoperatively because of shortening of the vagina. The results obtained with this type of radical surgery in cervical cancer Stages I-IIA are good and do not differ from other methods reported in the literature. However this also means that this more difficult and time-consuming approach does not improve survival rates. For this reason there are no reasons to change from the Wertheim operation to this combined approach.

Correlation of aromatase activity and steroid receptors in human ovarian carcinoma.

Androgen receptors (AR) predominated (98%) in the cytosols of human ovarian carcinomas (n = 40), compared to estrogen (ER)-45%, and progestin (PgR)-53% receptors. The average age of the patients was 58 years. Serum levels of estradiol-17 beta (E2), testosterone (T), follicle stimulating hormone (FSH) and luteinizing hormone (LH) were within the normal range. One third of the cases showed a measurable aromatase activity, while in the majority of the cases this activity was undetectable. The distribution of PgR in the 40 tumors studied appeared to correlate with aromatase activity. The distribution of ER and AR did not differ significantly in aromatase positive and aromatase negative tumors. Interestingly the majority of aromatase positive cases were the endometrioid type of carcinomas. Patients with this type of ovarian carcinoma may probably benefit from anti-estrogen, progestin or aromatase inhibitor treatment. All tumors which were negative for aromatase activity contained AR. In these aromatase negative tumors androgens may not be further metabolized into estrogens and the tumor cells may be influenced by the androgens through the AR present in them. Anti androgen treatment could possibly benefit the patients with such tumors.

Multiple parameter analyses of human ovarian cancer: morphology, immunohistochemistry, steroid hormone receptors and aromatase.

All human ovarian tumors (n = 32) analysed were positive for cytokeratin except for a single case. OV-TL 3 stained 96% (26/27) and 1 out of 4 controls, while OC-125 stained 86% (24/27) and 3 out of 4 non-ovarian carcinomas. Androgen receptors predominated (AR-96%) compared to estrogen (ER-32%) or progestin (PgR-50%) receptors in the ovarian carcinomas. Aromatase activity was detected in 6 ovarian carcinomas and in 3 non-ovarian carcinomas. No definite relationship was observed between the parameters measured. Ovarian carcinomas stained brightly with OV-TL 3 and OC-125 had high AR levels, while focal or absent reaction was related to low AR levels. A role for androgens in ovarian cancer is suggested.

High uridine phosphorylase activity in human melanoma tumor.

Uridine (Urd) phosphorylase and Urd kinase activities were examined in 4 human tumor types including melanoma and human and mouse melanoma cell lines. Urd phosphorylase activity in melanoma tumor specimens was higher than in specimens of colon, ovarian, and breast tumors. Urd kinase activity levels were similar in the 4 tumor types. In 3 human melanoma cell lines examined, Urd phosphorylase activity was markedly greater than in mouse B16 melanoma cells, while Urd kinase activity did not differ appreciably in the human and mouse cell lines. Urd phosphorylase activity in crude extract preparations from different melanoma cell lines showed similar substrate affinity and sensitivity to 1-(2'-deoxy-beta-D-glucopyranosyl)-thymine, a specific inhibitor. The high Urd phosphorylase activity found in melanoma tumor tissue may be exploited in the treatment of malignant melanoma with antipyrimidine agents. Cultured human melanoma cells retain this biochemical characteristic and may serve as appropriate in vitro models for the human tumor in studies concerning pyrimidine metabolism.

Is partial nephrectomy appropriate treatment for unilateral Wilms' tumor?

PURPOSE: After nephrectomy for unilateral Wilms' tumor (WT), two potential hazards threaten the remaining kidney. The development of a metachronous WT (2% to 3%), and decrease in renal function after chemotherapy. Our study aims included: (1) to clarify how many WT patients could benefit from partial nephrectomy (PN) without jeopardizing the high cure rate, (2) to establish the function of the kidney remnant, and (3) to test the radiological criteria for preoperative selection of PN candidates. METHODS: A retrospective analysis of 90 consecutive cases of histologically verified WT (1982 to 1992) was carried out. Data were studied independently by the surgeon, the radiologist, and the pathologist. The preoperative selection criteria for PN were functioning kidney, tumor confined to upper or lower pole leaving two thirds of the kidney tumor free, and no hilar or vascular structures involved. After PN, renal function was estimated by a calculated creatinine clearance (CC) combined with the assessment of the relative function of each kidney by renal scintigraphy. RESULTS: There were 46 boys and 44 girls with median age at diagnosis of 3 years 6 months (range, 3 months to 16 years 7 months). Stage I disease occurred in 40 patients, stage II in 23, stage III in 16, and stage IV occurred in 11 patients. Nearly all patients received preoperative chemotherapy. Radiological analysis of 85 available data sets (5 missing) suggested that PN was possible in 13 patients, and data were inconclusive in two. All 13 patients selected by the radiologist appeared to be in agreement with the pathological criteria for resectability. Of these cases, complete resection by PN was performed in five, could have been possible in retrospect in two, and appeared impossible in six. In two more patients, PN was performed; in both cases the radiologist had predicted PN to be impossible. Median follow-up after PN was 61 months, range, 45 to 167 months. Two patients died of distant metastasis, and no local recurrence occurred. Five are in remission with a median CC level of 110 mL/min, range, 85 to 124. Relative functions of the kidney remnants were 20% to 50%. Contralateral nephrectomy for progressive obstruction was performed in one, but CC level remained normal (85 mL/min). Comparing the preoperative radiological prediction with the combined surgical and pathological findings in a 2 x 2 frequency table, the sensitivity of the radiological findings could be calculated to be 80%, the specificity 97%, and the accuracy 87%. CONCLUSIONS: (1) Partial nephrectomy is safe in approximately 10% of Wilms' tumor patients. (2) The function of the kidney remnant remains well, and even permits contralateral nephrectomy. (3) Preoperative imaging shows an accuracy of 87% to predict the possibility for partial nephrectomy.

The clinical relevance of classification of squamous cell hyperplasia of the larynx by morphometry.

By means of morphometry, differentiation between the classes of laryngeal squamous cell hyperplasia can easily be performed, mutually (Kleinsasser's classification) and in comparison with normal epithelium. It is rather difficult, however, to distinguish between class II (hyperplasia and atypia) and class III (carcinoma in situ). In the group of class II lesions, two groups of patients could be differentiated: a prognostically favourable and an unfavourable group. When using a linear discriminant analysis, the two groups mentioned could be distinguished morphometrically. In histopathological examination, lesions classified as hyperplasia and atypia (class II), must also be examined with morphometry, because in this way the group at risk can be traced.

The prognostic significance of morphometry for squamous cell hyperplasia of the laryngeal epithelium.

Laryngeal biopsies of squamous cell hyperplasia with atypia were graded by means of morphometry, using five non-correlated nuclear parameters preselected with linear discriminant analysis, and were tested for their prognostic significance, in a follow-up study. Fifty-two biopsy specimens were obtained from 18 patients who were merely followed and if necessary underwent a repeated biopsy examination. The lesions of 10 patients progressed to invasive carcinoma. In 8 patients the second or further biopsies were again classified as squamous cell hyperplasia with atypia. For both groups the mean follow-up period was 7.2 years (range: 3 1/2-11). In the progressive group 73% of the biopsies were morphometrically classified as prognostically unfavourable, whereas the clinical outcome on the basis of the last biopsy was correctly predicted for 6 out of the 10 cases (mean probability: 94%), the other 4 cases were 'mis-classified', although for 3 cases with a low probability (mean: 60%). For a valuable morphometrical classification of lesions of individual patients, the results as presented are still insufficient. Morphometrical classification probabilities may be improved when the numbers of untreated patients with squamous cell hyperplasia with atypia do increase.