The causes of cancer in France.

BACKGROUND: While external factors are responsible for many human cancers, precise estimates of the contribution of known carcinogens to the cancer burden in a given population have been scarce. METHODS: We estimated the proportion of cancer deaths which occurred in France in 2000 attributable to known risk factors, based on data on frequency of exposure around 1985. RESULTS: In 2000, tobacco smoking was responsible for 23.9% of cancer deaths (33.4% in men and 9.6% in women), alcohol drinking for 6.9% (9.4% in men and 3.0% in women) and chronic infections for 3.7%. Occupation is responsible for 3.7% of cancer deaths in men; lack of physical activity, overweight/obesity and use of exogenous hormones are responsible for 2%-3% of cancer deaths in women. Other risk factors, including pollutants, are responsible for <1% of cancer deaths. Thus, known risk factors explain 35.0% of cancer deaths, and 15.0% among never smokers. CONCLUSIONS: While cancer mortality is decreasing in France, known risk factors of cancer explain only a minority of cancers, with a predominant role of tobacco smoking.

Detection of activated ras oncogenes in human thyroid carcinomas.

Focus formation following DNA transfection of mouse 3T3-Vill cells was used to search for the presence of activated oncogenes in human thyroid tumors. Oncogenes belonging to the ras family were detected in four out of six thyroid carcinomas (Ki-ras in one anaplastic tumor and one follicular moderately differentiated tumor and Ha-ras and N-ras in two papillary tumors). Normal thyroid tissue samples obtained from two patients, one with an anaplastic tumor and one with a benign adenoma, and samples from 4 benign adenomas and from one toxic goiter of a patient with Graves' disease gave negative results. In one case, restriction enzyme analysis demonstrated the presence of a mutation in codon 12 of the activated Ha-ras oncogene. Our data show that all three ras proto-oncogenes can become activated in malignant thyroid tumors.

Presence of mutations in all three ras genes in human thyroid tumors.

Polymerase chain reaction (PCR) amplification followed by oligonucleotide probing was used to investigate the presence of ras genes mutations in human thyroid adenomas and carcinomas. The results confirm the frequent occurrence of mutations in all three ras genes in both adenomas and carcinomas, in agreement with the hypothesis that the ras mutations may constitute early steps in thyroid tumorigenesis. No evident correlation between the frequency of ras mutations, the identity of the mutated ras gene, the position affected in the ras gene or the type of mutation and the pathological features is apparent. However, definitive conclusion on this point is precluded because of the small number of tumors examined at the present time.

Evolution of erythrocyte sedimentation rate as predictor of early relapse in posttherapy early-stage Hodgkin's disease.

A retrospective study was undertaken at the Institut Gustave Roussy (IGR) to determine the predictive ability of changes in the erythrocyte sedimentation rate (ESR) during posttherapy periods for early relapse (within 18 months from start of therapy) and long-term survival in Hodgkin's disease (HD). Three hundred one patients with clinical stages (CS) I or II HD entered in the European Organization for Research and Treatment of Cancer (EORTC) clinical trials were included in this study. All relevant data and long-term follow-up were available for these patients. A stepwise logistic regression was performed to assess the prognostic value of ESR changes independent of other prognostic parameters and treatment. The incidence of early relapse was found to be significantly increased in patients in whom ESR remained elevated (greater than 30 mm at one hour) after completion of therapy, regardless of the value before therapy. This was true whether the ESR was elevated in plateau fashion, oscillating between normal and abnormal, or was lower than at onset, but still abnormal. Moreover, early relapse predicted by elevated ESR posttherapy was associated with poor survival despite subsequent initiation of combination chemotherapy. Thus, the persistence of an abnormal ESR appears to be a reliable indicator for high probability of early relapse and subsequent poor prognosis. This might be introduced as a prognostic variable in the design of future therapy programs for HD.

Prognostic significance of erythrocyte sedimentation rate in clinical stages I-II of Hodgkin's disease.

A prospective study was undertaken in 1963 on the respective prognostic significances of erythrocyte sedimentation rate (ESR) and presence or absence of systemic symptoms in Hodgkin's disease. Six hundred seventy-six patients with clinical stages I or II were included in this study; 376 from 1963 to 1971 who were included in the H1 trial of the European Organization for Research and Treatment of Cancer (EORTC) and 300 who had been enrolled in the EORTC H2 trial from 1972 to 1976. All relevant data and long-term follow-up are available from 649 patients who were analyzed in this study. Multivariate analysis (Cox model) was carried out to assess the prognostic value of ESR independently of the other prognostic parameters and of the treatment. The results showed that of all the prognostic indicators studied, ESR is the one which has the highest correlation with relapse-free survival; however, initial ESR is not correlated with the probability of death after relapse. The presence or absence of systemic symptoms has less prognostic impact. Despite a close correlation between systemic symptoms and ESR, the two are not redundant and it is useful to combine both.

Report of a committee convened to discuss the evaluation and staging of patients with Hodgkin's disease: Cotswolds meeting.

The Ann Arbor classification for describing the stage of Hodgkin's disease at initial presentation has formed the basis upon which treatment is selected and has allowed comparison of results achieved by different investigators for almost two decades. A meeting was convened to review the classification and modify it in the light of experience gained in its use and new techniques for evaluating disease. It was concluded that the structure of the classification be maintained. It was particularly recommended: (1) that computed tomography (CT) be included as a technique for evaluating intrathoracic and infradiaphragmatic lymph nodes; (2) that the criteria for clinical involvement of the spleen and liver be modified to include evidence of focal defects with two imaging techniques and that abnormalities of liver function be ignored; (3) that the suffix 'X' to designate bulky disease (greater than 10 cm maximum dimension) be introduced; and (4) that a new category of response to therapy, unconfirmed/uncertain complete remission (CR[u]), be introduced to accommodate the difficulty of persistent radiological abnormalities of uncertain significance.

Evolution of thyroid 127I stores measured by X-ray fluorescence in subacute thyroiditis.

Evaluation of the thyroid iodine content by x-ray fluorescence was performed in 13 patients throughout the course of subacute thyroiditis. In the initial hyperthyroid phase of the disease, the iodine stores of the thyroid were not completely depleted. The iodine content (6.5 +/- 3 mg) was about 2.5 times lower than normal values when thyroiditis had developed in a normal thyroid (10 patients); in 3 patients with goiter, it was elevated (29.6 +/- 6.7 mg) but was still within the normal range of euthyroid goitrous patients. After clinical remission, the iodine content of the gland increased only in two patients (+105% and +43% over the initial value, respectively). For the other patients, the iodine content decreased (from -5% to -100% of the initial value). Restoration of iodine stores occurred subsequently and appeared to be a slow and progressive phenomenon; in six patient, the iodine content was still below normal values 12 months after clinical remission (6.6 +/- 1.6 mg). These data suggest that the course of subacute thyroiditis might be longer than would appear from the clinical data, the hormonal assays, or the radioactive thyroid uptake data.

Human thyroid cancer: membrane thyrotropin binding and adenylate cyclase activity.

To characterize the relationship of the TSH receptor-adenylate cyclase system to differentiation in human thyroid cancers, adenylate cyclase and TSH binding were studied in membranes from primary and metastatis thyroid carcinomas of varying histological types (n = 33) and normal thyroids (n = 12). Membranes from differentiated carcinomas (n = 23) exhibit wide patient to patient variability; some membranes show entirely normal adenylate cyclase and TSH-binding characteristics, and other membranes exhibit decreased TSH stimulation of adenylate cyclase which is accompanied by either a normal or decrease TSH-binding site concentration. With respect to the TSH-binding site concentration and TSH stimulation of the adenylat cyclase, the well differentiated carcinomas are not significantly different from normal thyroids, whereas the moderately differentiated and the papillary carcinomas are significantly different (P < 0.001 and P < 0.001, respectively). Membranes from undifferentiated carcinomas (n = 5) and those from medullary carcinomas (n = 5) are characterized by an absence of both TSH binding and TSH stimulation of the adenylate cyclase. In conclusion, while a general relationship exists between the impairment of TSH responsiveness and the dedifferentiation process, no pattern of membrane alteration is specific for any histological type.

Short and long term effects of radioiodine treatment on the iodine content of the thyroid gland.

Thyroid iodine content (TIC) was measured in nine patients with hyperthyroid Graves' disease for 5-26 months after treatment with 131I (100-125 muCi/g tissue). In all patients, TIC decreased; in eight patients it became undetectable within 5 +/- 3 (SD) months. This fall was parallel to those of serum T3 and T4 levels and was not prevented by the administration of large doses of stable iodine. In four patients, this decrease was irreversible and they became clinically hypothyroid. In the five other patients, it was partly reversible: the secondary increase of TIC was parallel to those of serum T3 and T4 and to a decrease in TSH levels. These data suggest that during the months after 131I treatment, determination of TIC may help to distinguish transient from irreversible hypothyroidism. The late effects of 131I were studied in 38 patients who had been treated for hyperthyroid Graves' disease from 1.5-22 yr previously. The 16 patients who, at the time of examination, were euthyroid with normal serum TSH levels (less than 8 microU/ml) had a TIC [3.2 +/- 3 (SD) mg] significantly lower than that of 10 euthyroid patients previously treated only with antithyroid drug therapy (16.7 +/- 8.2 mg). A significant negative correlation was found between log basal TSH and log TIC (r = 0.61, P less than 0.001) and a positive correlation between log T4 and log TIC (r = 0.56, P less than 0.002). The T3/T4 ratio in patients with undetectable TIC (19.9 +/- 7.9) was higher than that of the other patients (14.6 +/- 3.2) (P = 0.02, Wilcoxon test). This hormonal profile was not modified by iodide supplementation, which increased TIC only transiently. The turnover of thyroid iodine was accelerated, which appeared to be the consequence of a small thyroid functional mass and of hyperstimulation by TSH.

Differentiated thyroid carcinoma in childhood: long term follow-up of 72 patients.

Seventy-two children with differentiated thyroid cancer who were 16 years old or younger at the time of initial treatment were followed for a median time of 13 yr. Initially, 18% had lung metastases, and 74% had palpable lymph nodes. Capsular invasion was found in 67%, and histological lymph node involvement in 90%. The recurrent laryngeal nerve chain and the jugulo-carotid chain were involved with the same frequency (greater than 80%). The anterior superior mediastinum was involved only in patients with involvement of the recurrent laryngeal nerve chain. Forty-three patients had a complete remission after initial treatment. In patients without distant metastases for whom surgery was macroscopically incomplete, relapses occurred 5 times more frequently than in patients whose surgery was complete. Six patients died from thyroid carcinoma at ages ranging from 19-44 yr, 12-33 yr after initial treatment, and 1 died from intercurrent disease. Despite favorable long term survival (90.3% at 20 yr), the standardized mortality ratio was equal to 8.1. This study underlines the need for complete surgical treatment and compulsive follow-up, which should be continued throughout the patient's life, in order to detect and effectively treat relapses of thyroid cancer.

Relationship between thyrotropin stimulation and radioiodine uptake in lung metastases of differentiated thyroid carcinoma.

To examine whether the injection of bovine TSH (bTSH) produces maximal radioactive iodine uptake (RAIU) in lung metastases in patients with differentiated thyroid cancer, 10 patients were studied 12 times. In 10 of these studies, an initial RAIU measurement was performed immediately after 3 injections of 10 IU bTSH given immediately after T3 withdrawal. Another RAIU measurement was performed 7-19 days after T3 withdrawal. Uptake increased in all patients even when it was clearly detectable immediately after bTSH stimulation. Thus, 3 days of bTSH stimulation in these patients did not lead to maximal 131I uptake, and it could only be reached after prolonged endogenous TSH stimulation. bTSH was not injected in the 2 other patients, in whom 6 RAIU measurements were carried out. Radioiodine uptake increased with time in both patients. It appears that both the level of endogenous TSH and the length of stimulation play a determining role in RAIU. This might explain why 3 days of bTSH stimulation are insufficient to elicit maximal 131I uptake.

Long-term results of treatment of 283 patients with lung and bone metastases from differentiated thyroid carcinoma.

We assessed the results of treatment in 283 patients with lung or bone metastases from differentiated thyroid carcinoma who were followed for up to 40 yr (median, 44 months) after the discovery of the metastases. The survival rates from the time of discovery of the metastases were 53% at 5 yr, 38% at 10 yr, and 30% at 15 yr; 156 patients died. Multivariate analysis revealed that only 4 variables had an independent prognostic significance for survival. They were extensive metastases, older age at discovery of the metastases, absence of radioiodine uptake by the metastases, and moderately differentiated follicular cell type. The site of metastases (lung or bone) was not a prognostic factor for survival after treatment of metastatic disease. Remission was achieved in 79 patients after metastases were found. The only predictive factor for 5-yr disease-free survival after treatment of metastases was the initial extent of disease. Our results suggest that the aim of management should be to detect and treat metastases in patients with thyroid cancer as early as possible.

Organisation of screening.

The 'Europe against Cancer' programme aims to introduce systematic screening for breast cancer for women aged 50-69 and for cervical cancer for women aged 25-69. The programme initiated pilot projects on breast cancer screening in several European countries in 1989-1990. This initiative was followed by training for radiologists. European guidelines for quality assurance in breast cancer screening became available in 1992, and a working party on treatment of small breast lesions was formed. The 'Europe against Cancer' programme also launched pilot projects in cervical cancer screening and a cervical cancer screening surveillance programme in 1992.

European School of Oncology Advisory report to the European Commission for the "Europe Against Cancer Programme" European Code Against Cancer.

A European School of Oncology Advisory Group has reviewed the European Code Against Cancer after its initial use over a 6-year period. With minor modifications, the original ten recommendations were found to be adequate, although it was agreed that an Annex was necessary to explain the scientific evidence supporting each point, and is presented herewith. Tobacco smoking clearly remains the most important cause of cancer, and now it can be quantified better than ever before. It is also clear that it is never too late to stop smoking: stopping even in middle age, prior to the onset of serious illness has a beneficial effect on life expectancy. Alcohol drinking is an important cause of cancer, and yet modest consumption levels protect against cardiovascular disease mortality. The optimal strategy seems to be a consumption not exceeding 2-3 drinks per day, although this limit may be lower for women. Increased consumption of fruits and vegetables, reduction in consumption of fatty foods, reduction of obesity and increased physical activity can all be recommended to reduce cancer risk. Exposure to excessive sunlight remains a problem which should be limited. Control of occupational cancer is a three-way partnership: legislation identifies and limits exposure to known carcinogens, employers enact the legislation and workers should respect the measures introduced. There are a number of signs and symptoms which may lead to cancer being diagnosed earlier, and patients with these should be referred to a doctor. For women, participation in organised programmes of cervical cancer and breast cancer (after 50 years of age) should lead to a reduction in mortality from these forms of cancer. The key element is organised programmes, where quality control and quality assurance are in force. These revised recommendations are the result of an agreement following advice, review and dialogue with cancer experts throughout Europe. They were approved by the European Community Cancer Experts at their meeting in Bonn on 28-29 November 1994. Their implementation by the European population should greatly reduce cancer incidence and mortality.

L.H. Gray Medal lecture: cell kinetics and radiation oncology.

Development of the study of human tumor cell kinetics during the past decades has deepened our understanding of the natural history of human cancers. Mathematical models based on the data which have been accumulated may help to evaluate, for the various types of human tumors, the time during their growth that the dissemination process occurred and to calculate the size distribution of the subclinical metastases at the time of treatment of the primary tumor. The perturbations caused by radiotherapy and chemotherapy are complex and include reassortment of surviving cells and repopulation. Currently it appears difficult in clinical practice to take advantage of cell reassortment while the differences in the rate and in the duration of repopulation between normal and neoplastic tissues are exploited in most therapeutic regimens. A better knowledge of cell and tissue kinetics following treatment may help to optimize the treatment scheduling in particular during combined administration of radiotherapy and chemotherapy. The study of the kinetics of proliferation in normal tissue has shown the existence of several types of inhibitory and stimulatory humoral factors. These, when purified, can be used to manipulate the proliferation of critical normal tissues in order to protect them during the administration of cell cycle specific drug or to accelerate their regeneration after treatment.

The natural history of breast cancer: implications for a screening strategy.

In the data base of the Institut Gustave-Roussy, the clinical courses of over 7000 patients treated since 1951 are registered. For 3000 of them treated prior to the introduction of adjuvant chemotherapy, the follow-up ranges from 15 to 32 years. For all patients, the size of the primary tumor, its histologic grade, and the number of involved axillary nodes at the time of initial treatment were registered prospectively. This series of patients was used to analyze the relationship between the size of the primary tumor and the probability of distant metastatic spread, taking into account other prognostic variables. A simulation model of the natural history of breast cancer was built which satisfactorily fits the available data on breast cancer screening. The aim of this paper is to use this model to assess the influence of: a) the time interval between mammographies and b) the diagnostic ability of the screening program, on the proportion of patients with distant metastases. The results show that the proportion of patients with distant metastases at the time of diagnosis increases gradually from approximately 25% for an interval of 1 year to 40% for an interval of 5 years. Moreover, the proportion of patients with metastases is critically influenced by the size of the tumors which can be detected; for example, for a 2-year interval the proportion of patients with metastases increases from 32% for tumors screened of 1 cm in diameter to 40% for tumors of 1.7 cm in diameter.

The link between local recurrence and distant metastases in human breast cancer.

PURPOSE: To distinguish between two possible explanations for the increased incidence of distant metastases observed in patients with locoregional recurrences (LR). Either LR is the signature of tumor aggressiveness, and avoiding recurrences (i.e., by radiotherapy) is of little value. The alternative is that LR is a nidus for metastatic dissemination. METHODS AND MATERIALS: Four thousand patients consecutively treated in the same institution from 1954 to 1975 were studied. None of them had received adjuvant chemotherapy. Tumor characteristics, local recurrence, and distant metastases had been prospectively registered. Duration of metastatic growth and probability of metastatic dissemination were estimated in the subsets of patients. RESULTS: The proportion of metastasis-free patients was reduced by about 80% in all subsets of patients with LR. In patients without LR, the monthly rate of distant metastases incidence decreases continuously with time after initial treatment. Conversely, in patients with local recurrence, this rate increases during the first year at initial treatment and the metastases in excess appear slightly later than in patients without local recurrence. Using a mathematical model, it can be shown that, in patients with local recurrence, nearly all of the metastases in excess had been initiated after initial treatment. The data also suggest that each year a small proportion of grade 1 residual tumors progresses toward a more malignant histologic type. CONCLUSIONS: Our results are not consistent with the hypothesis that a greater tumor aggressiveness in patients with LR could explain the excess of metastases. This conclusion is supported by the analysis of the delays between metastases' emergence, and death, which shows that tumors with or without LR have similar biological characteristics.

Human cancer natural history, radiation induced immunodepression and post-operative radiation therapy.

For several types of cancers, post-operative radiation therapy is able to reduce the incidence of local recurrences, but has only a relatively small beneficial effect on total survival. Conversely to what has been claimed, this discrepancy is not due to a detrimental effect of radiotherapy. The data do not substantiate the hypothesis that irradiation through an impact on the immune system enhances growth of neoplastic foci outside of the irradiated volume. Several sets of data show that uncontrolled primary tumors or lymph node metastases can be important foci for distant spread. However the analysis of the data shows that post-operative radiotherapy can prevent metastatic spread only in a small subset of patients, those without distant metastases at the initial treatment and in whom local recurrences can be a nidus for distant dissemination before being detected and treated. The results of the clinical trials carried out on patients with breast cancers show that this situation is frequently observed in patients with tumors located in the inner quadrants of the breast who are those in whom the involvement of the internal mammary chain is relatively frequent.

Late effects on human bone marrow after extended field radiotherapy.

Thirty-two patients with lymphoma were treated with extended radiotherapy (RT) at a dose of Gy and were studied by ferrokinetic studies and surface counting at various times following irradiation. Loss of hematopoietic activity in the irradiated areas is compensated by increased activity in the non-irradiated areas. Despite the return of peripheral blood counts to normal, the hyperactivity of the non-irradiated bone marrow persists over up to 13 years after RT, while the hematopoietic activity of the irradiated areas remains depressed and is only slightly higher than immediately after RT. The hypoactivity persisted even when the hemopoietic tissues had been subjected to the intense stimulation provoked by an aplasia caused by chemotherapy. However, a recovery was observed for dose of 20 Gy or lower. The hemopoietic activity of the irradiated bone marrow appears to be related to the volume of the marrow irradiated and is higher after a mantle + inverted Y field than after a mantle field. Both marrow scintigraphies with 59Fe in 7 out of 9 patients studied revealed an extension of hematopoiesis into a normally dormant area of the marrow, such as the femora. In 2 patients an erythropoietic activity was observed in spleens which had received a dose of 40 Gy, and extra medullary erythropoiesis was found in approximately two-thirds of the patients.

The value of adjunctive radiotherapy when chemotherapy is the major curative method.

Chemotherapy is the main treatment in many human malignancies including non-Hodgkin lymphomas and some solid tumors such as those of embryonal origin and small cell lung carcinomas. The high responsiveness to chemotherapy of these tumors has led some groups to treatment policies limited to chemotherapy alone. A long follow-up has shown a high incidence of recurrence in the sites that were initially macroscopically involved. Some randomized trials evaluating the adjunction of radiotherapy to chemotherapy have shown that a failure in local control can be associated with a decreased overall survival. The survival benefit of combined chemotherapy and radiotherapy is generally moderate and is best evaluated by randomized trials entering a large number of patients. The adjunction of radiotherapy to chemotherapy can lead to an increased rate of acute and late toxicity that may overshadow a therapeutic benefit. Critical points of the combined approach are: types of drugs, radiotherapy parameters, radiotherapy-chemotherapy doses, and timing. In this review, two clinical models, one with a low potential of cure, limited small cell lung cancer, and one with a medium potential of cure, non-Hodgkin lymphoma, are reviewed emphasizing information obtained from randomized trials. The modalities of combining radiotherapy and chemotherapy, particularly the timing, are analyzed to define optimal schedules for a definite therapeutic gain.