Right colon cancer: Left behind.

INTRODUCTION: Prognosis of colon cancer (CC) has steadily improved during the past three decades. This trend, however, may vary according to proximal (right) or distal (left) tumor location. We studied if improvement in survival was greater for left than for right CC. METHODS: We included all CC recorded at the Geneva population-based registry between 1980 and 2006. We compared patients, tumor and treatment characteristics between left and right CC by logistic regression and compared CC specific survival by Cox models taking into account putative confounders. We also compared changes in survival between CC location in early and late years of observation. RESULTS: Among the 3396 CC patients, 1334 (39%) had right-sided and 2062 (61%) left-sided tumors. In the early 1980s, 5-year specific survival was identical for right and left CCs (49% vs. 48%). During the study period, a dramatic improvement in survival was observed for patients with left-sided cancers (Hazard ratio [HR]: 0.42, 95% confidence interval [CI]: 0.29-0.62, p < 0.001) but not for right CC patients (HR: 0.76, 95% CI: 0.50-1.14, p = 0.69). As a consequence, patients with distal CC have a better outcome than patients with proximal CC (HR for left vs. right CC: 0.81, 95% CI: 0.72-0.90, p < 0.001). CONCLUSION: Our data indicate that, contrary to left CC, survival of patients with right CC did not improve since 1980. Of all colon cancer patients, those with right-sided lesions have by far the worse prognosis. Change of strategic management in this subgroup is warranted.

Stage IVB endometrial cancer: clinical course and survival of patients with single and multiple metastases.

OBJECTIVE: Metastatic endometrial cancer (EC) at initial presentation is a rare disease. The present aim was to evaluate prognostic factors and overall survival in patients diagnosed with metastatic EC. STUDY DESIGN: Using data from the Geneva Cancer Registry, the authors included all patients diagnosed with Stage IVB EC from 1980-2007. Estimates of survival were calculated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: A total of 38 patients were identified. The most frequent metastases were peritoneal or pleural carcinomatosis (66%, n=25) and hematogenous metastases (53%, n=20). Five-year survival rate was 5.7% (95% confidence interval: 0.0-13.3), and median survival was 7.6 months. Survival of patients with a single metastasis at the time of diagnosis was longer than for patients with multiple metastases (16 versus two months, respectively; p < 0.00 1). CONCLUSION: Metastatic EC is rare disease with very poor prognosis particularly for patients with multiple site metastases.

Breast lesions in reduction mammaplasty specimens: a histopathological pattern in 534 patients.

BACKGROUND: The prevalence of breast lesions (benign, precancerous and cancer lesions) in reduction mammaplasty (RM) specimens has rarely been reported in Europe and never in the Swiss population. METHODS: Personal and histopathological data from 534 female patients who underwent RM were reviewed. RESULTS: Benign and/or malignant lesions were detected in 76.2% of all patients. Benign breast lesions associated with an increased risk of developing breast cancer represented 2.8% of all lesions. Breast cancer in situ was identified in 5 (0.9%) patients. Patient age and previous history of breast cancer were risk factors for incidental breast cancer. CONCLUSION: The rate of incidental carcinoma in situ was higher for patients with breast cancer history. Probably due to preoperative breast cancer investigation, no occult invasive breast cancer was found in reduction mammary specimens. Therefore before RM, breast cancer evaluation should be considered for all patients, especially for those with breast cancer risk factors (e.g., patient age, personal history of breast cancer).

How many ovarian cancer patients are eligible for fertility-sparing surgery?

OBJECTIVE: To assess how many epithelial ovarian cancer (EOC) patients are eligible for fertility-sparing surgery (FSS) in a population-based study. STUDY DESIGN: Using data from the Geneva Cancer Registry, we conducted a retrospective review of all women diagnosed with epithelial ovarian cancer (EOC) between January 1979 and December 2008. Patients were classified into two age groups ("young group"≤45 years and "old group">45 years) and as "eligible for FSS" (FIGO IA, G1-G2 or unilateral ICG1) and "non-eligible for FSS" (FIGO IA, G3; IC G2-G3; IB or II-IV). Patients and tumor characteristics were tested with the chi-square test. Estimates of survival were calculated using the Kaplan-Meyer method and differences between groups were analyzed by the log-rank test. RESULTS: A total of 888 EOC patients were analyzed. The young group included 87 patients (9.8%): eleven (1.2%) were identified as eligible for FSS and 6 (0.6%) were nulliparous. The annual incidence of EOC women eligible for FSS in Geneva was 0.48/100,000 (0.5 women/year) and the expected annual incidence rate for Switzerland (8 million inhabitants) is 6.5 women/year. CONCLUSION: Only a very small proportion of EOC patients are eligible for FSS. These results highlight the need to centralize FSS data in dedicated European units, in order to maintain expertise and quality of care for these patients.

Omission of excisional therapy is associated with an increased risk of invasive cervical cancer after cervical intraepithelial neoplasia III.

BACKGROUND: Using data from the population-based Geneva Cancer Registry we evaluated the risk of invasive cervical cancer following carcinoma in situ (CIS) or cervical intraepithelial neoplasia (CIN) III according to type of treatment. METHODS: Included in the study were all women diagnosed with CIS/CIN III in Geneva (Switzerland) between 1970 to 2002 (n=2658) and followed for invasive cervical cancer occurrence until 31st December 2008. We calculated age and period standardised incidence ratios (SIR) and multiadjusted hazard ratios (HR) of invasive cervical cancer by treatment groups. RESULTS: During follow-up, 17 women developed invasive cervical cancer, conferring a SIR of 5.1 (95% confidence intervals [CI] 3.0-8.1). The risk of cervical cancer was significantly increased until 10 years after diagnosis. The risk was highest for women ≥ 50 years (SIR=7.3, 95% CI: 2.7-15.8) and for women who did not undergo excisional treatment (SIR=25, 95% CI: 12.0-46.0). The multiadjusted HR of invasive cervical cancer for women who did not undergo surgical excisional treatment was 9.4 (95% CI: 2.8-32.2) compared with women who did. CONCLUSION: Women diagnosed with CIS/CIN III are at increased risk of developing invasive cervical cancer. This risk is particularly high for women who did not have excision of cervical lesions.

Tumor incidence in related hematopoietic stem cell donors.

Late malignancies have been discussed as a potential risk for growth factor mobilized donors of hematopoietic stem cells. Little is known about the incidence and potential risk factors. This single center retrospective cohort study evaluated all HLA-identical sibling pairs with hematopoietic stem cell transplantation (HSCT) for a hematological malignancy, treated from 1974 to 2001 at the University Hospital of Basel. Three hundred eighteen pairs were identified, 291 donors (92%) could be contacted. Median observation time was 13.8 years (range 5-32 years). Sixteen (5%) donors had developed a total of 18 tumors, 17 recipients a secondary tumor. According to the age- and sex-adapted cancer incidence, 3.3 tumors in male and 6.8 in female donors were expected, 3 (relative risk (RR): 0.91, 95% confidence interval: 0.19-2.66) and 4 (RR: 0.58, 95% confidence interval: 0.16-1.48), respectively, were found in donors between 0 and 49 years. Between 50 and 69 years, 4.5 tumors in males and 4.8 in females were expected, 5 (RR: 1.11, 95% confidence interval: 0.36-2.59) and 6 (RR: 1.23, 95% confidence interval: 0.45-2.67), respectively, were observed. Tumors do occur in donors of hematopoietic stem cells at least at the rate as expected in a normal population; whether incidence exceeds expected rates needs to be determined in larger international cohorts.

Excess of cardiovascular mortality among node-negative breast cancer patients irradiated for inner-quadrant tumors.

BACKGROUND: Radiotherapy of the left breast is associated with higher cardiovascular mortality linked to cardiotoxic effect of irradiation. Radiotherapy of inner quadrants can be associated with greater heart irradiation, but no study has evaluated the effect of inner-quadrant irradiation on cardiovascular mortality. PATIENTS AND METHODS: We identified 1245 women, the majority with breast-conserving surgery, irradiated for primary node-negative breast cancer from 1980 to 2004 registered at the Geneva Cancer Registry. We compared breast cancer-specific and cardiovascular mortality between inner-quadrant (n = 393) versus outer-quadrant tumors (n = 852) by multivariate Cox regression analysis. RESULTS: After a mean follow-up of 7.7 years, 28 women died of cardiovascular disease and 91 of breast cancer. Patients with inner-quadrant tumors had a more than doubled risk of cardiovascular mortality compared with patients with outer-quadrant tumors (adjusted hazard ratio 2.5; 95% confidence interval 1.1-5.4). Risk was particularly increased in the period with higher boost irradiation. Patients with left-sided breast cancer had no excess of cardiovascular mortality compared with patients with right-sided tumors. CONCLUSIONS: Radiotherapy of inner-quadrant breast cancer is associated with an important increase of cardiovascular mortality, a possible result of higher irradiation of the heart. For patients with inner-quadrant tumors, the heart should be radioprotected.

Outcome of uterine clear cell carcinomas compared to endometrioid carcinomas and poorly-differentiated endometrioid carcinomas.

OBJECTIVES: Our aim was to compare the survival between patients with clear cell carcinoma (CC) and patients with endometrioid carcinoma (EC). METHODS: Through the population-based Geneva Cancer Registry, we identified 1,380 resident women diagnosed with uterine cancer between 1970 and 2000. We excluded those with papillary serous endometrial carcinoma and uterine sarcomas. We categorized patients as CC (n = 32, 2.8%) or EC (n = 1,145, 97.2%). Uterine cancer-specific survival rates were calculated by Kaplan-Meier analysis. We used Cox proportional hazards analysis to compare uterine cancer mortality risks between groups, and adjusted these risks for other prognostic factors. RESULTS: CC patients presented with a more advanced stage at diagnosis than EC patients (p = 0.002). Compared to women with EC, women with CC had a significantly greater risk of dying from their disease (hazard ratio [HR] 2.9, 95% confidence interval (95% CI) 1.7-4.9). After adjustment for age, stage and adjuvant chemotherapy, the risk of dying from uterine cancer was still significantly higher for CC patients (HR 2.0, 95% CI 1.2-3.4). By univariate analysis, the risk of dying of endometrial cancer was not significantly higher in CC patients than in patients with poorly-differentiated EC (HR 1.3, 95% CI 0.7-2.3). CONCLUSION: This population-based investigation shows that patients with CC have a poorer outcome than those with EC. Studies to determine the role of adjuvant treatment in CC patients are needed.

Mortality from diseases other than cancer following low doses of ionizing radiation: results from the 15-Country Study of nuclear industry workers.

BACKGROUND: Ionizing radiation at very high (radio-therapeutic) dose levels can cause diseases other than cancer, particularly heart diseases. There is increasing evidence that doses of the order of a few sievert (Sv) may also increase the risk of non-cancer diseases. It is not known, however, whether such effects also occur following the lower doses and dose rates of public health concern. METHODS: We used data from an international (15-country) nuclear workers cohort study to evaluate whether mortality from diseases other than cancer is related to low doses of external ionizing radiation. Analyses included 275 312 workers with adequate information on socioeconomic status, over 4 million person-years of follow-up and an average cumulative radiation dose of 20.7 mSv; 11 255 workers had died of non-cancer diseases. RESULTS: The excess relative risk (ERR) per Sv was 0.24 [95% CI (confidence intervals) -0.23, 0.78] for mortality from all non-cancer diseases and 0.09 (95% CI -0.43, 0.70) for circulatory diseases. Higher risk estimates were observed for mortality from respiratory and digestive diseases, but confidence intervals included zero. Increased risks were observed among the younger workers (attained age <50 years, identified post hoc) for all groupings of non-cancer causes of death, including external causes. It is unclear therefore whether these findings reflect real effects of radiation, random variation or residual confounding. CONCLUSIONS: The most informative low-dose radiation study to date provides little evidence for a relationship between mortality from non-malignant diseases and radiation dose. However, we cannot rule out risks per unit dose of the same order of magnitude as found in studies at higher doses.

The 15-Country Collaborative Study of Cancer Risk Among Radiation Workers in the Nuclear Industry: design, epidemiological methods and descriptive results.

Radiation protection standards are based mainly on risk estimates from studies of atomic bomb survivors in Japan. The validity of extrapolations from the relatively high-dose acute exposures in this population to the low-dose, protracted or fractionated environmental and occupational exposures of primary public health concern has long been the subject of controversy. A collaborative retrospective cohort study was conducted to provide direct estimates of cancer risk after low-dose protracted exposures. The study included nearly 600,000 workers employed in 154 facilities in 15 countries. This paper describes the design, methods and results of descriptive analyses of the study. The main analyses included 407,391 nuclear industry workers employed for at least 1 year in a participating facility who were monitored individually for external radiation exposure and whose doses resulted predominantly from exposure to higher-energy photon radiation. The total duration of follow-up was 5,192,710 person-years. There were 24,158 deaths from all causes, including 6,734 deaths from cancer. The total collective dose was 7,892 Sv. The overall average cumulative recorded dose was 19.4 mSv. A strong healthy worker effect was observed in most countries. This study provides the largest body of direct evidence to date on the effects of low-dose protracted exposures to external photon radiation.

Treatments patterns of vulvar cancer in the elderly.

OBJECTIVE: To evaluate treatment patterns of vulvar cancer in patients over 80 years. MATERIAL AND METHODS: Between 1979 and 1999, the Geneva Tumor Registry identified 230 women with vulvar cancer. Treatment of patients over 80 years and younger were compared. Kaplan-Meier analysis was used to determine disease specific cumulative survival. RESULTS: Young women are more likely to present in situ lesions compared to their older counterparts. Majority of vulvar cancers were observed in women >or=80 (p<0.001) at more advanced stages. Elderly women have either no treatment, either unconventional or inadequate treatments. The Mantel-Haentzel analysis shows a 23.4 OR (IC (95%) 2.9-186.6) of not being treated if the patient is over 80. Specific 5-years survival was 93% in stage I, compared to 21% in stage IV. CONCLUSION: Patients over 80 years are diagnosed at more advanced stages. Less aggressive treatments decrease outcome.

Positive peritoneal cytology in early-stage endometrial cancer does not influence prognosis.

The aim of this study was to assess the prognostic importance of positive peritoneal cytology in early-stage endometrial cancer. All 278 stage I and 53 stage IIIA (without cervical involvement) endometrial cancer patients operated between 1980 and 1996, recorded at the Geneva Cancer registry, were included. Stage IIIA cancers were recategorised into 'cytological' stage IIIA (positive peritoneal cytology alone, n=33) and 'histological' stage IIIA (serosal or adnexal infiltration, n=20). Survival rates were analysed by Kaplan-Meier method and compared using log-rank test. The prognostic importance of cytology was analysed using a Cox model, accounting for other prognostic factors. The 5-year disease-specific survival of cytological stage IIIA cancer was similar to stage I (91 vs 92%) and better than histological stage IIIA cancer (50%, P<0.001). After adjustment for age, myometrial invasion, differentiation and radiotherapy, cytological stage IIIA patients were still at similar risk to die from endometrial cancer compared to stage I patients (hazard ratio (HR) 0.7, 95% confidence interval (CI): 0.18-2.3), while histological stage IIIA patients were at a four-fold increased risk to die from their disease (HR 4.2, 95% CI: 1.7-10.3). This population-based study shows that positive peritoneal cytology in itself has no impact on survival of patients with localised endometrial cancer. Based on the present and previous studies, FIGO (Fédération Internationale de Gynécologie et d'Obstétrique) might consider reviewing its classification system.

Impact of peritoneal cytology on survival of endometrial cancer patients treated with surgery and radiotherapy.

Stage IIIA endometrial cancer includes patients with serosal or adnexal invasion and patients with positive peritoneal cytology only. In this study, we assessed the impact of peritoneal cytology on endometrial cancer survival. All endometrial cancer patients receiving surgery and radiotherapy at the Geneva University Hospitals between 1980 and 1993 were included. Stage IIIA cancers were categorised into 'cytological' stage IIIA (only positive peritoneal cytology) and 'histological' stage IIIA (serosal or adnexal infiltration). Survival rates were analysed by Kaplan-Meier method and compared using log-rank test. The prognostic importance of peritoneal cytology was analysed by multivariate regression analysis. This study included 170 endometrial cancers (112 stage I, 17 cytological stage IIIA, 18 histological stage IIIA, 9 stage IIIB+). Disease-specific survival of cytological stage IIIA was not different from stage I (94 vs 88% respectively, P=0.5) but better than histological stage IIIA (94 vs 51% respectively, P<0.01). Histological stage IIIA patients were at increased risk to die from cancer compared to stage I patients (HR 2.7, 95% CI 1.0-7.7), while cytological stage IIIA patients were not (HR 0.3, 95% CI 0.3-2.0). Cytological stage IIIA endometrial cancer has similar prognosis as stage l and better prognosis than histological stage IIIA. Additional research, definitively separating stage and cytology is warranted.

Cancer prevalence in Central Europe: the EUROPREVAL Study.

BACKGROUND: Information on cancer prevalence is either absent or largely unavailable for central European countries. MATERIALS AND METHODS: Austria, Germany, The Netherlands, Poland, Slovakia, Slovenia and Switzerland cover a population of 13 million inhabitants. Cancer registries in these countries supplied incidence and survival data for 465 000 cases of cancer. The prevalence of stomach, colon, rectum, lung, breast, cervix uteri, corpus uteri and prostate cancer, as well as skin melanoma, Hodgkin's disease, leukaemia and all malignant neoplasms combined was estimated for the end of 1992. RESULTS: A large heterogeneity was observed within central European countries. For all cancers combined, estimates ranged from 730 per 100 000 in Poland (men) to 3350 per 100 000 in Germany (women). Overall cancer prevalence was the highest in Germany and Switzerland, and the lowest in Poland and Slovenia. In Slovakia, prevalence was higher than average for men and lower than average for women. This was observed for almost all ages. As shown by incidence data, breast cancer was the most frequent malignancy among women in all countries. Among men, prostate cancer was the leading malignancy in Germany, Austria and Switzerland, and lung cancer was the major cancer in Slovenia, Slovakia and Poland. The Netherlands had a high prevalence of both prostate and lung cancer. Time-related magnitude of prevalence within each country and the variability of such proportions across the countries has been estimated and cancer prevalence is given by time since diagnosis (1 year, 1-5 years, 5-10 years, >10 years) for each site. The weight of 1-year prevalence (248 per 100 000 among men and 253 per 100 000 among women) was <15% of total prevalence. Prevalent cases between 1 and 5 years since diagnosis represented between 22% and 34% of the total prevalence. Prevalent cases diagnosed from 5 to 10 years before (335 per 100 000 for men and 505 per 100 000 for women) represented between 17% and 23% of prevalent cancers. Finally, long-term cancer prevalence (diagnosed >10 years before), reflecting long-term survival, and number of people considered as cured from cancer were 490 per 100 000 for men and 1028 per 100 000 for women, with a range between 26% (The Netherlands, men) and 50% (Slovakia, women). CONCLUSION: It is clear from observing countries in Central Europe, that high cancer prevalence is associated with well-developed economies. This burden of cancer could be interpreted as a paradoxical effect of better treatments and thereby survival. It could also be taken as a sign for not being satisfied with the advances in treating patients diagnosed with cancer, and for supporting more primary prevention.

Adjuvant chemotherapy for colon carcinoma with positive lymph nodes: use and benefit in routine health care practice.

In 1990, an international consensus was reached on the efficacy of adjuvant chemotherapy for lymph node positive (stage III) colon carcinoma (CC). This study evaluates the use and benefit of such therapy in routine health care practice. The study includes all patients with stage III CC treated by putative curative surgery (n = 182) recorded at the Geneva cancer registry between 1990 and 1996. Factors modifying chemotherapy use were determined by logistic regression, considering patients with chemotherapy as cases (n = 55) and others as controls (n = 127). The effect of chemotherapy on the 5-year survival was evaluated by the Cox model. Analyses were adjusted for possible confounders. The use of chemotherapy increased over the period (P(trend) < 0.001). Age strongly modulated chemotherapy use. In 1996, 54% of eligible patients received chemotherapy, this proportion fell to 13% after age 70. Decisions to use chemotherapy significantly depended on stage, grade and cancer site. The chance to be treated was non-significantly lower among individuals of low social class, widowed and foreigners. Chemotherapy significantly decreased mortality rates (Hazard ratio: 0.35, 95%CI: 0.18-0.68), independently of the prognostic factors and with similar benefit regardless of stage and age group. Strong beneficial effect of adjuvant chemotherapy on stage III CC can be achieved in routine practice. However, this study shows that it is probably not optimally utilised in Switzerland, particularly among the elderly.

Multicentric study on malignant pleural mesothelioma and non-occupational exposure to asbestos.

Insufficient evidence exists on the risk of pleural mesothelioma from non-occupational exposure to asbestos. A population-based case-control study was carried out in six areas from Italy, Spain and Switzerland. Information was collected for 215 new histologically confirmed cases and 448 controls. A panel of industrial hygienists assessed asbestos exposure separately for occupational, domestic and environmental sources. Classification of domestic and environmental exposure was based on a complete residential history, presence and use of asbestos at home, asbestos industrial activities in the surrounding area, and their distance from the dwelling. In 53 cases and 232 controls without evidence of occupational exposure to asbestos, moderate or high probability of domestic exposure was associated with an increased risk adjusted by age and sex: odds ratio (OR) 4.81, 95% confidence interval (CI) 1.8-13.1. This corresponds to three situations: cleaning asbestos-contaminated clothes, handling asbestos material and presence of asbestos material susceptible to damage. The estimated OR for high probability of environmental exposure (living within 2000 m of asbestos mines, asbestos cement plants, asbestos textiles, shipyards, or brakes factories) was 11.5 (95% CI 3.5-38.2). Living between 2000 and 5000 m from asbestos industries or within 500 m of industries using asbestos could also be associated with an increased risk. A dose-response pattern appeared with intensity of both sources of exposure. It is suggested that low-dose exposure to asbestos at home or in the general environment carries a measurable risk of malignant pleural mesothelioma.

Sex differences in presentation, management, and prognosis of patients with non-small cell lung carcinoma.

OBJECTIVE AND METHODS: To characterize gender differences in lung cancer, we conducted a retrospective analysis including all patients undergoing surgery for non-small cell lung carcinoma in a single institution over a 20-year period. RESULTS: Compared with men (n = 839), women (n = 198) were more likely to be asymptomatic (32% vs 20%, P =.006), nonsmokers (27% vs 2%, P <.001), or light smokers (31 pack-years vs 52 pack-years; P <.001). Squamous cell carcinoma predominated in men (65%), and adenocarcinoma predominated in women (54%). Preoperative bronchoscopy contributed more frequently to a histologic diagnosis in men (69% vs 49% in women, P <.001), and fewer pneumonectomies were performed in women (22% vs 32% in men, P =.01). After multivariate Cox regression analysis, women survived longer than men (hazard ratio, 0.72; 95% confidence interval, 0.56-0. 92; P =.009) independently of age, presence of symptoms, smoking habits, type of operation, histologic characteristics, and stage of disease. The protective effect linked to female sex was present in early-stage carcinoma (stage I and II) and absent in more advanced-stage carcinoma (stage III and IV). CONCLUSIONS: This study emphasizes strong sex differences in presentation, management, and prognosis of patients with non-small cell lung cancer.

Permanent work incapacity, mortality and survival without work incapacity among occupations and social classes: a cohort study of ageing men in Geneva.

BACKGROUND: The objective of this retrospective cohort study was to investigate the burden of disability and death in men, from middle age to age of retirement, among occupational groups and classes in Geneva. METHODS: Men were included if they resided in the Canton of Geneva, were 45 years of age in 1970-1972, and were not receiving a disability pension at the start of the follow-up. The cohort of 5137 men was followed up for 20 years and linked to national registers of disability pension allowance and of causes of death. RESULTS: There was a steep upward trend in incidence of permanent work incapacity with lower social class for all causes as well as for the seven causes of disability studied. Compared with professional occupations (social class I), the relative risk (RR) of permanent work incapacity was 11.4 for partly skilled and unskilled occupations (class IV+V) (95% confidence interval [CI]: 5.2-28.0). The social class gradient in mortality was in the same direction as that in work incapacity although much less steep (RR class IV+V to class I = 1.6, 95% CI : 1.1-2.2). Survival without work incapacity at the time of the 65th birthday ranged from only 57% in construction workers and labourers to 89% in science and related professionals. Unemployment in Geneva was below 1.5% during almost all the study period. CONCLUSIONS: Medically-ascertained permanent work incapacity and survival without work incapacity have shown considerably greater socioeconomic differentials than the mortality differentials.

Gender ratio of offspring and exposure to shortwave radiation among female physiotherapists.

OBJECTIVES: The goal of this study was to investigate whether the deficit of male births found among the offspring of Danish physiotherapists exposed to shortwave radiation during the first month of their pregnancy could be confirmed among the offspring of physiotherapists from Switzerland. METHODS: A self-administrated questionnaire was mailed (two mailings) to all of the 2846 female members of the Swiss Federation of Physiotherapists. It included questions on the gender and birth-weight of all children of the physiotherapists, as well as on the use of shortwave or microwave equipment during the first month of each pregnancy. The response rate was 79.5%, and the analysis was based on 1781 pregnancies. RESULTS: The gender ratio (the number of males per number of females x 100) was 107 with a 95% confidence interval (95% CI) of 89-127 for the 508 pregnancies exposed to shortwave radiation and 101 (95% CI 90-113) for the 1273 unexposed pregnancies. There was no trend in the gender ratio with increasing intensity or duration of exposure. The prevalence of low birthweight (< or = 2500 g) was not related to exposure to shortwave radiation for either the boys or the girls. CONCLUSIONS: No atypical gender ratio was found for the children of female physiotherapists from Switzerland who had been exposed to shortwave radiation at the beginning of pregnancy. The findings of the Danish study could not be confirmed.