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PubMed2004

Biological features of bronchial squamous dysplasia followed up by autofluorescence bronchoscopy.

Some dysplasias in the bronchial epithelium are thought to be precancerous lesions that can develop into squamous cell carcinomas. In this investigation, we assessed the biological behavior of bronchial squamous dysplasia in order to define which dysplasias have the potential to progress to squamous cell carcinoma. Using autofluorescence bronchoscopy, we followed up periodically localized dysplasias and examined for correlation between histological outcome and smoking status during the follow-up period, telomerase activity, Ki-67 labeling index, and p53 immunoreactivity of initial biopsy specimens. Ninety-nine dysplasias from 50 participants mainly with sputum cytology suspicious or positive for malignancy were followed up. Of 99 dysplasias, 3 dysplasias progressed to squamous cell carcinoma, 41 dysplasias remained as dysplasia, 6 dysplasias changed to metaplasia, 14 dysplasias changed to hyperplasia, and 35 dysplasias regressed to bronchitis or normal bronchial epithelium. There were no significant associations between histological outcome and smoking status. Mean initial telomerase activity and Ki-67 labeling index values in the dysplasias increased in proportion to the severity of the histological outcome at the second biopsy. There was also a significant difference between p53-positive and p53-negative dysplasia in terms of histological outcome at the second biopsy. Our results suggested that dysplasias with high telomerase activity, increased Ki-67 labeling index, and p53-positivity tended to remain as dysplasia and might have the potential to progress to squamous cell carcinoma. Patients with dysplastic lesions with these characteristics should be carefully followed up.

Aged↗

PubMed2005

Loss of heterozygosity (LOH) in non-small cell lung cancer: difference between adenocarcinoma and squamous cell carcinoma.

BACKGROUND: In non-small cell lung cancer, a loss of heterozygosity (LOH) is frequently observed; however, few studies have investigated the differences in the LOH status between adenocarcinoma and squamous cell carcinoma. PATIENTS AND METHODS: In a consecutive series of 49 patients with adenocarcinomas and 22 patients with squamous cell carcinomas, the LOH in tumors was analyzed using polymerase chain reaction employing 5 fluorescence-labeled dinucleotide markers (D2S123, D5S107, D10S197, D11SS904, D13S175) and an autosequencer. RESULTS: LOH was more frequently observed in squamous cell carcinoma (20 of 22, 90%) than in adenocarcinomas (33 of 49, 67%) (P=0.0348), and the number of LOH per patient was also higher in the patients with squamous cell carcinoma (2.2+/-1.4) than in those with adenocarcinoma (1.5+/-1.2, P=0.037). In adenocarcinomas, the number of LOH per patients correlated significantly with the pack-year index, whereas the pathological stage significantly affected the number of LOH in squamous cell carcinomas. CONCLUSION: The presence of LOH is relatively uncommon in adenocarcinoma of the lung; however, the incidence of LOH tends to be associated with the smoking status.

Adenocarcinoma↗

PubMed2005

Local interleukin-2 and interleukin-12 therapy of bovine ocular squamous cell carcinomas.

Interleukin-2 and interleukin-12 have been used independently to successfully treat the induced and the spontaneous tumours in animals. This trial was done to determine if a combination of IL-2 and IL-12 in the treatment of spontaneous bovine ocular squamous cell carcinomas (BOSCC) would be more successful than IL-2 or IL-12 therapy by themselves. For this trial, we selected 25 BOSCC tumours seen on Holstein Fresian cows in Beatrice, Zimbabwe. The cows were randomly assigned to a treatment group of 5 days of IL-2 (200,000 U/day), 5 days of IL-12 (0.5 microg/day) or 5 days of IL-2 (200,000 U/day) and IL-12 (0.5 microg/day). At 20 months after treatment, the IL-2 therapy group had 63% complete regressions; the combination group had 38% complete regressions, which were significantly higher than the IL-12 group, which had 0% complete regressions at 20 months, despite having 29% complete regressions at 6 months. These results show that IL-2 therapy by itself and in combination with IL-12 is more successful than IL-12 by itself. However, combination therapy does not improve the outcome in comparison to IL-2 as a single therapy. It also proves that IL-2 is consistently successful in the therapy of BOSCC with over 60% complete regression, which corresponds to a number of other studies we have done on IL-2 therapy of BOSCC [Rutten, V.P.M.G., Klein, W.R., De Jong, W.A., Misdorp, W., Den Otter, W., Steerenberg, P.A., De Jong, W.H., Ruitenberg, E.J., 1989. Local interleukin-2 therapy in bovine ocular squamous cell carcinoma. A pilot study. Cancer Immunol. Immunother. 30, 165--169; Stewart, R.J.E., Hill, F.W.G., Masztalerz, A., Jacobs, J.J.L., Koten, J.W., Den Otter, W., 2003. Local low dose interleukin-2 therapy of bovine ocular squamous cell carcinomas in cattle in Zimbabwe, submitted for publication; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H.M., Rutten, V.P.M.G., Ruitenberg, E.J., 1993. Low doses of interleukin-2 can cure large bovine ocular squamous cell carcinoma. Anticancer Res. 13, 2453-2455; Den Otter, W., Hill, F.W.G., Klein, W.R., Koten, J.W., Steerenberg, P.A., De Mulder, P.H., Rhode, C., Stewart, R., Faber, J.A., Ruitenberg, E.J., 1995. Therapy of bovine ocular squamous cell carcinoma with local doses of interleukin-2: 67% complete regressions after 20 months of follow-up. Cancer Immunol. Immunother. 41, 10-14].

Animals↗

PubMed2006

Optic neuropathy from metastatic squamous cell carcinoma of the cervix: an unusual CNS presentation.

BACKGROUND: Central nervous system (CNS) metastases from cervical carcinoma are uncommon events. Leptomeningeal involvement from cervical squamous cell carcinoma has not been extensively described. CASE: A 43-year-old woman with initial diagnosis of stage IB squamous cervical carcinoma at age 30 was treated with hysterectomy and left salpingo-oophorectomy. She recurred with nodal disease at age 39 and went into a clinical complete remission after chemotherapy and radiation treatment. Three years later, she presented with symptoms of optic neuropathy. Cerebral spinal fluid (CSF) was positive for squamous cells consistent with primary cervical squamous cell carcinoma. No measurable disease was evident outside of the CNS. CONCLUSION: Meningeal carcinomatosis from cervical squamous cell carcinoma involving optic nerves has not been reported. Rapid progression of this patient's CNS metastatic disease suggests this form of metastases may be more aggressive and carry extremely poor prognosis.

Adult↗

PubMed1975

Squamous neoplasia of vagina related to DES syndrome.

The emphasis to date in the DES syndrome has been confined to the presence of adenosis in the vagina and the occassional adenocarcinoma which may arise from this ectopic glandular epithelium (less than 250 to date). As these patients mature, however, the glandular epithelium in the vagina is replaced by squamous metaplastic epithelium. Forty-six patients with benign vaginal adenois were observed colposcopically for up to 2 years. Atypical squamous epithelium (white epithelium, punctation, or mosiac pattern) was observed in 40 of the 46 patients. Colposcopically directed biopsy revealed six cases ofdysplasia (mild to severe) and one unequivocal case of in situ squamous carcinoma. These squamous lesions in the vagina were identical, both colposcopically and histologically,to similiar lesions on the cervix. These data suggest that squamous neoplasia may be more frequent in the future of the DES-exposed patient than adenocarcinoma.

Adenocarcinoma↗

PubMed2001

Pigmented conjunctival squamous cell carcinoma simulating a conjunctival melanoma.

PURPOSE: To report a pigmented conjunctival squamous cell carcinoma that clinically simulated a conjunctival melanoma. DESIGN: Interventional case report. METHODS: Ocular examination, surgical excision, and clinicopathologic correlation. RESULTS: A 78-year-old white man developed a lightly pigmented mass at the temporal limbus of his right eye. The differential diagnosis included pigmented squamous cell carcinoma and malignant melanoma. Histopathologic examination revealed a malignant squamous cell tumor that contained foci of melanin pigment. The final diagnosis was pigmented conjunctival squamous cell carcinoma. CONCLUSION: Conjunctival squamous cell carcinoma may rarely be pigmented and simulate a conjunctival melanoma.

Aged↗

PubMed1994

Increased expression of basic fibroblast growth factor in squamous carcinogenesis of the head and neck is less prevalent following smoking cessation.

Basic fibroblast growth factor (bFGF), a potent angiogenic peptide, is thought to provide a growth advantage to a number of tumors including squamous cancer of the head and neck. The purpose of this study was to demonstrate the in situ expression of bFGF in lesions of the upper aerodigestive tract (UADT) and to correlate that with clinical parameters and known risk factors for carcinoma. On surgical specimens from 52 patients, we used a colorimetric in situ hybridization assay to determine the expression of bFGF mRNA in normal and pathologic conditions commonly seen in squamous mucosa. The extent of reactivity for the bFGF transcript was recorded on a subjective scale from 1+ to 3+, based on the visual intensity of labeling. These findings were subsequently correlated with clinical data. Basic fibroblast growth factor mRNA was detected at low to moderate levels in all sections of normal mucosa, with no distinction between patients with or without squamous cancer. Inflamed mucosa had comparatively strong expression of bFGF mRNA. Among lesions implicated in the stepwise nature of squamous carcinogenesis, we found increases in bFGF expression that were most significant at the level of carcinoma in situ, persisting through the invasive and nodal metastatic stages of the disease (P < 0.005). Interestingly, those increases were significantly less frequent among former smokers (P = 0.02). We have established the expression of bFGF mRNA in normal, inflammatory, and neoplastic tissue within the UADT. Furthermore, we note for the first time that increased expression is associated with the acquisition of more aggressive biologic behavior in squamous carcinogenesis.

Adult↗

PubMed2002

Clinical significance of telomerase activity in peripheral blood of patients with esophageal squamous cell carcinoma.

BACKGROUND: The presence of tumor cells in the blood stream is considered evidence of a high risk of distant organ metastasis. We examined the usefulness of telomerase activity in peripheral blood polymorphonuclear cells as an indicator of distant metastasis in patients with esophageal squamous cell carcinoma. METHODS: Telomerase activity was measured in the peripheral blood mononuclear cell and polymorphonuclear cell fractions obtained from blood samples of healthy volunteers mixed with squamous cell carcinoma cell lines, and cell distribution was analyzed by flow cytometry. Then telomerase activity of forty-two polymorphonuclear cell fractions obtained from esophageal squamous cell carcinoma patients was measured. RESULTS: Telomerase activity was detected in polymorphonuclear cell fractions and cell distribution analysis revealed the presence of esophageal squamous cell carcinoma cells. Organ metastasis was detected in 7 (78%) of the 9 patients with telomerase-positive polymorphonuclear cell fractions as opposed to only five (15%) of the 33 with telomerase-negative cases, and there was a significant positive correlation between telomerase activity and organ metastasis (p < 0.0008). CONCLUSIONS: Measurement of telomerase activity in the polymorphonuclear cell fractions is useful for identifying a high risk group for distant organ metastasis in patients with esophageal squamous cell carcinoma.

Aged↗

PubMed2002

Squamous cell carcinoma of the conjunctiva: clinicopathological features in 287 cases.

BACKGROUND: Squamous cell carcinoma is the most frequently encountered malignant tumour of the conjunctiva. The objective of this study was to describe the clinicopathological features of patients with squamous cell carcinoma of the conjunctiva seen at a large ophthalmologic hospital in Mexico City. METHODS: We reviewed the clinical and pathological files of all patients with documented squamous cell carcinoma of the conjunctiva seen at the hospital between 1957 and 1996. RESULTS: A total of 287 cases (286 patients) were reviewed. The mean age of the patients was 60.4 (range 12 to 99) years; 55% were male. The clinical diagnosis was accurate in 41% of cases. Typical keratinized squamous cell carcinoma of the conjunctiva accounted for 98% of the lesions, and there were small numbers of histologic variants: lymphoepithelioma-like carcinoma (three cases), spindle cell carcinoma (two cases) and mucoepidermoid carcinoma (one case). Evidence of local extension of the tumour was found in 150 patients (52%), with the cornea being most frequently involved (108 cases [38%]). Regional metastasis was found in two patients, to a submandibular lymph node in one and to a preauricular lymph node in the other. The most common form of treatment was local resection (258 cases [90%]). The mean length of follow-up was 7.7 (range 2 to 24) months. The recurrence rate was 5.2%. INTERPRETATION: We report a large series of patients with squamous cell carcinoma of the conjunctiva. The incidence of local extension was high. Three cases of lymphoepithelioma-like carcinoma, a variant not previously reported in the conjunctiva, were encountered and were confirmed by immunohistochemical reactions.

Adolescent↗

PubMed1997

The 28K protein in urinary bladder, squamous metaplasia and urine is triosephosphate isomerase.

OBJECTIVES: The objective of this study was to establish the identity of a protein found in high concentrations in squamous metaplasia of the bladder. DESIGN AND METHODS: The protein was isolated and subjected to a series of physical, chemical, and catalytic studies. RESULTS: In the normal urothelium the protein was confined to a juxtanuclear pattern on the luminal side of the umbrella cells; in squamous metaplasia and squamous cell carcinoma the protein was increased and exhibited a more diffuse intracellular distribution. The protein was found to be identical to triosephosphate isomerase (EC 5.3.1.1; TPI) with respect to its immunological properties, native and subunit molecular weights, electrophoretic mobility, catalytic activity, and amino acid sequence. CONCLUSIONS: While the basis for the altered distribution of TPI remains to be established, the increased amounts of the protein in urine or bladder tissue may be indicative of squamous metaplasia, squamous cell carcinoma, or other bladder injuries.

Carcinoma, Squamous Cell↗

PubMed2002

Racial variation in the incidence of squamous cell carcinoma of the bladder in the United States.

PURPOSE: Racial differences in the incidence of squamous cell carcinoma of the bladder may provide insight into the pathogenesis of this disease. We determined the incidence of squamous cell carcinoma of the bladder according to race in the United States. MATERIALS AND METHODS: Data obtained from the Surveillance, Epidemiology and End Results program from 1973 to 1997 were analyzed to determine the incidence of squamous cell carcinoma of the bladder in individuals 35 to 84 years old. Incidence rates by race and gender were then adjusted to the age distribution of the 1970 American population. RESULTS: The average annual incidence of squamous cell carcinoma of the bladder was 1.20/100,000 in black and 0.60/100,000 in white Americans (relative risk 2.0, 95% CI 1.74 to 2.29). Black men were at increased risk compared with white men and black women were at increased risk compared with white women. The higher incidence in black versus white individuals existed in all age groups beyond 45 years and was present throughout the study period. CONCLUSIONS: Squamous cell carcinoma of the bladder appears to be twice as common in black as in white individuals in the United States.

Adult↗

PubMed1997

Human papillomavirus in squamous cell carcinoma of the vulva by polymerase chain reaction.

OBJECTIVE: To investigate the prevalence of human papillomavirus (HPV) DNA in squamous cell carcinoma of the vulva by polymerase chain reaction (PCR). METHODS: Archival diagnostic phase biopsies from 74 patients with squamous cell carcinoma of the vulva were investigated for HPV DNA by PCR. We used both consensus primers located in the open reading frame L1 and type-specific primers for HPV 6 (open reading frame E5), HPV 11 (open reading frame L1), HPV 16, HPV 18, and HPV 33 (open reading frame E6). RESULTS: HPV DNA was detected in 27 (36%) of the 74 patients, of whom 19 had HPV 16, nine had HPV 18, one had HPV 33, and one had unclassified HPV DNA. No case of HPV type 6 or 11 was detected. Two squamous cell carcinomas were positive for both HPV 16 and 18, and one was positive for both HPV types 16 and 33. Three squamous cell carcinomas positive for E6 gene using type-specific primers were negative using L1 consensus primers. CONCLUSION: Our PCR methods using both consensus open reading frame L1-derived primers and type-specific open reading frame E6-derived primers of HPV types 16, 18, and 33 seemed to be an appropriate combination for the detection of HPV DNA in archival tissues of vulvar carcinoma. Both HPV types 16 and 18 were associated with squamous cell carcinoma of the vulva, although the prevalence of HPV 16 was considerably lower than in cervical carcinoma. It appears that vulvar and cervical carcinomas are not identical etiologically and that factors other than HPV are important in vulvar carcinogenesis.

Adult↗

PubMed2005

[Detection of the sentinal node in squamous-cell carcinoma of the oral cavity and oropharynx. Preliminary study].

INTRODUCTION: The sentinel lymph node is defined as the first relay of the lymphatic drainage of the tumor. Isotopic detection of the sentinel lymph node and absence of its metastatic invasion should theoretically be predictive of total drainage of the tumor. The goal of this study was to evaluate sentinel lymph node detectability by lymphoscintigraphy in N0 and/or N1 squamous-cell carcinoma of oral cavity and oropharynx and to determine its negative predictive value. MATERIAL AND METHOD: Lymphoscintigraphy was used for sentinel lymph node detection. The procedure required peritumoral injection of technicium-labeled colloids to enable anatomical and cutaneous location of the sentinel lymph node. A one-way Tyco-Mallinckrodt probe was used for intraoperative detection of the sentinel lymph node. This prospective study included 21 patients with N0 or N1 squamous-cell carcinoma of the oral cavity and the oropharynx. The surgical attitude based on T and N was not modified in this prospective study without direct individual benefit for the patient. Neck dissection was achieved without difficulty. RESULTS: The sentinel lymph node was identified in 20 out of 21 subjects. The sentinel lymph node was not identified in one patient with recurrence T2N0M0 squamous-cell carcinoma of the oropharynx radiated 3 years earlier. The percentage of false-negatives was 12.5% (1 false-negative out of 8 positive patients), giving a sensibility of the detection method of 87.5% (IC (95%)=[47.35-99.68]). This false-negative patient had a T3N0M0 squamous-cell carcinoma of the oropharynx with a sentinel lymph node removed in territory III. Neck dissection revealed 1 N + R- in the sub-mandibular territory associated with 27 N-R-. The probability of not finding a metastatic node at neck dissection when the sentinel lymph node is not metastatic (negative predictive value) was 92.3% (12/13) (IC (95)=[63.97-99.81]). The specificity of the method was 100%, as was the positive predictive value, because no sentinel node was diagnosed positive wrongly on frozen sections among patients without true histological node metastasis. DISCUSSION: For routine care of patients with squamous-cell carcinoma of the oral cavity and the oropharynx detection of the sentinel lymph node is proposed primarily for patients with T1T2N0 staging. Larger tumors can modify the architecture and flow within the lymphatic ducts, and consequently even the concept of a sentinel lymph node. Systematic neck dissection is required or T3T4, even when N0. Our series of T1T2N0 tumors is too small to enable statistically significant conclusions. A low level of false-negative in a larger series would be necessary to propose this technique instead of convention neck dissection for T1T2 tumors of the oral cavity and oropharynx.

Carcinoma, Squamous Cell↗

PubMed1978

The fine structure of large cell undifferentiated carcinoma of the lung. Evidence for its relation to squamous cell carcinomas and adenocarcinomas.

The light microscopic diagnosis of large cell undifferentiated carcinoma of the lung is known to be highly subjective and shows poor interobserver reproducibility; the very existence of this tumor as a separate entity has been challenged. The ultrastructure of seven large cell undifferentiated carcinomas was examined in an attempt to determine whether they were merely poorly differentiated adenocarcinomas and squamous cell carcinomas, or actually represented an entirely separate class of tumors. Four large cell undifferentiated carcinomas demonstrated intra- and intercellular lumina and were designated adenocarcinomas. In three cases there were well formed desmosomes with numerous tonofilaments and intercellular bridges. These tumors were classified as squamous cell carcinomas. An eighth tumor metastatic to the abdominal wall also showed the features of squamous carcinoma. In addition, all tumors contained a variable population of primitive cells without identifying features. The large cell undifferentiated carcinomas were compared ultrastructurally with eight cases of poorly differentiated adenocarcinomas and squamous cell carcinomas classified by light microscopy. These tumors were morphologically similar, but contained fewer primitive cells and greater numbers of differentiated cells. Cells with a clear cytoplasm as seen by light microscopy were present in both the large cell undifferentiated and poorly differentiated groups; these cells contained variable amounts of glycogen but were otherwise similar to the nonclear cells. It is suggested that most of the subcategories of large cell undifferentiated carcinoma represent very poorly differentiated adenocarcinomas and squamous carcinomas.

Adenocarcinoma↗

PubMed1984

Squamous cell carcinoma of the breast: a clinicopathologic analysis of eight cases and review of the literature.

Malignant neoplasms of the female breast composed of squamous cells are rare and constitute a particularly poorly understood facet of breast disease. Two pure squamous cell carcinomas ( SCCs ) of the breast and six tumors that displayed various combinations of malignant squamous elements and ductal breast adenocarcinoma were identified. Electron microscopy confirmed the diagnosis of SCC in two cases by the demonstration of regularly spaced desmosomes, tonofilament bundles, and keratohyaline granules. A review of the literature indicated that breast cancers with components of SCC are histologically variable. Approximately 30 cases of pure SCC and 80 cases of mixed adenocarcinoma and SCC (adeno-SCC) have been reported. Some of these squamous epithelium-containing tumors have displayed areas of cyst formation, spindle cell metaplasia, and pseudosarcomatous desmoplastic response, or origins in preexisting breast lesions, such as cystosarcoma phyllodes or dermoid cysts. Although this variability indicates a heterogeneous group of neoplasms, the overall prognosis for carcinomas of the breast with malignant squamous elements appears to be quite similar to that for ordinary breast adenocarcinomas of similar size and stage.

Adult↗

PubMed1988

Primary squamous cell carcinoma of the colon arising in a villous adenoma.

The first case of pure squamous cell carcinoma arising in a villous adenoma of the cecum is reported, and the literature of squamous cell carcinoma of the colon is reviewed. The possible origin of this neoplasm in adenomas of the colon, similar to that of adenocarcinoma, is discussed, and the site distributions of adenocarcinoma and squamous cell carcinoma are compared. The distribution of primary colonic squamous cell carcinoma is found to be predominantly right-sided in comparison to adenocarcinoma (p less than 0.05). Although this result does not preclude adenomas as the origin of most squamous cell carcinomas, it suggests the influence of as yet unknown site-asymmetric factors that are different from those for adenocarcinoma.

Adenocarcinoma↗

PubMed1996

Detection of human papillomavirus DNA in primary squamous cell carcinoma of the male urethra.

OBJECTIVES: The prevalence of human papillomavirus deoxyribonucleic acid (DNA) in primary squamous cell carcinoma of the male urethra and corresponding control tissue was studied. METHODS: The technique of polymerase chain reaction DNA amplification was used to detect specific human papillomavirus DNA sequences in archival pathologic and control tissue. We analyzed 16 cases of primary squamous cell carcinoma of the male urethra and 22 specimens of normal male urethra stratified by location within the urethra. RESULTS: Primary squamous cell carcinoma of the pendulous urethra was significantly associated with human papillomavirus type 16 DNA (6 of 6 cases), but the control tissue from the pendulous urethra was not (0 of 12, P < 0.001). Primary squamous cell carcinoma of the bulbous and posterior urethra was not associated with human papillomavirus infection. CONCLUSIONS: Infection of the male urethra with human papillomavirus type 16 may have a role in the pathogenesis of primary squamous cell carcinoma of the pendulous urethra, for which it has a strong predilection, vis-à-vis the bulbous and posterior urethra.

Carcinoma, Squamous Cell↗

PubMed1999

Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: a randomised controlled trial.

BACKGROUND: The use of sunscreens on the skin can prevent sunburn but whether long-term use can prevent skin cancer is not known. Also, there is evidence that oral betacarotene supplementation lowers skin-cancer rates in animals, but there is limited evidence of its effect in human beings. METHODS: In a community-based randomised trial with a 2 by 2 factorial design, individuals were assigned to four treatment groups: daily application of a sun protection factor 15-plus sunscreen to the head, neck, arms, and hands, and betacarotene supplementation (30 mg per day); sunscreen plus placebo tablets; betacarotene only; or placebo only. Participants were 1621 residents of Nambour in southeast Queensland, Australia. The endpoints after 4.5 years of follow-up were the incidence of basal-cell and squamous-cell carcinomas both in terms of people treated for newly diagnosed disease and in terms of the numbers of tumours that occurred. Analysis of the effect of sunscreen was based only on skin cancers that developed on sites of daily application. All analyses were by intention to treat. FINDINGS: 1383 participants underwent full skin examination by a dermatologist in the follow-up period. 250 of them developed 758 new skin cancers during the follow-up period. There were no significant differences in the incidence of first new skin cancers between groups randomly assigned daily sunscreen and no daily sunscreen (basal-cell carcinoma 2588 vs 2509 per 100,000; rate ratio 1.03 [95% CI 0.73-1.46]; squamous-cell carcinoma 876 vs 996 per 100,000; rate ratio 0.88 [0.50-1.56]). Similarly, there was no significant difference between the betacarotene and placebo groups in incidence of either cancer (basal-cell carcinoma 3954 vs 3806 per 100,000; 1.04 [0.73-1.27]; squamous-cell carcinoma 1508 vs 1146 per 100,000; 1.35 [0.84-2.19]). In terms of the number of tumours, there was no effect on incidence of basal-cell carcinoma by sunscreen use or by betacarotene but the incidence of squamous-cell carcinoma was significantly lower in the sunscreen group than in the no daily sunscreen group (1115 vs 1832 per 100,000; 0.61 [0.46-0.81]). INTERPRETATION: There was no harmful effect of daily use of sunscreen in this medium-term study. Cutaneous squamous-cell carcinoma, but not basal-cell carcinoma seems to be amenable to prevention through the routine use of sunscreen by adults for 4.5 years. There was no beneficial or harmful effect on the rates of either type of skin cancer, as a result of betacarotene supplementation.

Adult↗