Histopathological phenotyping of cancers in PTEN Hamartoma Tumor Syndrome for improved recognition: A single-center study.

PTEN hamartoma tumor syndrome (PHTS) has a broad clinical spectrum including various benign and malignant tumors at varying age of diagnosis. Many patients remain unrecognized, unaware of their increased cancer risk. We aimed to describe the cancer spectrum, age of onset and histopathological cancer characteristics to assess whether specific cancer characteristics could improve PHTS recognition. Genetic testing results and pathology reports were collected for patients tested for germline PTEN variants between 1997 and 2020 from the diagnostic laboratory and the Dutch nationwide pathology databank (Palga). The cancer spectrum and age of onset were assessed in patients with (PTENpos) and without (PTENneg) a germline PTEN variant. Histopathological cancer characteristics were assessed in a nested cohort. 341 PTENpos patients (56% females) and 2882 PTENneg patients (66% females) were included. PTENpos patients presented mostly with female breast (BC, 30%), endometrial (EC, 6%), thyroid (TC, 4%) or colorectal cancer (4%). PTENpos were significantly younger at cancer onset (43 vs. 47 years) and had more often (46% vs. 18%) a second BC than PTENneg. PTEN detection rates were highest for BC <40 years (9%), TC <20 years (15%) and EC <50 years (28%), and dropped to 6%, 4%, and 15% by age 60. Histopathological characteristics were similar between groups. No histopathological cancer characteristics were distinctive for PHTS. However, PTENpos were significantly younger at cancer onset. Therefore early-onset BC, EC, or TC warrants consideration of PHTS diagnostics either through a pre-screen for other PHTS features or direct germline testing.

A review on age-related cancer risks in PTEN hamartoma tumor syndrome.

Patients with PTEN hamartoma tumor syndrome (PHTS, comprising Cowden, Bannayan-Riley-Ruvalcaba, and Proteus-like syndromes) are at increased risk of developing cancer due to pathogenic PTEN germline variants. This review summarizes age-, sex-, and type-specific malignant cancer risks for PHTS patients, which is urgently needed for clinical management. A PubMed literature search for Standardized Incidence Ratios or Cumulative Lifetime cancer risks (CLTRs) resulted in nine cohort studies comprising four independent PHTS cohorts, including mainly index cases and prevalent cancer cases. The median age at diagnosis was 36 years. Reported CLTRs for any cancer varied from 81% to 90%. The tumor spectrum included female breast cancer (CLTRs including sex-specific estimates at age 60-70: 67% to 85%), endometrium cancer (19% to 28%), thyroid cancer (6% to 38%), renal cancer (2% to 24%), colorectal cancer (9% to 32%), and melanoma (0% to 6%). Although these estimates provide guidance for clinical care, discrepancies between studies, sample sizes, retrospective designs, strongly ascertained cases, and lack of pediatric research emphasizes that data should be interpreted with great caution. Therefore, more accurate and more personalized age-, sex-, and cancer-specific risk estimates are needed to enable counseling of all PHTS patients irrespective of ascertainment, and improvement of cancer surveillance guidelines.

Experience in a PHTS Expertise Centre: Yield of Thyroid Ultrasound Surveillance in Children with PTEN Hamartoma Tumor Syndrome.

Objective: Children with PTEN hamartoma tumor syndrome (PHTS) are at increased risk for developing thyroid abnormalities, including differentiated thyroid carcinoma (DTC). The Dutch PHTS guideline recommends ultrasound surveillance starting from age 18. Since the literature describes PHTS patients who developed DTC before age 18, the Dutch PHTS expertise centre has initiated annual ultrasound surveillance starting from age 12. The purpose of this study was to identify the yield of thyroid ultrasound surveillance in children. Methods: A retrospective single centre cohort study was conducted. Pediatric PHTS patients who received thyroid ultrasound surveillance before age 18 between 2016-2023 were included. Patients' medical records have been reviewed. Primary outcomes included prevalence and time to develop thyroid nodules ≥10mm, nodular growth, goiter, thyroiditis and DTC. Descriptive statistics and Kaplan-Meier analyses were performed. Results: Forty-three patients were included. Two patients (5%) were diagnosed with DTC at ages 12 and 17. Both DTCs were identified as minimally invasive follicular carcinoma at stages pT3NxMx and pT1NxMx respectively. A total of 84% were diagnosed with thyroid abnormalities at a median age of 12 years (range 9-18). Most common findings were benign, including nodular disease (74%), goiter (30%) and autoimmune thyroiditis (12%). Nodular growth was observed in 14 patients (33%) resulting in (hemi)thyroidectomy in 7 patients (16%). Conclusion: Thyroid ultrasound surveillance resulted in the detection of DTC in 2/43 PHTS patients before age 18. These findings support the recommendation to initiate thyroid ultrasound surveillance in children at least from age 12, preferably within an expertise centre.

Lifestyle Factors and Breast Cancer in Females with PTEN Hamartoma Tumor Syndrome (PHTS).

Females with PTEN Hamartoma Tumor Syndrome (PHTS) have breast cancer risks up to 76%. This study assessed associations between breast cancer and lifestyle in European female adult PHTS patients. Data were collected via patient questionnaires (July 2020-March 2023) and genetic diagnoses from medical files. Associations between lifestyle and breast cancer were calculated using logistic regression corrected for age. Index patients with breast cancer before PHTS diagnosis (breast cancer index) were excluded for ascertainment bias correction. In total, 125 patients were included who completed the questionnaire at a mean age of 44 years (SD = 13). This included 21 breast cancer indexes (17%) and 39 females who developed breast cancer at 43 years (SD = 9). Breast cancer patients performed about 1.1 times less often 0-1 times/week physical activity than ≥2 times (ORtotal-adj = 0.9 (95%CI 0.3-2.6); consumed daily about 1.2-1.8 times more often ≥1 than 0-1 glasses of alcohol (ORtotal-adj = 1.2 (95%CI 0.4-4.0); ORnon-breastcancer-index-adj = 1.8 (95%CI 0.4-6.9); were about 1.04-1.3 times more often smokers than non-smokers (ORtotal-adj = 1.04 (95%CI 0.4-2.8); ORnon-breastcancer-index-adj = 1.3 (95%CI 0.4-4.2)); and overweight or obesity (72%) was about 1.02-1.3 times less common (ORtotal-adj = 0.98 (95%CI 0.4-2.6); ORnon-breastcancer-index-adj = 0.8 (95%CI 0.3-2.7)). Similar associations between lifestyle and breast cancer are suggested for PHTS and the general population. Despite not being statistically significant, results are clinically relevant and suggest that awareness of the effects of lifestyle on patients' breast cancer risk is important.

Cancer risks by sex and variant type in PTEN hamartoma tumor syndrome.

BACKGROUND: PTEN Hamartoma Tumor Syndrome (PHTS) is a rare syndrome with a broad phenotypic spectrum, including increased risks of breast (BC, 67%-78% at age 60 years), endometrial (EC, 19%-28%), and thyroid cancer (TC, 6%-38%). Current risks are likely overestimated due to ascertainment bias. We aimed to provide more accurate and personalized cancer risks. METHODS: This was a European, adult PHTS cohort study with data from medical files, registries, and/or questionnaires. Cancer risks and hazard ratios were assessed with Kaplan-Meier and Cox regression analyses, and standardized incidence ratios were calculated. Bias correction consisted of excluding cancer index cases and incident case analyses. RESULTS: A total of 455 patients were included, including 50.5% index cases, 372 with prospective follow-up (median 6 years, interquartile range = 3-10 years), and 159 of 281 females and 39 of 174 males with cancer. By age 60 years, PHTS-related cancer risk was higher in females (68.4% to 86.3%) than males (16.4% to 20.8%). Female BC risks ranged from 54.3% (95% confidence interval [CI] = 43.0% to 66.4%) to 75.8% (95% CI = 60.7% to 88.4%), with two- to threefold increased risks for PTEN truncating and approximately twofold for phosphatase domain variants. EC risks ranged from 6.4% (95% CI = 2.1% to 18.6%) to 22.1% (95% CI = 11.6% to 39.6%) and TC risks from 8.9% (95% CI = 5.1% to 15.3%) to 20.5% (95% CI = 11.3% to 35.4%). Colorectal cancer, renal cancer, and melanoma risks were each less than 10.0%. CONCLUSIONS: Females have a different BC risk depending on their PTEN germline variant. PHTS patients are predominantly at risk of BC (females), EC, and TC. This should be the main focus of surveillance. These lower, more unbiased and personalized risks provide guidance for optimized cancer risk management.

Catch them if you are aware: PTEN postzygotic mosaicism in clinically suspicious patients with PTEN Hamartoma Tumour Syndrome and literature review.

PTEN germline variants cause PTEN Hamartoma Tumour Syndrome (PHTS). Of individuals fulfilling diagnostic criteria, 41-88% test negative for PTEN germline variants, while mosaicism could be an explanation. Here we describe two individuals with PTEN mosaicism. First, a 21-year-old female presented with macrocephaly and a venous malformation. Next generation sequencing analysis on her venous malformation identified the mosaic pathogenic PTEN variant c.493-2A>G (23%). This variant was initially missed in blood due to low frequency (<1%), but detected in buccal swab (21%). Second, a 13-year-old male presented with macrocephaly, language developmental delay, behavioral problems, and an acral hyperkeratotic papule. Targeted PTEN analysis identified the mosaic pathogenic variant c.284C>T (11%) in blood, which was confirmed via buccal swab. These two cases suggest that PTEN mosaicism might be more common than currently reported. PTEN mosaicism awareness is important to enable diagnosis, which facilitates timely inclusion in cancer surveillance programs improving prognosis and life expectancy.

Genotype-phenotype associations in a large PTEN Hamartoma Tumor Syndrome (PHTS) patient cohort.

BACKGROUND: Pathogenic PTEN germline variants cause PTEN Hamartoma Tumor Syndrome (PHTS), a rare disease with a variable genotype and phenotype. Knowledge about these spectra and genotype-phenotype associations could help diagnostics and potentially lead to personalized care. Therefore, we assessed the PHTS genotype and phenotype spectrum in a large cohort study. METHODS: Information was collected of 510 index patients with pathogenic or likely pathogenic (LP/P) PTEN variants (n = 467) or variants of uncertain significance. Genotype-phenotype associations were assessed using logistic regression analyses adjusted for sex and age. RESULTS: At time of genetic testing, the majority of children (n = 229) had macrocephaly (81%) or developmental delay (DD, 61%), and about half of the adults (n = 238) had cancer (51%), macrocephaly (61%), or cutaneous pathology (49%). Across PTEN, 268 LP/P variants were identified, with exon 5 as hotspot. Missense variants (n = 161) were mainly located in the phosphatase domain (PD, 90%) and truncating variants (n = 306) across all domains. A trend towards 2 times more often truncating variants was observed in adults (OR = 2.3, 95%CI = 1.5-3.4) and patients with cutaneous pathology (OR = 1.6, 95%CI = 1.1-2.5) or benign thyroid pathology (OR = 2.0, 95%CI = 1.1-3.5), with trends up to 2-4 times more variants in PD. Whereas patients with DD (OR = 0.5, 95%CI = 0.3-0.9) or macrocephaly (OR = 0.6, 95%CI = 0.4-0.9) had about 2 times less often truncating variants compared to missense variants. In DD patients these missense variants were often located in domain C2. CONCLUSION: The PHTS phenotypic diversity may partly be explained by the PTEN variant coding effect and the combination of coding effect and domain. PHTS patients with early-onset disease often had missense variants, and those with later-onset disease often truncating variants.