ABSTRACT
Cribriform morular thyroid carcinoma (CMTC) has been included within the group of thyroid tumors of uncertain histogenesis in the recent World Health Organization classification of endocrine tumors. Most CMTCs occur in young euthyroid women with multiple (and bilateral) thyroid nodules in cases associated with familial adenomatous polyposis (FAP) or as single nodules in sporadic cases. CMTC generally behaves indolently, while aggressiveness and mortality are associated with highgrade CMTC. This tumor histologically displays a distinctive combination of growth patterns with morular structures. Strong diffuse nuclear and cytoplasmic immunostaining for ßcatenin is the hallmark of CMTC. Tumor cells are also positive for thyroid transcription factor1 and for estrogen and progesterone receptors, but negative for thyroglobulin and calcitonin. It is possible that the CMTC phenotype could result from blockage in the terminal/follicular differentiation of follicular cells (or their precursor cells) secondary to the permanent activation of the Wnt/ßcatenin pathway. In CMTC, the activation of the Wnt/ßcatenin pathway is the central pathogenetic event, which in FAPassociated cases results from germline mutations of the APC regulator of WNT signaling pathway (APC) gene, and in sporadic cases from somatic inactivating mutations in the APC, AXIN1 and CTNNB1 genes. Estrogens appear to play a tumorpromoting role by stimulating both the PI3K/AKT/mTOR and the RAS/RAF/MAPK signaling pathways. Additional somatic mutations (i.e. RET rearrangements, or KRAS, phosphatidylinositol4,5bisphosphate 3kinase catalytic subunit α, telomerase reverse transcriptase or tumor protein 53 mutations) may further potentiate the development and progression of CMTC. While hemithyroidectomy would be the treatment of choice for sporadic cases without highrisk data, total thyroidectomy would be indicated in FAPassociated cases. There is insufficient clinical data to propose therapies targeting the Wnt/ßcatenin pathway, but multikinase or selective inhibitors could be used in a manner analogous to that of conventional thyroid tumors. It is also unknown whether adjuvant antiestrogenic therapy could be useful in the subgroup of women undergoing surgery with highrisk CMTC, as well as when there is tumor recurrence and/or metastasis.
Subject(s)
Thyroid Neoplasms , Humans , Thyroid Neoplasms/pathology , Thyroid Neoplasms/genetics , Female , Wnt Signaling Pathway , Adenomatous Polyposis Coli/genetics , Adenomatous Polyposis Coli/pathology , beta Catenin/genetics , beta Catenin/metabolismABSTRACT
BACKGROUND: There are few third- and fourth-line therapeutic options for metastatic colorectal cancer (mCRC). In RAS/BRAF wild-type (wt) mCRC previously treated with anti-epidermal growth factor receptor (anti-EGFR) (first-line) and relapsed after a good response, retreatment with anti-EGFR (rechallenge) emerges as a therapeutic alternative. OBJECTIVE: The aim was to show the activity and safety of anti-EGFR rechallenge in RAS/BRAF wt mCRC in real-world practice. PATIENTS AND METHODS: A multicenter, retrospective, observational study (six hospitals of the Galician Group of Research in Digestive Tumors) was conducted. Adult patients with RAS/BRAF wt mCRC, evaluated by liquid biopsy, were included. They received anti-EGFR rechallenge (cetuximab, panitumumab) as monotherapy, or combined with chemotherapy, in third- or subsequent lines. Efficacy (overall response rate [ORR], disease control rate [DCR], overall survival [OS], and progression-free survival [PFS]) and safety (incidence of adverse events [AEs]) were assessed. RESULTS: Thirty-one patients were analyzed. Rechallenge (median 6 cycles [range 1-27], mainly cetuximab [80.7%]), started at a median anti-EGFR-free time of 18.4 months (1.7-37.5 months) after two (38.7%) or more (61.3%) lines of treatment; 64.5% of patients received a full dose. Median OS and PFS were 9.8 months (95% confidence interval [CI] 8.2-11.4) and 2.6 months (95% CI 1.7-3.4), respectively. ORR was 10%, and DCR was 30%. The most common AEs were diarrhea (35.5%), anemia (29%), emesis (6.4%), and neutropenia (6.4%); < 5% grade ≥ 3; 48.4% of patients reported anti-EGFR-related skin toxicity (grade > 1). Hypomagnesemia required supplements in 29% of patients. Dose delays (≥ 3 days) and reduction (≥ 20%) were reported in 11 (35.5%) and seven patients (22.6%), respectively. CONCLUSIONS: In RAS/BRAF wt mCRC patients, an anti-EGFR rechallenge provides a feasible therapeutic option with clinical benefit (survival) and a manageable safety profile.
Subject(s)
Colorectal Neoplasms , ErbB Receptors , Humans , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/pathology , Male , Female , Middle Aged , Retrospective Studies , Aged , Adult , Proto-Oncogene Proteins B-raf/genetics , Neoplasm Metastasis , Aged, 80 and over , Cetuximab/therapeutic use , Cetuximab/pharmacology , Panitumumab/therapeutic use , Panitumumab/pharmacologyABSTRACT
INTRODUCTION: The mitogen-activated protein kinase (MAPK) signalling network aberrations in metastatic colorectal cancer (mCRC) generate intrinsic dynamic effects and temporal variations that are crucial but often overlooked in clinical trial populations. Here, we investigate the time-varying impact of MAPK pathway mutation genotype on each treatment line's contribution to the overall clinical course. METHODS: The PROMETEO study focused on mCRC patients undergoing second-line treatment at 20 hospitals. We evaluated genotypes and employed flexible models to analyse the dynamic effect of each mutation. RESULTS: We examined data derived from 1160 patients. The effects of KRAS G12C or G12V, and BRAF V600E are clearly time-varying, with unexpected consequences such as the deleterious effect of BRAF V600E vs other genotypes dissipating over time when subjects receive antiangiogenics, or KRAS G12V and G12C showing increasing aggressiveness over time. Thus, contrary to expectations, the 12-month survival rate from the second line for those who survived >6 months was 49.9% (95% CI, 32.7-67.3) for KRAS G12C and 59% (95% CI, 38.5-80.6) for BRAF V600E. CONCLUSIONS: The dynamic perspective is essential for understanding the behaviour of tumours with specific genotypes, especially from the second line onward. This may be relevant in patient monitoring and treatment decision-making, particularly in cases with distinct mutations.