Diagnosis and Treatment of Neoplasia PDF

Diagnosis and Treatment of Neoplasia DSPR 139: Neoplasia and Genetics Daria Vasilyeva, DDS  Diagnosis of neoplasia At a glance - - Tissue sampling - Tissue preparation - Diagnostic modalities...

Diagnosis and Treatment of Neoplasia DSPR 139: Neoplasia and Genetics Daria Vasilyeva, DDS  Diagnosis of neoplasia At a glance - - Tissue sampling - Tissue preparation - Diagnostic modalities - Features of neoplasia - Clinical features - Histologic features - Grading and staging - Treatment of neoplasia - Surgery - Radiation - Chemotherapy  Clinical management of neoplastic disease Several specialties play a vital role – Any specialty that samples tissue for pathologic diagnosis Surgery most of the time Dermatology, dentistry… – Pathology – Radiology – Oncology Surgical oncology Medical oncology Radiation oncology  Clinical features of neoplasia - Benign tumors tend to be slow growing, well circumscribed, distinct, and mobile - Malignant tumors are usually rapid growing, poorly circumscribed, infiltrative, and fixed to surrounding tissues and local structures - Biopsy or excision is generally required before a tumor can be classified as benign or malignant with certainty. - Some benign tumors can grow in a malignant-like fashion, and some malignant tumors can grow in a benign-like fashion  Sampling of tissue for pathology Excisional biopsy: removal of entire lesion (excision) with submission to pathology – Preferred technique for: Small, localized lesions where conservative excision would also be definitive (final) treatment approach Lesions where malignancy not realistically on differential diagnosis Malignancies cannot be treated by excisional biopsy – Conservative excision is not a sufficient surgical approach Usually more substantial margins needed – Defect from attempted excision may complicate further surgical planning Excisional biopsy  Sampling of tissue for pathology Incisional biopsy: partial removal of lesion with submission to pathology – Ideal biopsy if optimal patient management depends on diagnosis  Sampling of tissue for pathology Punch biopsy: type of incisional biopsy – More user-friendly technique than incisional biopsy with scalpel Sampling of tissue for pathology Fine needle aspiration (FNA) biopsy: very thin needle attached to syringe – Tissue from suspicious area withdrawn (aspirated) Procedure may be ultrasound guided to increase accuracy of needle insertion – Used in many organs including thyroid, parotid Method of providing tissue for cytopathology  Sampling of tissue for pathology Exfoliative cytology – Collecting of cells spontaneously shed by body or manually scraped off – Example: Pap smear Another method of providing tissue for cytopathology  Sampling of tissue for pathology Core needle biopsy: slightly larger, hollow needle is used to withdraw a thin amount (core) of abnormal tissue – Needle inserted multiple times to get several cores (thin slivers) of tissue – Used in organs such as breast, prostate Sampling of tissue for pathology Bone marrow biopsy and aspiration: often done together to examine bone marrow – Core needle biopsy plus fine needle aspiration  Sampling of tissue for pathology Endoscopic biopsy: used to reach some tissues inside of body (esophagus, paranasal sinuses) – Endoscope equipped with camera, light, small surgical tools Sampling of tissue for pathology Biopsied tissue is placed (fixed) in formalin and sent to pathology laboratory Formalin fixation: – Inactivates enzymes still viable in recently excised tissue Prevents enzymatic auto-digestion (autolysis) Autolyzed tissue cannot be interpreted by pathologist (looks like mush) – Increases mechanical strength or stability of tissue for further processing  Tissue preparation for histopathologic (microscopic) assessment After formalin fixation: – Tissue sampled for areas of specific interest or sectioned into multiple pieces by pathologist/ technician – Tissue embedded in paraffin (wax) for further processing  Tissue preparation for histopathologic (microscopic) assessment Sections then cut from paraffin block using microtome – Very thin: 6-7 μm (0.006-0.007 mm) in majority of cases  Tissue preparation for histopathologic (microscopic) diagnosis Sections are attached to glass slides  Tissue preparation for histopathologic (microscopic) diagnosis Slides are fixed and stained with hematoxylin and eosin (H&E)  Tissue preparation for histopathologic (microscopic) diagnosis Well-differentiated neoplasms can be diagnosed on H&E This is an ameloblastoma Poorly-differentiated neoplasms are not so easy This could be a lot of things  Immunohistochemistry (IHC) Immunohistochemistry: examination of biopsied tissue for presence of specific proteins – Proteins are present in biopsied tissue and can be identified using synthetically designed chromogenic antibodies – Cells from different tissues of origin express different genes And therefore different proteins – Presence/absence of a panel of proteins in a tumor (immunohistochemical profile) often assists pathologists in determining tissue of origin and/or diagnosis in challenging cases Neoplasms often express similar genes/proteins as normal tissue they arise from, even when poorly differentiated CD34 MelanA  Final diagnosis Dermatofibrosarcoma protuberans, pigmented type (Bednar tumor) DFSP very rare in neonatal setting, Bednar variant had not previously been reported in this age – Making this diagnosis without immunohistochemistry would essentially be ‘guessing’ (Guessing = malpractice)  In situ hybridization (ISH) ISH: in situ hybridization – Use of a DNA or RNA probe that is complementary to and can hybridize to a particular region of DNA or RNA – In head and neck: useful for identification of HPV or EBV DNA p16 and RB in HPV RB Directly or indirectly inactivated in most human cancers Named after tumor in which its role was first discovered (retinoblastoma) Regulates expression of genes necessary for dividing cells to pass through G1/S cell cycle checkpoint p16 - Tumor suppressor protein upstream from Rb - Overexpressed as a result of HPV-induced Rb inactivation  encode transcription factors critical for G1/S transition in cell cycle p16 tumor suppressor protein upstream of Rb, reliably overexpressed as a result of HPV-induced Rb inactivation p16 EBER (EBV ISH)  Fluorescent in situ hybridization (FISH) FISH: fluorescent in situ hybridization – Similar principles as ISH – Probe is labelled with fluorescent colors and stained tissue visualized through fluorescent microscope – Excellent method for identifying chromosomal translocations and gene amplifications  Most mucoepidermoid carcinomas are characterized by a t(11;19) CRTC-MAML2 translocation, separating MAML2 gene in half If half of the MAML2 gene is labeled one color and the other half another, translocation (separation) can be identified Flow cytometry Excellent diagnostic method for ‘liquid’ tumors of blood (leukemia, lymphoma) – Multiple antigens (proteins) can be assessed simultaneously as sample flows through cytometer – Also able to sort by size, charge, cellular complexity  Frozen sections Intraoperative pathologic consultation: – While patient is in OR and still in surgery, portion of tissue is delivered to ‘frozen room’ – Pathologist quickly processes tissue in rudimentary fashion, attempts to provide basic information that can guide remainder of surgery Diagnosis? Or at least benign vs. malignant? Margin status: has the entire tumor been removed? – 98% average concordance across sites when determining margin status (consistently over 90% for H&N SCC)  Cytopathology Fine needle aspiration biopsy: excellent primary diagnostic method for sites such as breast, thyroid, salivary glands, lymph nodes – Aspirate yields only floating cells with no tissue context Exfoliative cytology (e.g. Pap smears) also yields only cells with no tissue architecture These tissue samples are interpreted by cytopathologists  Cytopathology Even with such limited biopsy samples, cytopathologists may still be able to: – Give definitive diagnosis (occasionally) – Provide sufficient diagnostic information to guide patient management (more often) Benign vs. malignant Disease present or absent Papillary thyroid carcinoma Pleomorphic adenoma  Molecular pathology Genetic studies of tumors used to be limited to analysis of individual genes (e.g., FISH) Now introducing technologies that allow analysis of: – Entire DNA (genome) Or a subset of genes commonly implicated in cancer biology (targeted genome) – All of the RNA expressed (transcriptome) Useful because it is specific to actively transcribed DNA only – Genome wide epigenetic modifications (epigenome) – Measuring of cellular proteins (proteome) – Snapshot of cell metabolism (metabolome) Molecular tests: - may facilitate making a diagnosis - may provide info about genetic aberrations that can be specifically targeted by chemotherapy (targeted therapy) The Cancer Genome Atlas (TCGA) National Cancer Institute-funded effort to comprehensively classify various cancer types at a genomic level – Whole exome sequencing – Methylation profiles – microRNA profiles – Gene expression analysis  Serum tumor markers and Liquid biopsy - Serum tumor markers - released by tumor into serum - Usually proteins - Useful for screening, monitoring response to treatment, and monitoring recurrence - E.g. elevated PSA (prostate specific antigen) requires tissue biopsy to rule out/diagnose prostate carcinoma - Liquid biopsy detects cancer cells or circulating tumor DNA (ctDNA) in blood Questions?  Clinical features of neoplasia - Benign tumors tend to be slow growing, well circumscribed, distinct, and mobile - Malignant tumors are usually rapid growing, poorly circumscribed, infiltrative, and fixed to surrounding tissues and local structures - Biopsy or excision is generally required before a tumor can be classified as benign or malignant with certainty  Histologic features of neoplasia - Benign tumors are usually well differentiated. - Characteristics of differentiation: - Organized growth - Uniform nuclei - Low nuclear to cytoplasmic ratio - Minimal mitotic activity - Lack of invasion (of basement membrane or local tissue) - No metastatic potential - Malignant tumors range from well to poorly differentiated. - Characteristics of poor differentiation: - Disorganized growth (loss of polarity) - Nuclear pleomorphism and hyperchromasia - High nuclear to cytoplasmic ratio - High mitotic activity with atypical mitosis - Invasion (through basement membrane or into local tissue) - Metastatic potential is the hallmark of malignancy - Benign tumors do not metastasize  Tumor grading Microscopic assessment of degree of differentiation of a tumor based on microscopic appearance (i.e., how much a cancer resembles the tissue from which it originates) Based on architectural and nuclear features – Low-grade neoplasms resemble normal tissue (= well-differentiated) May correlate with lower mutational burden and less aggressive clinical behavior – High-grade neoplasms bear little resemblance to normal tissue (= poorly-differentiated) May correlate with higher mutational burden and more aggressive clinical behavior – Additional testing, e.g. immunohistochemistry, can be used to characterize tumors that are difficult to classify on histology Pathologic grading is a helpful, but not entirely sensitive or specific, predictor of biologic behavior Well-differentiated SCC Poorly-differentiated SCC  Tumor staging System of measuring extent (size and spread) of cancer in body Key prognostic factor, more important than grade Determined after final surgical resection of tumor American Joint Committee on Cancer Staging classifies tumors based on TNM system – T: size of primary tumor -- T1-T4 – N: presence/absence of locoregional lymph node metastasis -- N0-N3 – M: presence/absence of distant (bloodborne) metastases -- M0-M1  Cancer staging For many cancers, TNM combinations grouped into 4 overarching stages – Stage I = Primary tumor with no metastases – Stage II, III = Combination of size of primary tumor (T) and presence/ number of nodal metastases (N) – Stage IV = Cancer with distant metastases (M1) Extent of disease for staging purposes is best evaluated by radiographic imaging: CT MRI PET/CT PET/CT: PET scan superimposed on CT PET: imaging technique used for evaluation of metabolic processes/ diseases – Radioactive tracer injected prior to imaging Fluorodeoxyglucose: glucose with radioactive component attached (F18) – Glucose absorbed by organs/tissues with high metabolic activity Sites called PET-avid – Remember: cancer cells rely on aerobic glycolysis (Warburg effect) Very inefficient, generates only 2 molecules of ATP/glucose molecule Cancers require a lot of glucose…and are PET avid on imaging!  Oncology Field of medicine that deals with study and management of cancer patients – Surgical oncology: management of cancers by surgery – Radiation oncology: management of cancers by radiation – Medical oncology: management of cancers by medication  Tumor board: multidisciplinary cancer conference Patient-care discussions after diagnosis and before treatment – Tumor staging confirmed – Patient overall health and ability to withstand therapy discussed – Treatment algorithms considered and decided upon Treatment with curative or palliative intent? Can patient withstand treatment side effects? Medical specialists present: – Surgical oncologist, medical oncologist, radiation oncologist – Radiologist – Pathologist  Management of the cancer patient Patients are treated with surgery, chemotherapy, and/or radiation therapy – Based on inherent biologic behavior of cancer – Based on tumor stage – Based on patient health status  Surgical management of the cancer patient Usually performed on primary tumor with or without lymph node dissection – Generally curative intent – Typically contraindicated in stage IV cancers May be preceded by chemotherapy or followed by chemotherapy or radiation May result in significant loss of function and unavoidable cosmetic outcomes, even following reconstruction  Radiation therapy and the cancer patient Occasionally given as monotherapy but more often administered in adjuvant setting following surgery Radiation typically administered over many weeks – During outpatient visits to hospital/ treatment center – Usually given with machine called linear accelerator (linac)  Radiation therapy and the cancer patient Average total radiation dose 45-60 Grays – Exact dosage and frequency depend on patient and cancer variables – Usually administered in smaller doses called fractions to minimize side effects Typically given 5 days a week for 5-8 weeks Fractions are cumulative, giving rise to total radiation dose  Mechanism of action and of side effects in radiation therapy Radiation generates DNA-damaging oxygen free radicals – Cancer cells acquire lethal genomic damage and undergo apoptosis Basis of therapy – Normal cells in radiation field acquire lethal genomic damage and undergo apoptosis: basis of side effects Fibrosis, skin atrophy Organ dysfunction – Normal cells may potentially acquire cancer-promoting DNA damage Post-radiation sarcoma rare but real risk of radiation therapy Side effects of head and neck radiation therapy Salivary gland damage and xerostomia – Most common long-term complication of radiation therapy for head and neck cancer Average radiation dose results in >75% reduction in function – As little as 10-15 Gy can permanently damage salivary glands IMRT (intensity modulated radiation therapy): Delivers radiation beams from multiple sources, in varying strengths to minimize radiation dose to surrounding tissues Minimizes but does not eliminate side effects Brachytherapy (internal radiation therapy): Radiation sources implanted surgically in area of cancer Minimizes radiation to normal cells  Chemotherapy and the cancer patient Use of cytotoxic drugs for cancer treatment – Surgery, radiation therapy treats cancer in specific anatomic area Beneficial mostly in stage I-III cancers – Chemotherapy treats cancer everywhere in body May be administered in cancers of any stage – With curative or palliative intent Over 100 chemotherapy drugs exist – Alkylating agents, antimetabolites, anti-tumor antibiotics, topoisomerase inhibitors, mitotic inhibitors… Chemotherapy administered as single drug or drug cocktail Chemotherapy and the cancer patient Can be administered as monotherapy or in combination with surgery or radiation Neoadjuvant chemotherapy – Chemotherapy administered prior to surgery – Reduces size of primary tumor Adjuvant chemotherapy – Second-line chemotherapy after visible disease has been treated by surgery or radiation  Chemotherapy and the cancer patient Hematologic malignancies (like acute lymphocytic leukemia) frequently treated exclusively by induction and maintenance chemotherapy – Induction chemotherapy: intensive 1-month regimen to achieve remission Disappearance of signs/symptoms of cancer Greater than 99% of cancer cells destroyed – Maintenance therapy: 1-3 years of lower-dose chemotherapy to destroy remaining cancer cells To prevent relapse Chemotherapy and the cancer patient Cytotoxic effect is achieved by impairing cell division – Generates lethal genomic damage resulting in apoptosis – Inhibits cellular machinery involved in cell division Rapidly dividing cells (such as cancer cells) particularly susceptible  Chemotherapy and side effects Cytotoxic effect not limited to cancer cells – Normal cells/tissues also replicate and rapidly dividing tissues particularly susceptible Oral/gastrointestinal mucosa – Mucositis Bone marrow – Pancytopenia: anemia, thrombocytopenia, leukopenia » Risk of bleeding, infection, neutropenic fever – Contributes to accelerated aging Chemotherapy administered systemically and side effects may be distant from site of tumor Most survivors of childhood cancers have coexisting medical conditions, which may be life-threatening, by age 45  Chemotherapy and mucositis Acute complication of chemotherapy (and radiation therapy) – May be cause of discontinuing treatment May affect any portion of GI tract – ~ 5-15% of patients Oral mucositis particularly debilitating – Affects 80% of patients with head and neck radiation Near 100% of patients with oral/oropharyngeal cancers requiring adjuvant therapy  Chemotherapy and massive tumor cell lysis Successful chemotherapy may occasionally result in massive tumor cell lysis More common in rapidly dividing cancers, large cancers, or cancers particularly sensitive to cytotoxic chemotherapy – Release of large amounts of intracellular contents of dying cancer cells into blood (potassium, phosphate, nucleic acids) – Medical emergency Nausea, vomiting, diarrhea Heart failure, cardiac dysrhythmias Renal failure, hematuria Anorexia Possible sudden death  Chemotherapy and secondary malignancies Alkylating agents one of earliest cytotoxic agents discovered (1940s) and still in use today – Carboplatin, cisplatin, cyclophosphamide, others – Mechanism: DNA alkylation DNA cannot coil/uncoil properly – Transcription suppressed – Apoptosis initiated Alkylating agents weakly mutagenic and may predispose to development of secondary malignancy Often acute myeloid leukemia  Chemotherapy and targeted therapy Cytotoxic chemotherapy affects all rapidly dividing cells – Cancer cells and normally dividing cells Targeted chemotherapy targets specific cells harboring a genetic mutation or signaling pathway dysregulation – Side effects are reduced by targeting cancer cells but, in reality, not entirely eliminated Normal tissues in which targeted signaling pathway has physiologic role can be affected by targeted therapy Some breast cancers are characterized by HER2 amplification: Abnormal number of HER2 growth factor receptors Cells exquisitely sensitive to growth stimuli Trastuzamab (Herceptin) binds HER2 receptor on tumor cells, blocking downstream signaling and flagging cells for immune destruction  Chronic myelogenous leukemia: Characterized by t(9;22) chromosomal translocation ‘Philadelphia chromosome’ Results in hybrid BCR-ABL oncogene Imatinib (Gleevec): BCR-ABL tyrosine kinase inhibitor Capable of inducing sustained remission in CML patients 83F with multiply recurrent ameloblastoma, not candidate for surgery; 75% reduction in tumor volume 12 months following dabrafenib (BRAF inhibitor) therapy  Chemotherapy and immunotherapy Immunotherapy: type of chemotherapy augmenting host immune response against cancer Remember: cancer cells can downregulate activity of immune system by activating immune response checkpoints – May express PD-L1, PD-L2 (programmed death ligands) Activates PD-1 (programmed death-1) receptor on T cells Promotes apoptosis in certain T cells PD-L1 expression in lung cancer Checkpoint inhibitors: PD-1 or PDL-1 antagonists Enhance ability of immune system to recognize and destroy cancer cells Unfortunately, durable remission uncommon  Activated, antigen-specific CD8+ T-cells migrate from LNs to tumor to kill tumor cells Chimeric antigen receptor (CAR) T-cells: Genetically engineered CD8+ T-cells with tumor specificity Can be infused for treatment of various cancers  Adverse effects associated with all cancer therapies, including immunotherapy Inflammatory side effects may occur Colitis Rashes Polyendocrinopathies Cytokine storms Neurotoxicity Better safety profile than chemotherapy  FDA-approved therapies are emerging for epigenetic targets as well  Chemotherapy and drug resistance Once a cancer is established, genomic instability and accumulation of genomic alterations continues – Represents collection of genomically heterogeneous subsets Chemotherapy/targeted therapy may fail – Acquisition of new, drug-resistant mutations – Only cancer subclone (not entire cancer) may be susceptible to selected agent  One final therapeutic approach: hematopoietic stem cell transplantation Hematopoietic stem cells (HSCs) – Progenitor cells from which all formed elements of blood arise Hematologic malignancies are potentially curative by HSCT (bone marrow transplant) – These cancers usually originate from HSCs or HSC derivatives – Attempted cure by replacement of one’s HSCs (and therefore all formed elements of blood) with those of another  Hematopoietic stem cell transplantation: the basics HSCs harvested from donor: – Bone marrow (historically) – Peripheral blood after mobilization from bone marrow by administration of hematopoietic growth factors (most commonly) – Umbilical cord blood of newborn infants  Hematopoietic stem cell transplantation: the basics Prior to HSC transplant, recipient is irradiated and/or treated with chemotherapy – Destruction of cancer cells Heavier doses of chemoradiation than normal can often be employed without regard to bone marrow damage – Destruction of host immune system Allows donor HSCs to engraft in bone marrow niches occupied by previous HSCs Prevents host immune system from mounting attack on transfused HSCs (graft failure)  Complications of HSCT Immunodeficiency – Frequent complication – May result from: Prior treatment of cancer Myeloablative preparation for graft Delay in repopulation of recipient's immune system – Patients very susceptible to infection CMV (cytomegalovirus) particularly important and may be fatal  Complications of HSCT Graft-versus-host disease – Multisystem complication of allogeneic-HSCT Occurs in 30-70% of transplants May be acute or chronic – Functioning immune cells from non-identical donor (graft) recognize transplant recipient (host) as foreign Initiation of immune reaction targeting body of transplant recipient – Single most important factor determining long-term outcome and quality of life – Prophylactic immunosuppression cornerstone of patient management Increased risk of opportunistic infections and secondary malignancy  Oral erosions in aGVHD Lichenoid inflammation in cGVHD Atrophy, scaling, and hyperpigmentation in cGVHD SCC arising in patient with longstanding cGVHD  Clinical management of neoplastic disease Several specialties play a vital role – Any specialty that samples tissue for pathologic diagnosis Surgery most of the time Dermatology, dentistry… – Pathology – Radiology – Oncology Surgical oncology Medical oncology Radiation oncology