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Colorectal Carcinoma (CRC) An Update Dipen Maru, MD Associate Professor Department of Pathology

Objectives • Challenges associated with staging of CRC • Histopathologic features with potential impact on patient outcome • Pathologic predictors of response to neoadjuvant therapy in rectal cancer and hepatic colorectal metastases • Review of clinically relevant molecular markers in CRC

Five-year survival by the AJCC 6th edition system

Staging of CRC

O'Connell, J. B. et al. J. Natl. Cancer Inst. 2004 96:1420-1425; doi:10.1093/jnci/djh275


Stage II Changes-TNM 7th edition T and N Stage

6th edition

7th edition

T2/T3N0

IIA

IIA

T4aN0

IIB

IIB

T4bN0

IIB

IIC

Changes in Stage III T and N stage

6th edition

7th edition

T1-T2/N1

IIIA

IIIA

T3-T4a/N1

IIIB

IIIB

T4b/N1

IIIB

IIIC

T1/N2a

IIIC

IIIA

T1-T2/N2b

IIIC

IIIB

T2-T3/N2a

IIIC

IIIB

T3-T4a/N2b

IIIC

IIIC

T4aN2a

IIIC

IIIC

T4b/N2

IIIC

IIIC

T3 CRC

• Majority of tumors • Variable depending on the segment of colon or rectum involved • Appropriate gross examination is mandatory


T3 CRC-Site dependent • Entirely intraperitoneal: Cecum, Transverse and sigmoid colon • Partly retroperitoneal: Ascending, descending colon, upper and mid rectum • Completely retroperitoneal: Lower rectum From AJCC Cancer Staging Manual 6th edition

T3

T4 CRC • Tumor extension into adjacent organs • Tumor penetrating the visceral peritoneum • Presence of tumor cells and not the desmoplastic response required • Perforated tumor


T4

T4 CRC • Poor outcome compared to T3 • High rate of recurrence (particularly in rectal cancer) • High risk factor in stage II CRC • T4 tumors with direct extension to adjacent organs have poor outcome than T4 tumors which penetrates the visceral peritoneum* * SEER database, 2007

Proposed Changes in T4-7th TNM-AJCC staging • T4a: Tumor penetrates the visceral peritoneum (serosa) • T4b: Tumor histopathologically involves the adherent organ

T4 CRC Category TN

SEER Relative Survival, 5y

SE

TNM Stage, 6th Ed’n

SEER TNM Observed Stage, 7th Survival, 5y Ed’n

SE

T4aN0

79.6

1.0

IIB

IIB

60.6

0.8

T4bN0

58.4

1.3

IIB

IIC

45.7

1.0

T4aN1a

67.6

2.0

IIIB

IIIB

52.2

1.5

T4bN1a

38.5

2.2

IIIB

IIIC

30.6

1.8

SEER database, 2007


Stage II CRC-? Postoperative adjuvant chemotherapy • High risk histopathology factors: – T4 – Perforated tumors – Lymphovascular invasion – Poorly differentiated histology – High grade neuroendocrine histology – Inadequate numbers of lymph nodes examined

Nodal (N) Stage • Number of positive regional lymph nodes • ? Soft tissue tumor deposit • Isolated tumor cells: – Single tumor cell or minute cluster of tumor cells on H & E and IHC – pN0(i+)

Soft Tissue Tumor Deposit (TD)

Soft Tissue Tumor Deposit (TD) • Discrete foci of tumor in pericolic fat away from the leading edge of tumor without evidence of residual lymphoid tissue • If nodule has smooth contour consider as positive node

Irregular contour : Consider extramural large vessel invasion (6th edition) Consider satellite nodule and for T1 and T2 tumor include in N1c category (7th edition)


No. of positive LNS

AJJC staging 6TH edition

AJCC 7TH edition

1

N1

N1a

2-3

N1

N1b

4-6

N2

N2a

7 or more

N2

N2b

Tumor deposit with NA irregular border in pericolonic/rectal soft tissue with negative nodes

N1c for T1-T2 tumors

Unique histopathologic features with potential Impact on patient outcome

CRC staging-take home message • T3 is site dependent-Gross examination is critical • T4 category has significantly poorer outcome than T3 • T4 has three different histologic patterns • Clinically important to examine as many lymph nodes as possible even when more than 3 are positive

• Histologic features associated with microsatellite instability high CRC • High grade neuroendocrine carcinoma • Signet ring cell adenocarcinoma • Tumor budding


MSI-High CRC-Histologic features • • • •

Variegated histology Signet ring cell adenocarcinoma Mucinous adenocarcinoma Undifferentiated solid pattern (medullary carcinoma type) • Prominent intraepithelial lymphocytosis • Pushing border • Peritumoral lymphoid nodules

Neuroendocrine carcinoma

Synaptophysin

Neuroendocrine carcinoma (NEC) • Pure high grade NEC aggressive behavior • Up to 70% pts. have metastasis at presentation • 5 year survival 13% • Mixed adenocarcinoma/NEC: limited data for any conclusive observation


Signet ring cell adenocarcinoma

Signet ring cell adenocarcinoma-IBD associated

• Frequent association with inflammatory bowel disease • Microsatellite instability high CRC • Metastases or local extension of an appendiceal primary • Metastases from other sites

Signet ring cell adenocarcinoma-IBD associated

Signet ring cell adenocarcinoma-IBD associated


Tumor budding • Presence of cluster of 5 or less tumor cells at the invasive margin of tumor • Associated with poor outcome in T3N0 CRC • Method of counting tumor buds not uniform

Tumor budding • Need more data on method of quantitation • Small number of CRC show tumor budding-MDACC experience


Take home message • MSI-H CRC has variegated histology • MSI-H CRC can mimic metastatic carcinoma • High grade neuroendocrine carcinoma have poor prognosis • Signet ring cell adenocarcinoma are associated with MSI-H or IBD related CRC • Universal grading system required for tumor budding

Histopathologic response to chemoradiotherapy • Pathologic response to neoadjuvant therapy in rectal carcinoma – Tumor regression grade – Percentage of residual tumor cells

• Pathologic response in hepatic colorectal metastases

Histopathologic response to neoadjuvant or adjuvant therapy

Pathologic response to neoadjuvant therapy in rectal cancer – An independent prognostic indicator of patient outcome – Submission of entire scar area or majority of grossly identifiable lesion – Tumor regression grade – Quantitative pathologic response (% of residual tumor cells)


Rectal Cancer- Grading of Pathology Response to Preoperative Chemoradiation Description No viable cancer cells Single cells or small groups of cancer cells Residual cancer outgrown by fibrosis Minimal or no tumor kill; extensive residual cancer

Tumor Regression Grade 0 (Complete response)

Grade 0 (Complete Response) Acellular Mucin

1 (Moderate Response) 2 (Minimal response) 3 (Poor response)

Grade 1 (Moderate Response)

Grade 2 (Minimal Response)


Rectal Cancer- Tumor Regression Grade

Grade 0 or 1

Grade 2 and 3

Suarez et al, Colorectal dis. 2008

Grade 3 (Poor Response)

Quantitative Pathology Response

Quantitative Pathologic Response-Predictor of DFS

Complete , 0%

Near complete,< 5%

Major,5-<50%

Minor, â&#x2030;Ľ50% Agarwal A et al, Cancer, In Press


Tumor Regression Grade

Pathologic response to neoadjuvant therapy in colorectal liver metastases Three systems of assessing histopathology response to preoperative chemotherapy in resected CLM

TRG5: No regression TRG4: Residual cancer cells > fibrosis TRG3: Fibrosis predominates tumor cells TRG2: Rare cancer cells scattered throughout the fibrosis TRG1: Absence of residual cancer Rubbia-Brandt L et al. Ann Oncol, 2007

Pathologic response in hepatic colorectal metastases (HCRM)

Pathologic Response 1.0

Complete response (0% viable)

Blazer DG et al. J Clin Oncol, 2008

0.8 Cumulative survival rate

a.Complete response: No residual tumor cells b. Major response: <50% residual tumor cell c. Minor response: â&#x2030;Ľ50% residual tumor cells

Major response (1-49% viable)

0.6

0.4

Minor response (50-100%viable)

0.2

0.0 0

1

2

3

4

5

6

7

8

19 10

Survival (years)

Blazer et al, Journal of Clinical Oncology, 2009


Uninterrupted Tumor Thickness at TumorNormal Liver Interface

a. <0.5mm b. 0.5-<5mm c. ≥ 5mm

Maru DM et al. Am J Surg Pathol, 2010

Multicenter Validation of Pathologic Response and Tumor Thickness at the Tumor–Normal Liver Interface

Maru D et al. Am J Surg Path 2010

Correlation of Pathologic response and TNI with DFS

• Retrospective study four major hepatobiliary centers – The University of Texas MD Anderson Cancer Center, Houston, USA – Center Leon Bernard, Lyon, France – Ambroise Pare Hospital, Paris, France – Medical University of Vienna, Austria – N=171 Brouquet et al. Cancer, 2013

Brouquet et al. Cancer, 2013


Multicenter Validation of Pathologic Response and Tumor Thickness at the Tumor–Normal Liver Interface • Reproducibility Data: – Agreement for both parameters – 116/171 patients – Agreement for one parameter – 167/171patients – Disagreement for both parameters – 4/171 patients – Near perfect agreement (kappa = .82) for pathology response categories – Substantial agreement (kappa = .76) for tumor thickness at TNI

Take home message • Pathologic predictors of response to neoadjuvant therapy are required elements in pathology reports • Relatively a new histopathologic feature needs appropriate sampling and familiarity with the histopathology grading of the response

Major molecular pathways

Molecular Alterations in CRC

• Chromosomal instability (aneuploid) • DNA mismatch repair genes (MMR) abnormalities • Promoter region CpG island methylation (epigenetic changes)


Mismatch repair genes (MSI-high CRC) • DNA repair genes • Defective DNA repair and mutation in the effector genes • hMLH-1/hMSH-2/hMSH-6//hPMS-2 • Molecular assay and IHC

MSI Analysis using micro satellite markers

Loss of MLH-1 by immunohistochemistry MLH-1

IHC vs. Molecular assay • Sensitivity/specificity • IHC negative mol assay: Truncated mutation/ MSH-6 • MSI in adenoma • MSI in treated tumor

Amount of DNA

Size of DNA Fragments (bp)

Allelic shift in tumor demonstrated by presence of new peaks as compared to control normal tissue

MSH-2


MSI-high tumors can show aberrant CK7/CK20 immunoprofile

MSH-2

MLH-1


CK7

CK20

MSI-High CRC • Hereditary-HNPCC (Lynch) syndrome • Sporadic MSI high CRC

MSI-High CRC-HNPCC • Germline mutation in MMR in patient and family members • Commonly affected genes; MSH-2 and MLH-1 • Endometrial/Ovarian/Skin tumors


Revised Bethesda guidelines for HNPCC and testing for MSI 1. CRC diagnosed in a patient younger than 50 years 2. Synchronous, metachronous CRC or other HNPCC associated tumors regardless of age 3. CRC with MSI-H histology diagnosed in a patient who is younger than 60 years 4. CRC diagnosed in one or more first degree relatives with an HNPCC-related tumor, with one of the cancer diagnosed under 50 years 5. CRC in two or more first or second degree relatives with HNPCC related tumors, regardless of age

Sporadic MSI-high colon cancer • Methylation of promoter region • Common genes involved are BrafV600E and MGMT • Associated with serrated lesions • Histology not possible to differentiate familial versus sporadic forms

MSI-High CRC-Sporadic • No familial predisposition • Methylation of promoter region of MLH-1 • Survival advantage in stage II and stage III CRC • Poor response to fluropyrimidines

Ribic et al. NEJM;July 2003


MSI-high colon cancer • Survival advantage • Less likelihood of metastasis to regional lymph nodes • Resistance at least in vitro to some chemotherapeutic agents • Genetic implications • Risk of other malignancies

Markers for Fluoropyrimidines • Thymidylate Synthase- Target of fluoropyrimidines • Dihydropyrimidine dehydrogenase and thymidine phosphorylase- Catabolism of fluoropyrimidines • MSI-High tumors-Poor response

Molecular Alterations-Role in deciding Adjuvant Therapy • Markers for Fluoropyrimidines • Markers for Oxaliplatin/Irinotecan • Markers for AntiEGFR therapy

Markers for Oxaliplatin/Irinotecan • Excision Repair cross-complementing 1 (ERCC1) gene product removes oxaliplatin metabolite from the tumor DNA • High expression of this gene associated with poor outcome after Oxaliplatin • Polymorphism in UGT1A1 associated with increase toxicity of Irinotecan


Markers for AntiEGFR therapy • Immunohistochemistry for EGFR-Not predictive • EGFR mutation-Not predictive • Skin rash-Grade 3- Predictive of response • EGFR gene copy number by FISH- Lack standardization • KRAS mutation-Predicts the absence of response to Anti-EGFR therapy Siena et al. JNCI 2009

2/2008: Progressive Disease 12/2007

Third-Line Panitumumab vs. Best Supportive Care: Impact of KRAS Mutations—PFS PFS by KRAS Statusa and Treatmentb

New met Wild-Type KRAS

100 90 80 70 60 50 40

PMAB + BSC BSC Alone

Events/N (%) 76/84 (90) 95/100 (95)

Median in weeks 7.4 7.3

Mean in weeks 9.9 10.2

30 20 10

Proportion Event-Free (%)

Proportion Event-Free (%)

Mutated KRAS 100 90 80 70 60 50 40

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52

Events/N 115/124 114/119

(%) (93) (96)

Median in weeks 12.3 7.3

Mean in weeks 19.0 9.3

30 20 10

0

PMAB + BSC BSC Alone

Prior RFA 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52

a The quantitative interaction test comparing the magnitude of the relative treatment effect on PFS between wild type and mutant KRAS was statistically significant (P<.0001). b When treatment arms were combined, overall survival was longer in patients with wild-type KRAS vs. patients with mutant KRAS. Amado et al. JCO, April 2008

New met

P<0.0001

0


K-ras mutation and Anti-EGFR therapy

Negative Control

No. of Base pairs

Patient

GGT

GCT

No. of Base pairs

Markers for AntiEGFR therapy • B-raf V600E mutation: ~10% CRC • PI3K mutation: ~25% CRC • PTEN loss by immunohistochemistry: 1216% CRC

• 35% of metastatic CRC • Codon 12, 13, 61 • Discordant mutation results between primary and metastases • Use the most recent CRC • Multigene plate forms (sequenom, Ion Torrent) vs. pyrosequencing vs. sanger sequencing

Take Home Message • Limited applications in-spite of abundance of literature • MSI status in certain patient population • Methylation in MSI high tumors • KRAS mutation for Anti-EGFR therapy • Polymorphism in UGT1A1 associated with increase toxicity of Irinotecan


Conclusion Although the ongoing research in molecular alterations in CRC has significantly contributed in advancement of personalized care, an appropriate staging based on meticulous examination of pathology specimen and several histopathologic features are more important than any biomarker in assessing prognosis of majority of CRC patients

Thank you Questions?

Dr Maru colon cancer  

Handout de la conferencia "Colorectal Cancer, an update" dictada por el Dr. Dipen Maru del MD Anderson Cancer Center en Lima, Peru.