oncology

 

Definition of Oncology

ONCOLOGIST: An oncologist is a physician who specializes in the study and treatment of neoplastic diseases,particularly cancer.

Oncology subspecialities

1 surgical oncology

it provides definitive surgical treatment of localized malignancies, lnowledge of and ability to consult with other modalities in the choosing adjustment therapy preoperatively and postop,reconstruction and rehabil9itation for resected organs,provides debulking of residual cancers.

2 Radiation oncology

radiation therapy is used for local tunor control, an approach shared with suirgeru. Ot mau also vbe used in a locoregional approach. Effedrtivelu srerulizing the tumor within a field, including first station lunphnodes. In lukenias and lumphomas, radiarion can also ve used as a sustemic control.

3medical oncology:chemotherapu is curative for lukemiads, lumphomas,hodgkins disease,choriocarcinomas, some pediatric malignancies and especially testicular cancers.

An oncologist must have the following qualification

-graduation fron an approved medical school

completion of acgme accredited internal medicine residency program, which isw minimum of therr in length ,.

Completion of subspeciality fellowship in oncologym which must be three years


Major diseases

Leukemias

Hodgkins disease

Peadiatric solid tumors

Leukemias

Lukemias are clonal disorders characterized by uncontrolled proliferation of cells..typed of lukemias

Acutemyeloid leukemia,chronic myeloid leukemia,chronic lymphocytic leukemia,acutelymphocytic leukemia

Acute myeloid lukemia

Signs and symptoms

Weakness,fatigue reflecting anemia,dyspnoea on exercise,pustules and pyogenic skin infection,excessive bleeding following minor injuries,easy bruising,fever in about 50% patients,malaise and anorexia

Diagnostic testing diagnosis done based on signs and symptoms,physical examination,peripheral blood findings,bone marrow findings

Physical examination gingival hyperplasia,lymphadenopathy,hepatospleenomegaly,skin infiltration,painful red brown nodules

Peripheral blood findings presence of blast form cells,50%patients will have lukopenia and absolute neutropenia,5-20%will have elevated WBC counts,anemia,thrombocytopenia

Bone marrow findings bone marrow hypercellular,megacaryocytes are decreased or absent,monotonous infiltration of blast cellsbone marrow findings done by cytochemistry,cytogenesis,immunotyping

Risk factors environmental factors-eg.benzene

Ionizing radiations

Chemotherapy-alkylating agents-procarbazine

Genetic factors

Potential treatments of the disease induction chemotherapyinduction regimen ara-c plus continous infusion of ara-c at 100mg/m square/day for 7 days used with bolus infusion of daunorubicin at 45mg/m square/day for 3 days

Postremission therapy

Consolidation chemotherapy

Analogus bine marrow transplant

Allogenic bone marrow transplantation

Consolidation chemotherapy

Low dose maintainence chemotherapy following induction can prolong complete remission duration compared with no further therapy.

Patients entering remission following standard induction are randomized to receive four cycles of consolidation of three doses of ara-c:

100mg/m square * 5 doses

400mg/m square * 5 doses

3g/m square * 6doses

For patients younger than 60 , with favorable cytogenetics,consolidation using repetitive cycles of heavy dose ara-c yields best disease free survival results.

Autologus bone marrow transplantation

In auto bone marrow transplantation,haemopoetic recovery from high dosechemoradiation is provided by an infusion of patients own bone marrow

Allogenic bone marrow transplantation

Patientsw are rescued from consequences of marrow ablation by infusion of normal haemopoetic cells from allogenic donor.

Prognosis

Most trials consistently show higher relapse rates in patients undergoing autologous bone marrow transplant . chemotherapy results in complete remission rates of 50-90%

The transpolant related mortality for patients undergoing autologus bone marrow transplantation is less than 10%.mortality rate for allgenic bone marrow transplant .

Pathophysiology

Acute myeloid lukemisa is belived to result from malignant transformation of a single hemopoetic stem cell.clonal proliferation and a block in normal differentiation and maturation are characteristic features. Aml is a mukltistep process,with an initial transformation event in a haemopoetic stem cell followed by additional genetic abnormalities in descendents of clonally derived cells. Oncogenes and antioncogenes are believed to have a critical role in pathogenesis of acute leukemia.

Hodgkins disease

Signs and symptoms

Painless lymph node enlargement

Constitutional symptoms-unexplained fevers,drenching night sweats,significant weight loss,pruritis,malaise,alcohol intolerance

Diagnostic investigations

History and physical examination

Imaging

Chest xray,ctscan,mri

-abdomen ct scan-abdominal and pelvic nodes-nodes larget then 1 cm in short acis dianeter is considered abnornmal

bipedal lumphangiogram

gallium imaging with single photon emission computerized tomography-helpful for staging and monitoring respinse to therapyu

lab procedures

complete blood cell count

differential wbc count

esr

showing neutrophilic leukocytosis,mild normocytic,normochromic anemia and eosinophilia may occur

blood chemoistry

elevated alkaline phosphatase level reflects involvement of liver, bone marroe or bone.

Bone marrow biopsy

Biopsy of lymph nodes

Pathophysiology

In about 75% cases,cellular nodules containing plasma cells, neutrophilsand eosinophils are surrounded by bands of polarisable collagen.

Giant cells ,knoen as reed sternberg cells are pathognomic of this disease.


Potential treatment of the disease

Surgery

Primary rolr of surgry is to obtain tissyur for biopsyu

Radiation therapy

Dose required-

Clinically involvd nodes- 3.6-44 gy

Prophylactic treatment 25-36 gy

Each tratnent fraction delivers 1.5-1.8gy

Complications of radiation therapy

Transient bone marrow suppression,radiation pneumonitis(5%),pericarditis(5%)

Chemotherapy

MOPP-mechlorethamine,oncovin,procarbazine,prednisone

CHlVPP,ABVD,Stanford V

Bone marrow transplant

]used for advanced disease,relapsed disease,unresponsive to chemotherapy

combined modality treatment

started with chemotherapy-treats all sites of disease at the outset ,reduces bulky disease to facilitate subsequent irradiation

prognosis

relapse after initial therrapu occute nost often within 4 yeats-late relapses may occur

aprox 10-30% [atients with advanced hodgkins disease dinit achieve complete remissions wirth initial treatment of they have relapse afrer initialu efedtive treatment eith chemotherapy

stage IV disease 60-90% 5year survival

I &II 70-95% 5year survival




CLINICAL ONCOLOGY PHILIP RUBIN

PRINCIPLESAND PRACTICE OF ONCOLOGY VINCENT

CANCER TREATMENT HASKELL DE VITA

ONCOLOGY HANBOOK M.D. ANDERSON

Plowc.org

Cancernetwork.com

Oncolink.upenn.edu

Asco.org

Ons.org