ONCOLOGY – YESTERDAY, TODAY AND TOMORROW
Dr.V.P. Gangadharan MD, DM; HOD, Medical Oncology, Lakeshore Hospital, Kochi
Oncology of yesterday was a story of disaster and despair with crude
utilating surgeries, primitive radiotherapy techniques and highly toxic
chemotherapeutic drugs. Morbidity and mortality of treatment was high.
Oncology of today is a very promising arena in the field of medicine.
Few cancers are preventable, many are screenable, majority are treatable.
List of curable cancers are expanding. Oncology of tomorrow is heading
towards an era of vaccines and gene therapy. Oncology of today owes
very much to the advances in diagnosis and staging, especially to the
advances in pathology and radiology. Immunohistochemistry and tumour
markers have helped in specific diagnosis, prognostication, planning treatment and follow up. CT scan, MRI, PET scan and other advances in radiology have also contributed much to the progress in oncology. The advances in supportive care includes blood component therapy, new generation antibiotics, and growth factors like erythropoietin, G.CSF etc. Surgical oncology: Mutilating surgeries have given way for conservative surgeries. Organ conservation is the rule rather than
exception, without compromising cure. Even after radical surgeries, reconstruction techniques have helped to preserve the physical appearances. Surgical oncologist has become an integral part of the oncology team. Radiation oncology: Radiation oncology of yesterday was an area underdeveloped with severe morbidity following treatment, leaving behind permanent mutilitations and disfigurement and organ damages. Teletherapy units were with orthovoltage radiations lacking precision, poor penetration and high skin reactions. The newer machines are in the megavoltage ranges with facility for computerized simulation helping in precision to give maximum doses to the tumor and sparing normal tissues. In brachytherapy, radium has given way for safer, better isotopes like Cs132, Co60 etc. Advances in radiotherapy include electron beams, intraoperative radiotherapy, gamma knife, IMRT etc. Medical oncology: Perhaps, the maximum advances in oncology has
occurred in the field of Medical oncology. Newer drugs with better activity and less toxicity are available now Taxanes, Gemcitabine, newer platinums like oxaliplatin. Drugs selectively targeting the tumour cells has become areality. Capecitabine is a prodrug of 5 Flurouracil, which when given orally liberates the active drug at the tumour site. Tumour cells express antigens, monoclonal antibodies are developed against this antigens to selectively attack and kill these cells alone. Rituximab is a chimeric monoclonal antibody raised against CD20 antigen and is used in the treatment of Follicular Lymphomas. EGFR (Epidermal growth factor receptor) blocking: EGFR critically regulates tumour cell division, repair, and survival, and is involved in tumour metastases. Many human cancers express EGFR on cell surface. Inhibition of EGFR on tumour cells inhibit the growth or progression of EGFR expressing tumours. Binding of specific ligands to EGFR (eg. EGF, TGF alfa) activates the receptor and triggers the signal transduction cascades that affect cell proliferation. EGFR inhibition can be via monoclonal antibodies
blocking ligand binding (Trastuzumab, Cetuximab) or via tyrosine kinas inhibitors. (Geftinib, Erlotinib). Angiogenesis and cancer: Generation and growth of new bloods is essential for the tumour growth and spread. Tumour secretes growth factors (vascular endothelial growth factors, Fibroblastic growth factors, platelet
derived growth factors etc) which help this process. Antiangiogenic therapy in cancer is directed against neoangiogenesis. Agents developed along those lines are Bevacizumab, ZD 6474, Su 6668 etc. Host tumour interactions: Host tumour interactions through direct contact or soluble molecules help in tumour growth. Intra and extra cellular signals that help this process can be the targets for treatment of cancer. 26S proteosome is a target in this signaling cascade and Bortezomib is the
molecule directed at this target. Oncology of tomorrow is heading towards vaccines and gene therapy. Cancer is viewed as a play of genes. Correction of defective genes and augmentation of necessary genes may be the treatment of tomorrow. Oncology has made rapid stride in prevention, early detection, diagnosis, treatment and palliation. In the coming years, we are going to witness this disease yielding to the scientific advances and more and more cancer patients getting a cure.