Oncologist: diagnosis and treatment of cancer

An oncologist is a physician who diagnoses, stages, treats, and monitors malignant tumors, working in collaboration with surgeons, radiation therapists, pathologists, radiologists, molecular diagnostic specialists, nurses, and psychologists. Modern oncology relies on the principles of early detection, accurate histological and molecular confirmation, individualized therapy, and long-term follow-up, which has been shown to improve survival and quality of life. [1]

The global cancer burden remains high, so healthcare systems are implementing standardized patient pathways: from the initial recognition of warning signs to discussion at a multidisciplinary team and prompt initiation of treatment. Success is determined not only by technology but also by the organization of the patient journey and the quality of decision-making. [2]

Oncology is divided into three key clinical areas: drug-based oncology, surgical oncology, and radiation oncology. Each area is based on clinical guidelines and quality standards, and the treatment plan for a specific patient is developed jointly at an oncology consultation. [3]

The oncologist's responsibilities include informed consent, shared decision-making, oncopsychological support, prevention of treatment complications, early inclusion of palliative care when indicated, and development of a post-treatment follow-up plan. This comprehensive approach is recommended by international societies. [4]

When to see an oncologist

An oncologist is needed not only in cases of confirmed cancer. Persistent, concerning symptoms warrant a consultation: unexplained weight loss, a lump in the breast or under the skin, blood in the stool or urine, prolonged hoarseness or cough, persistent pain, progressive difficulty swallowing, changes in moles, enlarged lymph nodes, as well as imaging or test results suspicious for a tumor. If these signs are present, it is important to seek diagnosis immediately. [5]

A referral to an oncologist is also made in the case of positive screening tests, precancerous conditions, detection of oncogenic viruses, or a significant family history. In the latter case, genetic counseling and testing are discussed, which is advisable if there is an increased likelihood of hereditary syndromes. [6]

The right to a second opinion is important at the stages of diagnosis and treatment selection. A consultation and second opinion reduce the risk of erroneous decisions and improve compliance with clinical guidelines. [7]

For patients diagnosed with cancer, an oncologist explains treatment goals, alternatives, potential risks, and expected benefits, coordinates treatment initiation, and, if necessary, arranges rapid access to palliative care and rehabilitation. Early involvement of palliative care improves quality of life and can prolong it. [8]

Table 1. Warning signs and recommended actions

Symptom	Why is it important?	Act One
Blood in stool, urine; hemoptysis	A possible sign of a tumor in the colon, genitourinary system, or lungs	Urgent in-person assessment and further examination
A lump in the breast or under the skin	Risk of breast or soft tissue tumors	Examination, visualization and biopsy when indicated
Unexplained weight loss, anemia	Possible systemic oncopathology	Laboratory screening and imaging as indicated
Persistent cough, hoarseness	Risk of airway tumors	Specialist examination and instrumental diagnostics
Change in a mole	Sign of melanoma	Dermoscopy and removal with histology when indicated

Based on the principles of early diagnosis and patient routing for suspected cancer. [9]

What is an oncologist appointment like?

The initial consultation includes a detailed medical history, risk factor and symptom assessment, and a physical examination with a focus on regional lymph nodes and potential primary tumor. A personalized plan for confirming the diagnosis is then developed, typically including imaging and tissue verification. [10]

The "gold standard" is morphological confirmation: cytology and histology with immunohistochemistry, and, if indicated, molecular and genomic tests to select targeted or immune therapy. The oncologist explains why a biopsy is necessary, the risks it carries, and how the results will change treatment. [11]

After confirmation of the diagnosis, staging is carried out according to the TNM system, an assessment of the general condition according to the Eastern Cooperative Oncology Group scale and other indicators, which is critical for the choice of treatment tactics and prognosis. [12]

The results are discussed at a multidisciplinary meeting: a treatment plan is developed, along with the timing and sequence of interventions, the need for reconstruction, rehabilitation, fertility preservation, and the scope of supportive therapy. The patient receives a clear action plan. [13]

Table 2. Basic tests most often initiated by an oncologist

Method	Target	Comment
Computed tomography	Staging, search for metastases	Often combined with contrasting
Magnetic resonance imaging	Soft tissue and CNS assessment	The choice of method depends on the localization
Positron emission tomography	Metabolic activity and prevalence	According to indications for clarification of the stage
Biopsy with histology	Confirmation of tumor type	The key to choosing therapy
Molecular profiling	Search for driver mutations and response markers	Affects the choice of targeted and immune therapy

The approaches are consistent with international oncology guidelines. [14]

Diagnosis, staging and biomarkers

The TNM staging system, supported by international organizations, describes the size and extent of the primary tumor, the status of lymph nodes, and the presence of distant metastases. It is the universal language of oncologists and determines prognosis and treatment strategy. [15]

Immunohistochemistry and molecular testing expand upon the classic tumor characterization by identifying receptor expression, mutations, and microsatellite instability. These data allow for the prescription of targeted drugs and immune checkpoint inhibitors when warranted. [16]

Assessment of the overall performance status using the Eastern Cooperative Oncology Group scale and comorbidities is necessary for the safe selection of regimens. Patients with low functional status tolerate intensive therapy less well, which shifts priorities in favor of gentler options and symptom control. [17]

Specific markers are used for a number of tumors: examples include PD-L1, BRCA, NTRK, EGFR, ALK, ROS1, and others. The availability of validated biomarkers and their correct interpretation by the oncologist and molecular panel improves the accuracy of therapy selection. [18]

Table 3. TNM components and their meaning

Component	What does it describe?	Example of clinical significance
T	Primary tumor	Affects the extent of surgery and radiation therapy
N	Regional nodes	Determines the need for systemic therapy
M	Distant metastases	Key factor in prognosis and treatment goals

A standardized staging language applicable to most solid tumors. [19]

Table 4. Examples of biomarkers and therapeutic decisions

Marker	Where is it important?	Possible solution
EGFR mutations	Non-small cell lung cancer	Targeted therapy with tyrosine kinase inhibitors
ALK restructuring	Non-small cell lung cancer	Specific ALK inhibitors
PD-L1 expression	Different localizations	Checkpoint inhibitors
BRCA mutations	Breast and ovarian cancer	PARP inhibitors when indicated
MSI-high	Colorectal cancer, etc.	Immunotherapy when indicated

Illustrative examples, choice depends on specific localization guidelines. [20]

Screening and prevention: what does an oncologist recommend?

Screening is intended for asymptomatic individuals and has been shown to reduce mortality from a number of cancers when implemented effectively and target groups are appropriately selected. Many organizations consider screening for cervical, breast, and colorectal cancers to be priority programs. [21]

For cervical cancer, human papillomavirus testing is preferred at age 30 years, with intervals depending on system resources and national protocols. Vaccination against human papillomavirus remains a basic measure of primary prevention. [22]

For breast cancer, updated recommendations from independent experts suggest starting regular mammography at age 40, every one or two years, depending on national guidelines and individual risk. For women at high risk, the strategy may differ. [23]

For colorectal cancer, high-sensitivity fecal occult blood tests at specified intervals or visual colonoscopy according to accepted protocols are recommended for those at average risk starting at age 45. Specific intervals and methods depend on country guidelines. [24]

Table 5. Frequently used screening programs

Localization	Target group	Method	Interval
Cervix	30-49 years and older according to indications	Human papillomavirus test	According to the healthcare system protocol
Breast	40-74 years old with average risk	Mammography	Every 1-2 years
Colorectal cancer	45-75 years old with average risk	High sensitivity stool tests or colonoscopy	According to the country's protocol
Mild (high risk)	Age and smoking history according to criteria	Low-dose computed tomography	According to the program protocol
Hereditary risk	Based on the results of genetic counseling	Personalized program	Individually

A summary framework for discussion with an oncologist, taking into account local guidelines. [25]

Treatment: principles and options

The oncologist selects a strategy based on the tumor's biology, stage, general condition, and patient preferences. Surgery, radiation therapy, and drug treatments are used, including cytotoxic chemotherapy, hormonal therapy, targeted and immune therapy, and, in some cases, cell technologies. A combination approach is often used. [26]

Immunotherapy with checkpoint inhibitors activates T-cell responses and is effective against a range of tumors, but requires monitoring for immune-related side effects and their timely treatment. An oncologist explains the expected benefits, risks, and monitoring plan during therapy. [27]

CAR-T cell therapy has already become an option for a number of hematological malignancies and is being studied in solid tumors. Decisions on its use are made in specialized centers under strict safety criteria. [28]

If standard options are unavailable or to access innovative treatments, an oncologist may suggest participation in a clinical trial. The phases of the trial define the objectives and extent of the intervention, and participation requires informed consent. [29]

Table 6. Main groups of oncological treatment

Group	Where it is applied	Key risks
Surgery	Localized tumors, palliative purposes	Complications of surgery, need for reconstruction
Radiation therapy	Local control, pre- and postoperative, symptom control	Skin and organ-specific reactions
Cytotoxic chemotherapy	Multiple localizations	Myelosuppression, nausea, neuropathy
Targeted therapy	If there are driver changes	Specific target toxicity
Immunotherapy	Various tumors	Immunoside effects, the need for early recognition

The choice is determined by the evidence base and individual indications. [30]

Teamwork, support and quality of life

Cancer treatment is a team effort. Multidisciplinary consultations improve adherence to guidelines and treatment outcomes, and molecular consultations help accurately interpret complex genomic findings. [31]

Supportive and palliative care should begin early in patients with advanced disease: pain and symptom management, nutritional support, anemia correction, cachexia treatment, psychological and social support. This improves quality of life and may reduce unnecessary hospitalizations. [32]

Fertility is a separate issue. Before starting potentially gonadotoxic treatment, the oncologist discusses the preservation of reproductive function, refers the patient to reproductive medicine specialists, and documents the decision in the treatment plan. [33]

Integrative non-pharmacological approaches can complement standard therapy for pain and anxiety management, but their use requires coordination with an oncologist and assessment of drug interactions. Particular attention should be paid to herbs and dietary supplements due to the risk of affecting the pharmacokinetics and pharmacodynamics of anticancer drugs. [34]

Table 7. Who is on the team and what are they responsible for?

Specialist	Main tasks
Oncologist-supervisor	Treatment plan, coordination, monitoring
Surgeon, radiotherapist	Local methods, volume planning
Pathologist, molecular specialist	Diagnosis, biomarkers, report
Radiologist, nuclear medicine specialist	Visualization, staging, response
Nurse, pharmacist	Therapy safety, patient education
Psychologist, nutritionist, rehabilitation specialist	Quality of life, recovery, support

The team structure reflects modern oncology practice. [35]

Table 8. Fertility preservation: what options are being discussed

Patient	Methods	Comment
Women	Cryopreservation of oocytes or embryos, cryopreservation of ovarian tissue, ovarian transposition	The choice depends on the time before treatment and diagnosis
Men	Sperm cryopreservation	Recommended before starting therapy
Individual cases	Consultation before starting treatment and during the course of treatment	The decision is recorded in the plan

Follow current clinical guidelines. [36]

Life after treatment and observation

After the active phase is complete, a monitoring plan is developed: a schedule of visits, tests, and imaging, a vaccination and prophylaxis plan, recommendations for activity, nutrition, and management of comorbidities. The risk of relapse and actions to take if new symptoms appear are discussed. [37]

Survivorship care standards include monitoring late treatment effects, mental health, sexual function, and work capacity, as well as coordination between the oncologist and primary care physician. Having a written plan improves coordination. [38]

Monitoring is individualized: the frequency of visits decreases over time if there are no signs of recurrence, but attention to new symptoms and prevention remains constant. If in doubt, a low threshold for unscheduled examinations is preferable. [39]

For patients with chronic disease or long-term therapy, the goal is to maintain quality of life, control symptoms and toxicity, and provide social and psychological support. Early consultation at signs of deterioration allows for timely adjustments to the plan. [40]

Table 9. What the monitoring plan includes

Component	Content
Schedule of visits	Frequency and format of visits with indication of goals
Control studies	Tests and visualization as indicated
Prevention	Vaccination, correction of risk factors
Rehabilitation	Physical activity, nutritional support
Psychosocial aspects	Support, return to work, informing family

Based on guidelines for the care of patients after cancer treatment. [41]

What to prepare for a visit to the oncologist

It's helpful to gather all available medical records, test discs, medication and supplement lists, a list of questions, and information about family history of cancer. This will speed up decision-making and reduce the risk of missing important details. [42]

Be sure to disclose all supplements and herbs. Some may interact with anticancer drugs and alter their effectiveness and safety. The decision to use them should be made in consultation with your oncologist. [43]

If potentially gonadotoxic therapy is to be considered, it is important to discuss fertility preservation early, as some treatments require time before the main treatment can be started.[44]

When planning treatment, ask about the goals of therapy, the likelihood of response, alternative options, expected side effects, and what to do if they occur. This is the basis of informed consent and shared planning. [45]

It is important to remember

1. Any suspicious symptom that persists or worsens warrants an in-person evaluation. 2) The diagnosis of cancer is confirmed pathologically. 3) Treatment decisions are based on the stage, biology of the tumor, and the patient's condition. 4) Early involvement of palliative care, when indicated, improves quality of life. 5) A follow-up plan and support are necessary after completion of treatment. [46]