I85PREP
⌘ K
ABPS Radiation Oncology study materials
ABPS Radiation Oncology study resources

ABPS Radiation Oncology practice questions

One question at a time. Build your ABPS Radiation Oncology understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which histologic subtype of lung cancer is most strongly associated with smoking and typically arises centrally in the major bronchi?

  1. Squamous cell carcinoma Correct answer.
  2. Carcinoid tumor
  3. Adenocarcinoma
  4. Bronchioloalveolar carcinoma

Explanation

Squamous cell carcinoma classically arises in the central airways and has the strongest smoking association among non-small cell histologies. Adenocarcinoma is the most common subtype overall and tends to be peripheral.

Question 2Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with early-stage glottic laryngeal cancer has disease confined to the true vocal cord with normal cord mobility. What is the T category?

  1. T1 Correct answer.
  2. T4
  3. T3
  4. T2

Explanation

T1 glottic cancer is limited to the vocal cord(s) with normal mobility and may involve one or both cords. Impaired mobility or extension beyond the cord defines higher T categories.

Question 3Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the standard definitive non-surgical treatment for a patient with muscle-invasive bladder cancer who wishes to preserve the bladder?

  1. Maximal transurethral resection followed by concurrent chemoradiation Correct answer.
  2. Systemic chemotherapy alone
  3. Intravesical BCG alone
  4. Partial cystectomy alone

Explanation

Trimodality therapy with maximal TURBT plus concurrent chemoradiation is the established bladder-preservation approach for muscle-invasive disease. Intravesical therapy is for non-muscle-invasive disease, and systemic chemotherapy alone is not curative.

Question 4Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which nodal station is most commonly the first site of spread for a distal rectal cancer?

  1. Mesorectal nodes Correct answer.
  2. Superior mesenteric nodes
  3. Internal mammary nodes
  4. Inguinal nodes

Explanation

Rectal cancer drains primarily to the mesorectal nodal basin, which is why total mesorectal excision and mesorectal irradiation are central to management. Inguinal drainage occurs only with involvement of the anal canal below the dentate line.

Question 5Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most radiosensitive normal tissue in the central nervous system?

  1. Cerebral white matter
  2. Optic nerve Correct answer.
  3. Spinal cord
  4. Brainstem

Explanation

The optic nerve and chiasm are relatively radiosensitive and tolerance is limited to avoid optic neuropathy. The spinal cord and brainstem have higher tolerance but catastrophic injury if exceeded.

Question 6Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

What is the most common histology of thyroid cancer?

  1. Follicular carcinoma
  2. Anaplastic carcinoma
  3. Papillary carcinoma Correct answer.
  4. Medullary carcinoma

Explanation

Papillary thyroid carcinoma accounts for the majority of thyroid malignancies and generally has an excellent prognosis. Follicular, medullary, and anaplastic subtypes are less common.

Question 7Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following best describes the standard radiation field for a patient with early-stage seminoma after orchiectomy?

  1. Para-aortic and ipsilateral iliac nodal irradiation Correct answer.
  2. Cranial prophylaxis
  3. Whole-abdominal irradiation
  4. Involved-field irradiation of the scrotum only

Explanation

Seminoma spreads predictably along para-aortic and ipsilateral iliac lymphatics, so these are the classic target volumes. Scrotal and cranial irradiation are not part of standard management.

Question 8Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is a recognized risk factor for the development of breast cancer?

  1. Early menarche Correct answer.
  2. Early menopause
  3. High parity
  4. Late menarche

Explanation

Early menarche increases lifetime estrogen exposure and is an established breast cancer risk factor. Late menopause and nulliparity also increase risk, whereas high parity is protective.

Question 9Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with locally advanced cervical cancer is treated with definitive chemoradiation. Which concurrent chemotherapy agent is standard?

  1. Cisplatin Correct answer.
  2. Bevacizumab
  3. Gemcitabine
  4. Doxorubicin

Explanation

Weekly cisplatin given concurrently with external beam radiation improves survival in locally advanced cervical cancer. Other agents are not standard concurrent radiosensitizers in this setting.

Question 10Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a T2N0M0 non-small cell lung cancer in the right upper lobe is medically inoperable. Which treatment is most appropriate?

  1. Observation alone
  2. Prophylactic cranial irradiation
  3. Stereotactic body radiation therapy Correct answer.
  4. Whole-lung irradiation

Explanation

SBRT delivers ablative doses to a limited target and is standard for medically inoperable early-stage NSCLC. Whole-lung and cranial irradiation are not appropriate for localized disease.

Question 11Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

In a patient with a T3N1M0 rectal cancer, which sequence of therapy is most consistent with current standards for sphincter preservation and local control?

  1. Neoadjuvant chemoradiation followed by surgery Correct answer.
  2. Surgery followed by observation
  3. Systemic chemotherapy alone
  4. Definitive radiation alone

Explanation

Neoadjuvant chemoradiation improves local control and downstages tumors before surgery in locally advanced rectal cancer. Radiation or chemotherapy alone is not definitive local therapy.

Question 12Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following patients with prostate cancer is the best candidate for definitive external beam radiation therapy rather than active surveillance?

  1. A 72-year-old with Gleason 6, PSA 5, and T1c disease
  2. A 70-year-old with Gleason 8, PSA 15, and T2b disease Correct answer.
  3. A 68-year-old with Gleason 6, PSA 3, and T1c disease
  4. A 65-year-old with Gleason 6, PSA 4, and T1c disease

Explanation

High-risk features such as Gleason 8, elevated PSA, and palpable disease warrant definitive treatment. Low-risk disease (Gleason 6, low PSA, T1c) is often suitable for active surveillance.

Question 13Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a locally advanced head and neck squamous cell carcinoma is treated with definitive radiation. Which concurrent systemic agent improves overall survival?

  1. Methotrexate
  2. Cisplatin Correct answer.
  3. Interferon alfa
  4. Cetuximab monotherapy

Explanation

Concurrent high-dose cisplatin with radiation improves survival in locally advanced head and neck cancer. Other listed agents are not standard concurrent radiosensitizers with proven survival benefit.

Question 14Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a single brain metastasis from NSCLC has controlled systemic disease and a good performance status. Which approach offers the best local control and survival?

  1. Whole-brain radiation alone
  2. Surgical resection or stereotactic radiosurgery plus whole-brain radiation Correct answer.
  3. Observation
  4. Systemic chemotherapy alone

Explanation

For a single accessible metastasis with good prognosis, local aggressive therapy (surgery or SRS) plus whole-brain radiation improves local control and survival. Whole-brain radiation alone provides inferior local control for a solitary lesion.

Question 15Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following best describes the standard target volume for whole-breast radiation after breast-conserving surgery?

  1. The ipsilateral axilla only
  2. The entire breast tissue with a boost to the tumor bed in selected patients Correct answer.
  3. The tumor bed only
  4. The contralateral breast

Explanation

Whole-breast irradiation treats the entire remaining breast, with a tumor-bed boost added for higher-risk features. Treating only the tumor bed or axilla would leave at-risk tissue untreated.

Question 16Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with limited-stage small cell lung cancer is treated with concurrent chemoradiation. Which of the following is a standard component of management?

  1. Observation after chemotherapy
  2. Stereotactic body radiation therapy alone
  3. Prophylactic cranial irradiation after a complete response Correct answer.
  4. Routine whole-lung irradiation

Explanation

Prophylactic cranial irradiation reduces brain metastases and improves survival in patients with limited-stage SCLC who achieve a complete response. Whole-lung irradiation and SBRT alone are not standard.

Question 17Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate management for a patient with stage I seminoma and a normal post-orchiectomy evaluation who prefers surveillance?

  1. Retroperitoneal lymph node dissection
  2. Immediate para-aortic radiation
  3. Active surveillance with periodic imaging and tumor markers Correct answer.
  4. Systemic chemotherapy

Explanation

Surveillance is a standard option for stage I seminoma given the high cure rate and low relapse risk. Radiation and chemotherapy are alternatives but not mandatory.

Question 18Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with esophageal cancer has a tumor at 30 cm from the incisors. Which nodal basin is most at risk and should be included in the radiation field?

  1. Inguinal nodes
  2. Axillary nodes
  3. Mediastinal and celiac nodes Correct answer.
  4. Internal mammary nodes

Explanation

Mid-to-distal esophageal tumors drain to mediastinal and celiac nodal basins, which are included in target volumes. Inguinal, axillary, and internal mammary nodes are not primary drainage sites.

Question 19Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the standard radiation dose-fractionation for palliation of painful bone metastases?

  1. 8 Gy in a single fraction Correct answer.
  2. 40 Gy in 20 fractions
  3. 30 Gy in 30 fractions
  4. 50 Gy in 25 fractions

Explanation

Single-fraction 8 Gy provides equivalent pain relief to longer courses for uncomplicated bone metastases. Prolonged fractionation is unnecessary for palliation.

Question 20Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with Hodgkin lymphoma has bulky mediastinal disease. Which radiation technique consideration is most important to limit cardiac and pulmonary dose?

  1. Involved-site radiation with modern conformal planning Correct answer.
  2. Craniospinal irradiation
  3. Total nodal irradiation
  4. Mantle-field irradiation

Explanation

Involved-site radiation with modern conformal techniques reduces dose to heart and lungs compared with historic mantle fields. Mantle and total nodal irradiation expose large volumes unnecessarily.

Question 21Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a T1N0M0 anal canal squamous cell carcinoma is treated with definitive chemoradiation. Which chemotherapy regimen is standard?

  1. Mitomycin C and 5-fluorouracil Correct answer.
  2. Gemcitabine and carboplatin
  3. Doxorubicin and cyclophosphamide
  4. Cisplatin and paclitaxel

Explanation

Mitomycin C with 5-fluorouracil is the standard concurrent regimen with radiation for anal cancer. Other regimens are not standard for definitive anal cancer chemoradiation.

Question 22Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with localized prostate cancer is considering brachytherapy. Which factor most strongly favors brachytherapy as monotherapy?

  1. Low-risk disease with a small prostate volume Correct answer.
  2. Prior transurethral resection of the prostate
  3. Large prostate volume with obstructive symptoms
  4. High-risk disease with seminal vesicle invasion

Explanation

Brachytherapy monotherapy is best suited to low-risk disease with favorable gland size and no significant obstruction. High-risk disease, large glands, and prior TURP increase risk of failure or toxicity.

Question 23Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a brain metastasis from melanoma is treated with stereotactic radiosurgery. Which property of melanoma is most relevant to this choice?

  1. Relative radioresistance at conventional fractionation Correct answer.
  2. Complete lack of contrast enhancement
  3. Tendency for diffuse leptomeningeal spread only
  4. Extreme radiosensitivity

Explanation

Melanoma is relatively radioresistant at conventional doses, which is why high single-fraction doses with SRS are favored. Melanoma metastases are typically well visualized on contrast imaging.

Question 24Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a locally advanced pancreatic cancer has borderline resectable disease. Which sequence is most appropriate?

  1. Neoadjuvant chemotherapy with or without radiation followed by reassessment for surgery Correct answer.
  2. Observation until progression
  3. Immediate surgery without neoadjuvant therapy
  4. Definitive radiation alone

Explanation

Borderline resectable pancreatic cancer is managed with neoadjuvant chemotherapy, often with radiation, followed by restaging and surgery if feasible. Immediate surgery risks positive margins.

Question 25Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A patient with a T4a laryngeal cancer with thyroid cartilage penetration is treated with definitive chemoradiation. Which factor most strongly predicts the need for a post-treatment neck dissection?

  1. Absence of nodal disease at diagnosis
  2. Normal post-treatment PET scan
  3. Persistent nodal disease on imaging after chemoradiation Correct answer.
  4. Complete clinical response of the primary

Explanation

Persistent nodal disease after chemoradiation is the main indication for planned neck dissection. A complete response in nodes generally allows observation.

Question 26Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 62-year-old man presents with a 2 cm squamous cell carcinoma of the anal canal with no palpable inguinal lymph nodes. According to standard staging, what is the T category?

  1. T4
  2. T1
  3. T3
  4. T2 Correct answer.

Explanation

In anal canal carcinoma, T1 is tumor 2 cm or less in greatest dimension, T2 is more than 2 cm but not more than 5 cm, T3 is more than 5 cm, and T4 invades adjacent organs. A 2 cm tumor falls into the T1 category, not T2.

Question 27Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most common site of distant metastasis in patients with nasopharyngeal carcinoma?

  1. Liver
  2. Brain
  3. Bone Correct answer.
  4. Lung

Explanation

Bone is the most frequent site of distant metastasis in nasopharyngeal carcinoma, followed by lung and liver. Brain metastasis is uncommon.

Question 28Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 55-year-old woman with early-stage breast cancer is treated with breast-conserving surgery and whole-breast radiation. She has a history of implant-based breast reconstruction. Which radiation technique is most appropriate to minimize dose to the implant?

  1. Prone positioning
  2. Intensity-modulated radiation therapy (IMRT) Correct answer.
  3. Electron beam therapy
  4. Accelerated partial breast irradiation (APBI)

Explanation

IMRT allows better dose conformity and homogeneity, reducing high-dose volumes to the implant and improving cosmetic outcomes. Prone positioning may help in some cases but is not as effective as IMRT for implant sparing.

Question 29Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate radiation dose for palliation of dysphagia in a patient with metastatic esophageal cancer and a life expectancy of 3 months?

  1. 20 Gy in 5 fractions Correct answer.
  2. 35 Gy in 15 fractions
  3. 50 Gy in 25 fractions
  4. 30 Gy in 10 fractions

Explanation

For palliation of dysphagia with short life expectancy, shorter courses such as 20 Gy in 5 fractions are preferred to minimize treatment burden while providing symptom relief. Longer courses are used when prognosis is longer.

Question 30Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 45-year-old man with a T1N0M0 glottic squamous cell carcinoma is treated with definitive radiation therapy. What is the most common pattern of failure?

  1. Regional nodal recurrence
  2. Local recurrence Correct answer.
  3. Second primary tumor
  4. Distant metastasis

Explanation

Early-stage glottic cancer has a low rate of nodal and distant spread; the predominant pattern of failure is local recurrence. Salvage laryngectomy can be effective for local failures.

Question 31Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is a standard indication for postoperative radiation therapy after radical prostatectomy?

  1. Organ-confined disease
  2. Gleason score 6
  3. Preoperative PSA < 10 ng/mL
  4. Positive surgical margins Correct answer.

Explanation

Positive surgical margins, seminal vesicle invasion, and extracapsular extension are adverse pathologic features that increase the risk of biochemical recurrence and are indications for adjuvant or early salvage radiation. Low Gleason score and organ-confined disease are favorable features.

Question 32Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 60-year-old woman with a 3 cm HER2-positive breast cancer undergoes neoadjuvant chemotherapy followed by breast-conserving surgery. She achieves a pathologic complete response. Which of the following is the most appropriate adjuvant radiation target?

  1. Chest wall only
  2. Whole breast plus regional nodal irradiation Correct answer.
  3. Whole breast only
  4. No radiation therapy

Explanation

Patients with clinically node-positive breast cancer who convert to pathologic node-negative after neoadjuvant chemotherapy still have an indication for regional nodal irradiation based on their initial stage. Whole-breast radiation alone would undertreat the regional nodes.

Question 33Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most common histologic subtype of renal cell carcinoma?

  1. Chromophobe
  2. Clear cell Correct answer.
  3. Collecting duct
  4. Papillary

Explanation

Clear cell renal cell carcinoma accounts for approximately 70-80% of cases. Papillary and chromophobe are less common, and collecting duct carcinoma is rare.

Question 34Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 70-year-old man with metastatic castration-resistant prostate cancer has painful bone metastases in the lumbar spine and right femur. He has a life expectancy of 6 months. Which of the following is the most appropriate palliative radiation schedule?

  1. 30 Gy in 10 fractions
  2. 8 Gy in 1 fraction Correct answer.
  3. 40 Gy in 20 fractions
  4. 20 Gy in 5 fractions

Explanation

A single 8 Gy fraction is effective for palliation of painful bone metastases and is convenient for patients with limited life expectancy. Multiple fractionation schedules are also effective, but single-fraction is preferred for its convenience.

Question 35Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate management for a patient with a single brain metastasis from melanoma measuring 3 cm with surrounding edema and mass effect?

  1. Surgical resection followed by postoperative radiation Correct answer.
  2. Whole-brain radiation therapy alone
  3. Chemotherapy alone
  4. Stereotactic radiosurgery alone

Explanation

For a large brain metastasis with mass effect, surgical resection provides immediate relief and allows histologic confirmation, followed by postoperative radiation to reduce recurrence. Radiosurgery alone is less suitable for large lesions with mass effect.

Question 36Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 50-year-old woman with a 4 cm anal canal squamous cell carcinoma and no inguinal lymph node involvement is treated with definitive chemoradiation. Which of the following is the most appropriate radiation dose to the primary tumor?

  1. 70 Gy in 35 fractions
  2. 30 Gy in 15 fractions
  3. 45 Gy in 25 fractions
  4. 54-59 Gy in 30-33 fractions Correct answer.

Explanation

The standard dose for definitive chemoradiation of anal cancer is 50-59 Gy to the primary tumor, with a boost to 54-59 Gy for T2-T4 disease. Lower doses are inadequate, and higher doses increase toxicity without clear benefit.

Question 37Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate radiation technique for a patient with a T2N0M0 squamous cell carcinoma of the glottic larynx to minimize dose to the carotid arteries?

  1. Electron beam therapy
  2. Intensity-modulated radiation therapy (IMRT) Correct answer.
  3. Three-dimensional conformal radiation therapy (3D-CRT)
  4. Brachytherapy

Explanation

IMRT allows better sparing of the carotid arteries and other critical structures compared to 3D-CRT. This may reduce the risk of carotid stenosis and stroke, especially in patients with long life expectancy.

Question 38Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 65-year-old man with a T2N1M0 squamous cell carcinoma of the oral tongue is treated with surgery followed by postoperative radiation. Which of the following is the most appropriate radiation target volume?

  1. Tumor bed plus bilateral neck Correct answer.
  2. Tumor bed only
  3. Tumor bed plus ipsilateral neck
  4. Bilateral neck only

Explanation

For oral tongue cancer with nodal involvement, bilateral neck irradiation is often indicated because of the risk of contralateral nodal spread, especially for tumors near the midline or with multiple positive nodes. The tumor bed is always included.

Question 39Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most common site of metastasis from ocular melanoma?

  1. Lung
  2. Brain
  3. Liver Correct answer.
  4. Bone

Explanation

Ocular melanoma has a strong tropism for the liver, with liver metastasis being the most common site. Lung, bone, and brain metastases occur less frequently.

Question 40Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 55-year-old woman with a 2 cm, node-negative, hormone receptor-positive breast cancer is considering accelerated partial breast irradiation (APBI). Which of the following factors would make her a suitable candidate according to the ASTRO guidelines?

  1. BRCA1 mutation
  2. Positive surgical margins
  3. Age 55 years Correct answer.
  4. Extensive intraductal component

Explanation

ASTRO guidelines for APBI consider age 50 years or older as suitable, along with tumor size ≤2 cm, node-negative status, and negative margins. Positive margins, extensive intraductal component, and BRCA mutations are unsuitable.

Question 41Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate radiation dose for prophylaxis of heterotopic ossification after hip surgery?

  1. 5 Gy in 1 fraction Correct answer.
  2. 10 Gy in 5 fractions
  3. 20 Gy in 10 fractions
  4. 30 Gy in 15 fractions

Explanation

A single 5 Gy fraction is a standard regimen for prophylaxis of heterotopic ossification and is as effective as more prolonged courses. It is convenient and well tolerated.

Question 42Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 60-year-old man with a T3N0M0 prostate cancer (Gleason 4+4=8, PSA 15 ng/mL) is treated with external beam radiation therapy and androgen deprivation therapy. Which of the following is the most appropriate duration of androgen deprivation therapy?

  1. 6 months
  2. 24 months Correct answer.
  3. 4 months
  4. 12 months

Explanation

For high-risk prostate cancer, 2-3 years of androgen deprivation therapy combined with radiation is standard based on randomized trials. Shorter durations are used for intermediate-risk disease.

Question 43Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most common histology of lung cancer in never-smokers?

  1. Large cell carcinoma
  2. Adenocarcinoma Correct answer.
  3. Small cell carcinoma
  4. Squamous cell carcinoma

Explanation

Adenocarcinoma is the most common histologic subtype of lung cancer in never-smokers, often associated with EGFR mutations and other driver alterations. Squamous cell and small cell carcinomas are strongly associated with smoking.

Question 44Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 45-year-old woman with a 5 cm soft tissue sarcoma of the thigh undergoes limb-sparing surgery with negative margins. Which of the following is the most appropriate adjuvant treatment?

  1. Neoadjuvant chemotherapy
  2. Postoperative radiation therapy Correct answer.
  3. Observation
  4. Amputation

Explanation

Postoperative radiation therapy improves local control in patients with high-grade or large soft tissue sarcomas after limb-sparing surgery. Observation alone is associated with higher local recurrence rates.

Question 45Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate radiation dose for stereotactic body radiation therapy (SBRT) for a medically inoperable stage I non-small cell lung cancer?

  1. 60 Gy in 30 fractions
  2. 70 Gy in 35 fractions
  3. 45 Gy in 3 fractions Correct answer.
  4. 30 Gy in 1 fraction

Explanation

SBRT regimens for peripheral stage I NSCLC include 45-60 Gy in 3-5 fractions. A single fraction of 30 Gy is also used but is less common. Conventional fractionation (60-70 Gy in 30-35 fractions) is an alternative but not SBRT.

Question 46Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 70-year-old woman with a T2N0M0 estrogen receptor-positive breast cancer is treated with breast-conserving surgery and whole-breast radiation. She is considering omitting radiation therapy. Which of the following factors most strongly predicts for local recurrence if radiation is omitted?

  1. Positive surgical margins Correct answer.
  2. Lymphovascular invasion
  3. High histologic grade
  4. Young age

Explanation

Positive surgical margins are the strongest predictor of local recurrence and are a contraindication to omitting radiation therapy. Other factors such as young age and high grade also increase risk but are less influential than margin status.

Question 47Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most appropriate management for a patient with a T1N0M0 hepatocellular carcinoma who is not a candidate for surgery or transplantation?

  1. Radiofrequency ablation Correct answer.
  2. External beam radiation therapy
  3. Observation
  4. Chemotherapy

Explanation

Radiofrequency ablation is a standard curative treatment for small hepatocellular carcinomas (≤3 cm) in patients who are not surgical candidates. External beam radiation is an alternative but is less established.

Question 48Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 55-year-old man with a T2N0M0 squamous cell carcinoma of the base of tongue is treated with definitive chemoradiation. Which of the following is the most appropriate radiation dose to the primary tumor?

  1. 80 Gy in 40 fractions
  2. 50 Gy in 25 fractions
  3. 70 Gy in 35 fractions Correct answer.
  4. 60 Gy in 30 fractions

Explanation

The standard definitive radiation dose for head and neck squamous cell carcinoma is 70 Gy in 35 fractions, often with concurrent chemotherapy. Lower doses are inadequate for gross disease, and higher doses increase toxicity.

Question 49Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

Which of the following is the most common site of metastasis from differentiated thyroid cancer?

  1. Bone
  2. Liver
  3. Lung Correct answer.
  4. Brain

Explanation

Lung is the most common site of distant metastasis from differentiated thyroid cancer, followed by bone. Liver and brain metastases are less common.

Question 50Clinical Radiation Oncology: Disease Sites and Multidisciplinary Management

A 60-year-old man with a T3N1M0 rectal cancer is treated with neoadjuvant chemoradiation followed by surgery. Which of the following is the most appropriate radiation dose to the primary tumor?

  1. 50.4 Gy in 28 fractions Correct answer.
  2. 25 Gy in 5 fractions
  3. 45 Gy in 25 fractions
  4. 60 Gy in 30 fractions

Explanation

The standard neoadjuvant radiation dose for locally advanced rectal cancer is 50.4 Gy in 28 fractions with concurrent chemotherapy. A short-course regimen of 25 Gy in 5 fractions is an alternative but is less commonly used in the United States.