Radiation Oncology
Expert insights on radiation treatment planning, techniques, toxicity management, and multimodal cancer care.
Recent Discussions
What is the appropriate nodal coverage a invasive ductal carcinoma status post lumpectomy with 50% or more of the SLN biopsied (for example, 2 of 4 SLN) showing micrometastases?
I don't know what 50% or more for SNLN means, as knowing absolute number of nodes is more important as median number of SNLN dissected is usually between 1-2 . The treatment volume in patients with micromets is highly variable across practitioners- from no adjustment of field (based on IBCSG 23-01) ...
What is your preferred approach for late recurrence at a primary site only of a limited stage small cell lung cancer initially treated with chemoradiaton?
"Late" recurrences of small cell lung cancer are unusual. For example, brain metastases very rarely develop after 3 years, and most have developed by 2 (NEJM 1999;341:476). A similar pattern has been observed for local disease (JCO 1997;15:3030). Thus, one must be suspicious when a "late" recurrence...
What adjuvant therapy recommendations would you make for a patient with pT3N0M0 duodenal cancer?
The is not enough data to guide you on this question because duodenal cancer is an orphan disease. So, all you have is first principles and extraploation from similiar clinical senarios with more data. Duodenal cancer has a similar responsiveness to XRT as rectal and gastic cancer (pCR rate is about...
Is there a way to predict clinically or from CT which patients with left sided breast tumors would benefit more from the prone v. supine position?
We only set up patients in the prone position that do not require nodal radiation. I find that large breasted patients are most likely to benefit from a prone position.
When giving a breast boost, what are indications for a photon breast boost?
In general, once the surgical cavity depth approaches 5 cm then it is harder to cover with electrons. That being said, for these patients with disease in the outer quadrant, the lateral decubitus position helps significantly to bring the cavity close to the surface. We published this data: http://ww...
In laryngeal cancer (assuming no pharyngeal extension) with level II/III involvement, should RPs and level IB on the involved side be covered?
I do not cover RP, level Ib, or level V electively in the scenario you describe. I will cover level VI if the disease has broken through thyroid cartilage into soft tissues anteriorly (usually these patients go for total laryngectomy) or if there's subglottic extension.
Should patients with anal canal SCC undergo an FNA biopsy of any palpable inguinal LN that is also FDG avid on PET/CT or should these nodes be assumed to be positive and treated to a higher dose?
Even though PET/CT can be falsely positive in the inguinal region, in the era of IMRT we treat all metabolically positive node with the presumption that it is disease. Would not necessarily rely on FNA as this could be a sampling error. Since therapeutic dose can be delivered safely, I would err on ...
What do you consider negative or close margins for tonsillar cancers?
To answer your first question about margin for HPV+ (I assume) tonsillar cancers, one would have to go with the definition on clinical trial. Currently the WashU trial as well as RTOG 1221/ECOG 3311 and the ADEPT trial uses the 3mm cutoff. So a free margin is defined as something>/=3mm. Anything <3m...
When treating a patient with a high grade sarcoma in the post op setting, do I need to get full dose to the incision and drain site (assuming all margins negative)?
No, I would treat the incision and drain site with 45 Gy in 25 fractions using bolus only.
Does the dose rate of an external beam linear accelerator matter in terms of radiobiology?
Per Hall, "The dose-rate effect caused by repair of sublethal damage is most dramatic between 0.01 and 1 Gy/min; [a]bove and below this dose-rate range, the [cell] survival curve changes little, if at all, with dose rate." "Old" linacs could pump out about 6 Gy/min; new ones, up to 24 Gy/min. Sublet...