Radiation Oncology
Expert insights on radiation treatment planning, techniques, toxicity management, and multimodal cancer care.
Recent Discussions
What dose fractionation schedule do you use to treat head and neck cancer in a patient with Fanconi's Anemia?
If p16 positive oropharynx, 1.2 Gy bid to 64.8 Gy. Otherwise 74.4. Probably no chemo.
What is the best test to determine HPV status for SCC?
Good question. According to the new (8th) edition of the AJCC staging manual, and ACP, they recommend that you initially test for p16 only, for it is a good surrogate marker for HPV involvement. Further, as I recall, HPV testing maybe done if you suspect it is a negative p16 result, for example. Tha...
What constraints do you use for the normal brain when treating large CNS tumors with standard fractionation?
With photon therapy, we use guidance (not absolute), using the following principles, when using 1.8 to 2 Gy per fraction: Lenses max dose 7-10Gy Optic Chiasm and optic nerves max dose < 60Gy without chemotherapy and 56Gy with chemotherapy. Retina max dose < 50Gy without chemotherapy and 45Gy...
Do you routinely use PRVs for CNS planning?
We do not use PRVs specifically for primary CNS planning or for brain mets treated with Gamma Knife. We have PRV constraints for Spine SRS specifically for the spine.
Do you routinely use any type of motion management or breathing techniques when treating a lower esophageal cancer?
I obtain a 4DCT scan at simulation with free breathing. I do not use abdominal compression, gating, or other motion management techniques. There is certainly room for more data here to fully evaluate the potential value of these techniques. But for now, I don't use them in this situation. In my expe...
Is there any upper limit of volume or shape of a prostate gland which would be a red flag to cytoreduce prior to treatment?
Astro/aua consensus guidelines based on published data limits to 100cc or less
How would you manage an elderly patient with metastatic breast cancer with locally advanced bilateral primaries?
It depends on symptoms. If no impeding skin breakdown, ulceration or pain/lymphedema, I will see how they respond on endocrine therapy. If symptomatic, I will consider 30 Gy/10 fx using opposed tangents or in some cases with rapidly progressive disease 20 Gy/5 fx
How do you manage new brain metastases in patients on trastuzumab emtansine (TDM-1) who has controlled extracranial disease?
This is an increasingly common clinical scenario, because systemic control with antibodies is quite good, but HER2+ disease still has a strong predilection for the brain. There is a third treatment option here, which may have lower toxicity than either whole brain or SRS.Particularly where larger vo...
What dose constraint do you use for the spinal cord in the setting of re-irradiation?
Dr. Arjun Sahgal published the dose constraints in Red J.Reirradiation human spinal cord tolerance for stereotactic body radiotherapy.Sahgal A, Ma L, Weinberg V, Gibbs IC, Chao S, Chang UK, Werner-Wasik M, Angelov L, Chang EL, Sohn MJ, Soltys SG, Létourneau D, Ryu S, Gerszten PC, Fowler J, Wong CS,...
In a thin patient with anal cancer, do you use bolus over the inguinal nodal volume when treating with an IMRT technique?
Rarely, only if the tumor is involving the skin, but I always sue 6MV photons and more than enough dose. The skin gets plenty of dose with IMRT and 6MV photons. When there is gross node in a thin patient, it doesn't add morbidity to do so, however. The only inguinal recurrence I have ever had, gross...