Radiation Oncology In-service exam review: GI cancers

1. What is the treatment of choice for gastric MALT?

Low dose RT alone

Chemotherapy alone

Antibiotics directed at H. pylori

Surgical resection followed by chemoradiation

The treatment of choice for gastric MALT is antibiotics directed at H. pylori. This is because gastric MALT lymphoma is often associated with H. pylori infection, and eradicating the infection with antibiotics has been shown to lead to remission in many cases. Low dose RT alone, chemotherapy alone, and surgical resection followed by chemoradiation may be considered in certain cases, but antibiotics directed at H. pylori is the preferred initial treatment option.

Explanation

The treatment of choice for gastric MALT is antibiotics directed at H. pylori. This is because gastric MALT lymphoma is often associated with H. pylori infection, and eradicating the infection with antibiotics has been shown to lead to remission in many cases. Low dose RT alone, chemotherapy alone, and surgical resection followed by chemoradiation may be considered in certain cases, but antibiotics directed at H. pylori is the preferred initial treatment option.

2. What is Courvoisier's sign?

Palpable tumor nodule at the umbilicus

Palpable gallbladder

Migratory thrombophlebitis

Palpable axillary lymphadenopathy

Trousseau's sign is migratory thrombophlebitis, sister maty joseph nodule is umbilicus nodule, Irish's node is axillary adenopathy

Explanation

Trousseau's sign is migratory thrombophlebitis, sister maty joseph nodule is umbilicus nodule, Irish's node is axillary adenopathy

3. What is the appropriate superior border of the PA field for a rectal cancer plan?

L2-L3

L5-S1

L4-L5

Top of obturator foramen

L3-L4

PA field: superior: L5/S1; Inferior inferior obturator foramen or 3 cm below tumor; Lateral: 1.5 cm outside pelvic inlet
Lateral fields: posterior: behind bony sacrum; anterior: posterior pubic symphasis if T3, anterior pubic symphasis if T4

Explanation

PA field: superior: L5/S1; Inferior inferior obturator foramen or 3 cm below tumor; Lateral: 1.5 cm outside pelvic inlet
Lateral fields: posterior: behind bony sacrum; anterior: posterior pubic symphasis if T3, anterior pubic symphasis if T4

4. Via what drainage do rectal cancer metastases reach the liver?

Superior rectal vein

Inferior rectal vein

Middle rectal vein

Inferior mesenteric vein

Rectal cancer metastases can reach the liver through the superior rectal vein. The superior rectal vein drains blood from the rectum and it ultimately joins the portal vein system, which carries blood to the liver. This allows cancer cells from the rectum to travel through the bloodstream and establish metastases in the liver. The other options, such as the inferior rectal vein, middle rectal vein, and inferior mesenteric vein, are not the primary routes for liver metastases in rectal cancer.

Explanation

Rectal cancer metastases can reach the liver through the superior rectal vein. The superior rectal vein drains blood from the rectum and it ultimately joins the portal vein system, which carries blood to the liver. This allows cancer cells from the rectum to travel through the bloodstream and establish metastases in the liver. The other options, such as the inferior rectal vein, middle rectal vein, and inferior mesenteric vein, are not the primary routes for liver metastases in rectal cancer.

5. What was a major finding of the GITSG 91-73 trial for pancreatic cancer?

Addition of adjuvent gemcitabine to defintive RT for pancreatic cancer improved 1 year LC from 18% to 32%

The major finding of the GITSG 91-73 trial for pancreatic cancer was that the addition of adjuvant CRT (chemoradiotherapy) with 5-FU (fluorouracil) and a 40 Gy split course to surgery improved the 5-year overall survival (OS) rate from 5% to 14% in resectable pancreatic cancer. This means that patients who received this treatment had a higher chance of surviving for 5 years compared to those who did not receive the adjuvant CRT.

Explanation

The major finding of the GITSG 91-73 trial for pancreatic cancer was that the addition of adjuvant CRT (chemoradiotherapy) with 5-FU (fluorouracil) and a 40 Gy split course to surgery improved the 5-year overall survival (OS) rate from 5% to 14% in resectable pancreatic cancer. This means that patients who received this treatment had a higher chance of surviving for 5 years compared to those who did not receive the adjuvant CRT.

6. Which major rectal cancer trial showed an overall survival benefit to pre-op radiation?

German Rectal Cancer Trial (NEJM 2004)

Dutch Colorectal Cancer Group (NEJM 2001)

Swedish Rectal Cancer Trial (NEJM 1997)

GITSG 7175

Both the German and Dutch trials showed LRR improvements but no OS benefit to pre-op RT. Swedish trial showed OS improvement of 48% vs 58% at 5 years. GITSG evaluated post-op RT vs post-op CRT, which improved OS.

Explanation

Both the German and Dutch trials showed LRR improvements but no OS benefit to pre-op RT. Swedish trial showed OS improvement of 48% vs 58% at 5 years. GITSG evaluated post-op RT vs post-op CRT, which improved OS.

7. What is the appropriate dosing of concurrent 5-FU when given with RT for rectal cancer?

225 mg/m2 over 24 hours, 7 days per week during RT

150 mg/m2 over 24 hours, 7 days per week during RT

250 mg/m2 over 6 hours, 7 days per week during RT

250 mg/m2 over 12 hours, 5 days per week during RT

225 mg/m2 over 12 hours, 5 days per week during RT

The appropriate dosing of concurrent 5-FU when given with RT for rectal cancer is 225 mg/m2 over 24 hours, 7 days per week during RT.

Explanation

The appropriate dosing of concurrent 5-FU when given with RT for rectal cancer is 225 mg/m2 over 24 hours, 7 days per week during RT.

8. What was the chemoradiation used in the pre-op arm of the German Rectal Cancer Study (NEJM 2004)?

50.4 Gy with concurrent Xeloda

50.4 Gy with a 5.4 Gy boost with concurrent 5-FU

54 Gy with concurrent 5-FU

50.4 Gy with concurrent 5-FU

25 Gy in 5 fractions with concurrent 5-FU

25/5 was used as pre-op treatment in the Duth and Swedish rectal cancer studies; the post-op arm of the German trial included at 5.4 Gy boost.

Explanation

25/5 was used as pre-op treatment in the Duth and Swedish rectal cancer studies; the post-op arm of the German trial included at 5.4 Gy boost.

9. What was the randomization of the GITSG 91-73 trial for pancreatic cancer?

Surgery alone vs surgery followed by chemoradiation with 54 Gy and concurrent 5-FU

Definitive RT to 54 Gy versus Definitive CRT wtih 54 Gy and concurrent 5-FU

Surgery alone vs surgery followed by chemoradiation with a 40 Gy split course followed by adjuvent gemcitabine

Surgery alone vs surgery followed by chemoradiation with a 40 Gy split course and concurrent 5-FU

Surgery alone vs surgery followed by radiation with a 40 Gy split course

The randomization of the GITSG 91-73 trial for pancreatic cancer was comparing surgery alone to surgery followed by chemoradiation with a 40 Gy split course and concurrent 5-FU. This means that patients were randomly assigned to either undergo surgery alone or undergo surgery followed by a combination of radiation therapy with a split course of 40 Gy and concurrent administration of 5-FU chemotherapy. The purpose of this trial was to determine the effectiveness of adding chemoradiation to surgery in the treatment of pancreatic cancer.

Explanation

The randomization of the GITSG 91-73 trial for pancreatic cancer was comparing surgery alone to surgery followed by chemoradiation with a 40 Gy split course and concurrent 5-FU. This means that patients were randomly assigned to either undergo surgery alone or undergo surgery followed by a combination of radiation therapy with a split course of 40 Gy and concurrent administration of 5-FU chemotherapy. The purpose of this trial was to determine the effectiveness of adding chemoradiation to surgery in the treatment of pancreatic cancer.

10. Which of the following was a finding of the UKCCCR anal cancer trial working party (Lancet 1996?

Chemoradation with 5-FU and mitomycin improved 3 year OS from 35 to 48% as compared to RT alone

Chemoradiation with cisplatin and 5-FU improved LC from 36% to 59% as compared to RT alone

Addition of post-op RT after surgery improved OS at 3 years from 35 to 48%

Dose escalation from 45 Gy with 50.4 Gy improved LC from 36% to 59%

Chemoradation with 5-FU and mitomycin improved 3 year LC from 36% to 59% as compared to RT alone

The correct answer is that chemoradiation with 5-FU and mitomycin improved 3 year LC (local control) from 36% to 59% as compared to radiation therapy alone. This means that the addition of chemotherapy with 5-FU and mitomycin to radiation therapy resulted in a significant improvement in the control of the tumor at the local site. The study found that this combination treatment was more effective in preventing the recurrence or progression of anal cancer compared to radiation therapy alone.

Explanation

The correct answer is that chemoradiation with 5-FU and mitomycin improved 3 year LC (local control) from 36% to 59% as compared to radiation therapy alone. This means that the addition of chemotherapy with 5-FU and mitomycin to radiation therapy resulted in a significant improvement in the control of the tumor at the local site. The study found that this combination treatment was more effective in preventing the recurrence or progression of anal cancer compared to radiation therapy alone.

Radiation Oncology In-service Exam Review: GI Cancers