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IS THERE AN OPTIMAL TIME INTERVAL BETWEEN 2 RT-SERIES ?
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10/18/19 16:36
Prof.Seegenschmiedt 
10/18/19 16:36
Prof.Seegenschmiedt 

IS THERE AN OPTIMAL TIME INTERVAL BETWEEN 2 RT-SERIES ?

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THE ACTUALLY MOST APPLIED ACTUAL RT-SCHEDULE
CONSIST OF TWO RT_COURSES of EACH 5 x 3 Gy (= 15 Gy) UP TO 30 Gy TOTAL DOSE


HOWEVER, WHAT IS THE BEST TIMING OF THE TWO RT-SERIE(S) ?


Unfortunately, so far there is no sufficient or conclusive answer available, as so far only ONE CLINICAL RT-STUDY has ever explored the effects of the time-interval together with the use of two different RT total doses under controlled clinical study conditions within a randomized clinical trial (*): https://www.ncbi.nlm.nih.gov/pubmed/11172962
https://www.researchgate.net/publication...llierten_Studie

From this study, however, it can be concluded, that a RT-schedule of 7 x 3 Gy (with a total dose of 21 Gy) applied within a period of 2 weeks has caused MORE ACUTE RADIOGENIC SIDE-EFFECTS than a RT-schedule using a higher total RT dose of 30Gy (10 x 3 Gy), but splitted up into two separate RT-Series of each 5 x 3 Gy (= 15 Gy) separated by 6 - 8 weeks.


WHAT ARE REASONS TO USE 12 WEEKS BETWEEN TWO RT-SERIES ?

In my long-time radiotherapy practice over almost 30 years I initially have started with a 6 weeks interval between the 1st-RT-SERIES (5 x 3 Gy up to 15 Gy) and the 2nd RT-SERIES (5 x 3 Gy up to 30 Gy) for the total of TWO RT-SERIES,.

However I have abandoned this RT scheme since more than 10 years for the following reasons:


(1) BETTER EVALUATION of ACUTE RADIATION REACTIONS:

They have usually not faded away including treatment induced possible itching, new "pain" symptoms, burning sensations, tension or pressure feelings, evtl. some remaining swelling and other symptoms etc.

--> This may eventually prevent the start for the prescheduled 2nd RT-SERIES causing additional organisational problems


(2) BETTER TIME-POINT FOR EVALUATION OF SIDE-EFFECTS:

After an interval of 12 WEEKS or about 3 months after the 1st or 2nd-RT-SERIES the definition for the radiation induced reactions changes by definition from the "acute radiation effects" (day 1 - 90 post applied radiotherapy) to "chronic radiation reactions" ( day 91 and longer).

--> CONSEQUENCE: Acute radiation side effects can be better summarized after 90 days than after shorter time intervals.


(3) BETTER TIME-POINT FOR EVALUATION OF RESULTS:

12 weeks or 3 months after RT is usually a much better time point to study and EVALUATE FIRST RESULTS like changes in nodule and cord number(s), size(s) and consistencies. After such a time period there are often first hints available to foresee how the reaction to radiotherapy has affected the skin and subcutaneous tissues (e.g. affecting moisture and elasticity) and the special hand and finger functions (e.g. increased stiffness or better spreading of fingers ?).

--> RECOMMENDATION: Always use a pre-defined scheme for evaluation, e.g. AFTER CARE EVALUATION FORM (attached)


(4) RADIOBIOLOGICAL REASONS

Dupuytren & Ledderhose Disease is - unlikely to malignant tumors - not composed and driven by fast proliferating cells. Thus rapid performance of ALL TREATMENT in 1 SERIES is not useful, as some of the proliferating cells have not yet reached the radio-sensitive phase of cell division called MITOSIS.

-->Thus, a longer time interval of 12 weeks may be more useful and favorable, as more proliferating fibroblast cells could have reached this more radio-sensitive mitotic stage than after a much shorter interval of only 6 weeks or even shorter..



OVERALL CONCLUSION:

Delaying the 2nd RT-SERIES up to 12 weeks is practiced by myself now for almost 20 years in clinical studies with very good experience on several hundreds or over 1.000 patients with good outcome.

The same time interval is recommended for the EVALUATION after the 2nd RT-SERIES (after 30Gy) including the 3-months POST-TREATMENT EVALUATION.

The following after care intervals should also include a 6-MONTHS and 12-MONTHS = 1-YEAR-Evaluation and thereafter EVERY YEAR up to 5 YEARS using a standardized evaluation program:

https://www.dupuytren-online.info/Forum_...read=1558195801

Prof. Dr. med. M. Heinrich Michael Heinrich Seegenschmiedt

Edited 10/18/19 17:05

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DUPUYTREN - RT-KONZEPTE - Überblick.jpg DUPUYTREN - RT-KONZEPTE - Überblick.jpg (1x)

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Dupuytren_Post-RT-After-Care_Form_09_2019_MHS (1).pdf Dupuytren_Post-RT-After-Care_Form_09_2019_MHS (1).pdf (2x)

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RT-SERIES   read=1558195801   radio-sensitive   RECOMMENDATION   EVALUATION   dupuytren-online   2nd-RT-SERIES   consistencies   1-YEAR-Evaluation   RADIATION   POST-TREATMENT   1st-RT-SERIES   Seegenschmiedt   RADIOBIOLOGICAL   SIDE-EFFECTS   proliferating   organisational   radiotherapy   time-interval   INTERVAL